Chapter 6

Question 1

What is the primary difference between photosynthesis and cellular respiration?

Answer 1

Photosynthesis uses sunlight to produce organic molecules and releases oxygen, while cellular respiration consumes oxygen to break down organic molecules into carbon dioxide and water.

Question 2

Where does photosynthesis occur?

Answer 2

Photosynthesis occurs in chloroplasts.

Question 3

Where does cellular respiration occur?

Answer 3

Cellular respiration occurs in mitochondria.

Question 4

What is the formula for cellular respiration?

Answer 4

Glucose (C6H12O6) + 6O2 → 6CO2 + 6H2O + ATP + heat

Question 5

What percentage of energy from glucose is captured during cellular respiration?

Answer 5

About 34% of the available energy originally stored in glucose is captured, with the rest lost as heat.

Question 6

What is respiration often used to refer to?

Answer 6

Respiration is often used as a synonym for ‘breathing,’ referring to an exchange of gases.

Question 7

What gas does an organism obtain from its environment during respiration?

Answer 7

An organism obtains oxygen (O2) from its environment.

Question 8

What waste product is released during respiration?

Answer 8

Carbon dioxide (CO2) is released as a waste product.

Question 9

What is an oxidation-reduction reaction?

Answer 9

An oxidation-reduction reaction is the transfer of electrons from one molecule to another, also called redox reactions.

Question 10

What is oxidation?

Answer 10

Oxidation is the loss of electrons from a substance.

Question 11

What is reduction?

Answer 11

Reduction is the gain of electrons from a substance.

Question 12

What role does NAD+ play in cellular respiration?

Answer 12

NAD+ is a coenzyme that accepts electrons oxidized from fuel and becomes reduced to NADH.

Question 13

What is NADH compared to in cellular respiration?

Answer 13

NADH is like a taxicab carrying electrons and H+ during cellular respiration.

Question 14

What does NADH do during cellular respiration?

Answer 14

NADH passes electrons to an electron transport chain.

Question 15

What happens as electrons fall from carrier to carrier in cellular respiration?

Answer 15

Energy is released.

Question 16

What is FAD?

Answer 16

FAD is a coenzyme involved in the Citric Acid Cycle and Electron Transport Chain.

FAD will accept electrons to become FADH₂.

Question 17

What are the two types of stages in cellular respiration?

Answer 17

Aerobic and anaerobic.

Question 18

What is aerobic respiration?

Answer 18

Aerobic respiration requires oxygen.

Question 19

What is anaerobic respiration?

Answer 19

Anaerobic respiration does not require oxygen.

Question 20

Where does glycolysis occur?

Answer 20

Glycolysis occurs in the cytosol.

Question 21

Is glycolysis aerobic or anaerobic?

Answer 21

Glycolysis is anaerobic.

Question 22

What does glycolysis break down glucose into?

Answer 22

Glycolysis breaks down glucose into two molecules of a three-carbon compound called pyruvate.

Question 23

How many ATP are netted from glycolysis?

Answer 23

Glycolysis nets 2 ATP.

Question 24

Where does pyruvate oxidation and the citric acid cycle occur?

Answer 24

It occurs in the mitochondria matrix.

Question 25

Is the citric acid cycle aerobic or anaerobic?

Answer 25

The citric acid cycle is aerobic.

Question 26

What does the citric acid cycle complete?

Answer 26

It completes the breakdown of glucose to carbon dioxide to supply the third stage of respiration with electrons.

Question 27

How many ATP does the citric acid cycle yield?

Answer 27

The citric acid cycle yields 2 ATP.

Question 28

What occurs during oxidative phosphorylation?

Answer 28

It involves electron transport and chemiosmosis.

Question 29

Where does oxidative phosphorylation occur?

Answer 29

It occurs on mitochondrial cristae.

Question 30

How many ATP does oxidative phosphorylation yield?

Answer 30

Oxidative phosphorylation yields 28 ATP.

Question 31

What happens to the electrons at the end of oxidative phosphorylation?

Answer 31

The electrons are finally passed to oxygen, which becomes reduced to H₂O.

Question 32

What is the first step of glycolysis?

Answer 32

2 ATP are used to prime a glucose molecule by adding phosphate to each end.

Question 33

What happens to the six-carbon intermediate in glycolysis?

Answer 33

It splits into two three-carbon intermediates, G3P.

Question 34

What is produced when G3P is oxidized?

Answer 34

Two molecules of pyruvate are produced, yielding net 2 ATP and 2 NADH.

Question 35

How is ATP formed during glycolysis?

Answer 35

ATP is formed by substrate-level phosphorylation.

Question 36

What happens to pyruvate before entering the citric acid cycle?

Answer 36

Pyruvate is transported from cytosol into mitochondrion and is oxidized.

Question 37

What occurs during the oxidation of pyruvate?

Answer 37

Pyruvate undergoes decarboxylation (loses CO₂), produces NADH, and joins with coenzyme A to form acetyl CoA.

Question 38

What does the 2 carbon fragment do in the citric acid cycle?

Answer 38

It enters the Citric Acid Cycle and joins to a four-carbon molecule already present in mitochondrion, making 6 carbon citrate.