Active Transport.

Question 1

Define active transport.

Answer 1

Active transport is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration.

Question 2

Examples of active transport include:

Answer 2

• uptake of glucose by epithelial cells in the villi of the small intestine and by kidney tubules.
• uptake of ions from soil water by root hair cells in plants.

Question 3

Explain how active transport involves proteins.

Answer 3

Carrier proteins move substances from one side of the membrane to the other using energy.

Question 4

Active transport by using carrier proteins embedded in the cell membrane to pick up specific molecules and take them through the cell membrane against their concentration gradient:

Answer 4

1) Substance combines with carrier protein molecule in the cell membrane.
2) Carrier transports substances across the membrane using energy from respiration to give them the kinetic energy needed to change shape and move the substance through the cell membrane.
3) Substance released into cell.