Section 1.8 Active Transport

Question 1

What are the two main ways substances move into and out of the cell?

Answer 1

• Diffusion, down a concentration gradient (high to low concentration)
• Active transport, against the concentration gradient (low to high concentration)

Question 2

What is active transport?

Answer 2

Active transport is needed to move substances against the concentration gradient (low to high concentration).

Question 3

Does active transport or diffusion need energy? Explain.

Answer 3

Active transport needs energy as it is moving substances against the concentration gradient. On the other hand, diffusion moves along the concentration gradient, therefore does not require energy.

Question 4

Why is active transport needed?

Answer 4

Sometimes substances are needed in the cell, but cannot enter as the solution is hypotonic to the cell (more dilute to the cell), therefore active transport allows these substance to enter the cell against the concentration gradient

Question 5

Example of active transport.

Answer 5

Minerals ions in the soil, such as nitrate ions, are usually found in very dilute solutions, more dilute than the solution inside the cell. Using active transport, the root hair cells can absorbs these minerals.