Question 1

Which of the following best describes the role of enzymes in cellular energetics?

Accepted Answer

Enzymes lower the activation energy of biochemical reactions, increasing the rate of metabolic processes.

Question 2

A competitive inhibitor affects an enzyme-catalyzed reaction by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 3

Which equation correctly represents the overall process of cellular respiration?

Accepted Answer

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

Question 4

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

Accepted Answer

Electron Transport Chain and oxidative phosphorylation

Question 5

Which of the following statements about photosynthesis is correct?

Accepted Answer

The Calvin cycle uses ATP and NADPH to fix carbon dioxide into organic molecules.

Question 6

If a plant is exposed to a toxin that inhibits ATP synthase, what immediate effect would you expect on photosynthesis?

Accepted Answer

The synthesis of glucose in the Calvin cycle would decrease due to lack of ATP.

Question 7

Which of the following best explains why fermentation is important for cells under anaerobic conditions?

Accepted Answer

Fermentation allows glycolysis to continue by regenerating NAD$$^+.$$

Question 8

A mutation causes a plant to lack chlorophyll. Which process would be directly affected?

Accepted Answer

Light-dependent reactions of photosynthesis

Question 9

Which of the following is a correct description of chemiosmosis in cellular respiration?

Accepted Answer

Protons flow through ATP synthase, driving the phosphorylation of ADP to ATP.

Question 10

Which of the following is a real-world example of an enzyme being regulated by feedback inhibition?

Accepted Answer

ATP binding to phosphofructokinase to slow glycolysis when ATP levels are high.

Question 11

Which of the following best describes the relationship between photosynthesis and cellular respiration?

Accepted Answer

The products of photosynthesis serve as the reactants for cellular respiration.

Question 12

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which symptom is most likely?

Accepted Answer

Increased lactic acid production in muscle cells during exercise.

Question 13

Which of the following equations represents the net reaction of glycolysis?

Accepted Answer

$$C_6H_{12}O_6$ + 2NAD^+ + 2ADP + 2P_i \rightarrow 2C_3H_4O_3 + 2NADH + 2ATP + 2H_2O$$

Question 14

Which of the following would most likely increase the rate of an enzyme-catalyzed reaction?

Accepted Answer

Increasing substrate concentration up to a certain point.

Question 15

In a scenario where oxygen is not available, which pathway allows cells to continue producing ATP?

Accepted Answer

Fermentation

Question 16

Which of the following is a direct product of the light-dependent reactions of photosynthesis?

Accepted Answer

ATP

Question 17

A scientist adds a chemical that uncouples the electron transport chain from ATP synthesis in mitochondria. What is the most likely result?

Accepted Answer

Proton gradient is dissipated, and ATP synthesis decreases.

Question 18

Which of the following is an example of energy transformation in a living system?

Accepted Answer

Conversion of light energy to chemical energy during photosynthesis.

Question 19

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP hydrolysis releases energy that can be used to drive endergonic reactions.

Question 20

Which of the following is a correct statement about the role of NAD$$^+ in $$cellular respiration?

Accepted Answer

NAD$$^+ is $$reduced to NADH, carrying electrons to the electron transport chain.

Cellular Energetics: Metabolism, Photosynthesis, and Cellular Respiration

Study Guide - Practice Questions