Deck 24: Transport of Oxygen and Carbon Dioxide in Body Fluids With an Introduction to Acid- Base Physiology

Question 1

When oxygen binds with hemoglobin, why is this not oxidation?

A) When oxygen binds with hemoglobin, it is a full reduction reaction.
B) When oxygen binds with hemoglobin, there is no oxidation, only oxygenation.
C) Although electrons are partially transferred from iron atoms to oxygen, the transfer is not complete.
D) Although electrons are partially transferred from oxygen atoms to iron, the transfer is not complete.

Answer 1

C

Question 2

Mammalian fetal hemoglobin has a _______ oxygen affinity than the mother's hemoglobin in order to _______ the maternal blood.

A) higher; load oxygen from
B) higher; transfer oxygen to
C) lower; load oxygen from
D) lower; transfer oxygen to

Answer 2

A

Question 3

Which of the following is not a chemical category of respiratory pigment?

A) Hemocyanins
B) Hemerythrins
C) Chlorocruorins
D) Myoglobins

Answer 3

D

Question 4

Which statement about hemoglobin is false?

A) It plays a role in CO₂ transport.
B) It plays a role as a pH buffer.
C) It plays a role in N₂ transport.
D) It is affected by temperature.

Question 5

Which statement comparing human adult and fetal hemoglobin is true?

A) Fetal hemoglobin contains one particular subunit that lowers its P₅₀.
B) Fetal hemoglobin contains one particular subunit that raises its P₅₀.
C) All subunits of fetal hemoglobin are different and result in a lower P₅₀.
D) All subunits of fetal hemoglobin are different and result in a higher P₅₀.

Question 6

Which statement about myoglobin is true?

A) It is a respiratory pigment found in the red blood cell.
B) It is exactly like hemoglobin but is found in a different location in the body.
C) It is a type of fetal hemoglobin.
D) It is a respiratory pigment found in muscle cytoplasm.

Question 7

Hemocyanins occur in which animal groups?

A) Molluscs
B) Arthropods
C) Echinoderms and molluscs
D) Molluscs and arthropods

Question 8

When the body detects _______, _______ is secreted to increase the production of red blood cells.

A) high CO₂ levels; erythropoietin
B) high CO₂ levels; myoglobin
C) low O₂ levels; erythropoietin
D) low O₂ levels; myoglobin

Question 9

Respiratory pigments like hemoglobin have been labelled "honorary enzymes" because of their similarities. Choose the answer that is not one of those similarities.

A) Defined binding sites
B) Modification of the primary ligand
C) Binding site is highly specific
D) Binds to site by noncovalent, weak bonding

Question 10

_______ binds to hemoglobin at the allosteric site and _______.

A) O₂; increases the affinity of hemoglobin for O₂
B) CO₂; increases the affinity of hemoglobin for O₂
C) CO₂; decreases the affinity of hemoglobin for O₂
D) O₂; decreases the affinity of hemoglobin for O₂

Question 11

The image on a graph showing the functional relationship between the percentage of oxygenated binding sites and the O₂ partial pressure is best known as

A) the saturation curve.
B) the affinity curve.
C) the P₅₀ curve.
D) the oxygen dissociation curve.

Question 12

A respiratory pigment that requires a relatively low O₂ partial pressure for loading has _______ affinity for O₂.

A) a low
B) a high
C) no
D) a variable

Question 13

In a healthy human at rest, what is the approximate O₂ saturation of venous blood as it is leaving the tissues?

A) 75%
B) 50%
C) 25%
D) 0%

Question 14

Refer to the figure shown.
Which statement regarding the figure is false?

A) The right line depicts a pigment showing cooperativity.
B) The left line depicts a pigment displaying no cooperativity.
C) The left line could represent human hemoglobin.
D) The left line displays a generally higher O₂ affinity compared to the right line.

Question 15

Refer to the figure shown.
Which oxygen dissociation curve in the figure would represent a diving mammal such as a Weddell seal?

A) I
B) II
C) III
D) IV

Question 16

Refer to the figure shown.
Which oxygen dissociation curve in the figure would represent a hypoxia-adapted species such as a carp?

A) I
B) II
C) IV
D) V

Question 17

Refer to the figure shown.
Which oxygen dissociation curve in the figure carries the least amount of oxygen per unit volume of blood?

A) I
B) II
C) III
D) IV

Question 18

Refer to the figure shown.
On the graph, which oxygen dissociation curve represents a very high blood pH (e.g., 7.6)?

A) I
B) II
C) III
D) IV

Question 19

Refer to the figure shown.
On the graph, which oxygen dissociation curve represents blood with a high CO₂ partial pressure (e.g., 80 mm Hg)?

A) I
B) II
C) III
D) IV

Question 20

Refer to the figure shown.
On the graph, which oxygen dissociation curve represents a P₅₀ of about 4 kPa?

A) I
B) II
C) III
D) IV

Question 21

A respiratory pigment that requires a relatively low O₂ partial pressure for loading and has a high affinity for O₂ would also have

A) a relatively low P₅₀.
B) a relatively high P₅₀.
C) no P₅₀ at all.
D) a variable P₅₀.

Question 22

The effect of acid in reducing the affinity of hemoglobin for O₂ is called the _______ effect.

A) Haldane
B) dissociation
C) Root
D) Bohr

Question 23

Which statement is not directly related to the Bohr effect?

A) The Hb‒O₂ affinity increases as pH increases.
B) The Hb‒O₂ affinity decreases as temperature increases.
C) The Hb‒O₂ affinity decreases as CO₂ partial pressure increases.
D) The Hb‒O₂ affinity decreases as H⁺ concentration increases.

Question 24

The affinity of hemoglobin for O₂ increases with

A) decreasing temperature.
B) decreasing blood pH.
C) an increase in CO₂ partial pressure_.
D) increasing [H⁺].

Question 25

The venous blood displays a reduced O₂ affinity compared to arterial blood because its

A) CO₂ partial pressure is higher.
B) H⁺ concentration is higher.
C) hemoglobin concentration is lower.
D) CO₂ partial pressure is higher and its H⁺ concentration is higher.

Question 26

Refer to the figure shown.
The curve on the graph

A) represents oxygen delivery by human blood at rest and during vigorous exercise.
B) is a vertebrate oxygen dissociation curve.
C) is a mammalian oxygen dissociation curve.
D) represents the increase in oxygen concentration as blood travels to the lungs.

Question 27

Refer to the figure shown.
Region I in the figure represents the

A) amount of oxygen used by the tissues at rest.
B) oxygen concentration of blood in the tissues during exercise.
C) oxygen concentration of blood in the tissues at rest.
D) amount of oxygen used by the tissues during exercise.

Question 28

Refer to the figure shown.
According to the figure, approximately how much more oxygen is used by the tissues during exercise compared to at rest?

A) 15 mL O₂/100 ml of blood
B) 10 mL O₂/100 ml of blood
C) 15 mL O₂/g
D) 10 mL O₂/g

Question 29

The venous O₂ partial pressure below which aerobic catabolism becomes impaired is known as the

A) minimal venous O₂ partial pressure.
B) critical venous reserve.
C) venous threshold.
D) critical venous O₂ partial pressure.

Question 30

Refer to the figure shown.
The pattern of the curves in the figure demonstrates the _______ effect.

A) Haldane
B) Root
C) fixed-acid Bohr
D) CO₂ Bohr

Question 31

Refer to the figure shown.
As shown in the figure, the P₅₀ _______ declining pH.

A) increases with
B) decreases with
C) remains constant with
D) is unrelated to

Question 32

The Root effect applies to which physiological mechanism?

A) The unloading of O₂ in muscle tissue
B) The inflating of the swim bladder of many fish
C) The loading of O₂ at the gills
D) The unloading of O₂ in low pH regions of the stomach

Question 33

During chronic exposure to high altitude, increasing 2,3-DPG

A) increases Hb‒O₂ affinity.
B) increases the unloading of O₂ at tissues.
C) increases the loading of O₂ at the lungs.
D) decreases the P₅₀ of hemoglobin.

Question 34

Refer to the figure.
The figure shown shows that a reduction in O₂ affinity

A) impairs O₂ unloading less than it enhances loading.
B) impairs O₂ unloading more than it enhances loading.
C) enhances O₂ unloading more than it impairs loading.
D) enhances O₂ unloading less than it impairs loading.

Question 35

Which statement about respiratory pigments is false?

A) They serve as major buffers of blood pH.
B) They play critical roles in CO₂ transport.
C) They play critical roles in the transport of nutrients.
D) They can function as O₂ stores in invertebrates.

Question 36

Select the correct two functions of myoglobin.

A) Increase the rate of O₂ diffusion through the mitochondria; CO₂ buffering
B) Increase the rate of O₂ diffusion through cytoplasm; CO₂ buffering
C) Increase the rate of O₂ diffusion through the mitochondria; O₂ storage
D) Increase the rate of O₂ diffusion through cytoplasm; O₂ storage

Question 37

Different respiratory pigments can pass O2 from one to another because of differences in

A) enzymatic activity.
B) affinity.
C) cooperativity.
D) diffusion rates.

Question 38

Refer to the figure.
According to the figure shown, which statement is the most accurate?

A) O₂ concentrations of arterial blood are inversely proportional to swimming speed.
B) As O₂ concentrations of blood drop in venous blood, swimming speed increases.
C) Cold-acclimated fish have a much lower saturation level during exercise than other fish do.
D) As swimming speed increases, the arterial blood remains nearly saturated while the venous blood decreases in saturation.

Question 39

In octopuses, venous saturation is about _______% at rest and about _______% during exercise.

A) 75; 25
B) 30; 30
C) 30; 10
D) 10; 10

Question 40

An octopus meets the increased demand for O₂ at the tissues during intense exercise by

A) increasing its circulation rate.
B) pulling more O₂ from the blood (from its venous reserve).
C) switching to another form of hemoglobin.
D) increasing its circulation rate and pulling more O₂ from the blood (from its venous reserve).

Question 41

The P₅₀ in a fish species adapted to a low oxygen aquatic environment would likely be _______ the P₅₀ of a fish species adapted to a well-oxygenated aquatic environment.

A) higher than
B) equal to
C) lower than
D) extremely variable compared to

Question 42

Refer to the figure.
The figure shows that

A) larger primates have fewer red blood cells than smaller primates do.
B) the whole blood of smaller primates has lower O₂ affinity than that of larger primates.
C) the whole blood of smaller primates has greater O₂ affinity than that of larger primates.
D) larger primates have more red blood cells than smaller primates do.

Question 43

The exposure of Daphnia to O₂-poor water for days would result in

A) an increase in hemoglobin concentration.
B) a change in the globin subunits produced.
C) an increase in hemoglobin concentration and a decrease in the P₅₀ of the blood.
D) an increase in hemoglobin concentration, a decrease in the P₅₀ of the blood, and a change in the globin subunits produced.

Question 44

Antarctic icefish compensate for the lack of circulating red blood cells with

A) an increase in the amount of hemoglobin in their plasma.
B) the use of another type of respiratory pigment.
C) an increased circulation rate.
D) a lowering of their metabolic rate, along with general inactivity.

Question 45

In many cases, lowland people who travel to an area of high altitude for an extended period of time will develop a condition known as

A) polycythemia.
B) anemia.
C) bradycardia.
D) hypotension.

Question 46

What determines the shape of the CO₂ equilibrium curve?

A) The kinetics of HCO₃^- formation
B) The amount of dissolved CO₂
C) The number of carbamate groups and the amount of dissolved CO₂
D) The kinetics of HCO₃^- formation, the number of carbamate groups, and the amount of dissolved CO₂

Question 47

The deoxygenation of hemoglobin promotes CO₂ uptake, and the oxygenation of hemoglobin promotes the unloading of CO₂. This phenomenon is called the _______ effect.

A) Root
B) fixed-acid Bohr
C) Haldane
D) CO₂ Bohr

Question 48

The extent of bicarbonate formation in the blood depends primarily on the

A) solubility of bicarbonate in the plasma.
B) temperature.
C) blood buffers.
D) solubility of carbonic acid.

Question 49

The buffering effectiveness of any given buffer reaction is greatest when the prevailing pH _______ the pKʹ of the reaction.

A) is much greater than
B) matches
C) is much lower than
D) is as far away as possible from

Question 50

Which species would have the highest total blood CO₂ concentration?

A) Human
B) Turtle
C) Lungfish
D) Trout

Question 51

The key enzyme involved in the formation of bicarbonate from CO₂ is

A) lactate dehydrogenase.
B) alcohol dehydrogenase.
C) carbonic anhydrase.
D) bicarbonate dehydrogenase.

Question 52

The chloride shift refers to

A) rapid anion exchange proteins.
B) carbonic anhydrase.
C) carbamate formation.
D) the dissolving of CO₂ in plasma.

Question 53

In mammals, the bulk of the CO₂ is transported from the tissue to the lungs as

A) bicarbonate dissolved in the plasma.
B) CO₂ dissolved in the plasma.
C) CO₂ bound to hemoglobin.
D) bicarbonate bound to hemoglobin.

Question 54

The alphastat hypothesis attempts to explain why _______ as temperature falls.

A) blood pH of ectotherms decreases
B) blood pH of ectotherms increases
C) muscle pH of ectotherms decreases
D) blood pH of endotherms decreases

Question 55

Which of the following is(are) the main organ(s) responsible for adjusting blood pH in terrestrial animals?

A) Lungs
B) Kidneys
C) Lungs and kidneys
D) Lungs, kidneys, and liver

Question 56

If HCO₃^- is retained in the body, it binds with _______ and causes the body fluids to become more _______.

A) H⁺ ; acidic
B) H⁺ ; alkaline
C) CO₂ ; acidic
D) CO₂ ; alkaline

Question 57

If exhalation of CO₂ is abnormally increased relative to production, the likely result will be

A) respiratory acidosis.
B) metabolic acidosis.
C) metabolic alkalosis.
D) respiratory alkalosis.

Question 58

Sprinting until your legs give out is a great example of

A) respiratory acidosis.
B) metabolic acidosis.
C) metabolic alkalosis.
D) respiratory alkalosis.

Question 59

What do the main respiratory pigments have in common?

Question 60

In what way can hemoglobin be considered an "honorary enzyme"?

Question 61

Explain the significance of measurements of mixed venous O₂ partial pressure.

Question 62

Why is human hemoglobin a good example of evolutionary molecular design?

Question 63

Compare and contrast oxygen affinity with P₅₀.

Question 64

What is unique about the respiratory pigments and circulatory O₂ transport of the octopus?

Question 65

Compare and contrast the CO₂ Bohr effect and the Haldane effect.

Question 66

What determines the shape of the CO₂ dissociation curve?

Question 67

Why are carbonic anhydrase and anion transporters important in vertebrate CO₂ transport?

Question 68

Why does temperature alter blood pH in ectotherms?