Passive Transport Flashcards
Passive transport
Movement of materials across the cell membrane without the using energy
Happens because of differences in concentration
Concentration gradient
Gradual change in concentration from one region to another
Material spontaneously move from high to low
Diffusion
Refers to the movement of any molecule from high to low concentration
Simple diffusion
Diffusion of substances directly through the phospholipid bilayer
Facilitated diffusion
Diffusion of substances through the cell membrane via channel and carrier proteins
Channel protein
Provide a tunnel through which certain materials can diffuse
Has unique diameter and amino acid lining
Carrier protein
Bind to material and change their own shape to allow diffusion of material
Osmosis
Refers to the movement of water from an area of high to low water concentration across a semipermeable membrane
Concentration
Refers to the amount of solute in a solution
Isotonic, hypotonic and hypertonic
Words used to describe the concentration difference between 2 solutions
Isotonic (normal)
Solutions with equal solute concentrations
Rate at which water leaves the cell = rate at which water is entering the cell
Hypotonic
Solution with a lower solute concentration (high water concentration)
E.g. fresh water
Animal cells absorb water until it pops = lysed
Plant cells absorbs water but is stopped by cell wall = turgid
Hypertonic
Solution with a higher solute concentration (low water concentration)
E.g. salty ocean water - water moves out of cell to achieve balance
Animal cell is shriveled
Plant cell is flaccid - completely dry = plasmolyzed
Osmosis vs diffusion
Same = direction of material movement, passive
Osmosis = water across semipermeable membrane
Diffusion = any material across varied type of membrane
