SCIENCE TEACHER
Living processes
Cellular transport
SW-BIO-INT-0010(Answers)
Objectives
To understand active transport.
Answers
1. Active transport allows substances (ions/molecules) to move against their concentration
gradient. Active transport needs energy, whereas diffusion does not.
2.
Active
transport
Cell wall
Cell membrane
Active
transport
Nucleus
(You could also use this as an opportunity to discuss how the root cell is specialised to carry
out its function of absorbing nutrients.)
3. a) ATP stores energy from respiration and supplies it when it is needed for active transport.
b) Respiration uses oxygen and glucose to release energy in the cell.
c) Protein molecules change shape and pump substances across cell membranes.
4. a) Increasing temperature increases the rate of respiration, and so increases the rate of
active transport.
b) Increasing the concentration of oxygen also increases the rate of respiration, and so
increases the rate of active transport.
5. Too much water around root cells will prevent oxygen reaching the cells. This will slow down
respiration and active transport. The roots will not be able to take up sufficient nutrients from
the soil, so their growth will be reduced.
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