5.4 Active transport

Question 1

What is active transport

Answer 1

The movement of particles across a plasma membrane against a concentration gradient requiring metabolic energy

Question 2

Describe Active transport across a membrane using a carrier proteins

Answer 2

Molecule binds to specific complementary receptor on carrier protein
On inside of cell, ATP binds to carrier protein, hydrolysed ⟶ ADP + Pi
Phosphate binds to carrier protein, causes conformational change.
Molecule released into cell.
Phosphate released from carrier protein, phosphorylates ADP & causes carrier protein to return to original shape.

Question 3

What is bulk transport

Answer 3

Form of active transport
where large molecules or whole bacterial cells
are moved in/out of cells by exocytosis/endocytosis

Question 4

Describe endocytosis and exocytosis

Answer 4

ENDOCYTOSIS - bulk transport of material into cell by invagination of plasma membrane, forming vesicle
Phagocytosis (solids), pinocytosis (liquids)
EXOCYTOSIS - bulk transport of material out of cell by fusion of vesicles with plasma membrane & release of contents

Question 5

What causes the conformational change in shape of carrier proteins during active transport?

Answer 5

Binding of phosphate to carrier protein after ATP binds to carrier protein & is hydrolysed

Question 6

What’s phagocytosis

Answer 6

endocytosis of solid material