Question

QUESTIONS

1. In your own words, define the terms net movement and diffusion.

2. Is diffusion across a cell membrane a passive or active process? Explain your answer

3. Explain why some particles can diffuse through cell membranes but not others,​

Answer 1

Answer:

1.Diffusion is defined as the net movement of molecules from an area of greater concentration to an area of lesser concentration. The molecules in a gas, a liquid or a solid are in constant motion due to their kinetic energy. Molecules are in constant movement and collide with each other.

2.The simplest forms of transport across a membrane are passive. Passive transport does not require the cell to expend any energy and involves a substance diffusing down its concentration gradient across a membrane.

3.Small nonpolar molecules, such as O2 and CO2, are soluble in the lipid bilayer and therefore can readily cross cell membranes. Small uncharged polar molecules, such as H2O, also can diffuse through membranes, but larger uncharged polar molecules, such as glucose, cannot