Chapter 9 Cellular Respiration and Fermentation

Question 1

Cellular respiration

Answer 1

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

Question 2

Fermentation

Answer 2

A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid

Question 3

Aerobic respiration

Answer 3

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

Question 4

Redox- reaction

Answer 4

A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction

Question 5

Oxidation

Answer 5

The complete or partial loss of electrons from a substance involved in a redox reaction

Question 6

Reduction

Answer 6

The complete or partial addition of electrons to a substance involved in a redox reaction

Question 7

Reducing agent

Answer 7

The electron donor in a redox reaction

Question 8

Oxidizing agent

Answer 8

The electron acceptor in a redox reaction

Question 9

NAD+

Answer 9

The oxidized form of nicotinamide adenine dinucleotide, a coenzyme that can accept electrons, becoming NADH. NADH temporarily stores electrons during cellular respiration

Question 10

NADH

Answer 10

The reduced form of nicotinamide adenine dinucleotide that temporarily stores electrons during cellular respiration. NADH acts as an electron donor to the electron transport chain

Question 11

Electron Transport Chain

Answer 11

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP

Question 12

Glycolysis

Answer 12

A series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration

Question 13

Citric acid cycle (krebs cycle)

Answer 13

A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration

Question 14

Oxidative phosphorylation

Answer 14

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration

Question 15

Substrate level phosphorylation

Answer 15

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

Question 16

Acetyl CoA

Answer 16

the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme

Question 17

Cytochromes

Answer 17

An iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

Question 18

ATP synthase

Answer 18

A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes

Question 19

Chemiosmosis

Answer 19

An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occurs by chemiosmosis

Question 20

Proton- motive force

Answer 20

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

Question 21

Alcohol fermentation

Answer 21

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD + and releasing carbon dioxide

Question 22

Lactic acid fermentation

Answer 22

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide

Question 23

Obligate anaerobes

Answer 23

An organism that carries out only fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it

Question 24

Facultative anaerobes

Answer 24

An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present

Question 25

Beta oxidation

Answer 25

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