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Animal Physiology I > Lecture 10: Blood Gas Transport > Flashcards

Lecture 10: Blood Gas Transport Flashcards

1
Q

Why is oxygen transport in the blood necessary for animals with high metabolic rates?
A. Oxygen is insoluble in air.
B. Solubility of oxygen in aqueous fluids is low.
C. Animals cannot absorb oxygen directly from the environment.
D. Oxygen cannot bind to hemoglobin without transport.

A

Answer: B

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2
Q

What are metalloproteins also known as?
A. Hemoglobin
B. Respiratory pigments
C. Enzymatic carriers
D. Oxygen reducers

A

Answer: B

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3
Q

What is the function of metalloproteins in oxygen transport?
A. They dissolve oxygen in the blood.
B. They eliminate the need for oxygen transport.
C. They increase oxygen carrying capacity by 50-fold.
D. They decrease oxygen carrying capacity to maintain balance.

A

Answer: C

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4
Q

How do metalloproteins bind oxygen?
A. Through a covalent bond
B. By using metal ions that reversibly bind to oxygen
C. By permanently capturing oxygen molecules
D. By forming free radicals

A

Answer: B

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5
Q

Where do metalloproteins bind oxygen in the body?
A. In the digestive system
B. At the respiratory surface
C. In the lymphatic system
D. Inside the nucleus of cells

A

Answer: B

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6
Q

What effect does oxygen binding by metalloproteins have on blood PO₂?
A. It increases blood PO₂.
B. It reduces blood PO₂.
C. It has no effect on blood PO₂.
D. It eliminates blood PO₂ completely.

A

Answer: B

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7
Q

Which of the following is NOT one of the three major types of respiratory pigments?
A. Hemoglobins
B. Hemocyanins
C. Hemerythrins
D. Myoglobin

A

Answer: D

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8
Q

What is the primary role of respiratory pigments like hemoglobin?
A. To facilitate the elimination of carbon dioxide
B. To enhance oxygen solubility in the bloodstream
C. To provide nutrients to tissues
D. To regulate body temperature

A

Answer: B

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9
Q

What happens when metalloproteins bind oxygen?
A. The oxygen gradient in blood decreases.
B. The oxygen gradient in blood increases.
C. The oxygen gradient is eliminated.
D. The oxygen gradient becomes unpredictable.

A

Answer: B

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10
Q

Which of the following statements best summarizes the function of metalloproteins?
A. They provide an alternative to oxygen transport in animals.
B. They transport carbon dioxide away from tissues.
C. They increase oxygen transport capacity to meet high metabolic needs.
D. They store oxygen permanently in the bloodstream.

A

Answer: C

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11
Q

Which property allows metalloproteins to increase oxygen-carrying capacity?
A. They chemically break down oxygen.
B. They bind oxygen using metal ions reversibly.
C. They store oxygen permanently in tissues.
D. They transform oxygen into water for transport.

A

Answer: B

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12
Q

What is the relationship between metalloproteins and the oxygen diffusion gradient?
A. Metalloproteins decrease the diffusion gradient.
B. Metalloproteins eliminate the diffusion gradient.
C. Metalloproteins increase the diffusion gradient by reducing blood PO₂.
D. Metalloproteins stabilize the diffusion gradient.

A

Answer: C

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13
Q

Which of the following is the most common respiratory pigment?
A. Hemoglobin
B. Hemocyanin
C. Hemerythrin
D. Myoglobin

A

Answer: A

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14
Q

How is oxygen bound in hemoglobin?
A. To globin chains only
B. To iron in the heme group
C. Directly to globular proteins
D. As a free ion in plasma

A

Answer: B

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15
Q

How many oxygen molecules can a single hemoglobin molecule bind?
A. One
B. Two
C. Four
D. Eight

A

Answer: C

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16
Q

What structural feature is common to vertebrate hemoglobin?
A. Two beta and two gamma chains
B. Four globin molecules: two alpha and two beta chains
C. Only one alpha chain
D. Six globin molecules with varying compositions

A

Answer: B

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17
Q

Where is hemoglobin typically found in invertebrates and vertebrates?
A. In the nucleus of red blood cells in vertebrates
B. In blood cells of vertebrates and in the circulatory fluid of invertebrates
C. In muscle cells only
D. Free-floating in the cytoplasm

A

Answer: B

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18
Q

What is the primary function of myoglobin?
A. To transport oxygen in the blood
B. To serve as a reserve for oxygen in muscle cells
C. To facilitate carbon dioxide transport
D. To reduce blood pressure

A

Answer: B

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19
Q

How does myoglobin differ from hemoglobin?
A. Myoglobin is tetrameric, while hemoglobin is monomeric.
B. Myoglobin is found in blood, while hemoglobin is in muscle cells.
C. Myoglobin is monomeric and found in the cytoplasm of muscle cells.
D. Myoglobin binds carbon dioxide, while hemoglobin binds oxygen.

A

Answer: C

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20
Q

Which metal ion is central to the oxygen-binding capacity of hemoglobin?
A. Magnesium
B. Copper
C. Iron
D. Zinc

A

Answer: C

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21
Q

What is the second most common respiratory pigment?
A. Hemoglobin
B. Hemerythrin
C. Hemocyanin
D. Myoglobin

A

Answer: C

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22
Q

Which organisms primarily use hemocyanin for oxygen transport?
A. Vertebrates
B. Arthropods and molluscs
C. Amphibians
D. Reptiles

A

Answer: B

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23
Q

What metal ion does hemocyanin use to bind oxygen?
A. Iron
B. Copper
C. Zinc
D. Magnesium

A

Answer: B

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24
Q

What color does hemocyanin turn when oxygenated?
A. Red
B. Blue
C. Green
D. Clear

A

Answer: B

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25
Q

Where is hemocyanin typically found in arthropods and molluscs?
A. Blood cells
B. Hemolymph
C. Muscle cells
D. Plasma

A

Answer: B

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26
Q

What is the relationship between partial pressure of oxygen (pO₂) and oxygen saturation in hemoglobin?
A. It is linear.
B. It is sigmoidal due to cooperative binding.
C. It is hyperbolic.
D. It is logarithmic.

Answer: B

A

Answer: B

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27
Q

What is the significance of maintaining partial pressure in the systemic capillaries?
A. To prevent oxygen loss in mitochondria.
B. To drive oxygen diffusion to the mitochondria.
C. To store oxygen in the bloodstream.
D. To eliminate CO₂ from the body.

A

Answer: B

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28
Q

Why does hemoglobin show cooperative binding to oxygen?
A. To allow linear binding at low partial pressures.
B. To increase efficiency of oxygen binding at higher partial pressures.
C. To compete with other respiratory pigments.
D. To maintain a constant oxygen saturation regardless of pO₂.

A

Answer: B

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29
Q

What is P50 in the context of oxygen saturation?
A. The partial pressure of oxygen at which 100% saturation is achieved
B. The partial pressure of oxygen at which 50% oxygen saturation is achieved
C. The time it takes for hemoglobin to release 50% of bound oxygen
D. The affinity constant for oxygen binding to hemoglobin

A

Answer: B

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30
Q

What does a lower P50 value indicate about hemoglobin’s oxygen affinity?
A. Higher oxygen affinity
B. Lower oxygen affinity
C. No change in oxygen affinity
D. Oxygen release at higher partial pressures

A

Answer: A

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31
Q

Which of the following factors could shift the oxygen dissociation curve to the right, increasing P50?
A. Decrease in carbon dioxide levels
B. Increase in pH (alkalosis)
C. Increase in temperature
D. Decrease in 2,3-BPG levels

A

Answer: C

32
Q

If the P50 value increases, what can be inferred about hemoglobin’s oxygen release?
A. Oxygen release is more difficult.
B. Oxygen release occurs at higher partial pressures.
C. Hemoglobin binds oxygen more tightly.
D. Oxygen release occurs at lower partial pressures.

A

Answer: B

33
Q

How is the P50 value determined from an oxygen dissociation curve?
A. By identifying the oxygen partial pressure at 75% saturation
B. By finding the oxygen partial pressure corresponding to 50% saturation
C. By averaging the partial pressures at 25% and 75% saturation
D. By calculating the slope of the curve at 50% saturation

A

Answer: B

34
Q

What does a rightward shift in the oxygen dissociation curve indicate?
A. Increased oxygen affinity
B. Decreased oxygen affinity
C. Decreased ability to release oxygen to tissues
D. Higher oxygen saturation at lower pO₂

A

Answer: B

35
Q

In what situation might a lower P50 value be observed?
A. During exercise
B. In fetal hemoglobin
C. At higher temperatures
D. In an acidic environment

A

Answer: B

36
Q

What happens to oxygen affinity if the partial pressure of oxygen decreases below the P50 value?
A. Oxygen affinity decreases rapidly.
B. Oxygen affinity increases.
C. There is no effect on oxygen affinity.
D. Hemoglobin releases oxygen more quickly.

A

Answer: B

37
Q

Which condition would likely decrease the P50 value?
A. Acidosis (low pH)
B. Hypothermia (low temperature)
C. Increased levels of 2,3-BPG
D. Hypercapnia (high CO₂ levels)

A

Answer: B

38
Q

What does a “shift to the right” in the oxygen dissociation curve signify?
A. Increased oxygen affinity
B. Decreased oxygen affinity
C. Oxygen binds more tightly to hemoglobin
D. Lower P50 value

A

Answer: B

39
Q

Which of the following causes a “rightward shift” in the oxygen dissociation curve?
A. Low pCO₂ levels
B. Decrease in temperature
C. Increase in 2,3-DPG concentration
D. High pH

A

Answer: C

40
Q

What does a higher P50 value indicate?
A. Increased oxygen affinity
B. Decreased oxygen affinity
C. Constant oxygen affinity
D. Hemoglobin saturation is independent of pO₂

A

Answer: B

41
Q

Why does myoglobin have a lower P50 compared to hemoglobin?
A. Myoglobin is tetrameric.
B. Myoglobin binds oxygen more easily at low pO₂.
C. Myoglobin requires high pO₂ for oxygen binding.
D. Myoglobin’s function is to release oxygen, not store it.

A

Answer: B

42
Q

What is the relationship between oxygen affinity and P50?
A. Direct relationship: higher P50 means higher affinity.
B. Inverse relationship: higher P50 means lower affinity.
C. No relationship exists between P50 and affinity.
D. P50 and affinity are equal under normal conditions.

A

Answer: B

43
Q

Which hemoglobin type is better suited for oxygen storage in muscle tissues?
A. Myoglobin
B. Fetal hemoglobin
C. Adult hemoglobin
D. Hemocyanin

A

Answer: A

44
Q

What structural change in hemoglobin facilitates cooperative binding?
A. Transition from the relaxed (R) state to the tense (T) state
B. Disruption of salt bridges after the binding of the first O₂ molecule
C. Formation of salt bridges at high pO₂
D. Loss of hydrogen bonds in the globin chains

A

Answer: B

45
Q

What does the Bohr Effect describe?
A. Hemoglobin’s increased affinity for oxygen at low CO₂ levels
B. The effect of pH and CO₂ on hemoglobin’s oxygen affinity
C. The cooperative binding of oxygen to hemoglobin
D. The impact of temperature on hemoglobin saturation

A

Answer: B

46
Q

If blood pH decreases from 7.4 to 7.2, what happens to hemoglobin’s oxygen dissociation curve?
A. It shifts to the left, indicating higher affinity for oxygen.
B. It shifts to the right, indicating lower affinity for oxygen.
C. It remains unchanged because pH does not affect hemoglobin.
D. It becomes hyperbolic, indicating a loss of cooperativity.

A

Answer: B

47
Q

A respiratory pigment has a P50 value of 2 kPa. What can you infer about its oxygen affinity?
A. It has high oxygen affinity.
B. It has low oxygen affinity.
C. It releases oxygen readily at low pO₂.
D. It has the same affinity as hemoglobin.

A

Answer: A

48
Q

Using the oxygen dissociation curve, what happens to hemoglobin saturation at a pO₂ of 40 mmHg under normal physiological conditions?
A. It is almost completely saturated (~98%).
B. It is around 75% saturated.
C. It drops to 50% saturation.
D. It remains below 20% saturation.

A

Answer: B

49
Q

In tissues with high CO₂ production, how does the Bohr Effect enhance oxygen delivery?
A. By increasing hemoglobin’s oxygen affinity
B. By increasing pH and shifting the dissociation curve to the left
C. By decreasing pH and reducing hemoglobin’s oxygen affinity
D. By preventing cooperative binding of oxygen

A

Answer: C

50
Q

In high-altitude environments, what adaptive shift might occur in the oxygen dissociation curve?
A. Rightward shift due to increased 2,3-BPG production
B. Leftward shift to enhance oxygen affinity at low pO₂
C. Hyperbolic shift to improve cooperative binding
D. Flattening of the curve to stabilize oxygen levels

A

Answer: B

51
Q

Which of the following conditions would increase the P50 value of hemoglobin?
A. Decreased 2,3-BPG concentration
B. Increased temperature and lower pH
C. Fetal hemoglobin replacing adult hemoglobin
D. Hyperventilation leading to reduced CO₂ levels

A

Answer: B

52
Q
  1. How does the transition from the tense (T) state to the relaxed (R) state in hemoglobin affect its oxygen affinity?
    A. Oxygen affinity decreases as hemoglobin moves from the T state to the R state.
    B. Oxygen affinity increases as hemoglobin moves from the T state to the R state.
    C. The transition has no effect on oxygen affinity.
    D. The T state has higher oxygen affinity than the R state.
A

Answer: B

53
Q

Which of the following is NOT true about cooperative binding in hemoglobin?
A. It allows hemoglobin to bind oxygen more easily after the first oxygen molecule binds.
B. It results in a sigmoidal oxygen dissociation curve.
C. It occurs because myoglobin facilitates oxygen storage in muscle tissues.
D. It involves structural changes in hemoglobin from the T state to the R state.

A

Answer: C

54
Q

What happens to hemoglobin’s oxygen affinity when blood pH decreases?
A. Oxygen affinity increases.
B. Oxygen affinity decreases.
C. Oxygen affinity remains unchanged.
D. Hemoglobin becomes saturated at lower pO₂.

A

b)

55
Q

What is the physiological significance of a right shift in the oxygen dissociation curve?
A. Improved oxygen loading in the lungs
B. Enhanced oxygen unloading at active tissues
C. Increased hemoglobin saturation in acidic environments
D. Reduced oxygen delivery to tissues

A

Answer: B

56
Q

What effect does an increase in PCO₂ have on the oxygen dissociation curve?
A. Shifts the curve to the left, increasing oxygen affinity
B. Shifts the curve to the right, reducing oxygen affinity
C. Increases hemoglobin saturation at all pO₂ levels
D. Does not affect the oxygen dissociation curve

A

Answer: B

57
Q

How does an increase in body temperature affect oxygen affinity?
A. Increases oxygen affinity by stabilizing hemoglobin
B. Decreases oxygen affinity, promoting oxygen unloading
C. Increases oxygen loading in tissues
D. Has no effect on oxygen binding

A

Answer: B

58
Q

What is the function of 2,3-diphosphoglycerate (DPG) in oxygen transport?
A. Increases hemoglobin’s oxygen affinity
B. Decreases hemoglobin’s oxygen affinity to promote unloading
C. Stabilizes the T state to prevent oxygen binding
D. Shifts the oxygen dissociation curve to the left

A

Answer: B

59
Q

In what condition is 2,3-DPG production increased?
A. Low RBC count (anemia)
B. High blood pH
C. Reduced body temperature
D. High oxygen saturation

A

Answer: A

60
Q

Why is the Bohr Effect beneficial during exercise?
A. It increases hemoglobin’s oxygen affinity in tissues.
B. It enhances oxygen unloading in acidic, high-CO₂ environments like muscles.
C. It reduces oxygen consumption by hemoglobin.
D. It increases hemoglobin saturation in the lungs.

A

Answer: B

61
Q

Which of the following scenarios would result in a left shift of the oxygen dissociation curve?
A. Increased production of 2,3-DPG
B. High PCO₂ levels in tissues
C. Alkalosis (increased blood pH)
D. High body temperature

A

Answer: C

62
Q

In an anemic individual, how does increased 2,3-DPG production help with oxygen delivery?
A. It stabilizes the R state of hemoglobin, increasing oxygen affinity.
B. It stabilizes the T state of hemoglobin, reducing oxygen affinity and enhancing unloading.
C. It binds directly to oxygen, improving transport capacity.
D. It shifts the oxygen dissociation curve to the left, improving oxygen retention.

A

Answer: B

63
Q

How does high 2,3-DPG production affect oxygen affinity in hemoglobin?
A. It increases oxygen affinity, causing a left shift in the dissociation curve.
B. It decreases oxygen affinity, causing a right shift in the dissociation curve.
C. It stabilizes hemoglobin, reducing oxygen unloading.
D. It prevents oxygen binding at low partial pressures.

A

Answer: B

64
Q

Why do high-altitude mice produce little or no 2,3-DPG?
A. To enhance oxygen unloading to tissues
B. To increase oxygen extraction from the lungs at high altitudes
C. To promote anemia adaptation
D. To reduce oxygen binding at low pO₂

A

Answer: B

65
Q

What is the physiological advantage of a hyperbolic oxygen dissociation curve in high-altitude mice?
A. Easier oxygen unloading in tissues
B. Greater oxygen loading in the lungs despite low pO₂
C. Increased oxygen saturation at normal pO₂
D. Stabilized hemoglobin under acidic conditions

A

Answer: B

66
Q

What happens to the oxygen dissociation curve in humans acclimated to high altitudes?
A. It shifts to the left to improve oxygen loading at low pO₂.
B. It shifts to the right due to increased 2,3-DPG production.
C. It becomes hyperbolic, similar to high-altitude mice.
D. It remains unchanged as humans cannot adapt to high altitudes.

A

Answer: B

67
Q

What is a potential disadvantage of low 2,3-DPG production in high-altitude mice?
A. Reduced oxygen extraction in the lungs
B. Difficulty in oxygen unloading at tissues
C. Higher P50 values in the lungs
D. Increased oxygen delivery to inactive tissues

A

Answer: B

68
Q

Compare the oxygen affinity adaptations in high-altitude mice and humans. What are the advantages and disadvantages of these adaptations for oxygen transport at high altitudes?

A

High-altitude mice exhibit a hyperbolic oxygen dissociation curve due to low or no 2,3-DPG production. This allows them to extract oxygen more effectively in their lungs, even at low partial pressures, which is critical for survival at high altitudes. However, the disadvantage is that oxygen unloading at tissues is reduced, potentially impairing oxygen delivery to actively metabolizing tissues.

In humans, high-altitude acclimation is characterized by increased 2,3-DPG production, which shifts the oxygen dissociation curve to the right. This reduces hemoglobin’s oxygen affinity, improving oxygen unloading at tissues. The disadvantage is slightly reduced oxygen loading efficiency in the lungs compared to normal conditions, but this is offset by the higher altitude’s lower pO₂.

69
Q

Why does the human body produce more 2,3-DPG at high altitudes?
A. To increase oxygen affinity of hemoglobin
B. To decrease oxygen affinity and enhance oxygen unloading at tissues
C. To improve oxygen extraction from the lungs
D. To reduce the production of red blood cells

A

Answer: B

70
Q

What is a disadvantage of 2,3-DPG production at high altitudes?
A. Reduced oxygen loading at low partial pressures
B. Increased oxygen binding in tissues
C. Excessive red blood cell production
D. Decreased oxygen unloading in tissues

A

Answer: A

71
Q

What is the role of increased red blood cell production at high altitudes?
A. To increase oxygen delivery to tissues
B. To improve oxygen saturation at low pO₂
C. To reduce oxygen affinity in hemoglobin
D. To enhance oxygen unloading at higher temperatures

A

Answer: A

72
Q

How does the sigmoidal oxygen dissociation curve in humans benefit them at high altitudes?
A. Promotes oxygen unloading at tissues and loading at the lungs
B. Increases oxygen affinity for all partial pressures
C. Prevents oxygen release to inactive tissues
D. Improves cooperative binding at low pO₂

A

Answer: A

73
Q

What causes high-altitude pulmonary edema (HAPE)?
A. Decreased oxygen diffusion in the lungs
B. Constriction of pulmonary blood vessels due to low oxygen
C. Increased oxygen affinity of hemoglobin
D. Decreased blood pressure in pulmonary capillaries

A

Answer: B

74
Q

Which of the following is the most severe consequence of high-altitude exposure?
A. Hyperventilation
B. High-altitude pulmonary edema (HAPE)
C. High-altitude cerebral edema (HACE)
D. Increased 2,3-DPG production

A

Answer: C

75
Q

What physiological change helps the body adapt to reduced oxygen levels at high altitudes?
A. Decreased production of 2,3-DPG
B. Increased constriction of systemic blood vessels
C. Increased red blood cell production and hemoglobin concentration
D. Reduced hemoglobin-oxygen saturation

A

Answer: C

76
Q

How does the pulmonary circuit normally prevent fluid buildup?
A. By maintaining low pressure and high compliance
B. By constricting blood vessels to increase pressure
C. By increasing oxygen affinity in hemoglobin
D. By reducing the production of red blood cells

A

Answer: A

Animal Physiology I (20 decks)

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