4.4 - Active Transport

Question 1

What is active transport?

Answer 1

Movement of particles from low to high concentration

Question 2

Does active transport require energy?

Answer 2

Yes

Question 3

Why does active transport require energy?

Answer 3

Particles move against a concentration gradient

Question 4

Is active transport active or passive?

Answer 4

Active

Question 5

What type of proteins are involved in active transport?

Answer 5

Carrier proteins

Question 6

How does active transport work?

4 steps

Answer 6

1. The molecule or ion binds to the carrier protein.
2. ATP binds to the carrier protein.
3. Hydrolysis of ATP to ADP and phosphate (Pi) causes the carrier protein to change shape. This releases the molecule or ion on the opposite side of the membrane.
4. The phosphate (Pi) is released from the carrier protein, causing the carrier protein to return to its original shape, ready to be used again.

Question 7

What factors affect the rate of active transport?

4 factors

Answer 7

• Temperature - At higher temperatures, particles have more kinetic energy and travel faster. Respiration also increases with temperature. Very high temperatures denature carrier proteins, decreasing the rate of active transport.
• Thickness of membrane - Particles travel shorter distances through thin exchange surfaces, so travel faster.
• Number of carrier proteins - The more of these proteins, the faster the rate of active transport.
• Rate of respiration - The more respiration, the more ATP available for active transport.

Question 8

How does temperature affect active transport?

Answer 8

• Particles have more kinetic
  energy kinetic
  energy and travel faster
• Respiration also increases with temperature.
• Very high temperatures denature carrier proteins, decreasing the rate of active transport.

Question 9

How does membrane thickness affect active transport?

Answer 9

Particles travel shorter distances through thin exchange surfaces, so travel faster

Question 10

How does the number of carrier proteins affect active transport?

Answer 10

more of these proteins, the faster the rate of active transport.

Question 11

How does the rate of respiration affect active transport?

Answer 11

The more respiration, the more ATP available for active transport.