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Agar Medium and Organism Storage Quiz

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Questions and Answers

Why is a medium prepared from natural components preferable for storing organisms on agar?

It selects for a wider range of organisms (correct)
It is easier to prepare
It prevents early microbial death
It is more cost-effective

What precaution should be taken if glucose is used in the medium for lactic bacteria?

Increase the concentration of glucose
Lower the storage temperature
Add more natural components to the medium
Buffer the medium with calcium carbonate (correct)

Why is storage on agar popular despite its shortcomings?

It is more cost-effective than other methods
It prevents microbial death more effectively
It allows for longer storage periods
It is the most widely used method (correct)

What is the temperature range for preservation in deep freezers mentioned in the text?

<p>-20°C to -80°C (B)</p> Signup and view all the answers

Why is it important to avoid a stock culture medium rich in carbohydrates such as glucose?

<p>To prevent early microbial death (B)</p> Signup and view all the answers

Flashcards

Why are natural media preferred for storing organisms on agar?

A medium made from natural components allows a wider range of organisms to grow, leading to more diverse microbial populations.

Why buffer a medium with calcium carbonate when using glucose for lactic bacteria?

Glucose can be broken down by lactic bacteria, producing acidic byproducts that can harm the bacteria. Calcium carbonate acts as a buffer, neutralizing the acid and preventing the medium from becoming too acidic.

Why is agar storage popular despite its limitations?

Agar-based storage is commonly used because of its widespread availability and ease of use, despite having some limitations.

What is the temperature range for deep freezer preservation?

Deep freezers are used for long-term storage of microorganisms at temperatures ranging from -20°C to -80°C. This temperature range effectively inhibits microbial growth and slows down metabolic processes.

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Why avoid high carbohydrate stock cultures?

A high amount of carbohydrates, like glucose, can be quickly consumed by the microorganisms, leading to a depletion of nutrients and potentially causing their death.