Gas exchange in plants

9.What happens to guard cells when the plant has plenty of water?

10.Which of the following statements about the waxy cuticle is false?

11.In the leaf cross-section, which structure is labelled with the number 1?

12.The air spaces in the spongy mesophyll are important because they:

13.Which gas is taken in by a plant during photosynthesis?

14.Stomata are mainly located on which part of the leaf?

15.A plant is placed in a sealed container with a sensor that measures carbon dioxide concentration. The container is kept in bright light for 2 hours. Which graph shows the expected change in carbon dioxide concentration?

16.A student counts the number of stomata per mm² on the upper and lower surfaces of a leaf. The results show 120 stomata per mm² on the lower surface and 20 per mm² on the upper surface. What is the ratio of stomata on the lower surface to the upper surface?

17.In an experiment, a leaf is placed in a solution and air is bubbled through it. The bubbles are collected and tested. The gas collected turns a glowing splint brighter. Which process is occurring?

18.Which of the following leaf structures is primarily responsible for preventing water loss?

19.Guard cells control the opening and closing of which structure?

20.A plant is kept in a dark room for 24 hours and then placed in bright light. Which gas will the plant release into the air after 1 hour in bright light?

21.The diagram shows a cross-section of a leaf. Which layer contains air spaces that help gases move?

22.In the leaf cross-section diagram, which labelled part is responsible for photosynthesis?

23.A student measures the rate of oxygen production from a plant at different light intensities. The results show that oxygen production increases with light intensity up to a point, then levels off. What is the most likely reason for the levelling off?

24.Which of the following is NOT a gas exchanged by plants?

25.In an experiment to measure the rate of photosynthesis, a student places a pondweed in a beaker of water and counts the number of bubbles produced per minute. Which variable should be kept constant to ensure a fair test?

26.A student uses a potometer to measure the rate of water uptake by a leafy shoot. The shoot is placed in bright light. After 30 minutes, the water level in the capillary tube has moved 5 mm. The student then covers the leaves with petroleum jelly and repeats the measurement. What would be the most likely result?

27.A student sets up an experiment with two sealed glass jars, each containing a plant. Jar A is placed in bright light. Jar B is placed in darkness. After 24 hours, the air in each jar is tested for carbon dioxide concentration. Which statement correctly predicts the results?

28.Which of the following is the correct order of structures that carbon dioxide passes through when entering a leaf?

29.A leaf is placed in a solution and exposed to light. Bubbles of gas are produced. When a glowing splint is inserted into the gas, it relights. What is the gas?

30.The diagram shows a cross-section of a leaf. Which labelled part is the site of the majority of photosynthesis?

31.Which of the following is a function of the waxy cuticle on a leaf?

32.In an experiment, a student places a leaf in a sealed flask with a carbon dioxide sensor. The flask is kept in bright light. Which graph shows the expected change in carbon dioxide concentration over time?

33.A student investigates the effect of light intensity on the rate of photosynthesis using an aquatic plant. They count the number of bubbles released per minute at different distances from a lamp. The results are shown in the table. What conclusion can be drawn?

34.Which gas is released by plants during respiration?

35.Guard cells control the opening and closing of stomata. When do guard cells cause stomata to close?

36.A student wants to compare the number of stomata on the upper and lower surfaces of a leaf. Which piece of apparatus is most suitable for obtaining a clear view of the stomata?

37.Which of the following statements about gas exchange in plants is correct?

38.Stomata are small openings mainly located on which part of the leaf?

39.Which layer of the leaf contains loosely arranged cells with air spaces that help gases move?

40.Which of the following statements is false?

41.Stomata are small openings mainly located on the upper side of leaves.

42.The spongy mesophyll layer is tightly packed with cells rich in chloroplasts.

43.Guard cells open the stomata when the plant has plenty of water.

44.Photosynthesis occurs in the palisade cells.

45.During photosynthesis, oxygen is taken in and carbon dioxide is released.

46.Only animals undergo respiration, plants do not respire.

47.Which gas is taken in by plants during photosynthesis?

48.Match each leaf structure to its correct function.

49.Arrange the following steps in the correct order for carbon dioxide entering a leaf and being used in photosynthesis.

50.Which of the following statements about gas exchange in plants are correct? (Select all that apply)

51.Describe the role that guard cells have in gas exchange in plants.

52.Describe the function of the spongy mesophyll layer in a leaf.

53.Describe how the structure of the palisade mesophyll layer is suited for photosynthesis.

54.Describe the role of the waxy cuticle.

55.Complete the sentences about leaf structure.

56.A student counts the number of stomata on a leaf. On the lower surface, there are 120 stomata per mm². On the upper surface, there are 40 stomata per mm². What is the total number of stomata per mm² on both surfaces combined?

57.A student counts the number of stomata on a leaf. On the lower surface, there are 120 stomata per mm². On the upper surface, there are 40 stomata per mm². What is the total number of stomata per mm² on both surfaces combined?