Covers Lessons 6–10: transport in animals and plants, movement of photosynthesis products, gas exchange in plants, and gas exchange in animals.
1. Large multicellular animals need internal transport systems because:
2. Which vessel type carries blood away from the heart and is adapted to withstand high pressure?
3. The main function of xylem is to transport:
4. Which process creates the main pulling force that drives water upward through xylem?
5. Phloem transport is best described as the movement of:
6. After photosynthesis, glucose is commonly converted to sucrose for transport because sucrose:
7. Stomata are important because they:
8. Guard cells cause stomata to open when they:
9. Which combination gives the most efficient gas exchange surface?
10. In insects, oxygen is delivered to tissues mainly through the:
11. Fish gills are effective gas exchange surfaces because they:
12. In mammals, alveoli are well adapted for gas exchange because they are:
13. Explain why large multicellular animals require both specialised gas exchange surfaces and a transport system. 4 MARKS
14. Compare xylem and phloem in terms of what they transport, the direction of transport and the structural features that help them perform their role. 4 MARKS
15. Describe two advantages and one trade-off of stomata opening during the day. 3 MARKS
16. A student says, “Fish gills and mammalian alveoli are completely different, so you cannot compare them.” Evaluate this statement. 4 MARKS
1. B — Bigger bodies have less surface area per unit volume and longer diffusion distances, so diffusion alone becomes too slow.
2. D — Arteries carry blood away from the heart under higher pressure and have thick, elastic, muscular walls.
3. C — Xylem carries water and mineral ions, mainly upward from roots to shoots.
4. A — Transpiration from the leaf surface creates tension that helps pull water upward through xylem.
5. B — Phloem transports sugars and other organic solutes between source and sink tissues.
6. C — Plants commonly convert glucose to sucrose for phloem transport from sources such as leaves to sinks such as roots, fruits or growing tissues.
7. D — Stomata regulate gas exchange, but opening them also increases water loss.
8. A — Guard cells become turgid when they take up water, causing the stomatal pore to open.
9. B — Efficient exchange surfaces consistently maximise area, minimise distance, remain moist and maintain gradients.
10. C — Insects use the tracheal system to deliver oxygen directly to tissues instead of transporting it mainly through haemolymph.
11. D — Gills combine large surface area with strong gradients maintained by water and blood movement.
12. A — Alveoli are numerous, moist, one cell thick and closely associated with capillaries, making them excellent exchange surfaces.