Oxygen and carbon dioxide are exchanged in the lungs and through all cell membranes by a. active transport, b. diffusion, c. filtration, d. osmosis.

Verified step by step guidance

1. Identify the process by which gases like oxygen and carbon dioxide move across cell membranes.
2. Consider the characteristics of each option: active transport, diffusion, filtration, and osmosis.
3. Recall that active transport requires energy to move substances against their concentration gradient.
4. Understand that diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.
5. Recognize that oxygen and carbon dioxide exchange in the lungs occurs without energy input, aligning with the process of diffusion.

Key Concepts

Diffusion

Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. This passive transport mechanism is crucial for gas exchange in the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out, allowing for efficient respiratory function.

Active Transport

Active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, requiring energy input, usually in the form of ATP. This process is essential for transporting substances against their concentration gradient, but it is not the primary mechanism for gas exchange in the lungs.

Cell Membrane Permeability

Cell membrane permeability refers to the ability of substances to pass through the cell membrane. The lipid bilayer of cell membranes allows small, nonpolar molecules like oxygen and carbon dioxide to diffuse freely, facilitating gas exchange in tissues and the lungs without the need for energy.