Question 1

Most of the carbon dioxide produced by humans is ________.

Accepted Answer

A)  converted to bicarbonate ions by carbonic anhydrase, an enzyme in red blood cells 
B)  bound to hemoglobin 
C)  transported in the erythrocytes as carbonic acid 
D)  simply dissolved in the plasma 
E)  bicarbonate ions bound to hemoglobin 
A)  converted to bicarbonate ions by carbonic anhydrase, an enzyme in red blood cells 
B)  bound to hemoglobin 
C)  transported in the erythrocytes as carbonic acid 
D)  simply dissolved in the plasma 
E)  bicarbonate ions bound to hemoglobin

Question 2

The air pressure in Denver, Colorado, is about 83 percent of the air pressure in Miami Beach, which is at about sea level. Given that the air pressure in Miami Beach is 760 mm Hg and oxygen makes up 21 percent of the air in Miami Beach, what are the percentage of oxygen and the partial pressure of oxygen in Denver?

Accepted Answer

A)  21 percent; 21 mm Hg 
B)  21 percent; 132 mm Hg 
C)  17.4 percent; 132 mm Hg 
D)  17.4 percent; 21 mm Hg 
A)  21 percent; 21 mm Hg 
B)  21 percent; 132 mm Hg 
C)  17.4 percent; 132 mm Hg 
D)  17.4 percent; 21 mm Hg

Question 3

Some animals have no gills when young but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?

Accepted Answer

A)  The young of these animals are much more active than the adult, which leads to a higher BMR (basal metabolic rate) and, therefore, a higher need for oxygen. 
B)  Relative to their volume, the young have more surface area across which they can transport all the oxygen they need. 
C)  The young have a higher basal metabolic rate. 
D)  Relative to their surface area, the young have more body volume in which they can store oxygen for long periods of time. 
A)  The young of these animals are much more active than the adult, which leads to a higher BMR (basal metabolic rate) and, therefore, a higher need for oxygen. 
B)  Relative to their volume, the young have more surface area across which they can transport all the oxygen they need. 
C)  The young have a higher basal metabolic rate. 
D)  Relative to their surface area, the young have more body volume in which they can store oxygen for long periods of time.

Question 4

Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb = hemoglobin)

Accepted Answer

A)  Hb + 4 O2 → Hb(O2)4 
B)  Hb(O2)4 → Hb + 4 O2 
C)  CO2 + H2O → H2CO3 
D)  H2CO3 → H+ + HCO3− 
E)  Hb + 4 CO2 → Hb(CO2)4 
A)  Hb + 4 O2 → Hb(O2)4 
B)  Hb(O2)4 → Hb + 4 O2 
C)  CO2 + H2O → H2CO3 
D)  H2CO3 → H+ + HCO3− 
E)  Hb + 4 CO2 → Hb(CO2)4

Question 5

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through ________.

Accepted Answer

A)  one capillary bed 
B)  two capillary beds 
C)  three capillary beds 
D)  four capillary beds 
E)  five capillary beds 
A)  one capillary bed 
B)  two capillary beds 
C)  three capillary beds 
D)  four capillary beds 
E)  five capillary beds

Question 6

Which of the four muscular chambers of the human heart directly propels blood into the pulmonary circulation?

Accepted Answer

A)  right atrium 
B)  right ventricle 
C)  left atrium 
D)  left ventricle 
A)  right atrium 
B)  right ventricle 
C)  left atrium 
D)  left ventricle

Question 7

Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the ________.

Accepted Answer

A)  loss of osmotic pressure in the capillaries 
B)  development of an osmotic pressure difference across capillary walls that favors fluid retention in the capillary 
C)  loss of fluid from capillaries 
D)  increased diffusion of carbon dioxide 
E)  increased diffusion of hemoglobin 
A)  loss of osmotic pressure in the capillaries 
B)  development of an osmotic pressure difference across capillary walls that favors fluid retention in the capillary 
C)  loss of fluid from capillaries 
D)  increased diffusion of carbon dioxide 
E)  increased diffusion of hemoglobin

Question 8

Air rushes into the lungs of humans during inhalation because ________.

Accepted Answer

A)  the rib muscles and diaphragm contract, increasing the lung volume and decreasing the pressure within the lungs 
B)  the volume of the alveoli increases as smooth muscles contract 
C)  gas flows from a region of lower pressure to a region of higher pressure 
D)  pulmonary muscles contract and pull on the outer surface of the lungs 
E)  a positive respiratory pressure is created when the diaphragm relaxes 
A)  the rib muscles and diaphragm contract, increasing the lung volume and decreasing the pressure within the lungs 
B)  the volume of the alveoli increases as smooth muscles contract 
C)  gas flows from a region of lower pressure to a region of higher pressure 
D)  pulmonary muscles contract and pull on the outer surface of the lungs 
E)  a positive respiratory pressure is created when the diaphragm relaxes

Question 9

An increase in blood carbon dioxide content causes hemoglobin to ________.

Accepted Answer

A)  release all bound carbon dioxide molecules 
B)  bind more oxygen molecules 
C)  denature 
D)  increase its binding of H+ 
E)  give up more of its oxygen molecules 
A)  release all bound carbon dioxide molecules 
B)  bind more oxygen molecules 
C)  denature 
D)  increase its binding of H+ 
E)  give up more of its oxygen molecules

Question 10

One feature that amphibians and humans have in common is ________.

Accepted Answer

A)  the number of heart chambers 
B)  the type of gas-exchange tissues 
C)  a complete separation of circuits for circulation 
D)  the number of circuits for circulation 
E)  a low blood pressure in the systemic circuit 
A)  the number of heart chambers 
B)  the type of gas-exchange tissues 
C)  a complete separation of circuits for circulation 
D)  the number of circuits for circulation 
E)  a low blood pressure in the systemic circuit

Question 11

The pacemaker cells are found in what structure?

Accepted Answer

A)  sinoatrial node 
B)  the ventricles 
C)  left atrium 
D)  pulmonary veins 
E)  aorta 
A)  sinoatrial node 
B)  the ventricles 
C)  left atrium 
D)  pulmonary veins 
E)  aorta

Question 12

An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well formed, and had four chambers, with no connection between the right and left sides. A reasonable conclusion supported by these observations is that the ________.

Accepted Answer

A)  animal had evolved from birds 
B)  animal was endothermic and had a high metabolic rate 
C)  animal was most closely related to alligators and crocodiles 
D)  animal was likely an invertebrate animal 
E)  species had little to no need to regulate blood pressure 
A)  animal had evolved from birds 
B)  animal was endothermic and had a high metabolic rate 
C)  animal was most closely related to alligators and crocodiles 
D)  animal was likely an invertebrate animal 
E)  species had little to no need to regulate blood pressure

Question 13

As a person goes from rest to full-effort exercise, there is an increase in the ________.

Accepted Answer

A)  tidal volume 
B)  vital capacity 
C)  residual volume 
D)  total lung capacity 
A)  tidal volume 
B)  vital capacity 
C)  residual volume 
D)  total lung capacity

Question 14

The exhalation of air from human lungs is driven by ________.

Accepted Answer

A)  a decrease in the volume of the thoracic cavity with an associated increase in thoracic pressure 
B)  a decrease in the residual volume of the lungs 
C)  the contraction of the diaphragm 
D)  the closure of the epiglottis 
E)  the expansion of the rib cage 
A)  a decrease in the volume of the thoracic cavity with an associated increase in thoracic pressure 
B)  a decrease in the residual volume of the lungs 
C)  the contraction of the diaphragm 
D)  the closure of the epiglottis 
E)  the expansion of the rib cage

Question 15

Which of the following is the correct sequence of blood flow in birds and mammals?

Accepted Answer

A)  left ventricle → aorta → lungs → systemic circulation 
B)  vena cava → right atrium → right ventricle → pulmonary vein 
C)  pulmonary vein → left atrium → left ventricle → pulmonary circuit 
D)  vena cava → right atrium → right ventricle → pulmonary artery 
E)  right atrium → pulmonary artery → left atrium → ventricle 
A)  left ventricle → aorta → lungs → systemic circulation 
B)  vena cava → right atrium → right ventricle → pulmonary vein 
C)  pulmonary vein → left atrium → left ventricle → pulmonary circuit 
D)  vena cava → right atrium → right ventricle → pulmonary artery 
E)  right atrium → pulmonary artery → left atrium → ventricle

Question 16

What is the correct order of processes involving the movement of oxygen from the environment to mitochondria in vertebrates?

Accepted Answer

A)  ventilation, circulation, cellular respiration 
B)  circulation, ventilation, cellular respiration 
C)  diffusion in tissues, cellular respiration, diffusion at respiratory surface 
D)  ventilation, diffusion in tissues, circulation 
E)  circulation, cellular respiration, diffusion in tissues 
A)  ventilation, circulation, cellular respiration 
B)  circulation, ventilation, cellular respiration 
C)  diffusion in tissues, cellular respiration, diffusion at respiratory surface 
D)  ventilation, diffusion in tissues, circulation 
E)  circulation, cellular respiration, diffusion in tissues

Question 17

Determine the rate of diffusion (cm3/min or mL/min) in the gas-exchange organ of an air-breathing animal where the area for gas exchange in the lung is 2 cm2, the diffusion constant is 0.08 cm2/min, the PO2 (partial pressure of oxygen) of the air in the lung is 140 mm Hg, the PO2 in blood flowing into the lung is 90 mm Hg, and the thickness of the gas exchange membrane is 0.0001 cm.

Accepted Answer

A)  80,000 
B)  125 
C)  32,000 
D)  10,00,000 
A)  80,000 
B)  125 
C)  32,000 
D)  10,00,000

Question 18

Complete the statement correctly. Fetal hemoglobin ________.

Accepted Answer

A)  binds more carbon dioxide molecules than adult hemoglobin 
B)  is better able to release oxygen than is adult hemoglobin 
C)  has a higher affinity for oxygen than does adult hemoglobin 
D)  is better able to release carbon dioxide than is adult hemoglobin 
E)  has a higher affinity for carbon dioxide than does adult hemoglobin 
A)  binds more carbon dioxide molecules than adult hemoglobin 
B)  is better able to release oxygen than is adult hemoglobin 
C)  has a higher affinity for oxygen than does adult hemoglobin 
D)  is better able to release carbon dioxide than is adult hemoglobin 
E)  has a higher affinity for carbon dioxide than does adult hemoglobin

Question 19

Under identical atmospheric conditions, freshwater ________.

Accepted Answer

A)  has more oxygen than seawater 
B)  has less oxygen than seawater 
C)  can hold 10-40 times more carbon dioxide than air 
D)  can hold 10-40 times more oxygen than air 
A)  has more oxygen than seawater 
B)  has less oxygen than seawater 
C)  can hold 10-40 times more carbon dioxide than air 
D)  can hold 10-40 times more oxygen than air

Question 20

The circulatory systems of bony fishes, rays, and sharks are most similar to ________.

Accepted Answer

A)  those of birds, with a four-chambered heart 
B)  the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber 
C)  those of reptiles, with one pumping chamber driving blood flow to a gas-exchange organ, and a different pumping chamber driving blood to the rest of the circulation 
D)  those of sponges, where gas exchange in all cells occurs directly with the external environment 
E)  those of humans, where there are four pumping chambers to drive blood flow 
A)  those of birds, with a four-chambered heart 
B)  the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber 
C)  those of reptiles, with one pumping chamber driving blood flow to a gas-exchange organ, and a different pumping chamber driving blood to the rest of the circulation 
D)  those of sponges, where gas exchange in all cells occurs directly with the external environment 
E)  those of humans, where there are four pumping chambers to drive blood flow

Exam 42: Gas Exchange and Circulation

Most of the carbon dioxide produced by humans is ________.

Some animals have no gills when young but then develop gills that grow larger as the animal grows larger. What is the reason for this increase in gill size?

Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb = hemoglobin)

A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through ________.

Which of the four muscular chambers of the human heart directly propels blood into the pulmonary circulation?

Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the ________.

Air rushes into the lungs of humans during inhalation because ________.

An increase in blood carbon dioxide content causes hemoglobin to ________.

One feature that amphibians and humans have in common is ________.

The pacemaker cells are found in what structure?

As a person goes from rest to full-effort exercise, there is an increase in the ________.

The exhalation of air from human lungs is driven by ________.

Which of the following is the correct sequence of blood flow in birds and mammals?

What is the correct order of processes involving the movement of oxygen from the environment to mitochondria in vertebrates?

Complete the statement correctly. Fetal hemoglobin ________.

Under identical atmospheric conditions, freshwater ________.

The circulatory systems of bony fishes, rays, and sharks are most similar to ________.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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