4.4 Active transport

Question 1

Define active transport

Answer 1

The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins

Question 2

How does active transport differ from passive forms of transport?

Answer 2

• Metabolic energy in the form of ATP is required
  -Substances are moved against a concentration gradient instead of along one
  -Carrier proteins acting as pumped are involved

Question 3

Describe the direct active transport of a single molecule or ion

Answer 3

1. Molecule or ion binds to the receptor sites on the carrier protein
2. On the inside of the cell ATP binds to the carrier protein causing it to split into ADP and Pi causing the protein to change shape and open to the opposite side of the membrane
3. Molecule or ion is then released to the other side of the membrane
   4.

Question 4

Compare and contrast the process of active transport with facilitated diffusion

Answer 4

Both use carrier proteins
AT occurs against a conc gradient while FD occurs along a conc gradient
AT is active and requires metabolic energy in the form of ATP
FD is passive no metabolic energy required