Question 1

Which of the following is the correct sequence of metabolic pathways for the complete aerobic breakdown of glucose in eukaryotic cells?

Accepted Answer

Glycolysis → Krebs Cycle → Electron Transport Chain

Question 2

During cellular respiration, which molecule is oxidized and which is reduced in the overall reaction: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O$?

Accepted Answer

Glucose is oxidized; oxygen is reduced

Question 3

What is the net gain of ATP molecules produced directly by glycolysis from one molecule of glucose?

Accepted Answer

$2$ ATP

Question 4

Which enzyme catalyzes the final step of glycolysis, resulting in the formation of ATP by substrate-level phosphorylation?

Accepted Answer

Pyruvate kinase

Question 5

In the Krebs cycle, how many cycles are completed per molecule of glucose?

Accepted Answer

Two

Question 6

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

Accepted Answer

Electron Transport Chain and Oxidative Phosphorylation

Question 7

What is the role of oxygen in the electron transport chain?

Accepted Answer

It serves as the terminal electron acceptor

Question 8

If oxygen is not available, which metabolic pathway do some cells use to generate ATP?

Accepted Answer

Fermentation

Question 9

Which of the following best describes a redox reaction?

Accepted Answer

A reaction where electrons are transferred between molecules

Question 10

What is the main disadvantage of fermentation compared to aerobic respiration?

Accepted Answer

It is restricted to using glucose as a fuel

Question 11

Which molecule is produced as a result of the reduction of oxygen in the electron transport chain?

Accepted Answer

Water ($H_2O$)

Question 12

What is the consequence of proton leak in mitochondria?

Accepted Answer

Heat generation

Question 13

Which of the following is a product of alcohol fermentation?

Accepted Answer

Ethanol

Question 14

How many ATP molecules are produced per NADH during oxidative phosphorylation, according to the provided study materials?

Accepted Answer

$2.3$ ATP

Question 15

Which of the following is a potential harmful byproduct of the electron transport chain?

Accepted Answer

Reactive oxygen species (ROS)

Question 16

What is the net ATP yield from one molecule of glucose after glycolysis and the Krebs cycle, before oxidative phosphorylation?

Accepted Answer

$4$ ATP

Question 17

Which process is responsible for the conversion of ADP to ATP using the energy from a proton gradient across the mitochondrial membrane?

Accepted Answer

Oxidative phosphorylation

Question 18

Which molecule is regenerated during fermentation to allow glycolysis to continue in the absence of oxygen?

Accepted Answer

NAD+

Question 19

Which of the following is true about substrate-level phosphorylation?

Accepted Answer

It directly transfers a phosphate group to ADP from a substrate

Question 20

Which of the following is a real-world consequence of increased reactive oxygen species (ROS) production in cells?

Accepted Answer

Oxidative damage leading to aging and cancer

Metabolism and Cellular Respiration: Study Notes for General Biology

Study Guide - Practice Questions

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