Question 1

Which of the following best describes the role of enzymes in metabolic reactions?

Accepted Answer

Enzymes decrease the activation energy barrier, allowing reactions to proceed faster.

Question 2

The induced fit model of enzyme activity states that:

Accepted Answer

The enzyme changes shape after the substrate binds, stressing substrate bonds.

Question 3

Which part of the ATP molecule is removed to release energy for cellular work?

Accepted Answer

The last negatively charged phosphate group

Question 4

What is the overall chemical equation for aerobic cellular respiration?

Accepted Answer

$\mathrm{C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O}$

Question 5

During which stage of cellular respiration is the majority of ATP produced?

Accepted Answer

Electron transport chain and ATP synthesis

Question 6

Which of the following statements about glycolysis is TRUE?

Accepted Answer

Glycolysis breaks down glucose into two pyruvic acid molecules and produces 2 ATP.

Question 7

NAD$^+$ acts as an electron carrier during cellular respiration. What happens to NAD$^+$ during glycolysis?

Accepted Answer

It is converted to NADH by accepting electrons and hydrogen ions.

Question 8

Which step of cellular respiration does NOT require oxygen?

Accepted Answer

Glycolysis

Question 9

If carbohydrates and fats are unavailable, how are proteins metabolized for energy?

Accepted Answer

Amino groups are removed and the remaining components enter the citric acid cycle.

Question 10

Which of the following best explains why a very fit athlete might have a BMI value in the overweight category?

Accepted Answer

BMI tables do not distinguish between lean muscle and body fat.

Question 11

Which BMI classification is associated with the highest mortality risk compared to normal weight?

Accepted Answer

Greater than 40 (severe obesity)

Question 12

Which health consequence is associated with anorexia?

Accepted Answer

Amenorrhea (cessation of menstruation)

Question 13

Why does extreme dieting often fail to prevent obesity in the long term?

Accepted Answer

It lowers metabolic rate and alters hunger-controlling hormones, making weight regain likely.

Question 14

During intense exercise, muscle cells switch to anaerobic respiration. What is the main product of fermentation in human muscle cells?

Accepted Answer

Lactic acid

Question 15

Which of the following is TRUE regarding the metabolism of fats during cellular respiration?

Accepted Answer

Glycerol and fatty acids enter the citric acid cycle directly.

Question 16

Which statement about the specificity of enzymes is correct?

Accepted Answer

Enzyme specificity is determined by the shape of the active site, which is encoded by genes.

Question 17

Which analogy best describes the function of ATP synthase in the electron transport chain?

Accepted Answer

A turbine that converts mechanical energy to electricity as water passes through

Question 18

Which of the following is a direct result of hydrogen ions (H$^+$) passing through ATP synthase?

Accepted Answer

ATP molecules are synthesized from ADP and phosphate.

Question 19

Which of the following is NOT a function of ATP in the cell?

Accepted Answer

Storing genetic information

Question 20

A patient is experiencing muscle fatigue and heavy breathing after intense exercise. Which process is responsible for the need to continue breathing heavily after exercise stops?

Accepted Answer

The liver needs oxygen to convert lactic acid back to pyruvic acid.

Enzymes, Metabolism, and Cellular Respiration: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards