5.3 Diffusion Flashcards
What is diffusion?
Movement of molecules from an area of higher concentration to an area of lower concentration.
Is diffusion an active or passive process?
Passive process, does not require external energy.
What direction do molecules move during diffusion?
From high concentration to low concentration or down the concentration gradient.
How does the rate of diffusion relate to the concentration gradient?
The larger the concentration gradient, the faster the rate of diffusion.
What happens to diffusion when equilibrium is reached?
Molecules continue to move, but there is no net movement (equal concentrations).
How does distance affect the rate of diffusion?
Diffusion is faster over short distances and slower over long distances.
How does temperature affect diffusion?
Higher temperatures increase the rate of diffusion.
How does molecular size affect diffusion rate?
Smaller molecules diffuse faster than larger molecules.
What type of molecules cross membranes by simple diffusion?
Lipophilic (lipid-soluble) molecules.
Can water diffuse through cell membranes?
Yes, though slowly, depending on cholesterol content
How does membrane surface area affect diffusion?
Larger surface area increases the rate of diffusion.
What is Fick’s Law of Diffusion?
Rate of diffusion = Surface Area × Concentration Gradient / Membrane Permeability.
What keeps atmospheric oxygen from diffusing into our bodies across the skin?
The skin’s epithelial tissue is an impermeable barrier to gases.
What kind of molecules generally do not diffuse through membranes easily?
Large, polar, or charged molecules.
