Membrane Transport Flashcards
What are the two kinds of membrane transport?
(2)
Passive and active
What is passive transport?
(1)
Movement of substances across membranes with no use of energy
Energy in form of ATP
What is diffusion?
(1)
The passive movement of particles
High conc. to low conc.
What must be present for diffusion to occur?
(3)
- A concentration gradient
- Membrane permeability for that specific substance
- Movement in both directions
When does diffusion stop?
(1)
When an equilibrium is reached
What is simple diffusion?
(1)
When substances other than water diffuse between the phospholipid molecules
i.e. O2, CO2
Factors that affect ease of diffusion through a membrane
Whether or not simple diffusion is possible too
(2)
- Size of molecule
- Polarity and charge of molecule
small partiles diffuse faster, non polar substances move with more ease
What is facilitated diffusion?
clue: why does it occur
(1)
When ions or molecules diffuse through channels because they aren’t able to pass through the hydrophobic membrane
i.e. Na+, K+, glucose
How does facilitated diffusion work?
(3)
- Using transmembrane proteins called channels
- Channel proteins are specific to one particle
- Cells synthesize (control) certain channel proteins specialty
When does facilitated diffusion level off?
clue: saturation of something
(1)
When total saturation of carrier proteins occurs
What is a carrier protein?
clue: what does it change?
(1)
Other transmembrane proteins that transport larger molecules but by changing their conformation instead
other than channels
What is osmosis?
osmosis=diffusion of water
(1)
Passive movement of water molecules across a semipermeable membrane
Low conc. to high conc.
What does semi-permeable mean?
(1)
Only allows certain substances to pass through
i.e water for osmosis
What is a solute?
Clue: U like a test tube
(1)
The substance to be dissolved
What is a solvent?
Clue: V arrow pointing down
(1)
The substance the solute is dissolved in
