AP BIO TEST

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?

-20 kcal/mol

You collect data on the effect of pH on the function of the enzyme catalase in human cells. Which of the following graphs would you expect?

Graph that looks like mountain

Go back to your graph and put in data that would predict the results if the concentration of enzyme was doubled with the assumption that the substrate concentration is the same amount.

If substrate is kept constant while doubling enzyme concentration then the substrate would be consumed a lot faster but it would level off at the same concentrate of product made

In the figure, why does the reaction rate plateau at higher reactant concentrations? (The graph shows the rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant.)

Most enzyme molecules are occupied by substrate at high reactant concentrations.

Explain why a change in reaction was observed after 30 minutes

The substrate is limited, then reaction rate is leveled off because all the substrate was used up.

Identify two environmental factors that can change the rate of an enzyme-mediated reaction. Discuss how each of these two factors would affect the reaction rate of an enzyme.

Two factors that affect the rate f reaction of an enzyme are temp. And pH Raising temperature generally speeds up the reaction, and lowering tempeturre slows down the reaction.

Noncompetitive inhibitor

a molecule that binds to the enzyme at a site other than the active site, causing dthe enzyme to change shape and be unable to bind substrate

Competitive inhibition

a molecule that is so similar to the normal substrate that it can also bind to the active site of the enzyme

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

activation energy

Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?

b

How might a change of one amino acid at a site, distant from the active site of an enzyme, alter an enzyme's substrate specificity?

by changing the shape of an enzyme

Enymes are organic catalysts. How do they increase the rate of chemical reactions?

by lowering the activation energy of the reaction

A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.

changing the shape of the enzyme's active site

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

competitive inhibition

Which curves on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?

curves 3 and 5

Which of the following in the figure would be the same in either an enzyme-catalyzed or a noncatalyzed reaction?

d

For the enzyme- catalyzed reaction shown in the figure, if the initial reactant concentration is 1.0 micromolar, which of these treatments will cause the greatest increase in the rate of the reaction? (The graph shows the rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant.)

doubling the enzyme concentration

The graph below most accurately depicts the energy changes that take place in which of the following types of reactions?

exergonic

The active site of an enzyme is the region that _____.

is involved in the catalytic reaction of the enzyme

When substance A was added to an enzyme reaction, product formation decreased. The additon of more substrate did not increase product formation. From this we can conclude that

noncompetitive inhibitor

According to the induced fit hypothesis of enzyme catalysis,

the binding of the substrate changes the shape of the enzyme's active site

In an experiment, changing the pH from 7 to 6 resulted in an increase in product formation. From this we could conclude that

the enzyme's optimal pH is 6

Feedback Inhibition

the process by which a metabolic pathway is shut off by the product it produces