Multiple Choice
What is the approximate partial pressure of oxygen in the blood as it enters and leaves the capillaries of the alveoli?
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22. The Respiratory System
Respiration
1:39 minutesProblem 5
Textbook Question
Which of the following determines the direction of gas movement?
a. Solubility in water
b. Partial pressure gradient
c. Temperature
d. Molecular weight and size of the gas molecule
Verified step by step guidance1
Understand that gas movement, especially in biological systems like the lungs, occurs primarily by diffusion.
Recall that diffusion of gases depends on differences in partial pressures, which create a gradient that drives gas molecules from areas of higher partial pressure to areas of lower partial pressure.
Recognize that while solubility, temperature, and molecular weight can affect the rate of diffusion, they do not determine the direction of gas movement.
Identify that the key factor determining the direction of gas movement is the partial pressure gradient, because gases move down their partial pressure gradients.
Conclude that among the options given, the partial pressure gradient (option b) is the correct determinant of the direction of gas movement.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Partial Pressure Gradient
The partial pressure gradient refers to the difference in the partial pressures of a gas between two areas. Gas molecules move from regions of higher partial pressure to lower partial pressure, driving diffusion. This gradient is the primary factor determining the direction of gas movement in processes like respiration.
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Guided course
6:12
Partial Pressure
Solubility in Water
Solubility in water describes how well a gas dissolves in a liquid, such as blood or water. While it affects the amount of gas that can be carried or absorbed, it does not determine the direction of gas movement, which depends on pressure differences.
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01:54Introduction to Water
Molecular Weight and Size of Gas Molecules
Molecular weight and size influence the rate at which gas molecules diffuse, with smaller and lighter molecules generally diffusing faster. However, these factors do not dictate the direction of gas movement, which is governed by partial pressure gradients.
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7:17Classes of MHC Molecules
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