Why is the initial velocity (V 0 ) the best chance a reaction has at approaching its maximum velocity (V max )?

Alright. So this practice problem asks why is the initial reaction velocity v naught the best chance a reaction has at approaching its maximum velocity v max? And we've got these 5 potential answer options below. Now, looking at option c, it says that reaction rates increase over time, but we know from our previous lesson videos that reaction rates don't actually increase over time, instead, reaction rates naturally decrease over time. And so for that reason, we can cross off option c. Now, as a refresher, over here we have a plot where we have the reaction rate v on the y axis, and the time as the reaction progresses on the x axis. And so we already know from our previous lesson videos that as time progresses, the reaction rates will actually decrease over time in this fashion. And again, instead, what increases over time will be the product concentration. And so notice here, we have a plot of the product concentration on the y axis and time on the x axis, and so as the time proceeds to the right, notice that the product concentration steadily increases. And so, when the product concentration builds up over time, the reverse reaction from product backwards into the reactant actually becomes more and more significant. So, that reverse reaction will actually slow down the reaction and prevent the initial velocity from approaching the v max. And so, what we can do is measure the initial velocity, and, that will ultimately, reduce or minimize this reverse reaction. And, so b here is definitely one of the reasons that we're looking for. Now, a says that substrate concentration decreases over time, and we know that this is true that the substrate concentration does decrease over time because it's being converted into product, and substrate concentration is correlated with reaction rate. So we know from our previous lesson videos, the higher the substrate concentration, the higher the reaction rate. And as the substrate concentration decreases, we also expect the reaction rate to decrease. And so if the re, substrate is decreasing over time like it actually is, then the velocity will also be decreasing and that will prevent it from approaching the v max. And so both option a and option b are reasons for why the initial velocity has the best chance at approaching the v max. And so we can indicate that it's d here, which includes option a and option b, that are correct options. And so this concludes our practice problem, and I'll see you guys in our next video.

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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

6. Enzymes and Enzyme Kinetics

Initial Velocity

Biochemistry

6. Enzymes and Enzyme Kinetics

Initial Velocity

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Multiple Choice

Why is the initial velocity (V₀) the best chance a reaction has at approaching its maximum velocity (V_max)?

[Substrate] decreases over time.

Reverse reaction from Reactant ← Product becomes more significant over time.

Reaction rates increase over time.

a and b.

All the above.

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Verified step by step guidance

Understand that the initial velocity (V0) of an enzyme-catalyzed reaction is measured at the very beginning of the reaction, where the substrate concentration is at its highest.

Recognize that as the reaction proceeds, the substrate concentration ([Substrate]) decreases because it is being converted into product, which can lead to a decrease in the reaction rate.

Consider that over time, the reverse reaction (Product converting back to Reactant) can become more significant, especially as the product concentration increases, which can further reduce the net forward reaction rate.

Note that reaction rates do not inherently increase over time; instead, they typically decrease as substrate is depleted and product accumulates, making the initial velocity the best chance to observe the reaction approaching Vmax.

Conclude that the initial velocity (V0) is the best chance for the reaction to approach its maximum velocity (Vmax) because it is measured before substrate depletion and significant reverse reaction effects occur, supporting the correct answer of options a and b.