Question 1

Which statement best describes the First Law of Thermodynamics?

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 2

Which of the following best distinguishes catabolism from anabolism?

Accepted Answer

Catabolism releases energy by breaking down molecules; anabolism consumes energy to build molecules.

Question 3

A reaction has a $$\Delta G of$$ $$-30 kJ/$$mol. What does this indicate about the reaction?

Accepted Answer

The reaction is exergonic and releases energy.

Question 4

Which of the following best defines entropy?

Accepted Answer

The measure of disorder or randomness in a system.

Question 5

Refer to the reaction energy diagram (Image 1). What does the distance labeled 'a' represent?

Accepted Answer

The activation energy of the reaction.

Question 6

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes are consumed during the reaction.

Question 7

Which of the following best describes competitive inhibition?

Accepted Answer

The inhibitor binds to the active site, blocking substrate binding.

Question 8

In a redox reaction, what happens during oxidation?

Accepted Answer

A molecule loses electrons.

Question 9

During glycolysis, what are the net products from one molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 10

What is the primary role of NADH and FADH2 in the Krebs (citric acid) cycle?

Accepted Answer

To carry electrons to the electron transport chain.

Question 11

What drives ATP synthase during oxidative phosphorylation?

Accepted Answer

The diffusion of protons (H$$^+) $$down their gradient across the inner mitochondrial membrane.

Question 12

Which molecule is the final electron acceptor in aerobic cellular respiration?

Accepted Answer

O2

Question 13

Which of the following is a product of alcoholic fermentation?

Accepted Answer

Ethanol

Question 14

Given the equation for photosynthesis: $$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$, which molecule is reduced?

Accepted Answer

$$CO_2$$

Question 15

Where do the light reactions and the Calvin cycle take place in a plant cell?

Accepted Answer

Light reactions in the thylakoid membrane; Calvin cycle in the stroma.

Question 16

Which pigment is primarily associated with Photosystem II?

Accepted Answer

Chlorophyll a (P680)

Question 17

What is the function of Rubisco in the Calvin cycle?

Accepted Answer

It fixes carbon dioxide to RuBP.

Question 18

Which of the following best describes allosteric regulation of an enzyme?

Accepted Answer

A molecule binds to a site other than the active site, changing the enzyme's shape and activity.

Question 19

Which process is common to both aerobic and anaerobic respiration?

Accepted Answer

Glycolysis

Question 20

A patient’s muscle cells are producing lactate during intense exercise. What does this indicate about the cellular conditions?

Accepted Answer

Oxygen is limited, and anaerobic respiration (fermentation) is occurring.

Unit 3 Biology Study Guide – Thermodynamics, Enzymes, Redox, Respiration, and Photosynthesis

Study Guide - Practice Questions