Campbell Biology: Biology Ch 9 Flashcards


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Campbell Biology
Chapter 9
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1

What is the term for metabolic pathways that release stored energy by breaking down complex molecules? anabolic pathways catabolic pathways fermentation pathways thermodynamic pathways bioenergetic pathways

catabolic pathways

2

What is the term used for the metabolic pathway in which glucose (C6H12O6) is degraded to carbon dioxide (CO2) and water? cellular respiration glycolysis fermentation citric acid cycle oxidative phosphorylation

cellular respiration

3

Which of the following statements is (are) correct about an oxidation-reduction (or) redox reactions? The molecule that is reduced gains electrons. The molecule that is oxidized loses electrons. The molecule that is reduced loses electrons. The molecule that is oxidized gains electrons. Both A and B are correct.

Both A and B are correct.

4

Which statement is not correct with regard to redox (oxidation-reduction) reactions? A molecule is reduced if it loses electrons. A molecule is oxidized if it loses electrons. An electron donor is called a reducing agent. An electron acceptor is called an oxidizing agent. Oxidation and reduction always go together.

A molecule is reduced if it loses electrons.

5

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction gains electrons and gains energy. loses electrons and loses energy. gains electrons and loses energy. loses electrons and gains energy. neither gains nor loses electrons, but gains or loses energy.

loses electrons and loses energy.

6

When electrons move closer to a more electronegative atom, what happens? Energy is released. Energy is consumed. The more electronegative atom is reduced. The more electronegative atom is oxidized. A and C are correct.

A and C are correct.

7

Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy? The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide. Electrons are being moved from atoms that have a lower affinity for electrons (such as carbon) to atoms with a higher affinity for electrons (such as oxygen). The oxidation of organic compounds can be used to make ATP. The electrons have a higher potential energy when associated with water and CO2 than they do in organic compounds. The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.

Electrons are being moved from atoms that have a lower affinity for electrons (such as carbon) to atoms with a higher affinity for electrons (such as oxygen).

8

Which of the following statements about NAD+ is false? NAD+ is reduced to NADH during both glycolysis and the citric acid cycle. NAD+ has more chemical energy than NADH. NAD+ is reduced by the action of dehydrogenases. NAD+ can receive electrons for use in oxidative phosphorylation. In the absence of NAD+, glycolysis cannot functio

NAD+ has more chemical energy than NADH.

9

Where does glycolysis takes place? mitochondrial matrix mitochondrial outer membrane mitochondrial inner membrane mitochondrial intermembrane space cytosol (liquid portion of the cytoplasm)

cytosol (liquid portion of the cytoplasm)

10

The ATP made directly during glycolysis is generated by substrate-level phosphorylation. electron transport. photophosphorylation. chemiosmosis. oxidation of NADH to NAD+.

substrate-level phosphorylation.

11

The oxygen consumed during cellular respiration is involved directly in which process or event? glycolysis accepting electrons at the end of the electron transport chain resulting in the production of water the citric acid cycle the oxidation of pyruvate to acetyl CoA the phosphorylation of ADP to form ATP

accepting electrons at the end of the electron transport chain resulting in the production of water

12

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent? electron transport glycolysis the citric acid cycle oxidative phosphorylation chemiosmosis

glycolysis

13

Which of the following statements about glycolysis is false? Glycolysis has steps involving oxidation-reduction reactions. The enzymes of glycolysis are located in the cytosol of the cell. Glycolysis can operate in the complete absence of O2. The end products of glycolysis are CO2 and H2O Glycolysis makes ATP exclusively through substrate-level phosphorylation.

The end products of glycolysis are CO2 and H2O

14

During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is transferred to ADP, forming ATP. transferred directly to ATP. retained in the pyruvate. stored in the NADH produced. used to phosphorylate fructose to form fructose-6-phosphate.

retained in the pyruvate.

15

In addition to ATP, what are the end products of glycolysis? CO2 and H2O CO2 and pyruvate NADH and pyruvate CO2 and NADH H2O, FADH2, and citrate

NADH and pyruvate

16

Starting with one molecule of glucose, the "net" products of glycolysis are 2 NAD+, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. 2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. 2 FADH2, 2 pyruvate, 4 ATP, and 2 H2O. 6 CO2, 6 H2O, 2 ATP, and 2 pyruvate. 6 CO2, 6 H2O, 36 ATP, and 2 citrate.

2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O.

17

A molecule that is phosphorylated has an increased chemical reactivity; it is primed to participate in a chemical reaction. has a decreased chemical reactivity; it is less likely to provide energy for cellular work. has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate. has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate. has less energy than before its phosphorylation and therefore less energy for cellular work.

has an increased chemical reactivity; it is primed to participate in a chemical reaction.

18

Which kind of metabolic poison would most directly interfere with glycolysis? An agent that reacts with oxygen and depletes its concentration in the cell An agent that binds to pyruvate and inactivates it An agent that closely mimics the structure of glucose but is not metabolized An agent that reacts with NADH and oxidizes it to NAD+ An agent that blocks the passage of electrons along the electron transport chain

An agent that closely mimics the structure of glucose but is not metabolized

19

During cellular respiration, acetyl CoA accumulates in which location? cytosol mitochondrial outer membrane mitochondrial inner membrane mitochondrial intermembrane space mitochondrial matrix

mitochondrial matrix

20

How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate? 2 4 6 8 10

2

21

All of the following are functions of the citric acid (i. e., Krebs) cycle except production of ATP. production of NADH. production of FADH2. release of carbon dioxide. adding electrons and protons to oxygen, forming water.

adding electrons and protons to oxygen, forming water.

22

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? glycolysis and the oxidation of pyruvate to acetyl CoA oxidation of pyruvate to acetyl CoA in the citric acid (Krebs) cycle the citric acid cycle and oxidative phosphorylation oxidative phosphorylation and fermentation fermentation and glycolysis

oxidation of pyruvate to acetyl CoA in the citric acid (Krebs) cycle

23

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced? 4 5 6 10 12

12

24

Cellular respiration produces the most chemical energy in the form of ATP from which of the following? substrate-level phosphorylation oxidative phosphorylation converting oxygen to ATP transferring electrons from organic molecules to pyruvate generating carbon dioxide and oxygen in the electron transport chain

oxidative phosphorylation

25

During aerobic (oxygen present) respiration, electrons travel downhill in which sequence? food _ citric acid cycle _ ATP _ NAD+ food _ NADH _ electron transport chain _ oxygen glucose _ pyruvate _ ATP _ oxygen glucose _ ATP _ electron transport chain _ NADH food _ glycolysis _ citric acid cycle _ NADH _ ATP

food _ NADH _ electron transport chain _ oxygen

26

Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? pyruvate malate or fumarate acetyl CoA Ñ-ketoglutarate succinyl CoA

acetyl CoA

27

Where are the proteins of the electron transport chain located? cytosol mitochondrial outer membrane mitochondrial inner membrane mitochondrial intermembrane space mitochondrial matrix

mitochondrial inner membrane

28

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? NAD+ NADH ATP ADP + Pi FADH2

FADH2

29

The primary role of oxygen in cellular respiration is to yield energy in the form of ATP as it is passed down the respiratory chain. act as a terminal acceptor for electrons in electron transport combine with carbon, forming CO2. combine with lactate, forming pyruvate. catalyze the reactions of glycolysis.

act as a terminal acceptor for electrons in electron transport

30

During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis of the water come from? carbon dioxide (CO2) glucose (C6H12O6) molecular oxygen (O2) pyruvate (C3H3O3) lactate (C3H5O3)

molecular oxygen (O2)

31

Which metabolic process is most closely associated with intracellular membranes? substrate-level phosphorylation oxidative phosphorylation glycolysis the citric acid cycle alcohol fermentation

oxidative phosphorylation

32

Energy released by the electron transport chain is used to pump H+ ions into which location? cytosol mitochondrial outer membrane mitochondrial inner membrane mitochondrial intermembrane space mitochondrial matrix

mitochondrial intermembrane space

33

During aerobic cellular respiration, a proton gradient in mitochondria is generated by ________ and used primarily for ________. the electron transport chain; ATP synthesis the electron transport chain; substrate-level phosphorylation glycolysis; production of H2O fermentation; NAD+ reduction diffusion of protons; ATP synthesis

the electron transport chain; ATP synthesis

34

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is oxidation of glucose to CO2 and water. the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers. the final transfer of electrons to oxygen. the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane. the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.

the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane.

35

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the formation of ATP. reduction of NAD+. restoration of the Na+/K+ balance across the membrane. creation of a proton gradient. lowering of pH in the mitochondrial matrix.

creation of a proton gradient.

36

Where is ATP synthase located in the mitochondrion? cytosol electron transport chain outer membrane inner membrane mitochondrial matrix

inner membrane

37

Which process could be compared to how rushing steam turns a water wheel? the citric acid cycle ATP synthase activity formation of NADH in glycolysis oxidative phosphorylation the electron transport system

ATP synthase activity

38

How many molecules of carbon dioxide (CO2) would be released from the complete aerobic respiration of a molecule of sucrose (C12H22 O11), a disaccharide? 2 3 6 12 38

12

39

Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules (O2) are required? 1 2 6 12 38

6

40

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water? glycolysis fermentation oxidation of pyruvate to acetyl CoA citric acid cycle oxidative phosphorylation

oxidative phosphorylation

41

Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in cellular respiration? 2 4 15 38 76

76

42

Assume a mitochondrion contains 58 NADH and 19 FADH2. If each of the 77 dinucleotides were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis)? 36 77 173 212 1102

212

43

Which of the following occurs in the cytosol of the cell? glycolysis and fermentation fermentation and chemiosmosis oxidation of pyruvate to acetyl CoA citric acid cycle oxidative phosphorylation

glycolysis and fermentation

44

Which metabolic pathway is common to both cellular respiration and fermentation? the oxidation of pyruvate to acetyl CoA the citric acid cycle oxidative phosphorylation glycolysis chemiosmosis

glycolysis

45

The ATP made during fermentation is generated by which of the following? the electron transport chain substrate-level phosphorylation chemiosmosis oxidative phosphorylation aerobic respiration

substrate-level phosphorylation

46

Muscle cells in oxygen deprivation convert pyruvate to ________, and in this step gain ________. lactate; ATP alcohol; CO2 alcohol; ATP ATP; NADH2 lactate; NAD+

lactate; ATP

47

Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements concerning phosphofructokinase is not true? It is activated by AMP (derived from ADP). It is inhibited by ATP. It is activated by citrate, an intermediate of the citric acid cycle. It specifically catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. It is an allosteric enzyme.

NOT: It is inhibited by ATP. It is an allosteric enzyme.

48

Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount ATP in a cell would be expected to inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle. activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. activate the enzyme and increase the rates of glycolysis and the citric acid cycle. inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate.

inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

49

Pyruvate is formed on the inner mitochondrial membrane. in the mitochondrial matrix. on the outer mitochondrial membrane. in the nucleus. in the cytosol.

in the cytosol.

50

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the oxidation of glucose and other organic compounds. the flow of electrons down the electron transport chain. the affinity of oxygen for electrons. the H+ concentration gradient across the inner mitochondrial membrane. the transfer of phosphate to ADP.

the H+ concentration gradient across the inner mitochondrial membrane.

51

Which metabolic pathway is common to both fermentation and cellular respiration? the citric acid cycle the electron transport chain glycolysis synthesis of acetyl CoA from pyruvate reduction of pyruvate to lactate

glycolysis

52

The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is oxygen. water. NAD+. pyruvate. ADP.

oxygen.

53

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? The pH of the matrix increases. ATP synthase pumps protons by active transport. The electrons gain free energy. The cytochromes phosphorylate ADP to form ATP. NAD+ is oxidized.

The pH of the matrix increases.

54

Which of the following is a true distinction between fermentation and cellular respiration? Only respiration oxidizes glucose. NADH is oxidized by the electron transport chain in respiration only. Fermentation, but not respiration, is an example of a catabolic pathway. Substrate-level phosphorylation is unique to fermentation. NAD+ functions as an oxidizing agent only in respiration.

NADH is oxidized by the electron transport chain in respiration only.

55

Most CO2 from catabolism is released during glycolysis. the citric acid cycle. lactate fermentation. electron transport. oxidative phosphorylation.

the citric acid cycle.