Co Transport Flashcards
What is co transport
Co-transport is the coupled movement of substances across a cell membrane via a carrier protein
Describe how movement across membranes occurs by co transport
Two different substances bind to and move simultaneously via a co transporter protein
How is movement coupled in co transport?
One substance moving against it concentration gradient it often coupled with the movement of another down its concentration gradient
What is step one in co transport in the small intestines?
Na+ is pumped out of the intestinal cells actively by active transport
What is step two in co transport in the small intestines?
Na+ and glucose move into intestinal cells by facilitated diffusion using carrier proteins
What is step three in co transport in the small intestines?
Glucose diffuses into blood by facilitated diffusion using channel proteins
What pumps potassium in to the cell and sodium out?
A sodium potassium pump
What does a sodium potassium pump do
Pumps K+ in the cell and Na+ out
Why do we need glucose to go from the small intestine to the blood
So it can be transported around the body for respiration to release energy
What can movement of sodium be considered? Why?
It can considered indirect/secondary active transport
This is because it is reliant on a concentration gradient established by active transport
How does surface area affect the rate of movement across cell membranes
Increasing surface area of membrane increases the rate of movement
How does number of channel/carrier proteins affect the rate of movement across cell membranes
Increasing the number of channel/carrier proteins increases the rate of facilitated diffusion and active transport
How does concentration gradient affect the rate of movement across cell membranes
Increasing concentration gradient increases the rate of simple diffusion
Increasing concentration gradient increases the rate of facilitated diffusion until the number of channel or carrier proteins becomes a limiting factor as they are all being used.
How does water potential affect the rate of movement across cell membranes
Increasing water potential gradient increases the rate of osmosis
