Question 1: Define active transport in the context of cell biology.

Answer: Active transport is the process by which substances are moved across a cell membrane against their concentration gradient using energy from ATP.

Question 2: Explain how active transport differs from diffusion.

Answer: Active transport requires energy and moves substances against their concentration gradient, whereas diffusion is a passive process that moves substances from an area of higher to lower concentration without using energy.

Question 3: Describe the role of carrier proteins in active transport.

Answer: Carrier proteins change shape to move specific molecules across the cell membrane against their concentration gradient, using energy from ATP.

Question 1: Calculate the energy required to transport 1 million sodium ions (Na+) against their concentration gradient if each ion requires 1.2 x 10^-19 Joules of energy. Express your answer in Joules.

Answer: 1.2 x 10^-19 Joules x 1,000,000 ions = 1.2 x 10^-13 Joules

Question 2: A cell uses 2.4 x 10^-14 Joules of energy to transport 2000 potassium ions (K+). Calculate the energy used per ion in Joules.

Answer: 2.4 x 10^-14 Joules / 2000 ions = 1.2 x 10^-17 Joules per ion

Question 1: Design a simple experiment to investigate the rate of active transport in plant root hair cells. Include the variables you would control and the safety precautions needed.

Answer: Students would measure the uptake of a coloured dye or radioactive isotopes by root hair cells in different conditions. Variables include temperature, pH, and concentration gradient. Controls include using identical root hair samples. Safety precautions include handling radioactive materials with proper shielding and disposal, and wearing protective equipment.

Question 1: In an experiment, the rate of glucose uptake by cells increased when ATP supply was increased. Explain what this suggests about the process involved.

Answer: This suggests that active transport is involved in glucose uptake, as it requires energy from ATP. An increase in ATP supply enhances the active transport process, increasing glucose intake.

Question 1: Describe the process by which root hair cells absorb mineral ions from the soil through active transport. (6 marks)

Answer: Root hair cells absorb mineral ions by active transport, where carrier proteins in the cell membrane use energy from ATP to move ions such as nitrate or potassium against their concentration gradient. This process allows plants to accumulate essential nutrients even when soil concentrations are low.

Question 1: Explain how understanding active transport can improve the development of targeted drug delivery in medicine.

Answer: Understanding active transport allows scientists to design drugs that can be transported into specific cells using carrier proteins, improving efficiency and reducing side effects in targeted therapy.