$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} \rightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + \text{Energy (ATP and heat)}$$

Question 1

Which organelle is primarily responsible for ATP production via oxidative phosphorylation in eukaryotic cells?

Accepted Answer

Mitochondrion

Question 2

During glycolysis, which enzyme catalyzes the phosphorylation of glucose, and what is the significance of this step?

Accepted Answer

Hexokinase; it traps glucose in the cell and makes it more reactive

Question 3

What is the net ATP yield from glycolysis per molecule of glucose?

Accepted Answer

$$2$$

Question 4

Which molecule acts as the terminal electron acceptor in the electron transport chain of cellular respiration?

Accepted Answer

O$$_2$$

Question 5

In the citric acid cycle, how many NADH molecules are produced per acetyl CoA?

Accepted Answer

$$3$$

Question 6

Which step in glycolysis is considered a key regulatory point, and which enzyme is involved?

Accepted Answer

Step 3; phosphofructokinase

Question 7

What is the overall chemical equation for cellular respiration starting from glucose?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\ \mathrm{O_2$} ightarrow 6\ \mathrm{CO_2$} + 6\ \mathrm{H_2O} + 	ext{Energy (ATP and heat)}$$

Question 8

If oxygen is not present, what is the fate of pyruvate produced from glycolysis in most cells?

Accepted Answer

It is converted to lactate or ethanol via fermentation

Question 9

How many ATP molecules are generated from one NADH during oxidative phosphorylation?

Accepted Answer

$$2.5$$

Question 10

Which molecule is formed when the acetyl group of acetyl CoA combines with oxaloacetate at the start of the citric acid cycle?

Accepted Answer

Citrate

Question 11

During the energy payoff phase of glycolysis, which molecule is directly responsible for the reduction of NAD+ to NADH?

Accepted Answer

Glyceraldehyde 3-phosphate

Question 12

Which enzyme in the citric acid cycle catalyzes the oxidation of succinate to fumarate, and what electron carrier is reduced in this process?

Accepted Answer

Succinate dehydrogenase; FAD is reduced to FADH$$_2$$

Question 13

How many protons must flow through ATP synthase to generate one molecule of ATP?

Accepted Answer

$$4$$

Question 14

Which of the following statements best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated by transferring a phosphate group from a high-energy substrate to ADP

Question 15

What is the main function of the electron transport chain in cellular respiration?

Accepted Answer

To create a proton gradient across the inner mitochondrial membrane

Question 16

Which molecule is a vitamin B5 derivative and plays a key role in transferring acetyl groups in cellular respiration?

Accepted Answer

Coenzyme A (CoA)

Question 17

In the citric acid cycle, which step involves the release of CO$$_2$$ and the reduction of NAD+ to NADH?

Accepted Answer

Oxidation of isocitrate to $$	ext{α}-$$ketoglutarate

Question 18

Which process is responsible for the majority of ATP production in cellular respiration?

Accepted Answer

Oxidative phosphorylation

Question 19

If a mutation prevents the formation of the mitochondrial cristae, what would be the most direct consequence for cellular respiration?

Accepted Answer

Decreased surface area for electron transport chains, leading to less ATP production

Question 20

Which of the following best explains why NADH produced in glycolysis cannot directly enter the mitochondrial matrix?

Accepted Answer

NADH is too large to pass through the inner mitochondrial membrane

LEC 13: Cellular Respiration: Glycolysis, Citric Acid Cycle, and Oxidative Phosphorylation

Study Guide - Practice Questions