AP MCQ

Graphs Representing enzymes sensitive to changes in pH include which of the following?

E) I, II and III on

2 Enzymes with their highest activity at an alkaline (basic) pH are represented by which of the following graphs

2 only

3 The most likely explanation for the results shown in graph one is that

A) pH affects the shape of the active site of the enzymes

4 The diagram below shows energy changes in a specific chemical reaction with and without the addition of an enzyme to the reaction.

A Does the addition of an enzyme reduce the activation energy required for a reaction?

A researcher proposes a model of an enzyme catalyst which a reactant is converted to a product the model is based on the idea that the reactant goes through a transition state within the enzyme-substrate complex before the reactant is converted to the product.

The enzyme's active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.

6) Amylase is a protein that catalyzes the conversion of starch to simple sugars. Amylase activity in an aqueous solution can be measured by using iodine as a starch indicator. A solution containing iodine and starch will have a dark-blue color, whereas a solution containing iodine but no starch will have a light-brown color. The color change of an iodine solution from dark blue to light brown can be used to measure the rate at which starch is converted to simple sugars.
A student designs an experiment to investigate the effect of environmental pH on amylase function. The design of the experiment is presented in Table 1.
Which of the following statements best justifies the inclusion of test tube V as a control in the experiment?

It will show the color change that occurs in the absence of enzyme activity.

7) Which of the following statements best justifies the inclusion of test tubes 3 and 7 in the experiment?

They will show whether the isolated cellular contents have enzymatic activity.

A researcher designs an experiment on the environment temperature of the function of the enzyme. For each trial included in the experiment, the researcher wil add the enzyme and its substrate to an aqueous buffer solution and then measure the amount of product formed over 20 minutes

​​The initial concentration of the substrate

9) during which time interval is the reaction the lowest?

4-5 minutes

10)D Which of the following best describes why the discs rose to the surface faster in the more concentrated hydrogen peroxide concentration?

The higher substrate concentrations in the more concentrated solutions speeded the reaction

12) which of the following best describes why ice was used during this experiment?

To retard the breakdown of the catalase

if the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested the average time for the disks to float to the surface if the hydrogen peroxide solution will be?

More than 30 seconds

Which of the following statements best helps explain the reaction specificity of an enzyme?

The shape and charge of the substrates are compatible with the active site of the enzyme.

15)which of the following can be used to determine the rate of enzyme-catalyzed reactions

the rate of substrate used up

16)Which of the following would be the most appropriate control for this experiment?

A test tube containing a piece of exposed camera film submerged in water.

Trypsin and pepsin are enzymes that function in different areas of the digestive tract. One functions in the stomach, where the pH is between 1.5 and 3.5, while the other functions in the small intestines, where the pH is between 6 and 8. Based on Figure 1, which of the following best describes where each enzyme functions?

Pepsin works in the stomach because the optimal pH for pepsin is acidic.

Which of the following actions will provide the most appropriate negative control for the experiment?

repeating the experiment with denatured enzymes.

If the experiment is repeated at pH 11, the observed activity level of the enzyme will most likely be

lower than the level of pH 9.

Figure 1 shows the amount of product produced in an enzyme catalyze reaction over 5 minutes. Which of the following best explains how the rate of the reaction changes over time.

the rate decreases because the ratio of product to substrate increases.

which of the following statements best helps justify the inclusion of test tube 5

It will provide measurement of product formation in the presence of a denatured enzyme

the rate of reaction could also be determined by

Measuring the amount of substrate

Which of the following best predicts how the structure and function of pepsin will change as it enters the small intestine?

Pepsin will change in shape because of the basic environment of the small intestine; therefore, its enzymatic activity will decrease.

which of the following statements best explains the activity levels of trypsin shown in figure 1

At extremely low pH values, trypsin is denatured and cannot function efficiently

what is the most likely explanation up the slope of the line between 3 and 5 minutes

A large amount of substrate had been consumed

based on figure 1 which of the following statements best predicts the effect that a change from a moderately acidic environment PH near 6 to a basic environment will have on a peroxidase activity

Peroxidase activity will decrease

0ne of the researchers proposes using oxygen gas to measure reaction rates, which of the following statements best justifies the use if proposed modification as a way of creating appropriate control for the investigation?

It changes the three-dimensional structure of the active site so that ALAD is no longer compatible with its substrate.

A set of five additional test tubes were prepared and used as controls. Which of the following best describes the contents expected to be contained in one of the five control test tubes?

pH 4 buffer solution and hydrogen peroxide only

Which of the following best predicts the immediate result of adding more substrate to the reaction mixture at the point indicated by the arrow in Figure 1?

The amount of product will increase until the reaction reaches its equilibrium point or until the substrate is used up by the reaction.