Question 1

Which of the following statements best describes a characteristic of NAD+?

Accepted Answer

A)  NAD+ is reduced to NADH in glycolysis, pyruvate oxidation, and the citric acid cycle. 
B)  NAD+ stores more chemical energy than NADH. 
C)  NAD+ may donate electrons for use in oxidative phosphorylation. 
D)  NAD+ is oxidized in glycolysis to produce ATP. 
A)  NAD+ is reduced to NADH in glycolysis, pyruvate oxidation, and the citric acid cycle. 
B)  NAD+ stores more chemical energy than NADH. 
C)  NAD+ may donate electrons for use in oxidative phosphorylation. 
D)  NAD+ is oxidized in glycolysis to produce ATP. A

Question 2

Which of the summary statements below best describes the results of the following reaction?
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

Accepted Answer

A)  C6H12O6 is oxidized and O2 is reduced. 
B)  O2 is oxidized and H2O is reduced. 
C)  CO2 is reduced and O2 is oxidized. 
D)  O2 is reduced and CO2 is oxidized. 
A)  C6H12O6 is oxidized and O2 is reduced. 
B)  O2 is oxidized and H2O is reduced. 
C)  CO2 is reduced and O2 is oxidized. 
D)  O2 is reduced and CO2 is oxidized. A

Question 3

What is the oxidizing agent in the following reaction?
Pyruvate + NADH + H+ → Lactate + NAD+

Accepted Answer

A)  oxygen 
B)  NADH 
C)  lactate 
D)  pyruvate 
A)  oxygen 
B)  NADH 
C)  lactate 
D)  pyruvate D

Question 4

The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?

Accepted Answer

A)  glucose and NAD+ 
B)  AMP and ATP 
C)  ATP and citrate 
D)  citrate and CO2 
A)  glucose and NAD+ 
B)  AMP and ATP 
C)  ATP and citrate 
D)  citrate and CO2

Question 5

Exposing inner mitochondrial membranes to ultrasonic vibrations will fragment the membranes and pieces will reseal to form small vesicles that contain the intermembrane space. These vesicles can transfer electrons from NADH to oxygen and synthesize ATP. Which of the following statements best describes what will happen to the vesicles when NADH is added?

Accepted Answer

A)  The inside of the vesicles will become acidic. 
B)  The inside of the vesicles will become alkaline. 
C)  ATP will be produced from ADP and   i in the interior of the vesicle. 
D)  Protons will be pumped out of the interior of the vesicle to the exterior using energy from ATP hydrolysis. 
A)  The inside of the vesicles will become acidic. 
B)  The inside of the vesicles will become alkaline. 
C)  ATP will be produced from ADP and   i in the interior of the vesicle. 
D)  Protons will be pumped out of the interior of the vesicle to the exterior using energy from ATP hydrolysis.

Question 6

In chemiosmosis, the most direct source of energy used to convert ADP +   i to ATP is energy released ________.

Accepted Answer

A)  as electrons flow through the electron transport chain 
B)  from substrate-level phosphorylation 
C)  from movement of protons through ATP synthase, down their electrochemical gradient 
D)  as electrons are transported across the inner mitochondrial membrane 
A)  as electrons flow through the electron transport chain 
B)  from substrate-level phosphorylation 
C)  from movement of protons through ATP synthase, down their electrochemical gradient 
D)  as electrons are transported across the inner mitochondrial membrane

Question 7

If a cell produces on average 30 ATP molecules for each molecule of glucose that is completely oxidized to carbon dioxide and water, how many ATP molecules on average can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?

Accepted Answer

A)  8 
B)  12.5 
C)  14 
D)  25 
A)  8 
B)  12.5 
C)  14 
D)  25

Question 8

In mitochondria, exergonic redox reactions ________.

Accepted Answer

A)  are the source of energy driving prokaryotic ATP synthesis 
B)  provide the energy that establishes the proton gradient 
C)  reduce carbon atoms to carbon dioxide 
D)  are coupled via phosphorylated intermediates to endergonic processes 
A)  are the source of energy driving prokaryotic ATP synthesis 
B)  provide the energy that establishes the proton gradient 
C)  reduce carbon atoms to carbon dioxide 
D)  are coupled via phosphorylated intermediates to endergonic processes

Question 9

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the ________.

Accepted Answer

A)  oxidation of glucose and other organic compounds 
B)  flow of electrons down the electron transport chain 
C)  H+ concentration gradient across the membrane holding ATPsynthase 
D)  transfer of phosphate to ADP 
A)  oxidation of glucose and other organic compounds 
B)  flow of electrons down the electron transport chain 
C)  H+ concentration gradient across the membrane holding ATPsynthase 
D)  transfer of phosphate to ADP

Question 10

Substrate-level phosphorylation accounts for approximately what percent of the ATP formed by the reactions of glycolysis?

Accepted Answer

A)  0% 
B)  2% 
C)  38% 
D)  100% 
A)  0% 
B)  2% 
C)  38% 
D)  100%

Question 11

If the proteins of the electron transport chain were labeled with a fluorescent tag, the fluorescence observed by microscopy will be localized to which of the following regions of the mitochondria?

Accepted Answer

A)  outer membrane 
B)  inner membrane 
C)  intermembrane space 
D)  matrix 
A)  outer membrane 
B)  inner membrane 
C)  intermembrane space 
D)  matrix

Question 12

Which of the following statements best describes the primary role played by oxygen in cellular respiration?

Accepted Answer

A)  It yields energy in the form of ATP as it is passed down the electron transport chain. 
B)  It oxidizes glucose to form two molecules of pyruvate. 
C)  It serves as an acceptor for carbon, forming CO2 in the citric acid cycle. 
D)  It serves as the final acceptor for electrons from the electron transport chain. 
A)  It yields energy in the form of ATP as it is passed down the electron transport chain. 
B)  It oxidizes glucose to form two molecules of pyruvate. 
C)  It serves as an acceptor for carbon, forming CO2 in the citric acid cycle. 
D)  It serves as the final acceptor for electrons from the electron transport chain.

Question 13

Which of the following statements best explains why carbohydrates and fats may be considered high-energy foods?

Accepted Answer

A)  They contain many protons associated with oxygen atoms. 
B)  They contain no low-energy nitrogen atoms. 
C)  They contain many electrons associated with hydrogen atoms. 
D)  They are strong oxidizing molecules. 
A)  They contain many protons associated with oxygen atoms. 
B)  They contain no low-energy nitrogen atoms. 
C)  They contain many electrons associated with hydrogen atoms. 
D)  They are strong oxidizing molecules.

Question 14

The citric acid cycle.
If pyruvate oxidation is blocked, what is the most likely effect on the levels of oxaloacetate and citrate in the citric acid cycle shown in the accompanying figure?

Accepted Answer

A)  Oxaloacetate will decrease and citrate will accumulate. 
B)  Oxaloacetate will accumulate and citrate will decrease. 
C)  Both oxaloacetate and citrate will decrease. 
D)  Both oxaloacetate and citrate will accumulate. 
A)  Oxaloacetate will decrease and citrate will accumulate. 
B)  Oxaloacetate will accumulate and citrate will decrease. 
C)  Both oxaloacetate and citrate will decrease. 
D)  Both oxaloacetate and citrate will accumulate.

Question 15

Which of the following types of metabolic poison would most directly interfere with glycolysis?

Accepted Answer

A)  an agent that reacts with oxygen and depletes its concentration in the cell 
B)  an agent that binds to pyruvate and inactivates it 
C)  an agent that closely mimics the structure of glucose but is not metabolized 
D)  an agent that reacts with NADH and oxidizes it to NAD+ 
A)  an agent that reacts with oxygen and depletes its concentration in the cell 
B)  an agent that binds to pyruvate and inactivates it 
C)  an agent that closely mimics the structure of glucose but is not metabolized 
D)  an agent that reacts with NADH and oxidizes it to NAD+

Question 16

Which of the following is one of the molecules formed by the removal of a carboxyl group (as CO2) from a molecule of pyruvate?

Accepted Answer

A)  ATP 
B)  acetyl CoA 
C)  citrate 
D)  water 
A)  ATP 
B)  acetyl CoA 
C)  citrate 
D)  water

Question 17

New biosensors, applied like a temporary tattoo to the skin, can alert endurance athletes that they are about to "hit the wall" and will find it difficult to continue exercising. These biosensors monitor lactate present in sweat during strenuous exercise. Which of the statements below best explains the use of lactate as an indicator of exercise capacity?

Accepted Answer

A)  During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell contractions, and muscles begin to cramp, thus athletic performance suffers. 
B)  During anaerobic respiration, lactate levels increase when muscles cells need more energy; however, muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration. 
C)  During aerobic respiration, muscles cells produce too much lactate, which causes a rise in the pH of the muscle cells, thus athletes must consume increased amounts of sports drinks, high in electrolytes, to buffer the pH. 
D)  During anaerobic respiration, muscle cells receive too little oxygen and begin to convert lactate to pyruvate (pyruvic acid), thus athletes experience cramping and fatigue. 
A)  During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell contractions, and muscles begin to cramp, thus athletic performance suffers. 
B)  During anaerobic respiration, lactate levels increase when muscles cells need more energy; however, muscles cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration. 
C)  During aerobic respiration, muscles cells produce too much lactate, which causes a rise in the pH of the muscle cells, thus athletes must consume increased amounts of sports drinks, high in electrolytes, to buffer the pH. 
D)  During anaerobic respiration, muscle cells receive too little oxygen and begin to convert lactate to pyruvate (pyruvic acid), thus athletes experience cramping and fatigue.

Question 18

Which of the following sequences describes the path by which electrons move from high-energy to lower-energy molecules in aerobic respiration?

Accepted Answer

A)  glucose → NADH → electron transport chain → oxygen 
B)  glucose → pyruvate → ATP → oxygen 
C)  glucose → pyruvate → electron transport chain → NADH → ATP 
D)  food → glycolysis → citric acid cycle → NADH → ATP 
A)  glucose → NADH → electron transport chain → oxygen 
B)  glucose → pyruvate → ATP → oxygen 
C)  glucose → pyruvate → electron transport chain → NADH → ATP 
D)  food → glycolysis → citric acid cycle → NADH → ATP

Question 19

Which of the following reactions produces the majority of the CO2 released by the complete oxidation of glucose?

Accepted Answer

A)  glycolysis 
B)  electron transport 
C)  oxidation of pyruvate to acetyl-CoA 
D)  the citric acid cycle 
A)  glycolysis 
B)  electron transport 
C)  oxidation of pyruvate to acetyl-CoA 
D)  the citric acid cycle

Question 20

The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis. About 10% of Springer spaniels suffer from canine PFK deficiency. Dogs affected with this disorder most likely display which of the following symptoms?

Accepted Answer

A)  They die as embryos. 
B)  They constantly have low blood sugar. 
C)  They are lethargic and readily tire from exercise. 
D)  They carry out elevated levels of oxidative phosphorylation. 
A)  They die as embryos. 
B)  They constantly have low blood sugar. 
C)  They are lethargic and readily tire from exercise. 
D)  They carry out elevated levels of oxidative phosphorylation.

Exam 10: Cell Respiration

Which of the following statements best describes a characteristic of NAD+?

Which of the summary statements below best describes the results of the following reaction? C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+

The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?

In chemiosmosis, the most direct source of energy used to convert ADP + i to ATP is energy released ________.

If a cell produces on average 30 ATP molecules for each molecule of glucose that is completely oxidized to carbon dioxide and water, how many ATP molecules on average can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?

In mitochondria, exergonic redox reactions ________.

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the ________.

Substrate-level phosphorylation accounts for approximately what percent of the ATP formed by the reactions of glycolysis?

If the proteins of the electron transport chain were labeled with a fluorescent tag, the fluorescence observed by microscopy will be localized to which of the following regions of the mitochondria?

Which of the following statements best describes the primary role played by oxygen in cellular respiration?

Which of the following statements best explains why carbohydrates and fats may be considered high-energy foods?

The citric acid cycle. If pyruvate oxidation is blocked, what is the most likely effect on the levels of oxaloacetate and citrate in the citric acid cycle shown in the accompanying figure?

Which of the following types of metabolic poison would most directly interfere with glycolysis?

Which of the following is one of the molecules formed by the removal of a carboxyl group (as CO2) from a molecule of pyruvate?

Which of the following sequences describes the path by which electrons move from high-energy to lower-energy molecules in aerobic respiration?

Which of the following reactions produces the majority of the CO2 released by the complete oxidation of glucose?

The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis. About 10% of Springer spaniels suffer from canine PFK deficiency. Dogs affected with this disorder most likely display which of the following symptoms?

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Energy and Life

Cell Structure and Function

Cell Membranes

Cellular Signaling

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Control of Gene Expression

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Introduction to Viruses

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Energy Flow and Chemical Cycling in Ecosystems

Conservation and Global Ecology

Filters

Which of the summary statements below best describes the results of the following reaction? C6H12O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy

Which of the following is one of the molecules formed by the removal of a carboxyl group (as CO₂) from a molecule of pyruvate?

Which of the following reactions produces the majority of the CO₂ released by the complete oxidation of glucose?