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. BBigger bodies have less surface area per unit volume and longer diffusion distances, so diffusion alone becomes too slow.
2. DArteries carry blood away from the heart under higher pressure and have thick, elastic, muscular walls.
3. CXylem carries water and mineral ions, mainly upward from roots to shoots.
4. ATranspiration from the leaf surface creates tension that helps pull water upward through xylem.
5. BPhloem transports sugars and other organic solutes between source and sink tissues.
6. CPlants commonly convert glucose to sucrose for phloem transport from sources such as leaves to sinks such as roots, fruits or growing tissues.
7. DStomata regulate gas exchange, but opening them also increases water loss.
8. AGuard cells become turgid when they take up water, causing the stomatal pore to open.
9. BEfficient exchange surfaces consistently maximise area, minimise distance, remain moist and maintain gradients.
10. CInsects use the tracheal system to deliver oxygen directly to tissues instead of transporting it mainly through haemolymph.
11. DGills combine large surface area with strong gradients maintained by water and blood movement.
12. AAlveoli are numerous, moist, one cell thick and closely associated with capillaries, making them excellent exchange surfaces.