Chapter 9

Question 1

Fermentation

Answer 1

-Catabolic process
Is a partial degradation of sugars or other organic fuel that occurs without the use of oxygen.

Question 2

The relocation of electrons releases energy stored in organic molecules, and this energy ultimately is used to synthesize ATP.

Answer 2

True

Question 3

Oxidation-reduction reactions (redox reactions)

Answer 3

Electron transfers during chemical reactions.

Question 4

Oxidation

Answer 4

The loss of electrons from one substance.

Question 5

Reduction

Answer 5

The addition of electrons to another substance.

Question 6

Reducing agent

Answer 6

The electron donor.

Question 7

Oxidizing agent

Answer 7

The electron acceptor.

Question 8

An electron loses potential energy when it shifts from a less electronegative atom toward a more electronegative one.

Answer 8

True

Question 9

Only the barrier of activation energy holds back the flood of electrons to a lower energy state.

Answer 9

True

Question 10

NAD+

Answer 10

Electron carrier, coenzyme
Nicotinamide adenine dinucleotide (a derivative of the vitamin niacin)

Question 11

Reduced state of NAD+

Answer 11

NADH

Question 12

Electron transfer from NADH to oxygen is an exergonic reaction.

Answer 12

True

Question 13

Terminal electron acceptor

Answer 13

Has the greatest affinity for electrons in the ETC.

Question 14

In summary, during cellular respiration, most electrons travel the following “downhill” route:

Answer 14

Glucose —> NADH —> ETC —> Oxygen

Question 15

Glycolysis occurs in…

Answer 15

The cytosol

Question 16

Oxidative phosphorylation

Answer 16

The production of ATP using energy derived from the redox reactions of an electron transport chain.
-Is constituted by electron transport and chemiosmosis

Question 17

In eukaryotic cells, ____________________ is the site of electron transport and chemiosmosis

Answer 17

the inner membrane of the mitochondrion

In prokaryotes, in the plasma membrane

Question 18

Substrate-level phosphorylation

Answer 18

The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.

Question 19

For each molecule of glucose degraded to carbon dioxide and water by respiration, the cell makes up to about ____ molecules of ATP, each with ___________ of free energy.

Answer 19

32, 7.3kcal/mol

Question 20

The two phases of glycolysis

Answer 20

The energy investment phase
The energy payoff phase

Question 21

FAD

Answer 21

Flavin adenine dinucleotide
-derived from riboflavin

Question 22

FAD accepts _________________ to become FADH2

Answer 22

2 electrons and 2 protons

Question 23

The total yield per glucose from the citric acid cycle turns out to be…

Answer 23

6 NADH, 2 FADH2, and the equivalent of 2 ATP

Question 24

Ubiquinone (Coenzyme Q)

Answer 24

The only member of the electron transport chain that is not a protein.
-Electron carrier

Question 25

The power source for ATP synthase is a difference in the concentration of H+ on opposite sides of the inner mitochondrial membrane.

Answer 25

True

Question 26

Chemiosmosis

Answer 26

The process in which energy stored in the form of hydrogen ion gradient across a membrane is used to drive cellular work such as the synthesis of ATP

Question 27

Proton-motive force

Answer 27

The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of H+ across a biological membrane during chemiosmosis.

Question 28

During respiration, most energy flows in this sequence:

Answer 28

Glucose —> NADH —> ETC —> Proton-motive force —> ATP

Question 29

Glycolysis produces per molecule of glucose :

Answer 29

2 NADH
2 Pyruvate
2 ATP by substrate-level phosphorylation

Question 30

Pyruvate oxidation produces per molecule of glucose :

Answer 30

2 Acetyl CoA
2 NADH

Question 31

Citric Acid Cycle produces per molecule of glucose:

Answer 31

6 NADH
2 FADH2
2 ATP by substrate-level phosphorylation

Question 32

Oxidative Phosphorylation produces per molecule of glucose:

Answer 32

26 or 28 ATP by oxidative phosphorylation

Question 33

Each NADH that transfers a pair of electrons from glucose to the ETC contributes enough to the proton-motive force to generate a maximum of about _________

Answer 33

3 ATP

Question 34

About 34% of the potential chemical energy in glucose is transferred to ATP.

Answer 34

True

Question 35

Difference between anaerobic respiration and fermentation.

Answer 35

An electron transport chain is used in anaerobic respiration but not in fermentation.

Question 36

Fermentation consists of glycolysis plus reactions that regenerate NAD+ by transferring electrons from NADH to pyruvate or derivatives of pyruvate.

Answer 36

True

Question 37

In alcohol fermentation,

Answer 37

Pyruvate is converted to ethanol in two steps.
Pyruvate —> acetaldehyde —> ethanol
Loses CO2. Reduced

Question 38

During lactic acid fermentation,

Answer 38

Pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2.

Question 39

Obligate anaerobes

Answer 39

Carry out only fermentation or anaerobic respiration.

Question 40

Facultative anaerobes

Answer 40

Can make ATP to survive using either fermentation or respiration.
(Our muscle cells)

Question 41

Protein’s possible pathways in ATP harvesting

Answer 41

Pyruvate
Acetyl CoA
Citric Acid Cycle

Question 42

Fats possible pathways in harvesting ATP

Answer 42

Glycerol —> Glyceraldehyde-3-Phosphate
Fatty acids —> Acetyl CoA

Question 43

Beta oxidation

Answer 43

A metabolic sequence that breaks fatty acids down to two-carbon fragments, which enter the citric acid cycle as acetal CoA.
- NADH and FADH2 are also generated.

Question 44

A gram of fat oxidized by respiration produces more than twice as much ATP as a gram of carbohydrate.

Answer 44

True

Question 45

Phosphofructokinase can be considered the pacemaker of respiration.

Answer 45

True