Chapter 2: Cellular Respiration

Question 1

Photoautotrophs

Answer 1

Organisms that can build all the organic compounds required for life from simple inorganic materials, using light in the process.

Question 2

Heterotrophs

Answer 2

Organisms that feed on other organisms to obtain chemical energy.

Question 3

Chemoautotrophs

Answer 3

Organisms that can build all the organic compounds required for life from simple inorganic materials without using light energy.

Question 4

Aerobic Cellular Respiration

Answer 4

Harvesting energy from organic compounds using oxygen.

Question 5

Obligate Anaerobes

Answer 5

Organisms that cannot live in the presence of oxygen and obtain energy by oxidizing inorganic substances.

Question 6

Obligate Aerobes

Answer 6

Organisms that obtain energy by oxidizing organic substances using oxygen.

Question 7

Facultative Anaerobes

Answer 7

Organisms that obtain energy by oxidizing inorganic substances with or without oxygen.

Question 8

Substrate-level Phosphorylation

Answer 8

Mechanism forming ATP directly in an enzyme-catalyzed reaction.

Question 9

Oxidative Phosphorylation

Answer 9

Mechanism forming ATP indirectly through a series of enzyme-catalyzed redox reactions (oxidation and reduction) involving oxygen as the final electron acceptor.

Question 10

The final product from the electron transport chain that contains most of the electrons in which of the following?

Answer 10

Water

Question 11

In which of the following forms is energy immediately made available for use by living cells?

Answer 11

ATP

Question 12

The major advantage of aerobic respiration to humans is that we…

Answer 12

Obtain more usable energy by aerobic respiration.

Question 13

At the end of glycolysis, most of the energy originally found in glucose is located in the molecules of…

Answer 13

Pyruvate

Question 14

Differences between aerobic and anaerobic respiration.

Answer 14

Aerobic has a higher energy efficiency and anaerobic has a lower one. The products of Aerobic are water and carbon dioxide where the products of anaerobic are lactate or ethanol and carbon dioxide.

Question 15

Explain how fats can be used to release free energy to help with our metabolic needs.

Answer 15

• fats cannot be used directly to produce energy for a cell.
• First, fat must be hydrolyzed into glycerol and fatty acids. The glycerol can enter glycolysis after either being converted to glucose (via gluconeogenesis) or changed into dihydroxyacetone phosphate (DHAP).
• The fatty acids are broken down to two-carbon units (acetyl-CoA) in a process called β-oxidation, which can be fed directly into krebs cycle.

Question 16

Briefly explain how ATP is formed from NADH by the electron transport chain and chemiosmosis.

Answer 16

Electrons from NADH are passed to the enzyme NADH dehydrogenase, which is embedded in the inner mitochondrial membrane. The hydrogen that is released from the NADH is pumped to the intermembrane space, thus establishing a proton and pH gradient. The electrons move from electron carrier to electron carrier in the intermitochondrial membrane in a series of redox reactions and ultimatley combine with oxygen and protons at the cytochrome oxidase complex to form water, As electrons move along this pathway more protons, from the dissosiation of FADH2 are pumped from the matrix to the intermembrane space adding to the proton and pH gradient. The protons from the intermembrane space return to the matrix via special ATP synthase molecules embedded in the inner mitochondrial membrane. As they do, they help to catalyze the formation of ATP from ADP and P.

Question 17

Pyruvate (pyruvic acid) is an interesting molecule because there are so many possibilities for what can happen to it. Describe what the various fates of pyruvate are and under what circumstances these different pathways are used.

Answer 17

.

Question 18

Aerobic respiration involves which of the following?

Answer 18

The release of energy in cells with an adequate supply of oxygen.

Question 19

The following molecules can be found at various stages during cellular respiration:
I. acetyl-CoA
II. Carbon Dioxide
III. Glucose
IV. Glyceraldehyde
V. Pyruvate
Which of the following sequences represents the above molecules in order from the largest to the smallest amount of chemical energy?

Answer 19

Glucose, Glyceraldehyde, Pyruvate, acetyl-CoA, Carbon Dioxide

Question 20

In which of the following situations would you LEAST expect to find anaerobic respiration occuring?

a) a vat in which beer is being manufactured
b) a human brain engaged in writing this test
c) The inside of a bacterium living inside a human intestine
d) a runner’s leg muscle during a 400-m dash
e) the sediments at the bottom of a pond

Answer 20

A human brian enganged in writing this test.

Question 21

During cellular respiration, the oxygen we inhale ends up in the carbon dioxide we exhale.

Answer 21

False. During cellular respiration the oxygen we inhale ends up in the water we exhale or cecrete.

Question 22

Overall, glycolysis is an endergonic process.

Answer 22

False, it is an exergonic process.

Question 23

Electrons combine with oxygen and protons at the end of the electron transport chain.

Answer 23

True

Question 24

The following reaction takes place in animal cells but not in plant cells:
C6H12O6 + 6 O2 6 CO2 + 6 H2O

Answer 24

False

Question 25

Pyruvate is a three-carbon compound that is converted into acetyl-CoA in the mitochondrial matrix before entering the Krebs cycle.

Answer 25

True

Question 26

NADH is reduced by the first protein complex of the electron transport chain.

Answer 26

False. NADH is oxidized by the first protein complex of the electron transport chain.

Question 27

If a poison blocks the flow of protons through ATP synthase, the Krebs cycle will continue, but glycolysis will not.

Answer 27

False. If a poison blocks the flow of protons through ATP synthase, the Krebs cycle stops, but glycolysis will continue.

Question 28

Only the amino group of amino acids can be used for energy.

Answer 28

False. The amino group is first removed from the amino acid as waste and the rest of the amino acid is modified prior to entering glycolysis or the Krebs cycle.

Question 29

In oxidative phosphorylation, 2 NADH and 1 FADH2 theoretically produce 8 ATP.

Answer 29

True

Question 30

Fermentation oxidizes NADH to NAD+ so that glycolysis can continue.

Answer 30

True

Question 31

Maximum oxygen consumption, VO2 max, increases as people grow older.

Answer 31

False. Maximum oxygen consumption, VO2 max, decreases as people grow older.

Question 32

The complete oxidation of glucose to carbon dioxide and water has a G of 2870 kJ/mol glucose. Aerobic respiration captures about 930 kJ of this energy. What happens to the rest of the energy?

Answer 32

It is lost as heat and an increase in entropy.

Question 33

In glycolysis, glucose must first be activated. Which of the following does this require?

Answer 33

two molecules of ATP

Question 34

Why is anaerobic respiration less efficient than aerobic respiration? a. Fewer molecules of ATP are produced per glucose processed. b. Glucose is not completely oxidized to CO2 and H2O. c. The potential energy of NADH is not transferred to ATP. d. The electron transport system is not used.

Answer 34

All of the Above

Question 35

Which of the following is a product of lactate fermentation?

Answer 35

NAD+

Question 36

When the supply of acetyl-CoA exceeds the demand for energy, some of the acetyl-CoA can be diverted toward the synthesis of which one of the following?

Answer 36

fatty acids

Question 37

Cyanide poisoning occurs because cyanide binds cytochrome oxidase, preventing it from transferring electrons to the final electron acceptor of the mitochondrial electron transport chain. What is that acceptor molecule?

Answer 37

O2

Question 38

If the ATP level of a cell becomes too high, ATP can bind to phosphofructokinase and block the formation of fructose 1,6-bisphosphate. This is an example of which of the following?

Answer 38

feedback inhibition

Question 39

Which of the following is associated with increased levels of aerobic fitness?

Answer 39

a high VO2 max

Question 40

When oxygen is scarce in human muscle tissue, ethanol fermentation takes place to keep glycolysis running

Answer 40

False. The correct answer would be lactate fermentation.

Question 41

In the absence of oxygen, human muscle cells convert pyruvic acid to lactic acid to keep resupplying glycolysis with NAD+.

Answer 41

True

Question 42

Nicotinamide Adenine Dinucleotide (NAD+)

Answer 42

Coenzyme used to shuttle electrons to the first component of the electron transport chain in the mitochondrial inner membrane.

Question 43

Glycolysis

Answer 43

A process for harnessing energy in which a glucose molecule is broken into two pyruvate molcules in the cytoplasm of a cell.

Question 44

Mitochondria

Answer 44

Eukaryotic cell organelle in which aerobic cellular respiration occurs.

Question 45

Eukaryotic Cells

Answer 45

Cells possessing no intracellular membrane-bound organelles or nucleus.

Question 46

Cristae

Answer 46

The folds of the inner mitochondrial membrane

Question 47

Matrix

Answer 47

The fluid that fills the interior space of the mitochondrion.

Question 48

Intermembrane Space

Answer 48

The fluid filled space between the inner and outer mitochondrial membranes

Question 49

Krebs Cycle

Answer 49

A cyclic series of reactions that transfers energy from organic molecules to ATP, NADH, and FADH2 and removes carbon atoms as CO2.

Question 50

Electron Transport Chain

Answer 50

A series of membrane-associated protein complexes and cytochromes that transfer energy to an electro-chemical gradient by pumping H+ ions into an intermembrane space.

Question 51

Electrochemical Gradient

Answer 51

A concentration gradient created by pumping ions into a space surrounded by a membrane that is impermeable to the ions.

Question 52

Proton Motive Force (PMF)

Answer 52

A force that moves protons through an ATPase complex on account of the free energy stored in the form of an electrochemical gradient of protons across a biological membrane.

Question 53

Chemiosmosis

Answer 53

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

Question 54

Metabolic Rate

Answer 54

The amount of energy consumed by an organism at a given time.

Question 55

Basal Metabolic Rate (BMR)

Answer 55

The minimum amount of energy on which an organism can survive.

Question 56

Nomograms

Answer 56

Graphical methods for determining the value of an unknown quantity when the values of other quantities that is mathematically related to are known.

Question 57

Deamination

Answer 57

The first step in protein catabolism, involving the removal of the amino group of an amino acid as ammonia.

Question 58

β-oxidation

Answer 58

The sequential removal of acetyl groups in the catabolism of fatty acids.

Question 59

Fermentation

Answer 59

A process in which the hydrogen atoms of NADH are transferred to organic compounds other than an electron transport chain.

Question 60

Ethanol Fermentation

Answer 60

A form of fermentation occurring in yeast in which NADH passes its hydrogen atoms to acetaldehyde, generating carbon dioxide, ethanol and NAD+.

Question 61

Lactate (lactic acid) Fermentation

Answer 61

A form of fermentation occurring in animal cells in which NADH transfers its hydrogen atoms to pyruvate, regenerating NAD+ and lactate.

Question 62

Oxygen Debt

Answer 62

The extra oxygen required to catabolize lactate to CO2 and H2O

Question 63

Aerobic Fitness

Answer 63

A measure of the ability of the heart, lungs and bloodstream to supply oxygen to the cells of the body during physical exercise.

Question 64

Maximum Oxygen Consumption, VO2max

Answer 64

The maximum volume of oxygen, in mililitres, that the cells of the body can remove from the bloodstream in one minute per kilogram of body mass while the body experiences maximal exertion.

Question 65

Series of membrane-bound electron carriers in the ETC

Answer 65

Cytochromes

Question 66

Metabolism in the absence of oxygen

Answer 66

Anaerobic Respiration

Question 67

End Product of Glycolysis

Answer 67

Pyruvate

Question 68

Reactions involved in the synthesis of biological molecules.

Answer 68

Anabolism

Question 69

Cyclic series of reactions in which pyruvate is oxidized to CO2 and H2O

Answer 69

Citric Acid Cycle (Krebs Cycle)

Question 70

Reactions that involve the release of free energy

Answer 70

Exergonic

Question 71

Large enzymes that remove carbon dioxide from pyruvate

Answer 71

Decarboxylation

Question 72

The "priming" of glucose by the addition of a phosphate.

Answer 72

Phosphorylation

Question 73

The location for the cell in glycolysis

Answer 73

Cytoplasm

Question 74

ATP generation using a proton pump/ diffusion of H+ ions

Answer 74

Chemiosmosis

Question 75

Reactions that require the addition of energy

Answer 75

Endergonic

Question 76

Reactions in which a molecule gains electrons

Answer 76

Reduction

Question 77

The process by which a molecule gains a phosphate group.

Answer 77

Substrate Level Phosphorylation

Question 78

The ketone which is an isomer of PGAL

Answer 78

DAP

Question 79

ATP formation using PEP and an enzyme catalyzed reaction

Answer 79

Substrate Level Phosphorylation

Question 80

Series of respiratory proteins bound in the mitochondrial membrane which function to generate ATP

Answer 80

Electron Transport Chain

Question 81

Intermediate compound produced from the oxidation of pyruvate which enters the citric acid cycle.

Answer 81

Acetyl- CoA

Question 82

The structural isomer of glucose6phosphate

Answer 82

fructose6phosphate

Question 83

Reactions in which a molecule loses electrons

Answer 83

Oxidation

Question 84

One by-product of microbial fermentation

Answer 84

Ethanol

Question 85

The location of the electron transport chain

Answer 85

Inner Mitochondrial Membrane

Question 86

Reactions that break down large complex molecules

Answer 86

Catabolism

Question 87

Enzyme that regulates respiration by allosteric effect and precurser activation

Answer 87

Phosphofructokniase

Question 88

The product of anarobic respiration in muscle cells

Answer 88

Lactic Acid

Question 89

Anaerobic breakdown of glucose

Answer 89

Glycolysis

Question 90

"Reduced" form of most important electron carrier

Answer 90

NADH

Question 91

The biochemical pathway which releases energy in cells

Answer 91

Cellular Respiration

Question 92

The oxidized form of nicotinamide adenine dinucleotide

Answer 92

NAD+

Question 93

The oxidation of glucose in the presence of oxygen

Answer 93

Aerobic Respiration

Question 94

Compound which forms a complex with coenzyme A before entering the krebs cycle

Answer 94

Acetyl

Question 95

The process whereby glucose is split into 2 pyruvate.

Answer 95

Glycolysis