All Flashcards
What is the effect of the hydrophobic tails of the phospholipid bilayer?
They create a barrier that repels polar and charged molecules, restricting their passage across the membrane.
What is the effect of a high concentration of a substance on one side of a membrane?
Diffusion occurs, moving the substance to an area of lower concentration until equilibrium is reached.
What is the effect of a cell having a cell wall?
Provides structural support and protection to the cell.
Describe the process of diffusion across a membrane.
Molecules move from an area of high concentration to an area of low concentration, without requiring energy input from the cell. Small, nonpolar molecules can diffuse freely across the phospholipid bilayer.
Compare and contrast substances that can freely cross the cell membrane with those that require transport proteins.
Freely cross: Small, nonpolar molecules | Require transport proteins: Large, polar, charged molecules (ions)
Compare the cell wall composition of plants and fungi.
Plants: Cellulose | Fungi: Chitin