Storage granules are intracellular compartments found in various microorganisms, including bacteria, archaea, and fungi, that store various molecules, such as glycogen, polyhydroxyalkanoates, and polyphosphate. The function of storage granules is to provide a reserve of nutrients and energy for the cell to use during times of limited availability or high demand. Storage granules are not considered organelles because they are not membrane-bound structures. The synthesis and breakdown of storage molecules in storage granules are regulated by enzymes.

Facts about Storage Granules

1. Storage granules are intracellular compartments found in various microorganisms.
2. They are not considered organelles because they are not membrane-bound structures.
3. Storage granules store various molecules, such as glycogen, polyhydroxyalkanoates, and polyphosphate.
4. The function of storage granules is to provide a reserve of nutrients and energy for the cell to use during times of limited availability or high demand.
5. Storage granules can vary in size and shape depending on the type of molecule stored.
6. The synthesis and breakdown of storage molecules in storage granules are regulated by enzymes.
7. Storage granules are found in bacteria, archaea, and fungi, but can also be found in other microorganisms, such as algae.
8. Polyphosphate granules, also known as volutin granules, are often used as a diagnostic feature to identify certain bacteria.
9. Some bacteria, such as Mycobacterium tuberculosis, have multiple types of storage granules.
10. Storage granules can be observed using various microscopy techniques, such as transmission electron microscopy.
11. The size and number of storage granules in a cell can vary depending on the metabolic state of the cell.
12. The contents of storage granules can be mobilized by various signals, such as changes in nutrient availability or intracellular signaling pathways.
13. The breakdown of glycogen in storage granules involves a series of enzymatic reactions, including phosphorylation and dephosphorylation.
14. Polyhydroxyalkanoates stored in storage granules can be used as a source of biodegradable plastics.
15. Some storage granules, such as those containing polyphosphate, can also have a role in stress response and survival.
16. The storage of excess nutrients in storage granules can be a strategy for microorganisms to survive in harsh environments, such as nutrient-poor soils or extreme temperatures.
17. The synthesis of storage molecules in storage granules can be regulated by various transcription factors and signaling pathways.
18. Certain mutations or deletions in the genes involved in storage molecule synthesis or breakdown can result in abnormal storage granules or metabolic disorders.
19. Some microorganisms can form specialized structures, such as bacterial magnetosomes, which are storage granules that contain magnetic minerals and enable the microorganism to orient themselves in a magnetic field.
20. Storage granules have various biotechnological applications, such as the production of biofuels, bioplastics, and recombinant proteins, by engineering microorganisms to produce specific molecules of interest.