Chapter 9: Cellular Respiration and Fermentation

Question 1

Fermentation

Answer 1

Partial degradation of sugars or other organic fuel that occurs without the use of oxygen

Question 2

Aerobic respiration

Answer 2

Most efficient catabolic pathway. Oxygen is consumed as a reactant along with an organic fuel

Question 3

Redox reaction

Answer 3

Oxidation = loss of electrons from one substance (reducing agent)
Reduction = addition of electrons to another substance (oxidizing agent)

Question 4

Nicotinamide adenine dinucleotide

Answer 4

Derivative of the vitamin niacin
Coenzyme and electron carrier cycling between its oxidized form, NAD+, and its reduced form, NADH, during respiration

Question 5

Glycolysis

Answer 5

Sugar-splitting, oxygen-independent pathway that produces two molecules of pyruvate from one molecule of glucose.
Net gain of 2 pyruvate, 2 ATP, 2 NADH, and 2 H+

Question 6

Coenzyme A

Answer 6

CoA; sulfur-containing compound derived from a B vitamin

Question 7

Pyruvate oxidation

Answer 7

1) Pyruvate’s carboxyl group is given off as CO2
2) Remaining two-carbon fragment is oxidized to form NADH
3) Coenzyme A is attached to the two-carbon intermediate to form acetyl CoA

Question 8

Citric acid cycle

Answer 8

Krebs cycle or tricarboxylic acid cycle
For each molecule of pyruvate, the cycle produces 3 NADH, 1 FADH2, and the equivalent of 1 ATP in addition to expelling 2 CO2.
Mostly in mitochondrial matrix

Question 9

Prosthetic groups

Answer 9

Nonprotein components such as cofactors and coenzymes essential for the catalytic functions of certain enzymes

Question 10

Cytochrome

Answer 10

Protein with a heme group, which contains an iron atom that accepts/donates electrons

Question 11

ATP synthase

Answer 11

Enzyme that makes ATP from ADP and inorganic phosphate

Question 12

Chemiosmosis

Answer 12

Energy stored in an ion gradient is used to drive cellular work, such as ATP synthesis

Question 13

Proton-motive force

Answer 13

H+ gradient able to perform cellular work

Question 14

Oxidative phosphorylation

Answer 14

Coupling of electron transport to ATP synthesis via chemiosmosis
Most ATP generated

Question 15

Anaerobic respiration

Answer 15

Final electron acceptor of electron transport chain is not oxygen (unlike fermentation, which does not have an ETC)

Question 16

Alcohol fermentation

Answer 16

Pyruvate is converted into ethanol in two steps:
1) CO2 released from pyruvate, which turns into acetaldehyde
2) Acdetaldehyde is reduced to ethanol by NADH

Question 17

Lactic acid fermentation

Answer 17

Pyruvate is directly reduced by NADH to form lactate (ionized form of lactic acid)
No release of CO2

Question 18

Obligate anaerobes

Answer 18

Organisms that ONLY carry out fermentation or anaerobic respiration
Cannot survive in presence of oxygen

Question 19

Facultative anaerobes

Answer 19

Organisms that can live in either oxygen-present or absent settings

Question 20

Beta oxidation

Answer 20

Metabolic sequence that breaks down fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA

Question 21

Phosphofructokinase

Answer 21

Enzyme that catalyzes step 3 of glycolysis, which commits the substrate irreversibly to the glycolytic pathway –> Pacemaker of respiration