Alkaline peptone water is a nutrient medium that is used to isolate and cultivate certain types of microorganisms, such as Vibrio species. It is made by adding peptone, a mixture of hydrolyzed proteins, to water, and adjusting the pH to a slightly alkaline level (typically between 7.5 and 8.5). The pH of the medium is maintained by the addition of a buffer, such as sodium hydroxide or sodium carbonate. Alkaline peptone water is often used in industrial and laboratory settings for the production of antibiotics, quality control testing, and other applications. It can be stored at low temperatures (around 0-10°C) for a limited period of time before use.
1. What is the pH of alkaline peptone water?
a) Neutral b) Acidic c) Alkaline (pH 7.5-8.5) d) Variable
2. What is the purpose of the buffer in buffer peptone water?
a) To support the growth of microorganisms b) To maintain a stable pH level c) To inhibit the growth of unwanted bacteria d) To provide a source of nutrients
3. What is the main ingredient in alkaline peptone water?
a) Water b) Peptone c) Salt d) Antibiotics
4. What is alkaline peptone water used for in industrial applications?
a) Isolation and cultivation of microorganisms b) Production of antibiotics c) Quality control testing d) All of the above
5. What is the optimal incubation time for alkaline peptone water when isolating Vibrio species?
a) 5-6 hours at 35-37°C b) 18-20 hours at 18-20°C c) 24 hours at room temperature d) 48 hours at 4°C
6. What is the purpose of adding sodium chloride to alkaline peptone water?
a) To adjust the pH level b) To provide a source of nutrients c) To preserve osmotic balance d) To inhibit the growth of unwanted bacteria
7. What is the recommended storage temperature for alkaline peptone water?
a) 0-10°C b) 10-30°C c) 15-25°C d) 25-40°C
8. How should used or unusable preparations of alkaline peptone water be disposed of?
a) Incinerated b) Autoclaved and incinerated c) Flushed down the drain d) Poured down the sink
9. What is the recommended concentration of peptone for a 0.1% peptone water solution?
a) 0.01 grams per 100 milliliters b) 0.1 grams per 100 milliliters c) 1 gram per 100 milliliters d) 10 grams per 100 milliliters
10. What is the purpose of adding a sample of rectal swabs, faecal suspensions, or liquid stool to alkaline peptone water when cholera is suspected?
a) To enrich the sample b) To inhibit the growth of unwanted bacteria c) To preserve osmotic balance d) To provide a source of nutrients
11. How long should the infected media in alkaline peptone water arrive at the lab if cholera is suspected?
a) Within 4-6 hours b) Within 8 hours c) Within 12 hours d) Within 24 hours
12. What is the recommended incubation time for alkaline peptone water when studying aphthous ulcerative colitis?
a) 5-6 hours at 35-37°C b) 18-20 hours at 18-20°C c) 24 hours at room temperature d) 48 hours at 4°C
13. What is the main disadvantage of using alkaline peptone water?
a) Poor growth of certain Vibrio species b) Inaccurate results c) Limited storage life d) High cost
14. What is the recommended storage condition for opened alkaline peptone water?
a) Dry, protected from extremes of temperature and
Answer Key
- c) Alkaline (pH 7.5-8.5)
- b) To maintain a stable pH level
- b) Peptone
- d) All of the above
- a) 5-6 hours at 35-37°C
- c) To preserve osmotic balance
- a) 0-10°C
- b) Autoclaved and incinerated
- b) 0.1 grams per 100 milliliters
- a) To enrich the sample
- a) Within 4-6 hours
- a) 5-6 hours at 35-37°C
- c) Limited storage life
- a) Dry, protected from extremes of temperature and light
