Ch. 6 Mastering Biology

Question 1

Glycolysis, acetyl CoA, citric acid cycle, and electron transport chain are the sequence of steps as what happens during cellular respiration?

Answer 1

Energy is extracted from glucose.

Question 2

What is the correct general equation for cellular respiration?

Answer 2

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP.

Question 3

What process takes place in the cytosol of a eukaryotic cell?

Answer 3

Glycolysis.

Question 4

In what organelle do we find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

Answer 4

Mitochondrion.

Question 5

What does glycolysis do?

Answer 5

Splits glucose in half and produces 2 ATPs for each glucose.

Question 6

What does the citric acid cycle do?

Answer 6

Produces some ATP and carbon dioxide in the mitochondrion.

Question 7

What does the electron transport chain do?

Answer 7

Uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

Question 8

How do cells capture the energy released by cellular respiration?

Answer 8

They produce ATP.

Question 9

What are the by-products of cellular respiration?

Answer 9

Carbon dioxide and water.

Question 10

What happens as electrons move through the mitochondrial space?

Answer 10

The pH of the intermembrane space decreases.

Question 11

What does cellular respiration primarily do?

Answer 11

Makes ATP to power the cell’s activities.

Question 12

What is the transfer of electrons from one molecule to another?

Answer 12

An oxidation-reduction reaction, or redox reaction.

Question 13

In cellular respiration, what happens to glucose as it loses electrons (in hydrogen atoms)?

Answer 13

It becomes oxidized to carbon dioxide.

Question 14

In cellular respiration, what happens to oxygen as it gains electrons (in hydrogen atoms) that came from glucose?

Answer 14

It becomes reduced to water.

Question 15

In cellular respiration, organic molecules become oxidized as what happens?

Answer 15

NAD+ picks up electrons from H+ and becomes reduced to NADH.

Question 16

Where does NADH deliver electrons?

Answer 16

To an electron transport chain.

Question 17

What does an electron transport chain do?

Answer 17

Passes electrons through carrier molecules in a series of redox reactions to the final electron acceptor, oxygen.

Question 18

What does the cell use to make ATP?

Answer 18

The energy released from the redox reactions in the electron transport chain.

Question 19

What happens to a molecule that functions as the electron donor in a redox reaction?

Answer 19

It loses electrons and becomes oxidized.

Question 20

In cellular respiration, glucose ___ electrons, whereas oxygen ___ electrons.

Answer 20

Loses … gains.

Question 21

During cellular respiration, what happens to the energy in glucose?

Answer 21

It is carried by electrons.

Question 22

What happens to NADH during cellular respiration?

Answer 22

It delivers its electron load to the first electron carrier molecule.

Question 23

What is essentially a series of redox reactions that conclude cellular respiration?

Answer 23

The electron transport chain.

Question 24

What happens during the electron transport chain (redox reactions)?

Answer 24

NADH is oxidized, which reduces an electron accept in the electron transport chain.

Question 25

What is the final acceptor of cellular respiration?

Answer 25

Oxygen.

Question 26

Why can't oxidative phosphorylation occur without glycolysis and the citric acid cycle?

Answer 26

The two stages supply the electrons needed for the electron transport chain.

Question 27

What is oxidized and what is reduced in cellular respiration?

Answer 27

Glucose is oxidized and oxygen is reduced.

Question 28

How many NADH are produced by glycolysis?

Answer 28

2.

Question 29

In glycolysis, how are ATP molecules produced?

Answer 29

Substrate-level phosphorylation.

Question 30

What is not a product of glycolysis?

Answer 30

FADH2.

Question 31

What are the products of glycolysis?

Answer 31

Water, ATP, pyruvate, and NADH + H+.

Question 32

In glycolysis, what starts the process of glucose breakdown?

Answer 32

ATP.

Question 33

In glycolysis, there is a net gain of how many ATP?

Answer 33

2.

Question 34

How many NADH molecules are produced during glycolysis?

Answer 34

2.

Question 35

What is an end product of glycolysis?

Answer 35

NADH.

Question 36

Where do the reactions of the citric acid cycle occur in eukaryotic cells?

Answer 36

The mitochondrion.

Question 37

What is the main process that produces glucose and oxygen gas?

Answer 37

Photosynthesis.

Question 38

Which parts of cellular respiration require oxygen gas?

Answer 38

The citric acid cycle and the electron transport chain.

Question 39

What are the most important outputs of glycolysis?

Answer 39

Two pyruvic acid and two NADH molecules.

Question 40

Unlike the citric acid cycle and electron transport, where does glycolysis occur?

Answer 40

In the cytoplasm.

Question 41

Because glycolysis is the multi-step breakdown of glucose, what play an important role in this process?

Answer 41

Enzymes.

Question 42

What forms at the end of glycolysis?

Answer 42

Pyruvate.

Question 43

What is the process in which glucose is converted to pyruvate?

Answer 43

Glycolysis.

Question 44

What is the process where CO2 and H2O convert into organic compounds using energy from light?

Answer 44

Photosynthesis.

Question 45

In the absence of oxygen, cells need a way to regenerate which compound?

Answer 45

NAD+.

Question 46

Why is fat the most efficient molecule for long-term energy storage, even compared to carbohydrates?

Answer 46

Fats provide an abundant source of high-energy electrons with their numerous hydrogen atoms.

Question 47

When a cell uses fatty acids for aerobic respiration, what does it do?

Answer 47

It first hydrolyzes fats to glycerol and fatty acids.

Question 48

When a muscle cell is deprived of molecular oxgey, it will convert glucose to lactic acid to do what?

Answer 48

Recycle NADH through fermentation.

Question 49

Why can yeasts produce ATP by either fermentation or oxidative phosphorylation?

Answer 49

They are facultative anaerobes.

Question 50

What process produces the most ATP per molecule of glucose oxidized?

Answer 50

Aerobic respiration.

Question 51

During fermentation, ___ that was produced during glycolysis is converted back to ___.

Answer 51

NADH ... NAD+.

Question 52

Each turn of the citric acid cycle generates one ATP and four additional energy rich molecules. What are they?

Answer 52

3 NADH and 1 FADH2.

Question 53

What are the end products of the citric acid cycle?

Answer 53

ATP, FADH2, and CO2.

Question 54

What is not an end product of the citric acid cycle?

Answer 54

Pyruvate.

Question 55

At the end of the citric acid cycle, where is most of the energy remaining from the original glucose stored?

Answer 55

NADH.

Question 56

Where are most NADH molecules generated during cellular respiration?

Answer 56

The citric acid cycle.

Question 57

In preparing pyruvate to enter the citric acid cycle, what happens?

Answer 57

A compound called coenzyme A binds to a two-carbon fragment.

Question 58

In eukaryotes, what happens to most of the high-energy electrons released from glucose by cell respiration?

Answer 58

They reduce NAD+ to NADH, which then delivers them to the electron transport chain.

Question 59

Why is the citric acid cycle called a cycle?

Answer 59

Acetyl CoA binds to oxaloacetate and this compound is restored at the end of the cycle.

Question 60

What is the role of oxygen in cellular respiration?

Answer 60

It accepts high-energy electrons after they are stripped from glucose.

Question 61

The breakdown of glucose is complete by the end of what process?

Answer 61

The citric acid cycle.

Question 62

Most ATP molecules are produced during what process?

Answer 62

Electron transport.

Question 63

Electron transport produces how many ATP molecules per NADH molecule?

Answer 63

3.

Question 64

Electron transport produces how many ATP molecules per FADH2 molecule?

Answer 64

2.

Question 65

The energy released from electron transport is used to do what?

Answer 65

Transport protons into the intermembrane space of the mitochondria, where they become concentrated.

Question 66

What happens to protons after they become concentrated in the intermembrane space of the mitochondria?

Answer 66

They flow back out into the inner compartment (matrix) of the mitochondria.

Question 67

What happens as protons exit into the matrix of the mitochondria?

Answer 67

They turn ATP synthase turbines and produce ATP.

Question 68

For each glucose that enters glycolysis, how many NADH enter the electron transport chain?

Answer 68

10.

Question 69

In cellular respiration, most ATP molecules are produced by what process?

Answer 69

Oxidative phosphorylation.

Question 70

What is the final electron acceptor of cellular respiration?

Answer 70

Oxygen.

Question 71

During electron transport, energy from ___ is used to pump hydrogen ions into the ___.

Answer 71

NADH and FADH2 ... intermembrane space.

Question 72

What is the proximate (immediate) source of energy for oxidative phosphorylation?

Answer 72

Kinetic energy that is released as hydrogen ions diffuse down their concentration gradient.

Question 73

What is the energy production per glucose molecule through the citric acid cycle?

Answer 73

2 ATP, 6 NADH, 2 FADH2.

Question 74

In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to do what?

Answer 74

Pump protons (H+) across the mitochondrial membrane.

Question 75

The electron transport chain is a series of electron carrier molecules. Where can this be found in eukaryotes?

Answer 75

Mitochondria.

Question 76

What is the ultimate fate of the electrons that are stripped from glucose during cellular respiration?

Answer 76

They are used to form water.

Question 77

The majority of the energy the cell derives from glucose is found where?

Answer 77

In NADH and FADH2.

Question 78

What happens to the energy that is released by electrons as they move through the electron transport chain?

Answer 78

It pumps H+ through a membrane.

Question 79

In cellular respiration, what is the result of electrons moving through the electron transport chain (or its components)?

Answer 79

A proton gradient is formed.

Question 80

A single glucose molecule produces about 38 molecules of ATP through the process of cellular respiration. However, this only represents approximately 38% of the chemical energy present in this molecule. What happens to the rest of the energy from glucose?

Answer 80

It is converted to heat.

Question 81

What is the overall efficiency of respiration?

Answer 81

Approximately 40%.