Bio 212 Final Exam 2023
At an atmospheric pressure of 870 mm Hg with 21 percent oxygen, the partial pressure
of oxygen is _____.
A) 219 mm Hg
B) 127 mm Hg
C) 151 mm Hg
D) 182 mm Hg
E) 100 mm Hg - ANSWER D
At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the
atmosphere is still composed of 21percent oxygen, then the partial pressure of oxygen
at this altitude is about _____.
A) 80 mm Hg
B) 160 mm Hg
C) 0 mm Hg
D) 380 mm Hg
E) 760 mm Hg - ANSWER A
The sun shining on a tidal pool during a hot day heats the water. As some water
evaporates, the pool becomes saltier, causing _____.
A) an increase in its ability to sustain aerobic organisms
B) a decrease in its oxygen content
C) a decrease in the water's density
D) an increase in its carbon dioxide content - ANSWER B
A rabbit taken from a meadow near sea level and moved to a meadow high on a
mountainside would have some trouble breathing. Why?
A) The percentage of oxygen in the air at high elevations is higher than at sea level.
B) The partial pressure of oxygen in the air at high elevations is lower than at sea level.
,C) The percentage of oxygen in the air at high elevations is lower than at sea level.
D) The partial pressure of oxygen in the air at high elevations is higher than at sea level.
- ANSWER B
Determine the rate of diffusion in the gas-exchange organ of an air-breathing animal
where the area for gas exchange in the lung is 200 mm2, the diffusion constant is 0.08,
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 mmHg, and the thickness of the gas exchange
membrane is 0.001 mm.
A) 125
B) 800,000
C) 10,000,000
D) 00032 - ANSWER B
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?
A) Relative to their volume, the young have more surface area across which they can
transport all the oxygen they need.
B) The young have a higher basal metabolic rate.
C) 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.
D) Relative to their surface area, the young have more body volume in which they can
store oxygen for long periods of time. - ANSWER A
Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the
organism to sense a disturbance in gas levels as _____.
A) the medulla oblongata is able to control the concentration of bicarbonate ions in the
blood
B) the brain directly measures and monitors oxygen levels and causes breathing
changes accordingly
C) the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and
uses this measure to control breathing
D) stretch receptors in the lungs cause the medulla oblongata to speed up or slow
, breathing
E) the brain alters the pH of the cerebrospinal fluid to force the animal to retain more or
less carbon dioxide - ANSWER C
When you are jogging, your muscles are using more oxygen and releasing more carbon
dioxide into the blood than when you are at home on the couch. Which of the following
would occur during your jog?
A) The concentration of bicarbonate ions (HCO3-) in the blood would decrease.
B) The volume of the dead air space would decrease.
C) Blood pH would become more basic.
D) The medullary respiratory center would detect rising carbon dioxide levels. -
ANSWER D
To become bound to hemoglobin for transport in a mammal, atmospheric molecules of
oxygen must cross _____.
A) five membranes—in and out of the cell lining the lung, in and out of the endothelial
cell lining an alveolar capillary, and into the red blood cell—to bind with hemoglobin
B) one membrane—that of the lining in the lungs—and then bind directly to hemoglobin,
a protein dissolved in the plasma of the blood
C) zero membranes—oxygen binds directly to hemoglobin, a protein dissolved in the
plasma of the blood
D) two membranes—in and out of the cell lining the lung—and then bind directly to
hemoglobin, a protein dissolved in the plasma of the blood
E) four membranes—in and out of the cell lining the lung, in and out of the endothelial
cell lining an alveolar capillary—and then bind directly to hemoglobin, a protein dissolved
in the plasma of the blood - ANSWER A
A decrease from pH 7.4 to pH 7.2 causes hemoglobin to _____.
A) denature
B) release all bound carbon dioxide molecules
C) decrease its binding of H+
D) bind more oxygen molecules
E) give up more of its oxygen molecules - ANSWER E
At an atmospheric pressure of 870 mm Hg with 21 percent oxygen, the partial pressure
of oxygen is _____.
A) 219 mm Hg
B) 127 mm Hg
C) 151 mm Hg
D) 182 mm Hg
E) 100 mm Hg - ANSWER D
At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the
atmosphere is still composed of 21percent oxygen, then the partial pressure of oxygen
at this altitude is about _____.
A) 80 mm Hg
B) 160 mm Hg
C) 0 mm Hg
D) 380 mm Hg
E) 760 mm Hg - ANSWER A
The sun shining on a tidal pool during a hot day heats the water. As some water
evaporates, the pool becomes saltier, causing _____.
A) an increase in its ability to sustain aerobic organisms
B) a decrease in its oxygen content
C) a decrease in the water's density
D) an increase in its carbon dioxide content - ANSWER B
A rabbit taken from a meadow near sea level and moved to a meadow high on a
mountainside would have some trouble breathing. Why?
A) The percentage of oxygen in the air at high elevations is higher than at sea level.
B) The partial pressure of oxygen in the air at high elevations is lower than at sea level.
,C) The percentage of oxygen in the air at high elevations is lower than at sea level.
D) The partial pressure of oxygen in the air at high elevations is higher than at sea level.
- ANSWER B
Determine the rate of diffusion in the gas-exchange organ of an air-breathing animal
where the area for gas exchange in the lung is 200 mm2, the diffusion constant is 0.08,
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 mmHg, and the thickness of the gas exchange
membrane is 0.001 mm.
A) 125
B) 800,000
C) 10,000,000
D) 00032 - ANSWER B
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?
A) Relative to their volume, the young have more surface area across which they can
transport all the oxygen they need.
B) The young have a higher basal metabolic rate.
C) 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.
D) Relative to their surface area, the young have more body volume in which they can
store oxygen for long periods of time. - ANSWER A
Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the
organism to sense a disturbance in gas levels as _____.
A) the medulla oblongata is able to control the concentration of bicarbonate ions in the
blood
B) the brain directly measures and monitors oxygen levels and causes breathing
changes accordingly
C) the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and
uses this measure to control breathing
D) stretch receptors in the lungs cause the medulla oblongata to speed up or slow
, breathing
E) the brain alters the pH of the cerebrospinal fluid to force the animal to retain more or
less carbon dioxide - ANSWER C
When you are jogging, your muscles are using more oxygen and releasing more carbon
dioxide into the blood than when you are at home on the couch. Which of the following
would occur during your jog?
A) The concentration of bicarbonate ions (HCO3-) in the blood would decrease.
B) The volume of the dead air space would decrease.
C) Blood pH would become more basic.
D) The medullary respiratory center would detect rising carbon dioxide levels. -
ANSWER D
To become bound to hemoglobin for transport in a mammal, atmospheric molecules of
oxygen must cross _____.
A) five membranes—in and out of the cell lining the lung, in and out of the endothelial
cell lining an alveolar capillary, and into the red blood cell—to bind with hemoglobin
B) one membrane—that of the lining in the lungs—and then bind directly to hemoglobin,
a protein dissolved in the plasma of the blood
C) zero membranes—oxygen binds directly to hemoglobin, a protein dissolved in the
plasma of the blood
D) two membranes—in and out of the cell lining the lung—and then bind directly to
hemoglobin, a protein dissolved in the plasma of the blood
E) four membranes—in and out of the cell lining the lung, in and out of the endothelial
cell lining an alveolar capillary—and then bind directly to hemoglobin, a protein dissolved
in the plasma of the blood - ANSWER A
A decrease from pH 7.4 to pH 7.2 causes hemoglobin to _____.
A) denature
B) release all bound carbon dioxide molecules
C) decrease its binding of H+
D) bind more oxygen molecules
E) give up more of its oxygen molecules - ANSWER E
