130k views
3 votes
How does an auxotroph differ from a prototroph?

User Kkh
by
8.6k points

1 Answer

4 votes

Final answer:

Auxotrophs are bacterial mutants that cannot synthesize a specific nutrient due to a mutation, while prototrophs are wild-type strains that can synthesize all necessary nutrients. Replica plating is a technique used to distinguish between the two types by growing the bacteria on different types of media.

Step-by-step explanation:

An auxotroph is a type of bacterial mutant that is unable to synthesize a specific nutrient, such as an amino acid, due to a mutation in a gene encoding an enzyme in the biosynthesis pathway of that nutrient. In contrast, a prototroph is a wild-type bacterial strain that is able to synthesize all the necessary nutrients for growth on a minimal medium.

For example, let's consider histidine auxotrophs. These mutants are unable to synthesize histidine and therefore cannot grow on a medium lacking histidine. However, they can grow on a nutritionally complete medium that contains histidine. On the other hand, prototrophs can grow on both types of media.

The difference between auxotrophs and prototrophs can be identified using a technique called replica plating. This involves plating bacterial cells on both a nutritionally complete plate and a plate lacking a specific nutrient. Auxotrophs will only grow on the complete plate, while prototrophs will grow on both plates.

User Jason Etheridge
by
8.1k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories