Active Transport Flashcards
(8 cards)
What is active transport
A process which uses energy to move molecules and ions across a plasma membrane against a concentration gradient from an area of lower concentration to an area of higher concentration
What are involved in active transport
Carrier proteins and co transporters
Tell me about carrier proteins
A molecules attaches to the carrier protein, this changes its shape and moves the molecule across the membrane releasing it on the other side
Does active transport use energy
Yes
Tell me about co transporters
They are a type of carrier protein, they bind two molecules at a time, the concentration of one molecule is used to move the other molecule against its own concentration gradient
Explain co transport and the absorption of glucose
- Sodium ions are actively transported out of the epithelial cells in the ileum by the sodium potassium pump, this creates a concentration gradient - there is now a higher concentration of sodium ions in the lumen of the ileum than inside the cell
- This causes sodium ions to diffuse from the lumen of the ileum into the epithelial cell down their concentration gradient, they do this by the sodium glucose co transporter proteins, the co transporter carries glucose into the cell with the sodium, as a result the concentration of glucose inside the cell increases
- Glucose diffuses out of the cell into the blood down the concentration gradient through a channel protein by facilitated diffusion
What are the factors that affect the rate of active transport and explain
The speed of the individual carrier protein - the faster they work, the fast the rate if active transport
The number of carrier proteins present - the more proteins present, the faster the rate of diffusion
The rate of respiration in the cell and the availability of ATP - if respiration is inhibited, active transport can’t take place
What protein is involved in active transport
Carrier
