Fifteen bacterial colonies growing on a complete medium ...

Question

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

The serine biosynthetic pathway is a three-step pathway in which each step is catalyzed by the enzyme product of a different gene, identified as enzymes A, B, and C in the diagram below.

Mutant 1 grows only on In addition to growth on , mutant 2 also grows on and . Mutant 3 grows on and . Identify the step of the serine biosynthesis pathway at which each mutant is defective.

Diagram of the serine biosynthetic pathway with enzymes A, B, and C.

Accepted Answer

Hello everyone and welcome to today's video. So in bacteria, which enzyme is going to catalyze the first step in the production of serene. Remember that serene is an amino acid. Let's go over each of our answer choices so that we may solve the problem. Well, answer choice B we have forceful. Remember from previous videos that forceful fry is not going to be involved in the production of serene. It is rather going to be involved in the glyco li pathway and therefore it is not a correct answer choice and we're going to cancel it out. Then we have C which is going to be phospho serene phosphate and this is actually involved in the production of serene. However, it is not going to be the first. It is rather going to be the last step in that pathway. And therefore it is not the correct answer choice and we're going to cancel it out. Then we have R G S and R G NASE is going to be involved in the urea cycle. It is not going to be involved in the production of serene. So we're going to cancel it out. Finally, we have answer choice A which is going to be 344 glycate D hydrogenous and 344, glycate dehydrogenate is going to be the first of a three step route for the production of serene. So this is actually the first step in this pathway and therefore is the correct answer choice for this question. So we're going to highlight answer choice A three phospho glycate D hydrogenous as the correct answer to this question. I really hope this video helped you and I hope to see you in the next one.

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