B3.1 Membrane Transport Flashcards
What is passive transport?
Molecules moving across a cell membrane from a region of higher concentration to a region of lower concentration without the use of energy
What is diffusion?
The movement of particles from a region of high concentration to a low one, creates an equilibrium
Factors that affect the rate of diffusion?
The concentration gradient, the surface area, the length of diffusion path
How do steroids move across the plasma membrane of a cell?
They bind to receptors and move towards the cytoplasm or nucleus of a cell
What is osmosis?
It is the diffusion of water because the cell membrane is impermeable to solutes.
Types of solutions for osmosis
Isotonic = equilibrium
Hypotonic = water moves into the cell
Hypertonic = water moves out of the cell
Osmosis in plant cells
Water often moves into the cell, turgor pressure is exerted against the cell wall
What is facilitated diffusion?
Large and polar molecules cant get across the membrane, so they use a transmembrane protein as a vessel
Channel proteins and carrier proteins
What is active transport?
It requires ATP, integral protein pumps use ATP to move ions or large molecules uses across the cell membrane
How does ATP release energy
A adenosine and triphosphate and attached, when one phosphate is removes it releases energy
Types of protein pumps
Uniporter = one molecule can pass through
Symporter = Two molecules pass through in the same direction
Antiporter = Two molecules pass through in the different directions
