Diffusion, Active and Co transport Flashcards
2 types of diffusion
Simple
Facilitated
What is simple diffusion
All particles are in constant random motion and are distributed evenly
What is facilitated diffusion used for
Charged ions, large and polar molecules that can’t diffuse across the phospholipid bilayer
How do protein channels work
Complementary ions binds to protein
Changes shape of protein closing one side and opening the other
Ion passes through membrane
How do carrier proteins work
Complementary molecule binds to protein
Protein changes shape
Molecule passes through membrane
What is active transport
The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of high concentration using ATP and carrier proteins
What is diffusion
The net movement of molecules or ions from a region of high concentration to a region of low concentration via a selectively permeable membrane
How does active transport work
Molecule binds to complementary receptor on carrier protein
ATP binds to protein on inside of the cell
Phosphate breaks of ATP, releasing energy
Energy causes protein to change shape and allowing passage of molecule
ADP disconnects from protein causing it to revert to original shape
ADP eventually binds back with Pi to form ATP
Co transport process
Sodium ions are actively transported through sodium potassium pump into the blood
High concentration in lumen of the ileum and low concentration in cell causes facilitated diffusion
Sodium ions diffuse through carrier proteins, as they diffuse they can carry glucose/amino acids
Glucose/amino acids can pass into blood via facilitated diffusion
Factors that affect rate of diffusion
Conc gradient
Particle size/charge (uncharged +small diffuse faster )
Temperature
Surface area
Distance
Number of channels/carriers
