Question

This graph shows the rates of reaction in a chemical reaction with and without the addition of an enzyme.

• Explain the shape of each line. What is happening to the reaction rate as the reactant concentration
is changed?
• Explain what the enzyme appears to be doing.
• Why does the curve of the reaction with enzyme flatten out?

(Graph below)

Answer 1

Graph

Answer 2

The reason why the reaction without the enzyme is clear; as you increase the number of particles that can react (concentration), the number of reactions occurring \(simultaneously\) increases.

To understand the reaction with the enzyme requires a bit more background information. You have to know that an enzyme has a limited capacity to perform a number of reactions in a second (termed the \(turnover~rate\)) due to high-energy activation states and the diffusion of substrate molecules in and out of the active site. When an enzyme is surrounded by an optimal amount of material the rate will be the highest, typically, very high numbers - limited only by diffusion. After this optimal point in concentration, the enzyme is simply not capable of moving around any faster and the rate of the reaction plateaus.

(see file) So (in a system where the number of enzyme molecules is constant) when the concentration of the substrate is low, the rate appears to be linear just like the reaction without the enzyme (although much higher). After a certain concentration, the enzyme exhibits a non-linear relationship with the substrate as encounters problems with diffusion at the active site; these problems persist until the reaction reaches a concentration that does not increase the rate further.

Answer 3

plz close this question wen u r done with it

Answer 4

Thank you so much @aaronq!

Answer 5

no problem !