Alright, so this practice problem wants us to complete the sentence using one of these 4 potential answer options down below. And of course, this is regarding proinsulin, which we know from our last lesson video is the inactive Zymogen form of insulin. And so keeping that in mind, if we take a look at option b, it says that proinsulin is more active than insulin. But of course, we know that this cannot be true. And the reason that it cannot be true is again because proinsulin is the inactive Zymogen form, and so it's not going to be more active than insulin itself. And so, we can eliminate answer option b for that reason. Now option a says that proinsulin is synthesized in 3 parts and then assembled for storage. But really this is not consistent with anything that we mentioned in our previous lesson videos, and so for that reason we could have eliminated answer option a. So now we're between either option c or option d, And notice that option d says that proinsulin stimulates insulin secretion, which is again not something that we mentioned in our previous lesson video. So we know that option d here is not gonna be correct. And of course, this only leaves answer option c, which says that proinsulin is synthesized as a single polypeptide chain, then folded and cleaved into insulin. And of course, we know that's exactly what we discussed in our previous lesson video, That Proinsulin is the inactive Zymogen form and for it to be active and, converted into insulin, it first needs to, be cleaved. And so option c here is consistent with what we discussed in our previous lesson videos and it is the correct answer here. And that concludes this practice so I'll see you guys in our next video.

Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

12. Biosignaling

Insulin

Biochemistry

12. Biosignaling

Insulin

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Multiple Choice

Proinsulin:

Is synthesized in three parts and then assembled for storage.

Is more active than insulin.

Is synthesized as a single chain, folded and then cleaved into insulin.

Stimulates insulin secretion.

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Verified step by step guidance

Understand the structure of proinsulin: Proinsulin is a precursor to insulin and is synthesized as a single polypeptide chain.

Learn about the folding process: After synthesis, proinsulin folds into a specific three-dimensional structure, which is crucial for its function.

Explore the cleavage process: Proinsulin is cleaved by specific enzymes to form active insulin, which consists of two chains (A and B) linked by disulfide bonds.

Clarify the role of proinsulin: Proinsulin itself is not more active than insulin; it is an inactive precursor that must be processed to become active insulin.

Understand the function of insulin: Insulin is a hormone that regulates glucose levels in the blood, and it does not stimulate its own secretion; rather, it is secreted in response to high blood glucose levels.