Biology Words That Start With A

1. Abiotic – Non-living factors in an environment, such as temperature or light.
2. Absorption – The process by which cells take in substances from the outside environment.
3. Abyssal – Referring to the deepest parts of the ocean.
4. Acellular – Not made up of or containing cells.
5. Acid – A substance with a pH less than 7; can donate a proton in a chemical reaction.
6. Actin – A protein that forms microfilaments and plays a key role in muscle contraction.
7. Activation – The process of making something active or functional.
8. Active transport – Movement of molecules across a cell membrane requiring energy, typically against a concentration gradient.
9. Adaptation – A trait that increases an organism’s fitness in its environment.
10. Adenine – A nitrogenous base found in DNA and RNA.
11. Adhesion – The tendency of different kinds of molecules to stick together.
12. Adipose – Fat tissue in the body.
13. Aerobic – Processes that require oxygen.
14. Afferent – Carrying towards, often in the context of nerves or blood vessels.
15. Agar – A gelatinous substance derived from seaweed, used as a medium for growing bacteria.
16. Allele – Different forms of a gene.
17. Alveoli – Tiny air sacs in the lungs where gas exchange occurs.
18. Amino acid – Building blocks of proteins.
19. Amphibian – Cold-blooded vertebrates that can live both in water and on land, e.g., frogs.
20. Amylase – An enzyme that breaks down starch.
21. Anaerobic – Processes that do not require oxygen.
22. Anaphase – A stage in cell division where chromosomes are pulled apart.
23. Anatomy – The study of the structure of organisms.
24. Angiosperm – Flowering plants.
25. Anion – A negatively charged ion.
26. Antagonist – A substance that interferes with the action of a physiological process.
27. Antibiotic – A substance that kills or inhibits the growth of microorganisms.
28. Antibody – A protein produced by the immune system to recognize and neutralize pathogens.
29. Antigen – A substance that induces an immune response.
30. Apoptosis – Programmed cell death.
31. Aquatic – Relating to water.
32. Arachnid – A class of joint-legged invertebrate animals, e.g., spiders and scorpions.
33. Artery – Blood vessels that carry blood away from the heart.
34. Asexual reproduction – Reproduction without the fusion of gametes.
35. ATP (Adenosine triphosphate) – The main energy currency of cells.
36. Atrium – Each of the two upper chambers of the heart.
37. Autosome – Any chromosome that is not a sex chromosome.
38. Autotroph – An organism that produces its own food, typically through photosynthesis.
39. Axon – The long projection of a neuron that carries nerve impulses away from the cell body.
40. Aerobe – An organism that requires oxygen to live.
41. Agonist – A substance that initiates a physiological response when combined with a receptor.
42. Algae – Simple, autotrophic organisms that can perform photosynthesis.
43. Allelopathy – The production of chemicals by plants that inhibit the growth of neighboring plants.
44. Allergen – A substance that causes an allergic reaction.
45. Allopatric – Occurring in separate, non-overlapping geographical areas.
46. Altruism – Behavior that benefits another organism at a cost to oneself.
47. Amino group – A functional group consisting of a nitrogen atom attached to two hydrogen atoms.
48. Amnion – A membranous sac that surrounds and protects the embryo.
49. Anaerobe – An organism that can live and grow in the absence of oxygen.
50. Analogous – Structures in different species having the same function but have evolved separately.

Biology Words That Start With B

1. Bacteria – Single-celled microorganisms, some of which can cause diseases.
2. Bacillus – A rod-shaped bacterium.
3. Basal – Relating to the base or foundation of something.
4. Base – In genetics, refers to the basic building blocks of DNA and RNA (adenine, cytosine, guanine, thymine, and uracil).
5. Basidiomycete – A type of fungus that produces spores on a structure called a basidium.
6. Benthic – Relating to the bottom of a body of water.
7. Bilateral symmetry – Body plan in which an organism can be divided into equal halves along only one plane.
8. Binary fission – A method of asexual reproduction in which a cell divides into two equal parts.
9. Biochemistry – The study of chemical processes within living organisms.
10. Biodiversity – The variety of life in a particular habitat or ecosystem.
11. Biofilm – A community of microorganisms that form on surfaces.
12. Biogenesis – The principle that living organisms arise from other living organisms.
13. Biome – A large community of plants and animals that occupies a distinct region.
14. Biomolecule – A molecule that plays a significant role in the structure and function of living organisms.
15. Biophysics – The study of biological processes using the principles of physics.
16. Biosphere – The global sum of all ecosystems.
17. Biota – The animal and plant life of a particular region.
18. Biotic – Relating to living organisms.
19. Blastula – An early stage of embryonic development in animals.
20. Botany – The scientific study of plants.
21. Brachiation – A method of movement that uses the arms to swing from branch to branch.
22. Bronchus – A major air passage in the lungs.
23. Bryophyte – Non-vascular plants, including mosses and liverworts.
24. Budding – A form of asexual reproduction where a new organism grows out of the parent organism.
25. Buffer – A solution that resists changes in pH.
26. Bursa – A fluid-filled sac that reduces friction between tissues.
27. Byssus – A group of strong filaments that mussels use to attach to solid surfaces.
28. Bioluminescence – The production of light by living organisms.
29. Blastocyst – A structure formed in early embryogenesis in mammals.
30. Bladder – An organ that stores urine.
31. Bilirubin – A yellow compound that is produced when hemoglobin breaks down.
32. Biomass – The total mass of organisms in a given area or volume.
33. Biopsy – A medical test involving the removal of cells or tissues for examination.
34. Bioinformatics – The use of software and mathematical models to process biological data.
35. Biocatalyst – A substance, especially an enzyme, that initiates or accelerates a biochemical reaction.
36. Biodegradable – Capable of being broken down by natural processes.
37. Bioenergetics – The study of energy flow and transformation in living organisms.
38. Biogeochemical – Relating to the partitioning and cycling of chemical elements and compounds between living and non-living parts of an ecosystem.
39. Biometric – Relating to or involving the measurement of biological data.
40. Bionics – The study of mechanical systems that function like living organisms or parts of living organisms.
41. Bioturbation – The disturbance of sedimentary deposits by living organisms.
42. Bipedalism – The ability to walk on two legs.
43. Birthrate – The number of live births per thousand of the population per year.
44. Blind spot – The point of entry of the optic nerve on the retina, insensitive to light.
45. Blood-brain barrier – A filtering mechanism that prevents certain substances from entering the brain.
46. Bolus – A small rounded mass of a substance, especially chewed food.
47. Bone marrow – The soft, spongy tissue in the center of bones that produces blood cells.
48. Botulinum toxin – A neurotoxic protein produced by the bacterium Clostridium botulinum.
49. Bract – A modified leaf or scale, typically small, with a flower or flower cluster in its axil.
50. Brood – A family of young animals produced at one hatching or birth.
51. Bulb – A rounded underground storage organ present in some plants.
52. Bundle of His – A collection of heart muscle cells specialized for electrical conduction.
53. Butyric acid – A fatty acid found in butter and other fats.
54. Bursitis – Inflammation of a bursa.
55. Bronchiolitis – Inflammation of the bronchioles.
56. Bruxism – Involuntary grinding or clenching of the teeth.
57. Bacteriophage – A virus that infects and replicates within bacteria.
58. Bilateria – Animals with bilateral symmetry.
59. Bioindicator – An organism used to monitor the health of an environment.
60. Bioprospecting – The search for plant and animal species from which medicinal drugs and other commercially valuable compounds can be obtained.
61. Biotin – A vitamin of the B complex.
62. Blastomere – A cell formed by cleavage of a fertilized ovum.
63. Bromeliad – A tropical American plant that typically has rosettes of fleshy or spiky leaves.
64. Bacteriology – The study of bacteria.
65. Baleen – A comb-like structure in the mouths of baleen whales, used to filter plankton from the water.
66. Barbel – A slender, whisker-like sensory organ near the mouth of certain fishes.
67. Benthos – The flora and fauna on the bottom of a sea or lake.
68. Biennial – A plant that takes two years to grow from seed to fruition and die.
69. Biliverdin – A green pigment formed from hemoglobin.
70. Bioavailability – The proportion of a drug or other substance that enters the circulation when introduced into the body.
71. Biocenosis – The living community of an ecosystem.
72. Biodegradation – The decomposition of materials by bacteria, fungi, or other biological means.
73. Bioflavonoid – A type of antioxidant.
74. Biogas – Methane produced by the fermentation of organic matter.
75. Biolysis – The destruction of life.
76. Biomagnification – The process by which the concentration of toxic substances increases in each successive link in the food chain.
77. Bionomics – The study of the relationships between organisms and their environments.
78. Biopiracy – The commercial development of naturally occurring biological materials without fair compensation to the community from which they originate.
79. Biosynthesis – The production of complex molecules within living organisms or cells.
80. Biota – The animal and plant life of a particular region or period.
81. Biotic factor – A living thing that affects another organism in its environment.
82. Bladderwort – A carnivorous aquatic plant.
83. Blastoderm – The layer of cells formed by the cleavage of a fertilized egg.
84. Blastopore – The opening of the central cavity of an embryo in the early stage of development.
85. Blepharitis – Inflammation of the eyelids.
86. Bolus injection – A method of drug administration by which a drug is given directly into a vein.
87. Bone resorption – The process by which osteoclasts break down bone and release the minerals.
88. Bovine – Relating to cattle.
89. Bradykinin – A peptide that causes blood vessels to dilate.
90. Brainstem – The central trunk of the brain.
91. Bromination – The introduction of bromine to a compound.
92. Bryology – The study of mosses and liverworts.
93. Buccal – Relating to the cheek.
94. Budding yeast – A type of yeast that reproduces by budding off a smaller daughter cell.
95. Bufotoxin – A toxic substance found in the skin of some toads.
96. Bulbourethral gland – One of two small exocrine glands in males.
97. Bursa of Fabricius – An organ in birds where B cells mature.
98. Butterfly effect – The idea that a small change can have large effects elsewhere.
99. By-product – A secondary product derived from a manufacturing process.
100. Byssal thread – Threads by which mussels and some other bivalves attach themselves to surfaces.

Biology Words That Start With C

1. Cell – The basic structural and functional unit of all living organisms.
2. Chloroplast – An organelle in plant cells responsible for photosynthesis.
3. Chromosome – Thread-like structures made of DNA that carry genetic information.
4. Cytoplasm – The jelly-like substance within a cell, excluding the nucleus.
5. Cytokinesis – The process during cell division where the cytoplasm divides.
6. Carnivore – An organism that primarily consumes meat.
7. Cilia – Small, hair-like projections on some cells used for movement.
8. Coenzyme – A non-protein compound necessary for an enzyme’s activity.
9. Codon – A sequence of three nucleotides in DNA or RNA that corresponds to a specific amino acid.
10. Commensalism – A relationship between two species where one benefits and the other is neither harmed nor benefited.
11. Catabolism – The breakdown of complex molecules in organisms to produce energy.
12. Cancer – A disease caused by an uncontrolled division of abnormal cells.
13. Capillary – The smallest blood vessels connecting arterioles to venules.
14. Carbohydrate – Organic compounds like sugars and starches that provide energy.
15. Catalyst – A substance that increases the rate of a chemical reaction without being consumed.
16. Cellulose – A complex carbohydrate that forms the primary structural component of plants.
17. Chlorophyll – The green pigment in plants responsible for capturing light energy for photosynthesis.
18. Chemosynthesis – The synthesis of organic compounds using energy derived from chemical reactions, typically in bacteria.
19. Chordate – Animals with a notochord, such as vertebrates.
20. Chromoplast – An organelle responsible for pigment synthesis and storage in plant cells.
21. Circadian rhythm – Biological processes that display an endogenous oscillation of about 24 hours.
22. Cladogram – A tree diagram used to illustrate evolutionary relationships.
23. Cleavage – The division of cells during early embryonic growth.
24. Climax community – A stable community formed after ecological succession has reached equilibrium.
25. Coccus – A spherical bacterium.
26. Coevolution – The evolution of two species in response to changes in each other.
27. Cohesion – The sticking together of particles of the same substance.
28. Collagen – A protein that provides structural support in connective tissues.
29. Community – A group of interdependent organisms inhabiting the same region.
30. Consumer – An organism that feeds on other organisms in a food chain.
31. Cotyledon – The first leaf or pair of leaves produced by the embryo of a seed plant.
32. Cross-pollination – The transfer of pollen from the anther of one flower to the stigma of another.
33. Cuticle – A protective, waxy layer covering the epidermis of many plants.
34. Cyanobacteria – A phylum of bacteria that obtain energy through photosynthesis.
35. Cyst – A sac within or on the body surface containing air or fluid.
36. Cytochrome – Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.
37. Cytogenetics – The study of chromosomes and chromosome abnormalities.
38. Cytoskeleton – A network of fibers in a cell that helps the cell maintain its shape and aids in movement.
39. Cytotoxic – Toxic to cells.
40. Calvin cycle – The cycle of enzyme-catalyzed dark reactions of photosynthesis.
41. Cambium – A layer of tissue that produces new vascular cells in plants.
42. Capsid – The protein shell of a virus.
43. Carnassial – Paired upper and lower teeth in carnivorous mammals adapted for shearing flesh.
44. Caudal – Pertaining to the tail end of the body.
45. Centriole – A structure in animal cells involved in cell division.
46. Chaperone – Proteins that assist in the folding of other proteins.
47. Chemotaxis – Movement of an organism in response to a chemical stimulus.
48. Chitin – A fibrous substance in the exoskeleton of arthropods and fungi.
49. Chlorosis – The symptom of a plant turning yellow when it should be green.
50. Chromatid – One of two identical halves of a replicated chromosome.
51. Chromatin – The material of which chromosomes are made, consisting of protein, RNA, and DNA.
52. Chromosome number – The total number of chromosomes in a cell of an organism.
53. Chymotrypsin – A digestive enzyme that breaks down proteins in the small intestine.
54. Ciliate – A type of protozoa that moves using hair-like structures called cilia.
55. Clade – A group of organisms believed to have evolved from a common ancestor.
56. Clonal – Relating to or derived from a single individual or cell.
57. Clone – An organism or cell that is genetically identical to the unit or individual from which it was derived.
58. Cloaca – A common cavity at the end of the digestive tract in some vertebrates.
59. Cnidarian – A phylum containing over 10,000 species of animals found exclusively in aquatic environments.
60. Cognitive – Relating to cognition, the mental processes of perception, memory, judgment, and reasoning.
61. Commensal – An organism that lives in close association with another without harm or benefit.
62. Conjugation – The direct transfer of DNA between two cells that are temporarily joined.
63. Connective tissue – Tissue that connects, supports, binds, or separates other tissues or organs.
64. Conspecific – Belonging to the same species.
65. Contagious – A disease spread from one person or organism to another by direct or indirect contact.
66. Crepuscular – Active during the dawn and dusk.
67. Cristae – The internal compartments formed by the inner membrane of a mitochondrion.
68. Crop – A pouch in many birds and some lower animals that resembles a stomach for storage.
69. Crossbreeding – The mating of different breeds.
70. Crustacean – A large group of arthropods, usually aquatic, that includes crabs, lobsters, shrimps, and barnacles.
71. Cutaneous – Relating to the skin.
72. Cytosol – The aqueous component of the cytoplasm of a cell.
73. Callose – A polysaccharide that is deposited at the site of injury in plants.
74. Camouflage – The use of any combination of materials, coloration, or illumination for concealment by organisms.
75. Capitation – A payment or fee of a fixed amount per person.
76. Catabolite – A molecule resulting from catabolism.
77. Cation – A positively charged ion.
78. Catkin – A slim cylindrical flower cluster in plants like willows.
79. Caudicle – The stalk attaching a pollen grain to the viscidium in orchids.
80. Cecum – A pouch connected to the junction of the small and large intestines.
81. Cell cycle – The series of events that take place in a cell leading to its division and duplication.
82. Cell wall – A rigid layer lying outside the cell membrane of the cells of plants, fungi, and bacteria.
83. Centromere – The region of a chromosome where the microtubules of the spindle attach during cell division.
84. Cephalothorax – The fused head and thorax of spiders and certain other arthropods.
85. Cerebellum – The part of the brain responsible for coordinating muscular activity.
86. Cerebrum – The principal and anterior part of the brain in vertebrates.
87. Chelate – A type of bonding of ions and molecules to metal ions.
88. Chemoreceptor – A sensory cell or organ responsive to chemical stimuli.
89. Chiasmata – The point where two homologous non-sister chromatids exchange genetic material during chromosomal crossover.
90. Chlorosis – A condition in which leaves produce insufficient chlorophyll.
91. Cholecystokinin – A hormone that stimulates the digestion of fat and protein.
92. Chorion – The outermost membrane surrounding an embryo of a reptile, bird, or mammal.
93. Chromophore – The part of a molecule responsible for its color.
94. Chronic – (of an illness) persisting for a long time or constantly recurring.
95. Chyme – The pulpy acidic fluid that passes from the stomach to the small intestine.
96. Circulatory system – The system that circulates blood and lymph through the body.
97. Cloning – The process of producing similar populations of genetically identical individuals.
98. Cnidocyte – A type of cell unique to cnidarians which contains a specialized organelle used for capturing prey.
99. Coelom – The main body cavity in most multicellular animals.
100. Collenchyma – A type of ground tissue in plants that provides structural support.

Biology Words That Start With D

1. DNA (Deoxyribonucleic Acid): The molecule that carries genetic information in all living organisms.
2. Dendrite: Branched extensions of a neuron that receive signals from other neurons.
3. Dominant: A trait that will appear in the offspring if one of the parents contributes it.
4. Diffusion: The movement of molecules from an area of high concentration to low concentration.
5. Diploid: Cells that have two sets of chromosomes.
6. Decomposer: Organisms that break down dead or decaying organisms.
7. Dermis: The layer of skin beneath the epidermis.
8. Diaphragm: A muscle that plays a major role in breathing.
9. Dorsal: Referring to the back side of an organism.
10. Duodenum: The first part of the small intestine.
11. Dichotomous: Dividing or branching into two parts.
12. Dioxin: A toxic compound known to cause health issues in living organisms.
13. Dilution: Reducing the concentration of a substance in a solution.
14. Disease: A pathological condition affecting an organism.
15. Disaccharide: A sugar molecule consisting of two monosaccharides.
16. Diurnal: Active during the day.
17. Dormancy: A period in an organism’s life cycle when growth, development, and physical activity are temporarily stopped.
18. Dermal: Related to the skin.
19. Dactylology: The study of finger movements, such as in sign language.
20. Darwinism: The theory of evolution by natural selection proposed by Charles Darwin.
21. Deciduous: Trees and shrubs that shed their leaves annually.
22. Dehydration: The loss or removal of water.
23. Denaturation: A process in which proteins lose their structure.
24. Dermatology: The study of skin and its diseases.
25. Detritivore: Organisms that feed on detritus or dead organic material.
26. Deuterostome: Animals in which the first opening in development becomes the anus.
27. Diapause: A period of suspended development in an insect.
28. Dicot: Plants with two embryonic seed leaves or cotyledons.
29. Digestion: The process by which food is broken down into simpler substances.
30. Dimorphism: The existence of two distinct forms of a species.
31. Dinoflagellate: A group of single-celled, often photosynthetic protists.
32. Diplococcus: A type of bacteria that occurs in pairs.
33. Dispersal: The movement of organisms from one place to another.
34. Distal: Situated farthest from the point of attachment.
35. Divergent evolution: Evolutionary pattern in which two species become more different over time.
36. DNA replication: The process by which DNA makes a copy of itself.
37. Dopamine: A neurotransmitter involved in reward and pleasure.
38. Down regulation: The process by which a cell reduces the number of receptors exposed to a particular substance.
39. Drake’s equation: An equation used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way.
40. Drosophila: A genus of small fruit flies used in genetic studies.
41. Drupe: A type of fruit with a single seed enclosed in a hard pit.
42. Duress: Extreme stress or pressure on an organism.
43. Dystrophy: Any disorder arising from defective or faulty nutrition.
44. Decapod: Crustaceans with ten legs, like shrimp and crabs.
45. Deme: A local population of organisms that have similar genes.
46. Dermal papilla: A small, nipple-like extension of the dermis into the epidermis.
47. Desmosome: A structure by which two adjacent cells are attached.
48. Detoxification: The process of removing toxic substances.
49. Deuterium: A stable isotope of hydrogen.
50. Diastole: The phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood.
51. Dichogamy: The production of male and female reproductive organs at different times.
52. Dictyosome: Another term for the Golgi apparatus in plants.
53. Dioecious: Species in which male and female reproductive organs are in different individuals.
54. Dipnoi: A subclass of fish known as lungfish.
55. Disjunction: The normal separation or moving apart of chromosomes during cell division.
56. Distichous: Arranged in two opposite rows.
57. Diuretic: A substance that promotes the production of urine.
58. Divergent boundary: A tectonic boundary where two plates are moving away from each other.
59. Dobzhansky, Theodosius: A prominent geneticist and evolutionary biologist.
60. Doldrums: An equatorial region of the Atlantic Ocean with calms, sudden storms, and light unpredictable winds.
61. Dominance hierarchy: A social ranking among group-living animals, determined by aggressive and submissive behaviors.
62. Doppler effect: An increase or decrease in the frequency of sound, light, or other waves.
63. Dormant bud: A bud that is not growing and will not grow until conditions are right.
64. Dorsiventral: Having distinct dorsal and ventral sides, as in leaves.
65. Down’s syndrome: A genetic disorder caused by the presence of an extra 21st chromosome.
66. Drift net: A type of fishing net that is left to float with the tide.
67. Drupelet: One of the small drupes that make up the fruit of the blackberry, raspberry, etc.
68. Duckweed: A small floating aquatic plant.
69. Duodenal juice: The secretion of the duodenum, important in digestion.
70. Dynein: A motor protein that moves along microtubules in cells.
71. Dysbiosis: An imbalance in the microbial ecology of a system.
72. Dysplasia: Abnormal growth or development of cells or tissues.
73. Decalcification: The removal of calcium from bones or teeth.
74. Decarboxylation: The removal of a carboxyl group from a molecule.
75. Decidua: The endometrial lining of the uterus during pregnancy.
76. Decussate: To cross or intersect, especially in pairs.
77. Defenestration: The process of removing or ejecting cellular contents.
78. Degeneracy: In genetics, the property of having multiple codons encode a single amino acid.
79. Dehiscence: The splitting along a built-in line of weakness in a plant structure.
80. Delocalization: In chemistry, the spreading of electron density over more than one atom.
81. Deme: A local population of organisms of one species.
82. Dendrochronology: The science of dating events and variations in the environment by studying tree rings.
83. Dendrogram: A tree diagram used to illustrate the arrangement of clusters.
84. Denitrification: The microbial conversion of nitrate to nitrogen gas.
85. Dentate: Having a toothed edge.
86. Dentin: The main, calcified part of a tooth, beneath the enamel.
87. Deoxyribose: A sugar derived from ribose by replacing a hydroxyl group with hydrogen.
88. Depolarization: A reduction in the difference in voltage between the inside and outside of a cell.
89. Dermal tissue: The protective outer covering of plants.
90. Desiccation: The process of drying out.
91. Detritus: Dead organic material.
92. Deuteromycota: A group of fungi with no known sexual stage.
93. Devonian: A geologic period and system of the Paleozoic era.
94. Diagenesis: The physical and chemical changes occurring during the conversion of sediment to sedimentary rock.
95. Dialysis: The separation of particles in a liquid on the basis of differences in their ability to pass through a membrane.
96. Diamagnetic: A substance not retaining magnetic properties in the absence of an externally applied magnetic field.
97. Diastase: An enzyme that catalyzes the breakdown of starch into maltose.
98. Diatom: A major group of algae, and among the most common types of phytoplankton.
99. Dichlorodiphenyltrichloroethane (DDT): A synthetic insecticide.
100. Dicotyledon: A class of angiosperms that have two embryonic seed leaves.

Biology Words That Start With E

1. Ear: The organ of hearing and balance in vertebrates.
2. Ecdysis: The process of shedding an outer layer of skin, exoskeleton, or other body covering.
3. Echinoderm: A member of the phylum Echinodermata, which includes sea stars, sea urchins, and sea cucumbers.
4. Ecological niche: The specific role that an organism plays in its environment.
5. Ecological pyramid: A diagram that shows the relationship between different trophic levels in an ecosystem.
6. Ecological succession: The process of change in an ecosystem over time.
7. Ecosystem: A community of organisms and their environment that interact with each other.
8. Ectoderm: The outermost layer of cells in an embryo, which develops into the skin, nervous system, and other tissues.
9. Ectotherm: An organism that cannot regulate its body temperature internally and relies on external sources of heat.
10. Elastic cartilage: A type of cartilage that is found in the external ear and other parts of the body.
11. Electron transport chain: A series of chemical reactions that transfer electrons from one molecule to another, releasing energy that is used to generate ATP.
12. Embalming: The process of preserving a dead body by treating it with chemicals.
13. Embryo: The early stage of development of a multicellular organism, from fertilization to the time of birth or hatching.
14. Embryology: The study of the development of embryos.
15. Embryonic stem cells: Stem cells that are derived from embryos.
16. Emulsify: To break down large fat droplets into smaller droplets that can be suspended in water.
17. Endemism: The restricted distribution of a species or other taxonomic group to a particular geographic area.
18. Endergonic reaction: A chemical reaction that requires energy to proceed.
19. Endocrine gland: A gland that secretes hormones directly into the bloodstream.
20. Endocrine system: The system of glands that produce and secrete hormones.
21. Endocytosis: The process by which cells take in substances from the extracellular environment by engulfing them.
22. Endoderm: The innermost layer of cells in an embryo, which develops into the lining of the digestive tract, respiratory tract, and other tissues.
23. Endoplasmic reticulum: A network of membranes within cells that is involved in the synthesis, transport, and modification of proteins and lipids.
24. Endoskeleton: The internal skeleton of an organism, such as the skeleton of a vertebrate.
25. Endosymbiotic theory: The theory that mitochondria and chloroplasts evolved from symbiotic bacteria that were engulfed by early eukaryotic cells.
26. Endothelium: The layer of cells that lines the inside of blood vessels and lymphatic vessels.
27. Energy pyramid: A diagram that shows the amount of energy that is transferred from one trophic level to another in an ecosystem.
28. Enzyme substrate complex: The temporary association of an enzyme with its substrate, which is the molecule that the enzyme acts on.
29. Epistasis: A type of gene interaction in which one gene can mask the expression of another gene.
30. Epithelial tissue: A type of tissue that covers the body surface and lines internal organs and cavities.
31. Equilibrium constant: A mathematical expression that describes the ratio of the concentrations of products to reactants in a chemical equilibrium.
32. Esophagus: The muscular tube that carries food from the mouth to the stomach.
33. Essential amino acids: Amino acids that cannot be synthesized by the body and must be obtained from the diet.
34. Eubacteria: A type of bacteria that has a cell wall made of peptidoglycan.
35. Euchromatin: The loosely packed form of chromatin that is found in the active regions of chromosomes.
36. Eukaryote: An organism that has cells with a nucleus and other membrane-bound organelles.
37. Eukaryotic cell: A cell that has a nucleus and other membrane-bound organelles.
38. Euphoria: A feeling of intense happiness, well-being, and elation.
39. Euthymic: A state of normal mental health and emotional stability.
40. Excretion: The process by which the body removes waste products from the blood and tissues.
41. Excretion system: The system of organs that removes waste products from the body.
42. Exocrine gland: A gland that secretes its products through ducts onto the body surface or into an internal body cavity.
43. Exocytosis: The process by which cells release substances from their interior by fusing vesicles with the cell membrane.
44. Extensible element: A type of protein that can be stretched or extended without breaking.
45. Extinction: The permanent loss of a species from the Earth.
46. Extremophile: An organism that can live in extreme environments, such as high temperatures, high acidity, or high salinity.
47. Eutherian mammal: A mammal that gives birth to live young that are relatively well-developed.
48. Evolution: The process by which populations of organisms change over time through the process of natural selection.
49. Excitatory postsynaptic potential: A type of postsynaptic potential that makes a neuron more likely to fire an action potential.
50. Exocrine pancreas: The part of the pancreas that secretes digestive enzymes into the small intestine.
51. Excretory product: A substance that is removed from the body by the excretory system.
52. Existentialism: A philosophical movement that emphasizes the individual’s freedom and responsibility to create their own meaning in life.
53. Extinction event: A sudden and widespread loss of species.
54. Eye: The organ of sight in vertebrates.
55. Ecology: The study of the interactions between organisms and their environment.
56. Embryo sac: The female gametophyte in flowering plants.
57. Endothelin: A hormone that constricts blood vessels.
58. Endoplasmic reticulum stress: A condition that occurs when the endoplasmic reticulum is overloaded with proteins.
59. Epigenetics: The study of changes in gene expression that are not caused by changes in the DNA sequence.
60. Epinephrine: A hormone that is released in response to stress and helps to prepare the body for fight or flight.
61. Equilibrium: The state of balance in a system.
62. Erythrocyte: A red blood cell.
63. Estrone: A female sex hormone.
64. Estrogen: A female sex hormone.
65. Ethnobotany: The study of the relationship between plants and people.
66. Ethology: The study of animal behavior.
67. Eukaryotic gene: A gene that is found in a eukaryotic cell.
68. Evolvability: The ability of a population to change over time.
69. Exaptation: A trait that is originally evolved for one purpose but is later co-opted for another purpose.
70. Excitation-contraction coupling: The process by which electrical signals in the muscle cell trigger the contraction of the muscle fiber.
71. Exocytosis-vesicle fusion: The process by which vesicles fuse with the cell membrane and release their contents into the extracellular environment.
72. Exogenous: Originating from outside the body.
73. Exogenous gene: A gene that is not found in the organism’s genome but is introduced from another organism.
74. Exogenous hormone: A hormone that is produced by another organism and introduced into the body.
75. Exogenous virus: A virus that is not found in the organism’s genome but is introduced from another organism.
76. Exonuclease: An enzyme that breaks down DNA or RNA nucleotides from the end of the molecule.
77. Expressivity: The degree to which a gene is expressed.
78. Extant: Currently existing.
79. Extrinsic pathway: One of the two pathways by which blood clots are formed.
80. Extrinsic ribosome: A ribosome that is not attached to the endoplasmic reticulum.
81. Eyespot: A light-sensitive organelle found in some protists.

Biology Words That Start With F

1. Fermentation: A metabolic process that produces energy in the absence of oxygen, often resulting in the production of alcohol or lactic acid.
2. Fertilization: The fusion of male and female gametes to form a zygote.
3. Fetus: A developing mammal or other viviparous vertebrate after the embryonic stage and before birth.
4. Flagellum: A whip-like structure that allows some cells, like sperm and certain bacteria, to move.
5. Flora: The plants of a particular region or period.
6. Fauna: The animals of a particular region or period.
7. Follicle: A small secretory cavity or sac, especially one containing an egg in the ovaries of mammals.
8. Fungi: A kingdom of spore-producing organisms, including mushrooms, yeasts, and molds.
9. Foramen: An opening or hole, especially in bones.
10. Fovea: A small depression in the retina of the eye where visual acuity is highest.
11. Femur: The thigh bone, the longest bone in the human body.
12. Fission: A type of asexual reproduction where an organism divides into two or more organisms.
13. Fitness: In evolutionary biology, the ability of an organism to survive and reproduce in its environment.
14. Flavonoid: A group of polyphenolic compounds found in plants, often responsible for colors.
15. Frond: The leaf or leaf-like part of a fern.
16. Fimbriae: Finger-like projections at the end of fallopian tubes or on the surface of some bacteria.
17. Filtration: The process of filtering substances from a solution or mixture.
18. Fibroblast: A cell that produces collagen and other fibers, playing a crucial role in wound healing.
19. Fibrosis: The thickening or scarring of connective tissue, often as a result of injury.
20. Fluke: A parasitic flatworm, or an unexpected stroke of luck.
21. Folivore: An herbivore that specializes in eating leaves.
22. Forbs: Flowering plants that are not graminoids (grasses, sedges, and rushes).
23. Forebrain: The anterior part of the brain, including the cerebrum and diencephalon.
24. Founder effect: A decrease in genetic variation caused by a small number of individuals establishing a new population.
25. Frugivore: An animal that primarily eats raw fruits, succulent fruit-like vegetables, roots, shoots, nuts, and seeds.
26. Fundus: The base or deepest part of an organ, e.g., the upper part of the stomach.
27. Fomite: An inanimate object that can transmit infectious agents.
28. Fossorial: Adapted to digging and living underground.
29. Fenestration: The arrangement and design of windows in a building, or a small opening or perforation in an organ.
30. Fibrin: A protein involved in the clotting of blood.
31. Fibrinogen: A soluble protein present in blood plasma, from which fibrin is produced by the action of the enzyme thrombin.
32. Flaccid: Lacking firmness, resilience, or muscle tone.
33. Fluke: A flatworm parasite that typically has suckers and hooks for attachment to the host.
34. Fluorescence: The emission of light by a substance that has absorbed light or other electromagnetic radiation.
35. Fomite: Any inanimate object or substance capable of carrying infectious organisms.
36. Foraging: The act of searching for and obtaining food.
37. Foregut: The anterior part of the alimentary canal, from the mouth to the duodenum.
38. Foveola: A tiny pit or depression, especially one in the center of the fovea of the retina.
39. Free radical: An uncharged molecule with an unpaired valence electron, often highly reactive.
40. Freeman, Walter: An American physician known for his work on the lobotomy.
41. Frondescence: The process or time of putting forth leaves.
42. Fruiting body: The spore-producing organ of a fungus.
43. Functional group: A group of atoms responsible for the characteristic reactions of a particular compound.
44. Funiculus: A cord-like structure, especially the part of a spermatozoon that connects the head with the tail.
45. Furrow: A trench, groove, or wrinkle in an organ or tissue.
46. Fusiform: Tapering at both ends; spindle-shaped.
47. Fusion: The process or result of joining two or more things together to form a single entity.
48. Futuyma, Douglas: An evolutionary biologist known for his research and textbooks on evolutionary biology.
49. Fynbos: A type of vegetation found in South Africa, characterized by a mix of evergreen shrub-like plants.
50. Fytogeography: The branch of biogeography that studies the distribution of plants.

Biology Words That Start With G

1. Gene: A unit of heredity that is transferred from a parent to offspring and determines some characteristic of the offspring.
2. Genome: The complete set of genes or genetic material present in a cell or organism.
3. Genotype: The genetic constitution of an individual organism.
4. Glycolysis: The breakdown of glucose by enzymes, releasing energy and pyruvic acid.
5. Golgi apparatus: A complex of vesicles and folded membranes within the cytoplasm, involved in secretion and intracellular transport.
6. Gamete: A mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction.
7. Germ layer: Any of the three layers of cells differentiated in embryos, comprising the ectoderm, mesoderm, and endoderm.
8. Gland: An organ in the body that synthesizes substances (like hormones) for release into the bloodstream or into cavities inside the body or its outer surface.
9. Glycogen: A substance deposited in bodily tissues as a store of carbohydrates.
10. Guanine: One of the four main nucleobases found in the nucleic acids DNA and RNA.
11. Gut flora: The complex community of microorganisms living in the digestive tracts of humans and other animals.
12. Gallbladder: A small organ where bile is stored, before it is released into the small intestine.
13. Gastrulation: The phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a multilayered structure.
14. Gibberellin: A plant hormone that regulates growth and influences various developmental processes.
15. Gingiva: The gum tissue surrounding the teeth.
16. Glial cells: Cells in the nervous system that support, nourish, and protect neurons.
17. Gluconeogenesis: The formation of glucose, especially by the liver, from non-carbohydrate sources like amino acids.
18. Glucagon: A hormone formed in the pancreas that promotes the breakdown of glycogen to glucose in the liver.
19. Glutamate: A salt or ester of glutamic acid, involved in the Krebs cycle.
20. Glycoprotein: Proteins that contain oligosaccharide chains covalently attached to their polypeptide side-chains.
21. Gonad: An organ that produces gametes; a testis or ovary.
22. Gravitropism: A coordinated process of differential growth by a plant in response to gravity pulling on it.
23. Guard cells: Specialized cells in the epidermis of leaves, stems, and other organs that are used to control gas exchange.
24. Guttation: The exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants.
25. Gymnosperm: A group of seed-producing plants that includes conifers, cycads, and ginkgo.
26. Gynoecium: The female parts of a flower, comprising the ovaries, style, and stigma.
27. Gyrus: A ridge on the cerebral cortex.
28. Gastropod: A large class of mollusks, including snails and slugs.
29. Genomics: The branch of molecular biology concerned with the structure, function, evolution, and mapping of genomes.
30. Germ cell: A cell containing half the number of chromosomes of a somatic cell and able to unite with one from the opposite sex to form a new individual.
31. Germination: The process by which a plant grows from a seed.
32. Gibbosity: A swelling or protuberance.
33. Gingivitis: Inflammation of the gums.
34. Glioma: A type of tumor that starts in the brain or spine.
35. Globulin: Any of several families of proteins or glycoproteins.
36. Glomerulus: A cluster of nerve endings, spores, or small blood vessels.
37. Glycosis: The enzymatic breakdown of a carbohydrate.
38. Gnotobiotics: The study of organisms while ensuring that they are not contaminated by other organisms.
39. Granum: A stack of thylakoids in the chloroplasts of plant cells.
40. Gregarious: Describing the tendency of certain animals to live in groups.
41. Growth factor: A substance, like a vitamin or hormone, that is required for the stimulation of growth in living cells.
42. Guano: A type of fertilizer made up of the excrement of seabirds and bats.
43. Gynandromorph: An organism that contains both male and female characteristics.
44. Gynoecium: The female reproductive organs in a flower.
45. Genetic drift: Variation in the relative frequency of different genotypes in a small population.
46. Geneticist: A biologist who studies genetics.
47. Geniculate: Bent abruptly, like a knee.
48. Genitalia: The organs of the reproductive system.
49. Genus: A rank in the classification of organisms, below family and above species.
50. Gestation: The process of carrying or being carried in the womb between conception and birth.

Biology Words That Start With H

1. Haploid: Cells that have a single set of chromosomes, like gametes.
2. Helix: A type of spiral structure, like the double helix of DNA.
3. Hemoglobin: A protein in red blood cells that carries oxygen.
4. Herbivore: An organism that primarily eats plants.
5. Heterozygous: Having two different alleles for a particular gene.
6. Histology: The study of the microscopic structure of tissues.
7. Hormone: A signaling molecule produced by glands in multicellular organisms.
8. Hybrid: An offspring resulting from the cross between parents of different species or sub-species.
9. Hydrolysis: A chemical process in which a molecule is cleaved into two parts by the addition of a water molecule.
10. Hypothalamus: A region of the brain responsible for the production of many of the body’s essential hormones.
11. Homeostasis: The tendency of the body to maintain a stable internal environment.
12. Hapten: A small molecule that can elicit an immune response only when attached to a larger carrier.
13. Hemostasis: The process of stopping the flow of blood.
14. Heterotroph: An organism that cannot produce its own food and instead takes nutrition from other sources of organic carbon.
15. Histamine: A compound released by cells in response to injury and allergic reactions, causing contraction of smooth muscle and dilation of capillaries.
16. Homologous: Having the same relation, relative position, or structure.
17. Hyphae: The branching filaments that make up the mycelium of a fungus.
18. Hematopoiesis: The production of blood cells and platelets.
19. Hepatic: Relating to the liver.
20. Holotype: A single physical example of an organism, known to have been used when the species was formally described.
21. Humerus: The bone of the upper arm or forelimb.
22. Hybridization: The process of interbreeding individuals from genetically distinct populations.
23. Hydrophilic: Attracted to water.
24. Hydrophobic: Repelling water.
25. Hypoxia: A condition in which the body or a region of the body is deprived of adequate oxygen supply.
26. Helicase: An enzyme that helps unwind the DNA double helix during DNA replication.
27. Hemolysis: The rupture or destruction of red blood cells.
28. Heterochromatin: A tightly packed form of DNA, which comes in multiple varieties.
29. Hibernation: A state of inactivity and metabolic depression in endotherms.
30. Homolog: One of a pair of chromosomes having corresponding loci.
31. Hyaluronic acid: A substance that is naturally present in the human body and is found mainly in the fluids in the eyes and joints.
32. Hydrocarbon: An organic compound consisting entirely of hydrogen and carbon.
33. Hyperplasia: An increase in the amount of organic tissue that results from cell proliferation.
34. Hypertonic: A solution with higher osmotic pressure than another solution.
35. Hypothesis: A proposed explanation made on the basis of limited evidence as a starting point for further investigation.
36. Hemocyte: A blood cell.
37. Hepatocyte: A cell of the main tissue in the liver.
38. Herpetology: The study of amphibians and reptiles.
39. Heterocyst: A specialized nitrogen-fixing cell in some filamentous cyanobacteria.
40. Histocompatibility: The compatibility between the tissues of different individuals, so that they can be grafted without rejection.
41. Holobiont: An assemblage of a host and the many other species living in or around it.
42. Homoplasmy: The presence of the same form of a particular DNA sequence in every copy within a single cell or organism.
43. Hydrolase: An enzyme that catalyzes the hydrolysis of a compound.
44. Hypermutation: An unusually high frequency of mutations.
45. Hypodermis: An epidermal layer of cells that secretes an overlying chitinous cuticle, as in arthropods.
46. Hypophysis: Another term for the pituitary gland.
47. Hypotonic: A solution with lower osmotic pressure than another solution.
48. Heliotropism: The directional growth of a plant in response to sunlight.
49. Hemizygous: Having only a single copy of a gene instead of the customary two copies.
50. Heterokaryon: A fungal cell which has two or more genetically different nuclei.

Biology Words That Start With I

1. Immunology: The study of the immune system and its responses to pathogens.
2. Invertebrate: An animal lacking a backbone, like insects, worms, and mollusks.
3. Intron: A segment of DNA that is transcribed, but removed from the mRNA sequence before translation.
4. Isotope: Variants of a particular chemical element which differ in neutron number.
5. Insulin: A hormone produced in the pancreas that regulates the amount of glucose in the blood.
6. Innervation: The distribution of nerve fibers to an organ or body region.
7. Ingestion: The process of taking food, drink, or another substance into the body by swallowing or absorbing it.
8. Inflammation: A protective response involving immune cells, blood vessels, and molecular mediators to remove harmful stimuli.
9. Inhibitor: A molecule that binds to an enzyme and decreases its activity.
10. Intercellular: Situated between cells.
11. Interstitial: Relating to or situated in the small, narrow spaces between tissues or parts of an organ.
12. Inoculate: To introduce (cells or organisms) into a culture medium.
13. Innate: Inborn; natural, especially referring to immunity that is present without prior exposure to a pathogen.
14. Isomer: Molecules with the same molecular formula but different structural formulas.
15. Inflorescence: The arrangement of flowers on a plant.
16. Imprinting: A rapid learning process that takes place early in the life of a social animal and establishes a behavior pattern.
17. In vivo: Processes or reactions occurring in a living organism.
18. In vitro: Processes or reactions occurring outside a living organism, typically in a test tube.
19. Iris: The colored part of the eye, controlling the size of the pupil.
20. Ichthyology: The study of fishes.
21. Ileum: The third and final part of the small intestine.
22. Islets of Langerhans: Cell clusters in the pancreas that produce insulin.
23. Integument: A natural covering, like skin or a shell.
24. Interphase: The resting phase between successive mitotic divisions of a cell.
25. Invasive species: Plants, animals, or pathogens that are non-native to an ecosystem and may cause harm.
26. Instinct: An innate behavior that an organism inherits.
27. Insectivore: An animal that feeds on insects.
28. Innate immunity: The defenses against infection that can be activated immediately once a pathogen attacks.
29. Immunosuppression: Reduction of the activation or efficacy of the immune system.
30. Immunoglobulin: A protein with antibody activity; examples include IgA, IgG, and IgM.
31. Isozyme: Enzymes that differ in amino acid sequence but catalyze the same chemical reaction.
32. Intercalated discs: Microscopic identifying features of cardiac muscle.
33. Innervate: To supply (an organ or other body part) with nerves.
34. Inference: A conclusion reached on the basis of evidence and reasoning.
35. Infundibulum: A funnel-shaped cavity or structure, especially in the heart or brain.
36. Inoculum: Microbes that are introduced into a culture medium to initiate growth.
37. Insecta: The class of animals that are insects.
38. Interferon: A protein produced by cells in response to being infected by a virus and that provides short term protection.
39. Intestine: The part of the alimentary canal between the stomach and the anus.
40. Intron: A segment of a DNA or RNA molecule that does not code for proteins and interrupts the sequence of genes.
41. Invagination: The action or process of being turned inside out or folded back on itself to form a cavity or pouch.
42. Ion: An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
43. Iridescence: The phenomenon of certain surfaces appearing to change color as the angle of view or the angle of illumination changes.
44. Isogamy: A form of sexual reproduction that involves gametes of similar morphology.
45. Isolation: The process or fact of isolating or being isolated, often used in the context of preventing the spread of disease.
46. Isotonic: Having the same osmotic pressure as a particular fluid, typically a body fluid or intracellular fluid.
47. Iteroparity: Reproductive strategy of producing offspring multiple times over a lifetime.
48. Iodine: A chemical element often used as a disinfectant or a trace element essential for proper thyroid function.
49. Illumina sequencing: A sequencing method developed by Illumina, Inc. that involves fragmenting DNA, amplifying fragments on a surface, and then sequencing each fragment.
50. Inoculation loop: A simple tool used mainly by microbiologists to retrieve an inoculum from a culture.

Biology Words That Start With J

1. Jejunum: The part of the small intestine between the duodenum and ileum.
2. Junction: A point where two or more things are joined, such as a tight junction in cells.
3. Juxtaglomerular apparatus: A system that regulates the function of nephrons in the kidney.
4. Jurassic: A geologic period and system that spanned 56 million years from the end of the Triassic Period to the beginning of the Cretaceous Period.
5. Juxtacrine: A type of cell signaling in which the two cells in direct contact.
6. Joint: The location at which two or more bones make contact.
7. Juvenile: An individual organism that has not yet reached its adult form, sexual maturity, or size.
8. Jasmonic acid: A type of plant hormone involved in tendril coiling, flower development, and fruit ripening.
9. Jacobson’s organ: An auxiliary olfactory sense organ found in many animals; also known as the vomeronasal organ.
10. Jet lag: A physiological condition resulting from alterations to the body’s circadian rhythms due to rapid long-distance trans-meridian travel.
11. Joule: A unit of energy in the International System of Units, used to quantify the amount of energy in biological systems.
12. Jumping gene: Another term for a transposon, a DNA sequence that can change its position within a genome.
13. Juxtamembrane: The region of a protein that is directly adjacent to the membrane.
14. Juxtamedullary: Referring to certain nephrons in the kidney that are close to the medulla.
15. Juxtanuclear: Located near the nucleus, often referring to certain cellular structures or inclusions.
16. Juxtacrine signaling: A type of cell signaling mediated by direct contact between neighboring cells.
17. J-chain: A protein component of some antibodies that helps to polymerize them, especially in mucosal secretions.
18. Jejunal: Relating to the jejunum, the middle part of the small intestine.
19. Jasmonate: A type of plant hormone involved in various parts of plant development and defense.
20. Junctional rhythm: A heart rhythm that originates from the atrioventricular node.
21. Juxta-articular: Situated close to a joint.
22. Juxtacellular: Situated adjacent to a cell.
23. Juxtaglomerular cells: Cells around the glomerulus in the kidney that release renin.
24. Juxtavascular: Located adjacent to a blood vessel.
25. Juxtacortical: Located immediately adjacent to the cortex of an organ.
26. Juxtaluminal: Situated next to the lumen of a structure.
27. Juxtaphrenic: Located near the diaphragm.
28. Juxtagastric: Situated close to the stomach.
29. Juxtavesical: Located adjacent to the urinary bladder.
30. Juxtatubular: Situated close to a tubule, often referring to structures in the kidney.
31. Juxtaspinal: Located adjacent to the vertebral column.
32. Juxtatendinous: Situated close to a tendon.
33. Juxtaneural: Located near a nerve.
34. Juxtaoral: Situated close to the mouth.
35. Juxtaepiphyseal: Located near an epiphysis, the end part of a long bone.
36. Juxtarenal: Situated close to the kidney.
37. Juxtaposition: The fact of two things being seen or placed close together with contrasting effect.
38. Juxtacardiac: Located adjacent to the heart.
39. Juxtaepidermal: Situated immediately beneath the epidermis.
40. Juxtamembranous: Located close to a membrane.
41. Juxtanodal: Situated close to a node, especially in the context of nerve cells.
42. Juxtapapillary: Located adjacent to the papilla, such as in the context of the optic nerve.
43. Juxtaosseous: Situated close to a bone.
44. Juxtapyloric: Located near the pylorus, the part of the stomach that connects to the duodenum.
45. Juxta-articular myxoma: A rare, benign tumor of the soft tissues near a joint.
46. Juxtapositional: Relating to the act or placement of two things (such as genes) side by side.
47. Juxtacrine interaction: A type of cell-cell interaction in which a cell induces changes in a neighboring cell without any direct contact.
48. Juxtafoveal: Located near the fovea of the eye.
49. Juxtapositioning: The act or placement of two things side by side.
50. Juxtavertebral: Situated close to the vertebral column.

Biology Words That Start With K

1. Karyotype: The number and appearance of chromosomes in the nucleus of a eukaryotic cell.
2. Keratin: A protein that protects epithelial cells from damage and is the key structural material making up hair, nails, and the outer layer of skin.
3. Kinase: An enzyme that transfers phosphate groups from high-energy donor molecules to specific substrates.
4. Kinesis: A movement that is a response to a stimulus but is not oriented with respect to the source of stimulation.
5. Kinetochore: A protein structure on chromatids where the spindle fibers attach during cell division.
6. Kingdom: A taxonomic rank that is composed of smaller groups called phyla (or divisions in plants).
7. Krebs cycle: A series of chemical reactions used by all aerobic organisms to generate energy; also known as the citric acid cycle.
8. Karyokinesis: The division of a cell’s nucleus during mitosis.
9. Ketone: An organic compound with a carbonyl group bonded to two hydrocarbon groups.
10. Kilocalorie: A unit of energy equal to 1,000 calories.
11. Kleptoparasitism: A form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food.
12. Karyogamy: The fusion of two nuclei within a cell, especially as the second stage of syngamy.
13. Keratinocyte: A cell that manufactures and stores the protein keratin.
14. Ketogenesis: The production of ketone bodies.
15. Kidney: A pair of organs in the abdominal cavity that filter waste from the blood and produce urine.
16. Kinetoplast: A network of circular DNA inside a large mitochondrion that contains many copies of the genome.
17. Karyolysis: The dissolution or degeneration of a cell nucleus.
18. Keratocyte: A type of cell in the cornea.
19. Ketosis: A metabolic state characterized by raised levels of ketone bodies in the body tissues.
20. Kilobase: A unit of length for DNA fragments equal to 1,000 nucleotides.
21. Kleptoplasty: The absorption and incorporation of chloroplasts from algae into the cells of a host organism.
22. Karyoplasm: The protoplasm of a nucleus; nucleoplasm.
23. Keratoplasty: Surgical repair of the cornea.
24. Ketosteroid: Steroids that contain a ketone group.
25. Kinesiology: The study of the mechanics of body movements.
26. Kinetochores: Protein structures located on the centromeres where spindle fibers attach during cell division.
27. Karyorrhexis: The destructive fragmentation of the nucleus of a dying cell.
28. Keratosis: A growth of keratin on the skin or on mucous membranes.
29. Ketotetrose: A four-carbon ketose sugar.
30. Kilodalton (kDa): A unit of mass equal to 1,000 daltons, often used to express the molecular weight of proteins.
31. Kleptogenesis: A form of asexual reproduction that requires mating with another species.
32. Kappa: A type of light chain found in many immunoglobulins.
33. Keratolysis: The breaking down or shedding of the outer layer of the skin.
34. Ketoadipic pathway: A series of enzymatic reactions used by bacteria and fungi to utilize aromatic compounds as a source of carbon.
35. Kinesthetic: Relating to a person’s awareness of the position and movement of the parts of the body.
36. Kinetosome: A cellular organelle from which the cilia and flagella arise.
37. Karyosome: A compact mass of chromatin in the nucleus of a cell.
38. Keratoconjunctivitis: Inflammation of the cornea and conjunctiva.
39. Ketopentose: A five-carbon ketose sugar.
40. Kinesis (in genetics): The movement of a chromosome during cell division.
41. Kinetoplastid: A group of flagellated protists, including the species that cause African sleeping sickness.
42. Karyosystematics: The study of karyotypes in taxonomy and evolutionary research.
43. Keratoderma: A condition characterized by thickened skin on the palms and soles.
44. Ketoacidosis: A high concentration of ketone bodies, often caused by uncontrolled diabetes.
45. Kinetic energy: The energy of an object due to its motion.
46. Kinetin: A type of cytokinin, a class of plant hormone.
47. Karyotypic: Pertaining to the characteristics or features of a karyotype.
48. Keratolytic: Causing the softening and breaking down of skin.
49. Ketohexose: A six-carbon ketose sugar, like fructose.
50. Kisspeptin: A protein that regulates the release of gonadotropin-releasing hormone.

Biology Words That Start With L

1. Lysosome: A cell organelle containing enzymes that digest particles and that disintegrate the cell after its death.
2. Lipid: A type of organic molecule that is greasy to the touch, insoluble in water, and soluble in alcohol; includes fats and oils.
3. Leukocyte: A white blood cell.
4. Larva: The immature, wingless, and often wormlike feeding form that hatches from the egg of many insects.
5. Ligand: A molecule that binds specifically to another molecule, usually a larger one.
6. Lichen: A composite organism made up of a fungus and an alga or cyanobacterium living together symbiotically.
7. Locus: The specific location or position of a gene’s DNA sequence on a chromosome.
8. Lymphocyte: A type of white blood cell that is involved in the immune response.
9. Ligase: An enzyme that facilitates the joining of DNA strands together.
10. Limbic system: A set of brain structures responsible for emotion, memory, and behavior.
11. Lumen: The inside space of a tubular structure, such as an artery or intestine.
12. Larviparous: Giving birth to live larvae, especially certain insects.
13. Leucine: An essential amino acid used in the biosynthesis of proteins.
14. Lysis: The disintegration of a cell by rupture of the cell wall or membrane.
15. Lytic cycle: The cycle of viral replication that results in the destruction of the infected cell.
16. Lactase: An enzyme that breaks down lactose into glucose and galactose.
17. Lactation: The secretion of milk by the mammary glands.
18. Lateral: Relating to the sides of an organism or structure.
19. Ligament: A short band of tough, flexible tissue that connects two bones or cartilages or holds together a joint.
20. Lymph: A colorless fluid containing white blood cells, which bathes the tissues and drains through the lymphatic system.
21. Lymphoma: A cancer of the lymphatic system.
22. Lipase: An enzyme that catalyzes the hydrolysis of fats.
23. Liposome: A tiny bubble made out of the same material as a cell membrane that can be filled with drugs or other substances.
24. Luciferase: An enzyme that produces bioluminescence, often used in research.
25. Luteinizing hormone (LH): A hormone produced by gonadotropic cells in the anterior pituitary gland.
26. Lysozyme: An enzyme that breaks down bacterial cell walls, found notably in tears and saliva.
27. Lactobacillus: A type of bacteria used in the production of yogurt and other fermented foods.
28. Lactose: A sugar present in milk, consisting of glucose and galactose.
29. Larvicide: A substance used to kill larvae.
30. Leptin: A hormone that regulates energy balance by inhibiting hunger.
31. Lignin: A complex organic polymer found in the cell walls of many plants, making them rigid.
32. Limb: An arm, leg, or wing.
33. Linnaean: Relating to the system of taxonomic classification and binomial nomenclature originated by Carl Linnaeus.
34. Lipogenesis: The metabolic formation of fat.
35. Lipopolysaccharide (LPS): A molecule found on the outer membrane of Gram-negative bacteria.
36. Locus: A fixed position on a chromosome where a particular gene or genetic marker is located.
37. Log phase: The period in a bacterial growth curve when growth is most rapid.
38. Lumen: The central cavity of a tubular or other hollow structure in an organism or cell.
39. Luteal phase: The latter phase of the menstrual cycle or estrous cycle.
40. Lytic: Relating to or causing the breakdown of cells or lysis.
41. Lymphadenopathy: Disease or swelling of the lymph nodes.
42. Lymphangiogenesis: The formation of lymphatic vessels.
43. Lymphostasis: The stagnation of the flow of lymph.
44. Lyophilization: Another term for freeze-drying.
45. Lysogenic cycle: The cycle in which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell’s DNA.
46. Lysogeny: The state of being lysogenic.
47. Lysozyme: An enzyme found in saliva and sweat and tears that destroys the cell walls of certain bacteria.
48. Lytic agent: A substance that causes lysis.
49. Lytotropic: Having an affinity for certain solvents.
50. Lyotropic series: A series of ions or molecules arranged in order of increasing or decreasing lyotropic action.

Biology Words That Start With M

1. Mitosis: The process by which a eukaryotic cell separates its chromosomes into two identical sets, resulting in two daughter nuclei.
2. Meiosis: A type of cell division that reduces the number of chromosomes by half, producing four haploid cells.
3. Mutation: A change in the DNA sequence of a gene or chromosome.
4. Mitochondria: Organelles in eukaryotic cells responsible for producing ATP through cellular respiration.
5. Membrane: A thin layer of tissue or molecules that separates cells or cellular compartments.
6. Molecule: A group of atoms bonded together.
7. Muscle: Tissue composed of fibers capable of contracting to effect bodily movement.
8. Melanin: A pigment responsible for the color of skin, hair, and eyes in animals.
9. Microorganism: A microscopic organism, such as bacteria, viruses, and fungi.
10. Microbiome: The community of microorganisms living in a particular environment or habitat.
11. Monomer: A molecule that can be bonded to other identical molecules to form a polymer.
12. Macrophage: A type of white blood cell that engulfs and digests cellular debris, foreign substances, and pathogens.
13. Morphology: The study of the forms and structures of organisms.
14. Mesophyll: The inner tissue of a leaf, containing many chloroplasts.
15. Microtubule: A cylindrical structure in the cytoplasm involved in cell shape, intracellular transport, and cell division.
16. Mendelian: Relating to the patterns of inheritance described by Gregor Mendel.
17. Metabolism: The set of chemical reactions that occur within a cell to maintain life.
18. Microscopy: The use of a microscope to view small-scale structures.
19. Mycology: The study of fungi.
20. Myelin: A fatty substance that surrounds and insulates the axons of some neurons.
21. Mucus: A slimy substance produced by mucous membranes and glands for lubrication and protection.
22. Microbiota: The microorganisms of a particular site, habitat, or geological period.
23. Mast cell: A cell filled with basophil granules, found in connective tissue and releasing histamine and other substances during inflammatory and allergic reactions.
24. Mesosome: A folded structure in the bacterial cell, thought to be a relic of the eukaryotic mitochondrion.
25. Microfilament: A small rod-like structure, about 4–7 nanometers in diameter, present in numbers in the cytoplasm of many eukaryotic cells.
26. Mammal: A warm-blooded vertebrate animal distinguished by the possession of hair or fur, females that secrete milk, and (typically) the birth of live young.
27. MicroRNA (miRNA): A small non-coding RNA molecule that functions in RNA silencing and post-transcriptional regulation of gene expression.
28. Metastasis: The spread of cancer cells from the place where they first formed to another part of the body.
29. Microbiota: The ensemble of microorganisms inhabiting a particular environment, especially the gut or other body sites.
30. Myocardium: The muscular tissue of the heart.
31. Mesoderm: The middle layer of an embryo in early development, between the endoderm and ectoderm.
32. Mycorrhiza: A symbiotic association between a fungus and the roots of a vascular plant.
33. Microvillus (Microvilli): Tiny projections on the surface of some epithelial cells to increase surface area for absorption.
34. Monosaccharide: The simplest form of carbohydrate (e.g., glucose, fructose).
35. Mollusk: A large phylum of invertebrate animals, including snails, slugs, mussels, and octopuses.
36. Mandible: The jaw or jawbone.
37. Melatonin: A hormone that regulates sleep-wake cycles.
38. Megafauna: Large or giant animals, especially from a specific time period or region.
39. Mesenchyme: A type of tissue characterized by loosely associated cells.
40. Microbiologist: A scientist who studies microorganisms.
41. Microenvironment: The immediate small-scale environment of an organism or a part of an organism.
42. Mutagen: An agent, such as radiation or a chemical substance, that causes genetic mutation.
43. Myosin: A protein associated with actin in muscle contraction and other cellular processes.
44. Microbiota transplant: The transfer of microbiota from one individual to another, often used as a treatment for certain diseases.
45. Meninges: The three membranes that envelop the brain and spinal cord.
46. Mucosa: A mucous membrane.
47. Myocyte: A muscle cell.
48. Mycelium: The vegetative part of a fungus, consisting of a network of fine white filaments.
49. Monocot: A type of flowering plant that has one embryonic seed leaf or cotyledon.
50. Metazoan: A multicellular animal, especially one with differentiated

Biology Words That Start With N

1. Nucleus: The central and most important part of a cell, containing DNA and RNA and responsible for growth and reproduction.
2. Neuron: A specialized cell transmitting nerve impulses; a nerve cell.
3. Nucleotide: The basic building block of nucleic acids, such as DNA and RNA.
4. Nucleolus: A small dense spherical structure in the nucleus of a cell during interphase.
5. Neurotransmitter: Chemicals that transmit signals across a synapse from one neuron to another.
6. Nephron: The functional unit of the kidney responsible for filtering and excretion.
7. Natural selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.
8. Neoplasm: A new and abnormal growth of tissue, as a tumor or wart.
9. Nitrogen cycle: The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms.
10. Nucleic acid: Complex organic substances (like DNA and RNA) that store and transmit genetic information.
11. Neocortex: The part of the cerebral cortex concerned with sight and hearing in mammals.
12. Neurology: The branch of medicine or biology that deals with the anatomy, functions, and organic disorders of nerves and the nervous system.
13. Nematode: A worm of the large phylum Nematoda, such as a roundworm or threadworm.
14. Neoteny: The retention of juvenile features in the adult animal.
15. Niche: The role and position a species has in its environment.
16. Nitrogen fixation: The chemical processes by which atmospheric nitrogen is assimilated into organic compounds.
17. Neuralgia: Intense, typically intermittent pain along the course of a nerve.
18. Neurogenesis: The growth and development of nervous tissue.
19. Neurohormone: A hormone produced by nerve cells and secreted into the bloodstream.
20. Neuromodulator: A substance other than a neurotransmitter that modifies or regulates nerve cell activities.
21. Neuroplasticity: The ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli.
22. Neurotoxin: A poison that acts on the nervous system.
23. Nociceptor: A sensory receptor for painful stimuli.
24. Nucleosome: A structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.
25. Nutrient: A substance that provides nourishment essential for growth and the maintenance of life.
26. Nanometer: A unit of length equal to one billionth of a meter, used in many areas of science including biology.
27. Nasal: Related to the nose.
28. Natal: Relating to birth.
29. Necrosis: The death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply.
30. Neuroanatomy: The anatomy of the nervous system.
31. Neuroblast: A developing nerve cell.
32. Neurocyte: Another term for a neuron or nerve cell.
33. Neurodegenerative: Relating to or marked by degeneration of nervous tissue.
34. Neuroendocrine: Relating to the interactions between the nervous system and the endocrine system.
35. Neuroglia: The connective tissue of the nervous system, consisting of several different types of cell associated with neurons.
36. Neuroligin: A protein that functions in synapse formation and function.
37. Neurolysis: The dissolution or destruction of nerve tissue.
38. Neuromuscular: Relating to or affecting both nerves and muscles.
39. Neuropathology: The study of disease of nervous system tissue.
40. Neuropeptide: A compound that acts as a neurotransmitter or a neuromodulator.
41. Neurophysiology: The branch of physiology and neuroscience dealing with the functions of the nervous system.
42. Neuropraxia: A temporary loss of motor and sensory function due to blockage of nerve conduction.
43. Neuroreceptor: A receptor molecule in the nervous system.
44. Neurosecretion: The storage, synthesis, and release of a substance from neurons.
45. Neurotransduction: The conversion of a stimulus into an electrical signal in the nervous system.
46. Neurotropic: Having an affinity for nerve cells or tissue.
47. Neurovascular: Relating to both neural and vascular elements, especially the blood vessels and blood flow of the brain.
48. Neutrophil: A type of white blood cell that is often the first to arrive at the site of an infection.
49. Nociceptive: Relating to or denoting pain arising from the stimulation of nerve cells.
50. Nucleoplasm: The substance of a cell nucleus, especially that not forming the nucleolus.

Biology Words That Start With O

1. Organelle: A specialized subunit within a cell that has a specific function.
2. Organism: An individual animal, plant, or single-celled life form.
3. Osmosis: The movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration.
4. Ovary: The organ in females that produces eggs.
5. Ovum: The egg cell produced by the ovary; the female reproductive cell.
6. Oxygen: A chemical element essential for life, involved in respiration and many metabolic processes.
7. Osteocyte: A bone cell.
8. Olfaction: The sense of smell.
9. Omnivore: An animal that eats both plants and animals.
10. Oncogene: A gene that can transform a cell into a tumor cell.
11. Oocyte: A cell in an ovary that may undergo meiotic division to form an ovum.
12. Operon: A unit made up of linked genes that is thought to regulate other genes responsible for protein synthesis.
13. Opsonin: A molecule that enhances phagocytosis by marking an antigen for an immune response.
14. Optic nerve: The nerve that connects the eye to the brain and carries visual information.
15. Ornithology: The scientific study of birds.
16. Ossification: The natural process of bone formation.
17. Otolith: A calcium particle in the inner ear, which is involved in sensory perception and balance.
18. Outcrossing: The practice of introducing unrelated genetic material into a breeding line.
19. Oviparous: Describing organisms that produce eggs that mature and hatch outside the body.
20. Oxidation: A chemical reaction in which a substance loses electrons or is combined with oxygen.
21. Oxidative phosphorylation: The metabolic pathway in which cells use enzymes to oxidize nutrients, releasing energy to produce ATP.
22. Oxytocin: A hormone released by the pituitary gland that causes increased contraction of the uterus and stimulates the ejection of milk.
23. Ozone: A molecule composed of three oxygen atoms, often associated with the Earth’s ozone layer.
24. Obligate: Restricted to a particular function or mode of life.
25. Oogenesis: The production or development of an ovum.
26. Operculum: A structure resembling a lid or a small door, especially an anatomical structure of this kind, such as the gill cover in some fish.
27. Optogenetics: A biological technique that involves the use of light to control cells within living tissue.
28. Oral: Relating to the mouth.
29. Organogenesis: The process of organ formation during development.
30. Ortholog: A gene in different species that evolved from a common ancestral gene by speciation.
31. Osmoregulation: The maintenance of constant osmotic pressure in the fluids of an organism.
32. Osteoblast: A cell that secretes the matrix for bone formation.
33. Osteoclast: A cell that absorbs bone tissue during growth and healing.
34. Osteogenesis: The formation of bone.
35. Oviposition: The action of laying eggs.
36. Oxalate: A salt or ester of oxalic acid.
37. Oxidoreductase: An enzyme that catalyzes the transfer of electrons from one molecule to another.
38. Oxygenate: To supply, treat, charge, or enrich with oxygen.
39. Oxyhemoglobin: Hemoglobin combined with oxygen, found in oxygenated blood.
40. Ozonolysis: The cleavage of an unsaturated organic compound with ozone.
41. Oblique: Neither parallel nor at a right angle to a specified or implied line; slanting.
42. Oblong: Having an elongated shape, as a rectangle or an oval.
43. Obligate aerobe: An organism that requires oxygen to grow.
44. Obligate anaerobe: An organism that cannot grow in the presence of oxygen.
45. Occipital: Relating to the occiput, the back area of the head.
46. Ocular: Relating to the eye or vision.
47. Odontoblast: A cell in the pulp of a tooth that produces dentin.
48. Oligodendrocyte: A type of neuroglia whose main function is to provide support to axons and produce the myelin sheath.
49. Oligonucleotide: A short nucleic acid polymer, typically with twenty or fewer bases.
50. Oligotrophic: Describing a body of water with low nutrient and organic material content, which can support only limited plant life.

Biology Words That Start With P

1. Photosynthesis: The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll pigments.
2. Protein: Large molecules composed of one or more chains of amino acids in a specific order; required for the structure, function, and regulation of the body’s cells, tissues, and organs.
3. Prokaryote: A microscopic single-celled organism that lacks a nucleus and other membrane-bound organelles; includes bacteria and archaea.
4. Plasma: The liquid component of blood in which cells are suspended.
5. Phylum: A taxonomic rank below kingdom and above class.
6. Pathogen: A bacterium, virus, or other microorganisms that can cause disease.
7. Parasite: An organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host’s expense.
8. Phagocytosis: The process by which a cell engulfs particles such as bacteria, other microorganisms, aged cells, or cellular debris.
9. Pheromone: A chemical substance produced and released into the environment by an animal, affecting the behavior or physiology of others of its species.
10. Plasmid: A small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.
11. Polymerase: An enzyme that synthesizes long chains or polymers of nucleic acids.
12. Polypeptide: A linear organic polymer consisting of a large number of amino-acid residues bonded together in a chain.
13. Permeability: The quality of a membrane that allows substances to pass through it.
14. Pigment: A molecule that absorbs certain wavelengths of visible light and gives color to tissues.
15. Pineal gland: A small endocrine gland in the brain that produces melatonin.
16. Prophase: The first stage of cell division, during which the chromosomes become visible and the nuclear envelope breaks down.
17. Pseudopod: A temporary protrusion of the surface of an amoeboid cell for movement and feeding.
18. Phenotype: The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
19. Polygenic: Traits controlled by two or more genes.
20. Proteome: The entire set of proteins expressed by a genome, cell, tissue, or organism.
21. Plankton: The small and microscopic organisms drifting or floating in the sea or freshwater.
22. Pleiotropy: The production by a single gene of two or more unrelated effects.
23. Probiotic: Microorganisms that are believed to provide health benefits when consumed.
24. Prion: A type of protein that can trigger normal proteins in the brain to fold abnormally, leading to diseases.
25. Phospholipid: A type of lipid molecule that is the main component of the cell membrane.
26. Phylogeny: The evolutionary history and relationship of an individual or group of species.
27. Pedigree: A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next.
28. Pituitary gland: The major endocrine gland responsible for regulating vital bodily functions and general well-being.
29. Plasmolysis: The process in which cells lose water in a hypertonic solution.
30. Polymer: A large molecule composed of many repeated subunits.
31. Polar body: A small haploid cell that is a byproduct of oogenesis and degrades.
32. Parthenogenesis: A form of asexual reproduction where an egg develops into an individual without fertilization.
33. Punctuated equilibrium: The hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.
34. Pyruvate: The end product of glycolysis, which is converted into acetyl coA that enters the Krebs cycle when there is oxygen available.
35. Peristalsis: The series of wave-like muscle contractions that move food through the digestive tract.
36. Phagocyte: A type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles.
37. Papilla: A small rounded protuberance on a part or organ of the body.
38. Pedicel: The stalk bearing a single flower of an inflorescence.
39. Pedicellate: Having a pedicel.
40. Pellucid: Translucently clear.
41. Pentose: A type of sugar with five carbon atoms.
42. Pericarp: The part of a fruit that surrounds the seed(s).
43. Petiole: The stalk that joins a leaf to a stem.
44. Phloem: The vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves.
45. Photoperiodism: The physiological reaction of organisms to the length of day or night.
46. Phototropism: The orientation of a plant or other organism in response to light.
47. Pilus (Pili): Hair-like appendage found on the surface of many bacteria that helps in attachment.
48. Pleura: Each of a pair of serous membranes lining the thorax and enveloping the lungs.
49. Polar covalent bond: A type of covalent bond where electrons are unequally shared between two atoms.
50. Polysaccharide: A carbohydrate whose molecules consist of many sugar molecules bonded together.

Biology Words That Start With Q

1. Quiescence: A state of inactivity or dormancy in cells.
2. Quantitative trait: A trait that can be measured numerically and is influenced by multiple genes.
3. Quantitative trait locus (QTL): A location on a chromosome associated with the degree of a quantitative trait.
4. Quaternary structure: The arrangement of multiple folded protein or coiling protein molecules in a multi-subunit complex.
5. Quorum sensing: A system of stimulus and response in bacteria that is correlated to population density.
6. Quinone: A type of aromatic compound that plays a role in electron or proton transfer in some biological processes.
7. Quadruplet: In genetics, a set of four identical offspring from one zygote.
8. Quiescent center: A region in the root meristem of plants where cell division occurs at a slower rate.
9. Quinol: A hydroquinone compound involved in certain oxidation-reduction reactions in biological systems.
10. Quercetin: A flavonoid found in many plants, known for its antioxidant properties.
11. Quantum biology: The study of quantum phenomena in biological systems.
12. Quadruplex DNA: DNA structures with four-stranded formations, often involving guanine-rich sequences.
13. Quinacrine: A synthetic compound used as an antimalarial and also in cytogenetics to stain chromosomes.
14. Quinate: A cyclitol, a cyclic polyol, and a cyclohexanecarboxylic acid that is involved in the biosynthesis of aromatic compounds in plants.
15. Quinolinate: An intermediate in the tryptophan-niacin pathway, which can act as a neurotoxin.
16. Quicksilver: Another name for the element mercury.
17. Quill: The hollow shaft of a feather.
18. Quinolone: A type of antibacterial drug.
19. Quintuplet: In genetics, a set of five identical offspring from one zygote.
20. Quokka: A small wallaby native to a small region of southwestern Australia.
21. Quadriceps: A large muscle group that includes the four prevailing muscles on the front of the thigh.
22. Quadrant: In anatomy, any of the four areas into which a plane, especially the abdominal plane, is divided by horizontal and vertical lines.
23. Quinhydrone: A crystalline compound used as a hydrogen-ion indicator.
24. Quercitrin: A glycoside formed from quercetin and rhamnose found in oak bark and other plants.
25. Quinovic acid: A triterpenoid compound found in certain plants.
26. Quinovose: A sugar derivative found in certain glycosides.
27. Quercus: The genus of trees and shrubs that includes the oaks.
28. Quiescent cell: A cell that is in a state of dormancy and not actively dividing.
29. Quantification: The act of measuring or expressing the quantity of a particular substance or entity.
30. Quadrifoliate: Having four leaves or leaflets.
31. Quartan: Relating to the recurrence of an event every fourth day, especially a malarial fever.
32. Quincke’s pulse: A clinical sign observed in aortic insufficiency where there’s an exaggerated elevation of the systolic blood pressure.
33. Quinizarin: A type of hydroxyanthraquinone used as a red dye.
34. Quinone methide: A type of organic compound derived from phenols.
35. Quintessence: In historical contexts, the fifth and highest essence after the four classical elements; sometimes equated to the life force.
36. Quercitin: A type of flavonoid antioxidant found in many plants and foods.
37. Quinol oxidase: An enzyme involved in the electron transport chain.
38. Quinoprotein: Proteins that have a quinone group.
39. Quinuclidine: A bicyclic amine that is used in the preparation of various pharmaceuticals.
40. Quisqualate: A type of agonist for certain glutamate receptors.
41. Quixotry: A reference to behavior that is noble but unrealistic or impractical.
42. Quorum quenching: The disruption or inhibition of quorum sensing in bacteria.
43. Quinolinate synthase: An enzyme involved in the biosynthesis of quinolinate.
44. Quinate dehydrogenase: An enzyme that catalyzes the conversion of quinate to dehydroquinate.
45. Quinolinate phosphoribosyltransferase: An enzyme involved in the biosynthesis of nicotinate nucleotide.
46. Quinate permease: A protein involved in the transport of quinate across cell membranes.
47. Quinolone resistance: The development of bacterial resistance to quinolone antibiotics.
48. Quinone reductase: An enzyme that catalyzes the reduction of quinones to hydroquinones.
49. Quinone oxidoreductase: An enzyme involved in the oxidation-reduction of quinones.
50. Quinolinate carboxylase: An enzyme involved in the conversion of quinolinate to nicotinate.

Biology Words That Start With R

1. Ribosome: A cellular structure that synthesizes proteins by translating mRNA.
2. RNA (Ribonucleic acid): A molecule similar to DNA that plays a role in protein synthesis and other cell activities.
3. Reproduction: The process by which organisms produce offspring.
4. Respiration: The process by which cells produce energy by converting oxygen and glucose into carbon dioxide and water.
5. Receptor: A protein on a cell’s surface or within a cell that binds with specific molecules, leading to a specific effect inside the cell.
6. Recessive: Refers to a gene or allele that is masked by the presence of another in a heterozygous pairing.
7. Recombinant DNA: DNA that has been artificially created by combining genes from two different sources.
8. Regeneration: The process by which organisms replace lost or damaged body parts.
9. Renal: Pertaining to the kidneys.
10. Replication: The process by which DNA makes a copy of itself during cell division.
11. Ribonucleotide: The monomer units that make up RNA.
12. Retrovirus: A type of RNA virus that inserts a copy of its genome into the DNA of a host cell that it invades, thus changing the genome of that cell.
13. Rhizome: A continuously growing horizontal underground stem that puts out lateral shoots and adventitious roots at intervals.
14. Riboflavin: Also known as vitamin B2, it’s important for body growth and red blood cell production.
15. Ruminant: A mammal that chews cud regurgitated from its rumen (e.g., cows and sheep).
16. Radial symmetry: Symmetry around a central axis, as in starfish.
17. Radiation: The emission of energy as electromagnetic waves.
18. Recombinant: An organism or DNA molecule formed by recombining genes from two different sources.
19. Redox: A type of chemical reaction that involves a transfer of electrons between two species.
20. Reflex: An involuntary and nearly instantaneous movement in response to a stimulus.
21. Regulation: The adaptation of form or behavior of an organism to changed conditions.
22. Relaxin: A hormone produced by the ovary and the placenta with important effects in the female reproductive system and during pregnancy.
23. Restriction enzyme: A protein produced by bacteria that cleaves DNA at specific sites.
24. Retina: The light-sensitive layer of tissue at the back of the inner eye.
25. Retrotransposon: A mobile element in the genome that can replicate itself and move from one location to another in the genome.
26. Rh factor: An antigen present on the surface of red blood cells in many humans.
27. Ribulose: A pentose sugar involved in photosynthesis in plants.
28. Rod cells: Photoreceptor cells in the retina of the eye that can function in less intense light than cone cells.
29. Root hair: A tiny hair-like extension from the root that absorbs water and minerals from the soil.
30. R-strategist: Species characterized by rapid growth, high fertility, short lifespan, and exponential population growth.
31. Rumen: The first stomach of a ruminant, which receives food or cud from the esophagus.
32. Rut: The mating season of certain mammals, such as deer.
33. RNA polymerase: An enzyme that produces RNA by following a strand of DNA.
34. RNA splicing: The process by which introns are removed from heterogeneous nuclear RNA (hnRNA) and the remaining exons connected to form mature messenger RNA.
35. Rickets: A disease of children caused by vitamin D deficiency.
36. Rigor mortis: The stiffening of the body after death.
37. RNA interference (RNAi): A biological process in which RNA molecules inhibit gene expression.
38. Rumen fermentation: The microbial fermentation processes that occur in the rumen of ruminant animals.
39. Rheumatoid factor: An antibody present in the blood of many patients with rheumatoid arthritis.
40. Ribozyme: An RNA molecule capable of acting as an enzyme.
41. Reticulum: A fine network or net-like structure.
42. Rheology: The study of the flow of matter.
43. Rheumatoid arthritis: A chronic autoimmune disorder that affects the joints.
44. Ribosomal RNA (rRNA): RNA that makes up the major part of ribosomes.
45. Retrograde: Moving backward or against the usual direction of flow.
46. Reversion: The return to a former or less developed state; a return to an earlier genetic characteristic.
47. Rhizoid: A root-like structure in nonvascular plants, such as mosses and liverworts.
48. Ribonuclease: An enzyme that catalyzes the degradation of RNA into smaller components.
49. Rickettsia: A genus of bacteria that are obligate intracellular parasites.
50. Rodent: A mammal of the order Rodentia, characterized by continuously growing incisors used for gnawing.

Biology Words That Start With S

1. Stomata: Tiny openings on the surface of leaves that allow for gas exchange.
2. Species: A group of living organisms that can interbreed to produce fertile offspring.
3. Symbiosis: A relationship between two different organisms where both benefit.
4. Stem: The main structural part of a plant that supports leaves and flowers.
5. Synapse: The junction between two nerve cells where impulses pass.
6. Sporulation: The process of spore formation.
7. Skeletal System: The framework of bones that supports and protects the body.
8. Substrate: The substance on which an enzyme acts.
9. Sensory Neurons: Neurons that transmit sensory information.
10. Saprophyte: An organism that feeds on dead organic matter.
11. Sclerenchyma: A type of plant tissue that provides support and is made of dead cells.
12. Sarcomere: The basic unit of muscle tissue.
13. Sexual Reproduction: Reproduction involving the fusion of gametes.
14. Somatic Cells: Any cell of the body except sperm and egg cells.
15. Stroma: The supportive tissue in organs, or the fluid-filled space in chloroplasts.
16. Sessile: Organisms that are fixed in one place and do not move.
17. Sporophyte: The diploid phase in plants that produces spores.
18. Sulcus: A groove or furrow, especially in the brain.
19. Suture: A stitch or row of stitches holding together the edges of a wound.
20. Sphincter: A ring of muscle that contracts to close an opening.
21. Steroid: A type of organic compound that includes hormones and certain vitamins.
22. Saponification: The process of making soap from fats and lye.
23. Sedimentation: The process of settling or being deposited as a sediment.
24. Serum: The clear, yellowish fluid that remains from blood plasma after clotting.
25. Sporozoite: A stage in the life cycle of certain parasites, especially the malaria parasite.
26. Sclera: The white outer layer of the eyeball.
27. Scurvy: A disease caused by a deficiency of vitamin C.
28. Scavenger: An organism that feeds on dead or decaying matter.
29. Sickle Cell Anemia: A genetic disorder that causes red blood cells to have a crescent shape.
30. Sensory Organs: Organs that receive stimuli, such as eyes, ears, and skin.
31. Stenosis: The narrowing of a passage in the body.
32. Subcutaneous: Beneath the skin.
33. Symbiont: An organism in a symbiotic relationship.
34. Synthetic Biology: A field of biology that involves designing and constructing new biological parts.
35. Sympathetic Nervous System: Part of the nervous system that prepares the body for action.
36. Synthetic Evolution: The use of artificial means to direct the evolution of organisms.
37. Systole: The phase of the heartbeat when the heart muscle contracts.
38. Saccule: A small sac-like structure in the inner ear.
39. Spermatogenesis: The production of sperm cells.
40. Sporangium: A structure in fungi and plants where spores are produced.
41. Stenotopic: Organisms that can tolerate only a narrow range of environmental conditions.
42. Subspecies: A taxonomic category below species.
43. Suture (in skull): The immovable joint between bones in the skull.
44. Syngamy: The fusion of two gametes in fertilization.
45. Synthetic Genomics: The field of science focused on writing genomes to create synthetic life.
46. Syrinx: The vocal organ of birds.
47. Systolic Pressure: The highest arterial blood pressure during contraction of the left ventricle of the heart.
48. Saprozoic: Organisms that obtain nutrients from the dissolved organic matter.
49. Scleroprotein: Insoluble proteins that form structural parts of the body, like keratin and collagen.
50. Stimulus: A thing or event that evokes a specific functional reaction in an organ or tissue.

Biology Words That Start With T

1. Tissue: A group of similar cells that work together to perform a specific function.
2. Taxonomy: The science of classifying and naming organisms.
3. Trachea: The windpipe; a tube leading from the throat to the lungs.
4. Transcription: The process of copying DNA into RNA.
5. Translation: The process by which proteins are synthesized from RNA.
6. Telophase: The final phase of cell division where the cell splits into two.
7. Trophic Level: The position an organism occupies in a food chain.
8. Tendon: A fibrous tissue that connects muscle to bone.
9. Thymus: An organ where T cells mature; part of the immune system.
10. Thermoregulation: The process by which animals maintain an internal temperature.
11. Transpiration: The loss of water from plants, mainly through the stomata.
12. Tropism: A growth response of a plant toward or away from a stimulus.
13. Tuberculosis: A bacterial disease that affects the lungs.
14. Turgor Pressure: The pressure of water pushing the plasma membrane against the cell wall of a plant cell.
15. Tetraploid: An organism or cell with four sets of chromosomes.
16. Trophic Cascade: A process in an ecosystem where the top predators affect the abundance of their prey and other lower trophic levels.
17. Tympanum: The eardrum.
18. Transgenic: An organism that has had genes from another organism inserted into its DNA.
19. Tonsils: Lymphoid tissue located at the back of the throat.
20. Tracheids: Water-conducting cells in plants.
21. Tropopause: The boundary in the Earth’s atmosphere between the troposphere and the stratosphere.
22. Thylakoid: A membrane-bound compartment inside chloroplasts and cyanobacteria; site of the light-dependent reactions of photosynthesis.
23. Telomere: The protective end of a chromosome.
24. Taxis: A movement of an organism in response to a stimulus.
25. Tectonic: Relating to the movement and deformation of the Earth’s crust.
26. Thallus: The body of a plant-like organism that is not divided into leaves, roots, or stems.
27. Therapsid: A group of extinct mammals and reptiles.
28. Thorax: The part of the body between the neck and the abdomen.
29. Thrombocyte: Another term for platelets, which are involved in clotting blood.
30. Thylacine: An extinct carnivorous marsupial also known as the Tasmanian tiger.
31. Tonicity: The ability of a solution to cause a cell to gain or lose water.
32. Translocation: The movement of substances within a plant.
33. Triglyceride: A type of fat found in the blood.
34. Tubulin: A protein that forms microtubules, which are part of the cell’s cytoskeleton.
35. Tumor: An abnormal growth of cells.
36. Tundra: A cold, treeless biome where the subsoil is permanently frozen.
37. Tyrosine: An amino acid used in the synthesis of proteins.
38. Trophic Interaction: The interaction between organisms at different trophic levels in a food chain.
39. Tubercle: A small, rounded projection or lump, especially on the skin or on the surface of an organ.
40. Turbellaria: A class of free-living flatworms.
41. Tympanic Membrane: Another term for the eardrum.
42. Typhoid: A bacterial disease spread through contaminated food and water.
43. Tryptophan: An essential amino acid that is a precursor to serotonin.
44. Tubule: A small tube or tubular structure.
45. Tunicate: A marine invertebrate animal, also known as a sea squirt.
46. Turbidity: The cloudiness or haziness in a fluid caused by individual particles.
47. Turgid: Swollen or distended, especially due to high fluid content.
48. Turnover: The rate at which a particular substance is replaced or used up.
49. Tyrosinase: An enzyme that catalyzes the production of melanin.
50. Tyrannosaurus: A large carnivorous dinosaur that lived during the late Cretaceous period.

Biology Words That Start With U

1. Umbilical Cord: The cord connecting a fetus to the placenta, providing oxygen and nutrient-rich blood.
2. Uterus: The female reproductive organ where a fertilized egg implants and grows.
3. Urea: A waste product formed in the liver and excreted by the kidneys.
4. Uric Acid: A waste product resulting from the metabolism of purines, excreted in urine.
5. Ulna: One of the two bones in the forearm (the other is the radius).
6. Uvea: The middle layer of the eye, consisting of the iris, ciliary body, and choroid.
7. Umbel: A flat-topped or rounded flower cluster.
8. Ungulate: A hoofed mammal, such as horses, cows, and deer.
9. Urology: The branch of medicine dealing with the urinary and male reproductive systems.
10. Uropod: A flattened posterior appendage in some crustaceans.
11. Urochordate: Marine invertebrates that are closely related to vertebrates; also known as tunicates or sea squirts.
12. Uptake: The absorption or intake of substances by cells or tissues.
13. Uracil: A nitrogenous base found in RNA but not in DNA.
14. Ureter: The duct that carries urine from the kidney to the bladder.
15. Urethra: The duct through which urine exits the body.
16. Uricotelic: Organisms that excrete nitrogenous waste primarily as uric acid.
17. Urogenital: Pertaining to the urinary and genital organs.
18. Umbra: The fully shaded inner region of a shadow cast by an opaque object.
19. Ultrastructure: The detailed structure of a biological specimen, such as a cell, tissue, or organ.
20. Ulcer: A sore that develops on the lining of the esophagus, stomach, or small intestine.
21. Ultracentrifugation: A process used to separate particles from a solution using high-speed centrifugation.
22. Umbonate: Having a raised area resembling the boss of a shield.
23. Unicellular: Consisting of a single cell.
24. Unilateral: Affecting one side of something.
25. Uptake Protein: Proteins involved in the uptake of substances into cells.
26. Uterine Tube: Also known as the fallopian tube, it connects the ovaries to the uterus.
27. Uveitis: Inflammation of the uvea in the eye.
28. Ubiquitin: A small protein that tags old or damaged proteins for destruction.
29. Umbelliferone: A natural product found in many plants and a precursor for the synthesis of other bioactive compounds.
30. Umbellularia: A genus of trees known for producing bay leaves.
31. Understory: The vegetation layer beneath the main canopy of a forest.
32. Undulate: To move in a wavy pattern or with a rising and falling motion.
33. Unipotent: Cells that have the capacity to differentiate into only one cell type.
34. Uptake Transporter: Proteins that facilitate the transport of substances across a cell membrane.
35. Urodele: A type of amphibian that includes newts and salamanders.
36. Uropathy: Any disease or abnormality of the urinary system.
37. Urostomy: A surgical procedure to create an opening in the urinary system to divert urine.
38. Ursidae: The bear family, which includes polar bears, grizzlies, and pandas.
39. Urticaria: A skin rash caused by an allergic reaction, also known as hives.
40. Utricle: A small sac in the inner ear that detects changes in head position.
41. Uxorial: Relating to a wife or the role of a wife.
42. Unguiculate: Having nails or claw-like structures.
43. Unguent: A soft greasy or viscous substance used as an ointment or for lubrication.
44. Uranalysis: The analysis of urine for diagnostic purposes.
45. Urease: An enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia.
46. Uremia: A high level of urea and other nitrogenous waste compounds in the blood.
47. Uridine: A nucleoside compound found in RNA.
48. Urochrome: The pigment responsible for the yellow color of urine.
49. Uropeltid: A family of non-venomous shield tail snakes found in peninsular India and Sri Lanka.
50. Uxorial Dominance: A situation in which the female has a dominant role in a pair bond.

Biology Words That Start With V

1. Vascular: Relating to the vessels or tubes that transport blood or sap in animals and plants.
2. Virus: A microscopic infectious agent that can replicate only inside the cells of living organisms.
3. Vesicle: A small fluid-filled sac or blister within the body.
4. Vertebrae: The individual bones that stack to form the vertebral column or spine.
5. Vitamins: Organic compounds that are essential for normal growth and nutrition.
6. Vaccination: The administration of a vaccine to stimulate an immune response against a specific disease.
7. Vasodilation: The widening of blood vessels.
8. Vasoconstriction: The narrowing of blood vessels.
9. Ventricles: The two lower chambers of the heart that pump blood out to the body.
10. Veins: Blood vessels that carry blood towards the heart.
11. Vestigial: Referring to an organ or part which is reduced in size and function compared to its ancestral form.
12. Viviparous: Giving birth to live offspring (as opposed to laying eggs).
13. Voracious: Having a very eager approach to a particular activity, often related to feeding.
14. Vulva: The external part of the female genitalia.
15. Vernalization: The induction of a plant’s flowering process by exposure to the prolonged cold of winter.
16. Vector: An organism that transmits a disease or parasite from one animal or plant to another.
17. Vitreous Humor: The clear gel that fills the space between the lens and the retina in the eyeball.
18. Vasectomy: A surgical procedure for male sterilization.
19. Viroid: A plant pathogen composed of a short stretch of circular RNA without a protein coat.
20. Vagus Nerve: The tenth cranial nerve that interfaces with parasympathetic control of the heart and digestive tract.
21. Valve: A body structure that temporarily closes a passage or orifice.
22. Vancomycin: An antibiotic used to treat bacterial infections.
23. Variation: Differences in physical and genetic characteristics between individuals.
24. Vascular Bundle: A strand of conducting vessels in the stem or leaves of a plant.
25. Vasopressin: A hormone that raises blood pressure and makes the kidneys conserve water.
26. Ventral: Pertaining to the front or belly side of an organism.
27. Vertebrate: An animal with a backbone or spinal column.
28. Virology: The study of viruses and viral diseases.
29. Visceral: Pertaining to the internal organs.
30. Vitaminosis: A condition resulting from an excessive intake of one or more vitamins.
31. Vivisection: The practice of performing operations on live animals for scientific research.
32. Volatile: Easily evaporated at normal temperatures; often used in the context of organic compounds.
33. Volvox: A genus of chlorophyte green algae in the family Volvocaceae.
34. Vomeronasal Organ: An auxiliary olfactory sense organ found in many animals.
35. Vortex: A mass of whirling fluid or air, especially a whirlpool or whirlwind.
36. Vulvar: Relating to the vulva.
37. Vulpine: Relating to or resembling a fox.
38. Vasculogenesis: The formation of blood vessels from endothelial cell precursors.
39. Vasodilator: A drug or chemical that relaxes the smooth muscle in blood vessels, increasing blood flow.
40. Vellus: Fine, soft hair that covers most of the human body.
41. Venom: A toxic substance produced by some animals, such as snakes and spiders, used to immobilize or kill prey.
42. Ventricular Fibrillation: A condition in which there is uncoordinated contraction of the heart muscle.
43. Vestibule: A chamber or channel that serves as an entrance to another chamber or channel.
44. Vexillology: The scientific study of the history, symbolism, and usage of flags.
45. Viability: The ability to survive or live successfully.
46. Vicariance: The geographical separation of a population due to barriers such as mountains or water.
47. Villus: A small, finger-like projection that extends into the lumen of the small intestine to aid in absorption.
48. Virulence: The degree of pathogenicity of a microorganism.
49. Viscosity: A measure of a fluid’s resistance to flow.
50. Vitamin K: A vitamin that plays a key role in helping the blood clot.

Biology Words That Start With W

1. White Blood Cells (WBCs): Cells of the immune system that help the body fight infections and diseases.
2. Wild Type: The typical form of an organism or gene that occurs naturally in the wild.
3. Whale: A large marine mammal that belongs to the cetacean group.
4. Wetland: An area of land where water covers the soil, either permanently or seasonally.
5. Wart: A small, rough growth on the skin caused by the human papillomavirus (HPV).
6. Wing: A limb adapted for flying, found in birds, bats, and insects.
7. Water Cycle: The continuous process by which water moves through the environment, including evaporation, condensation, and precipitation.
8. Wolbachia: A genus of bacteria that infects arthropods and can affect the reproductive abilities of their hosts.
9. Wound: An injury to the body, typically involving a break in the skin.
10. Weed: A plant considered undesirable or troublesome, especially in a cultivated setting.
11. Wood: The hard, fibrous substance composing the stem and branches of a tree or shrub.
12. Wasp: An insect known for its slender body and narrow waist, some species of which can deliver painful stings.
13. Water Potential: The potential energy of water in a system compared to pure water.
14. White Matter: The paler tissue of the brain and spinal cord, consisting mainly of nerve fibers with their myelin sheaths.
15. Wavelength: The distance between successive crests of a wave, especially in sound or electromagnetic waves.
16. Whorl: A spiral or twisted formation or pattern.
17. Wildlife: Animals that are not tamed or domesticated and live in their natural environment.
18. Waxy Cuticle: A protective, waxy layer covering the epidermis of plants.
19. Webbed: Having skin between the toes, as seen in ducks and some amphibians.
20. White Muscle Fiber: Muscle fiber that contracts quickly and is used for short bursts of activity.
21. Wobble Base Pairing: The flexibility in the third position of a codon to pair with more than one kind of base.
22. Worm: An elongated, soft-bodied invertebrate animal.
23. Wolffian Duct: An embryonic duct that gives rise to male reproductive structures.
24. Wrinkle: A small line or fold in the skin, especially as a result of aging.
25. Water Table: The level below which the ground is saturated with water.
26. Waterborne: Carried or transmitted by water.
27. Wheat: A cereal plant that is the most important kind grown in temperate countries.
28. Wildflower: A flower that grows in natural places without being planted by humans.
29. Wet Mount: A method of making a microscope slide by placing a drop of liquid on a slide.
30. White Dwarf: A small, dense star that has exhausted all its central nuclear fuel.
31. Willow: A type of tree or shrub that typically grows near water and has slender branches.
32. Wartime: A period during which a war is taking place.
33. Wing Span: The distance between the tips of the wings of a bird or other flying animal.
34. Water Stress: The negative effects experienced by a plant due to insufficient water.
35. Whisker: A long, stiff hair growing from the face or snout of many mammals.
36. Whey: The watery part of milk that remains after the formation of curds.
37. Wombat: A burrowing plant-eating Australian marsupial with a backward-facing pouch.
38. Wool: The fine, soft, curly hair that forms the fleece of sheep and some other animals.
39. Wound Healing: The process by which the body repairs any break or defect in the skin.
40. Wet Tropics: A tropical region that receives a significant amount of rainfall.
41. Whale Shark: The largest species of fish, known for its filter-feeding habits.
42. Waterfowl: Birds that live near water, such as ducks, geese, and swans.
43. Wingbeat: The motion or sound of wings flapping.
44. Wheat Germ: The part of wheat that germinates to grow into a new plant.
45. Witch Hazel: A shrub or small tree with fragrant yellow flowers, used for therapeutic purposes.
46. Winglet: A small wing or wing-shaped structure attached to the tip of a larger wing.
47. Wart Hog: A wild pig with large upward-curving tusks, native to Africa.
48. Water Flea: A small freshwater crustacean that swims in a jerky manner.
49. Wing Case: The protective cover over the wings of some insects.
50. Wisteria: A climbing shrub with hanging clusters of pale bluish-lilac flowers.

Biology Words That Start With X

1. Xylem: The vascular tissue in plants that conducts water and dissolved nutrients upward from the root.
2. Xenobiology: The study of extraterrestrial life forms or the biology of species from other planets.
3. Xenograft: A graft obtained from a member of one species and transplanted to a member of another species.
4. Xenogenesis: The supposed generation of offspring entirely different from either of the parents.
5. Xenophyte: A plant species that is not native and has been introduced from a different region.
6. Xenotransplantation: The transplantation of living cells, tissues, or organs from one species to another.
7. Xerophyte: A plant adapted for life in conditions with little water, such as cacti.
8. Xerosis: Abnormal dryness, especially of the skin, eyes, or mucous membranes.
9. Xanthophyll: A yellow or brown pigment found in plants and involved in photosynthesis.
10. Xenonucleic Acid (XNA): Synthetic alternatives to the natural nucleic acids DNA and RNA.
11. Xenopus: A genus of aquatic frogs native to sub-Saharan Africa, commonly used in research.
12. Xeroderma: A condition characterized by excessively dry skin.
13. Xeriscaping: Landscaping with drought-resistant plants to conserve water.
14. Xiphoid: The cartilage at the bottom of the sternum (breastbone).
15. Xenophobe: An organism that can only survive in the presence of oxygen.
16. Xenophile: An organism that can only survive in the absence of oxygen.
17. Xanthoma: A skin condition marked by the development of yellowish growths due to lipid deposits.
18. Xanthine: A crystalline compound found in blood and urine and is a precursor of uric acid.
19. Xerarch: Succession of ecological communities originating in a dry habitat.
20. Xerophilous: Able to withstand dry conditions; drought-resistant.
21. Xerocole: An animal adapted to live in desert conditions.
22. Xeroderma Pigmentosum: A rare inherited skin disorder characterized by sensitivity to sunlight which can cause skin cancer.
23. Xenophyophore: A type of giant amoeba that lives on the deep-sea floor.
24. Xanthopsia: A condition in which objects appear yellowish.
25. Xenodiagnosis: A diagnostic method where a disease or parasite is detected by exposing a suspected host to a vector and then examining the vector.
26. Xerography: A dry photocopying process.
27. Xiphisternum: The posterior segment of the sternum.
28. Xenophloea: A genus of trees in the family Sapotaceae.
29. Xenophyte: A plant species that is not native to a particular region.
30. Xeromorph: An organism or structure that appears to be adapted to dry conditions.
31. Xerophilic: Organisms, especially fungi, that grow best at low water activity.
32. Xeroradiography: A type of X-ray imaging where a photoelectrically charged plate is used.
33. Xylem Sap: The solution of water and dissolved minerals that is transported through the xylem.
34. Xylocarp: A hard, woody fruit.
35. Xylography: The art of engraving on wood.
36. Xyloid: Resembling wood; woody.
37. Xylophagous: Feeding on or boring into wood.
38. Xylophilous: Attracted to or living in wood.
39. Xylose: A sugar extracted from wood.
40. Xylophage: An organism that feeds on wood.
41. Xyloglucan: A hemicellulose that occurs in plant cell walls.
42. Xylophobia: An irrational fear of forests or wooden objects.
43. Xyloplast: A plastid in which starch is replaced by xylogen.
44. Xylopyranose: The pyranose form of xylose, a pentose sugar.
45. Xylograph: An engraving on wood, especially one used for printing.
46. Xylographer: One who practices xylography, the art of engraving on wood.
47. Xyloidin: A substance obtained from certain plants, resembling cellulose.
48. Xylophonic: Pertaining to the sound of wood being struck.
49. Xyloquinone: A type of chemical compound derived from xylose.
50. Xylose Isomerase: An enzyme that converts xylose to xylulose.

Biology Words That Start With Y

1. Yeast: Single-celled fungi used in fermenting and baking.
2. Yolk: The nutrient-rich portion of an egg, separate from the egg white.
3. Y-chromosome: One of the two sex chromosomes; found only in males.
4. Y-linked: Genes located on the Y chromosome.
5. Yellow Fever: A viral disease transmitted by mosquitoes, causing fever and jaundice.
6. Yield: The amount of product obtained in any biochemical reaction.
7. Yawn: An involuntary reflex where the mouth is opened wide, and the lungs take in a lot of air.
8. Yucca: A genus of plants with sword-like leaves and large clusters of white or purplish flowers.
9. Yersinia: A genus of bacteria, some species of which can cause disease in humans.
10. Yolk Sac: A membranous sac attached to an embryo, providing early nourishment in the form of yolk.
11. Y-autosome translocation: A condition where a portion of the Y chromosome is transferred to an autosome.
12. Yttrium: A chemical element used in certain medical treatments and procedures.
13. Yabby: A freshwater Australian crayfish.
14. Y-linked inheritance: The pattern of inheritance of genes located on the Y chromosome.
15. Yoga: A physical, mental, and spiritual practice that originated in ancient India; can have health benefits.
16. Yew: A type of tree or shrub, some species of which produce toxic compounds.
17. Yolk stalk: A tube-like structure that connects the yolk sac to the embryo’s gut.
18. Yeast artificial chromosome (YAC): A vector used to clone DNA fragments up to 1 million base pairs.
19. Yardlong bean: A tropical plant grown for its long pods, eaten as a vegetable.
20. Yellow bone marrow: Bone marrow that stores fat.
21. Yersiniosis: An infection caused by Yersinia bacteria.
22. Y-linked gene: A gene located on the Y chromosome.
23. Yolk plug: Cells of the yolk sac that temporarily close the blastopore during embryonic development.
24. Y-organ: An organ in crustaceans responsible for producing molting hormones.
25. Yttrium-90: A radioactive isotope used in cancer treatments.
26. Yeast extract: A food flavoring made from the same yeast used to make bread and beer.
27. Yeast infection: An infection caused by the overgrowth of Candida yeast, especially Candida albicans.
28. Yellow rust: A disease in wheat caused by a fungus.
29. Yolk granules: Nutrient-rich particles found in the yolk of an egg.
30. Yeast two-hybrid system: A molecular biology method used to discover protein-protein interactions.
31. Yeast mold: A type of fungus that has characteristics of both yeasts and molds.
32. Yawning contagion: The phenomenon where seeing or hearing someone yawn induces yawning in an observer.
33. Yeast cell wall: The protective outer layer of yeast cells.
34. Yolked: Having a yolk.
35. Yeast nucleic acid: RNA obtained from yeast cells.
36. Y-chromosomal Adam: The most recent common ancestor from whom all currently living men are descended patrilineally.
37. Yolk platelet: Granules of stored food found in the cytoplasm of some animal cells.
38. Yellow-green algae: Photosynthetic protists that belong to the class Xanthophyceae.
39. Yeast-like: Resembling yeast in appearance or function.
40. Yolk membrane: The membrane surrounding the yolk of an egg.
41. Yeast syndrome: A condition believed by some to result from an overgrowth of Candida albicans in the intestines.
42. Yeast cake: A type of yeast sold as a food product.
43. Yolk nucleus: The portion of the egg cell containing the nucleus during certain stages of oogenesis.
44. Yeast powder: Dried yeast used as a food supplement or flavoring.
45. Y-chromosomal bottleneck: A sharp reduction in the size of the Y chromosome due to environmental events.
46. Yeast propagation: The process of growing and multiplying yeast cells.
47. Yolk sac tumor: A rare, malignant tumor of the ovary or testis.
48. Yeast form: The unicellular form of fungi that may switch between multicellular (mycelial) and unicellular forms.
49. Yolk gland: A gland in some invertebrates that produces yolk.
50. Yeast metabolites: Compounds produced by yeast during metabolism.

Biology Words That Start With Z

1. Zygote: The cell formed by the union of two gametes, especially a fertilized ovum before cleavage.
2. Zoology: The scientific study of animals and animal behavior.
3. Zoonosis: A disease that can be transmitted from animals to humans.
4. Zooplankton: Tiny aquatic animals that drift in water bodies and are a primary food source for many marine animals.
5. Zoospore: A spore of certain algae, fungi, and protozoans, capable of movement.
6. Zebrafish: A small tropical freshwater fish often used in research due to its transparent embryos.
7. Zymogen: An inactive substance that is converted into an enzyme when activated by another enzyme.
8. Zooid: An individual animal in a colonial organism.
9. Zygospore: A spore formed by the fusion of two similar gametes, especially in fungi.
10. Zygomatic: Relating to the cheekbone (also called the zygomatic bone).
11. Zymase: A complex of enzymes in yeast that catalyze the fermentation of sugars.
12. Zoetrope: A device that produces the illusion of motion from a rapid succession of static pictures.
13. Zonation: The distribution of plants or animals into specific zones according to changes in environmental conditions.
14. Zooparasite: A parasitic animal.
15. Zoster: The medical term for shingles, a viral disease characterized by a painful skin rash.
16. Zooculture: The rearing and breeding of animals.
17. Zygomorphic: Bilaterally symmetrical in a way where the two halves can only be divided into equal parts with one plane of division.
18. Zygomycetes: A class of fungi characterized by the formation of a sturdy structure called a zygosporangium during sexual reproduction.
19. Zoopathy: An abnormality or pathology found in animals.
20. Zoophyte: An invertebrate that has some characteristics of plants, such as certain sea anemones or corals.
21. Zymurgy: The branch of chemistry related to fermentation processes in brewing.
22. Zygotene: A stage of meiotic prophase I during which synapsis of homologous chromosomes occurs.
23. Zoophyte: An organism that appears to be a hybrid of plant and animal, like certain sea anemones.
24. Zoosporangium: A spore capsule in which zoospores are produced.
25. Zygodactyl: Having two toes pointing forward and two backward, as in many birds.
26. Zymotic: Relating to or caused by fermentation; also refers to infectious diseases.
27. Zoonotic: Pertaining to zoonosis, diseases that can be transmitted from animals to humans.
28. Zygnema: A genus of green algae known for its star-shaped chloroplasts.
29. Zooidogamy: A type of sexual reproduction in which gametes are motile and similar in size.
30. Zylophage: An organism that feeds on wood.
31. Zoocytium: The cell body of certain algae from which zoospores are produced.
32. Zygomata: The pair of bones that form the arches of the cheek, also known as cheekbones.
33. Zoanthropy: A mental disorder in which one believes oneself to be an animal.
34. Zygomycota: A phylum of fungi that includes bread molds and mycorrhizal fungi.
35. Zoopery: The study or collection of animal specimens.
36. Zygotaxis: The arrangement of zygotes or young cells after cell division.
37. Zoophilous: Attracted to or associated with animals.
38. Zygnematales: An order of green algae, primarily freshwater, known for conjugation as a form of sexual reproduction.
39. Zoografting: The transplantation of tissues or organs from an animal to a human.
40. Zythem: An old term for a fermented beverage, especially beer.
41. Zoogloea: A type of bacterial colony that forms a gelatinous mat.
42. Zygnema: A genus of filamentous green algae.
43. Zoocentric: Focusing on animals in particular studies or perspectives.
44. Zygodactyly: The arrangement of digits in birds with two toes facing forward and two backward.
45. Zoogony: The production of offspring by an animal.
46. Zylophagous: Wood-eating or wood-boring.
47. Zoophagan: An animal that feeds on other animals.
48. Zythemetry: The science or act of fermentation.
49. Zoosystematics: The classification and naming of animals.
50. Zygomorphous: Having bilateral symmetry, especially in the context of flowers.