Question 1

At which point(s)in the figure below would the blood have the highest concentration of CO₂?

Accepted Answer

The answer of At which point(s)in the figure below would...

Question 2

The oxygen-carrying component in red blood cells is

Accepted Answer

The oxygen-carrying component in red blood cells is hemoglobin. Hemoglobin is a protein found in red blood cells that binds to oxygen and carries it from the lungs to the rest of the body.

Question 3

Which part of the diagram shows alveoli?

Accepted Answer

The answer of Which part of the diagram shows alveoli?...

Question 4

Most CO₂ is transported to the lungs in which of the following ways?

Accepted Answer

The majority of CO₂ is transported from the tissues to the lungs as either bicarbonate ions (HCO₃⁻), which are formed by the reaction of CO₂ with water in the presence of the enzyme carbonic anhydrase, or it is carried by hemoglobin as carbamino compounds. Only a small amount of CO₂ is transported dissolved in the plasma or as carboxyl.

Question 5

Sometime after a human baby is born, the expression of fetal hemoglobin ceases and the expression of adult hemoglobin begins. Imagine that a baby is born and this switch from fetal to adult hemoglobin does not occur. In which part of the world would this baby be well-adapted to living?

Accepted Answer

Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, which would be advantageous in high-altitude cities where oxygen levels are lower.

Question 6

When bar-headed geese fly at very high altitudes (possibly over Mount Everest!), they breathe very thin air where the partial pressure of oxygen is very low compared to that at sea level. They are able to do this because they have a modified version of the hemoglobin protein. Which of the following is their hemoglobin protein most likely similar to in terms of its ability to bind oxygen?

Accepted Answer

The hemoglobin of bar-headed geese is most likely similar to that of a human fetus because fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, allowing for efficient oxygen uptake in the low-oxygen environment at high altitudes. The hemoglobin of a bird that lives at sea level or an earthworm would not be adapted for high altitude oxygen uptake.

Question 7

What prompts a newborn baby to start to breathe?

Accepted Answer

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Question 8

When bar-headed geese fly at very high altitudes (possibly over Mount Everest!), they breathe very thin air where the partial pressure of oxygen is very low compared to that at sea level. Which of the following adaptions would help the geese efficiently exchange gases when flying at high altitudes?

Accepted Answer

Hemoglobin with a high affinity for oxygen would allow the geese to efficiently take up as much oxygen as possible from the thin air at high altitudes.

Question 9

Some crocodiles and turtles have an exceptional ability to divert blood flow through the heart when they are diving and no longer breathing and exchanging gases. Which of the following most likely occurs when these animals dive?

Accepted Answer

When these animals dive and are no longer breathing and exchanging gases, they can divert the blood flow through a specialized blood vessel called the bypass tract. This allows oxygenated blood to be sent to the rest of the body to support bodily functions, instead of being sent to the lungs for gas exchange which is not happening while underwater.

Question 10

At which point(s)in the figure is blood oxygen-rich?

Accepted Answer

The answer of At which point(s)in the figure is blood...

Question 11

After reading the paragraphs below, answer the questions that follow.
Many amphibians (including many frogs, toads, and salamanders) spend the early part of their lives in water but live on land as adults. The adults of many species return to water to breed and lay their eggs. Frogs have small lungs and supplement their oxygen intake by breathing through the skin. Although large frogs have more total surface area than smaller frogs, the larger frogs have a lower surface area/volume ratio (less skin surface relative to their total body volume). To keep their respiratory surfaces moist, frogs are generally found in wet or very moist locations.
In an experiment designed to investigate oxygen consumption in relation to body size, frogs from five different species were weighed and placed in a respirometer (a machine that measures oxygen consumption) for 1 hour. The table shows the results of the experiment.
 
-From the data in the table, it is reasonable to conclude that

Accepted Answer

The answer of After reading the paragraphs below, answer the...

Question 12

Which of the figures below represents countercurrent exchange? The arrows indicate direction of flow, and the numbers indicate temperatures in degrees Celsius.

Accepted Answer

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Question 13

Which of the following contributes to gas exchange in the human fetus?

Accepted Answer

Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, allowing it to efficiently extract oxygen from maternal blood in the placenta, facilitating gas exchange in the developing fetus.

Question 14

If the hemoglobin molecules in your red blood cells suddenly were unable to bind carbon dioxide and hydrogen ions, what would happen to your blood pH?

Accepted Answer

If hemoglobin cannot bind carbon dioxide and hydrogen ions, these molecules will remain in the blood, leading to an increase in acidity (lowering of pH) as they combine with water to form carbonic acid.

Question 15

Pulmonary fibrosis is a lung disease that is characterized by damage and scarring of lung tissue. This results in the lungs becoming stiff and inelastic. What function is most likely to be impaired in someone with pulmonary fibrosis?

Accepted Answer

The answer of Pulmonary fibrosis is a lung disease that...

Question 16

The flow rate of a gas through a tube is proportional to the diameter of the tube. Through which structure in the human respiratory system does air flow the fastest?

Accepted Answer

The trachea has a larger diameter than the bronchi and bronchioles, so according to the given principle, air should flow fastest through the trachea.

Question 17

Which respiratory structure likely has the largest surface area for gas exchange to occur?

Accepted Answer

The alveoli of a pig have a very large surface area due to their numerous small sacs and their location in the lungs, which are highly branched structures. This means that there is a lot of surface area in a relatively small space, which allows for efficient gas exchange. The other options, such as the body surface of a worm or the tracheal system of a house fly, have much less surface area for gas exchange to occur. Although the gills of a trout are also specialized for gas exchange, they are not as efficient as the alveoli due to their location in the water, which provides less oxygen than air.

Question 18

After reading the paragraphs below, answer the questions that follow.
Many amphibians (including many frogs, toads, and salamanders) spend the early part of their lives in water but live on land as adults. The adults of many species return to water to breed and lay their eggs. Frogs have small lungs and supplement their oxygen intake by breathing through the skin. Although large frogs have more total surface area than smaller frogs, the larger frogs have a lower surface area/volume ratio (less skin surface relative to their total body volume). To keep their respiratory surfaces moist, frogs are generally found in wet or very moist locations.
In an experiment designed to investigate oxygen consumption in relation to body size, frogs from five different species were weighed and placed in a respirometer (a machine that measures oxygen consumption) for 1 hour. The table shows the results of the experiment.
 
-If you could alter the shape of a frog so that it was long and thin instead of compact, the frog's oxygen transfer efficiency would

Accepted Answer

A long and thin frog would have a higher surface area/volume ratio, meaning there would be more skin surface relative to its body volume. This would increase the frog's oxygen transfer efficiency.

Question 19

When you hyperventilate (breathe too fast), respiratory alkalosis (elevated blood pH)can occur, which can cause you to faint. A common but potentially dangerous method to reverse respiratory alkalosis is to hold a paper bag over your mouth and take normal breaths, thereby rebreathing the exhaled air. How might this method reverse respiratory alkalosis?

Accepted Answer

By rebreathing exhaled air in the paper bag, the concentration of carbon dioxide in the inhaled air increases. Carbon dioxide will then diffuse back into the blood and combine with the water to form carbonic acid, which decreases blood pH and corrects respiratory alkalosis.

Question 20

Cigarette smoking can sometimes lead to development of a "smoker's cough," which results from paralysis of cilia in the airways. Why would the paralysis of cilia lead to smoker's cough?

Accepted Answer

Paralyzed cilia can no longer clear the airways of mucus, which can accumulate and cause irritation, leading to coughing as a reflex to remove the mucus.

Quiz 22: Gas Exchange

At which point(s) in the figure below would the blood have the highest concentration of CO₂?