All Flashcards
Define selective permeability.
The cell membrane controls which substances can pass in and out of the cell.
What is a phospholipid bilayer?
A double layer of phospholipids that forms the cell membrane. It has hydrophilic heads facing outwards and hydrophobic tails facing inwards.
Define diffusion.
The movement of molecules from an area of high concentration to an area of low concentration.
What is cellulose?
A type of carbohydrate that is the primary component of plant cell walls.
Define chitin.
A polysaccharide that makes up the cell walls of fungi.
Define peptidoglycan.
A substance that makes up the cell walls of bacteria.
What are aquaporins?
Transport proteins that facilitate the movement of water across the cell membrane.
Label the components of the phospholipid bilayer.
1: Hydrophilic head, 2: Hydrophobic tail, 3: Phospholipid bilayer
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.