Also involves Translocation
The diagram shows part of a cross-section of a plant leaf.
Describe the function of layer A.
Name the cells labelled B, C and D.
Explain the role of cell D in controlling gas exchange in the leaf.
Describe the function of the tissue labelled E.
Human lungs and plant leaves both contain gas exchange surfaces. These gas exchange surfaces have a number of features in common.
The diagram shows a cross-section through human lung tissue.
Explain, with reference to features shown in the diagram, how lung tissue enables efficient gas exchange.
Explain how the structure of a leaf is adapted for efficient gas exchange.
The amount of light falling on plant leaves is an abiotic (non-living) factor that affects photosynthesis.
Give the balanced chemical equation for photosynthesis.
The leaves of plants that live in the shade (low light) are different to the leaves of plants that live in full sunlight.
Suggest why leaves from plants that live in the shade are darker green than leaves from plants that live in full sunlight.
Explain why leaves from plants that live in the shade are thinner than leaves from plants that live in full sunlight.
The rate of photosynthesis changes during the day.
Explain the factors that affect the rate of photosynthesis in the early morning.
Explain the factors that affect the rate of photosynthesis in the early afternoon.
Describe how you could compare the rate of photosynthesis in two different plant species.
Plants make food by the process of photosynthesis.
Write a balanced chemical symbol equation for photosynthesis.
The leaf of a plant is adapted to carry out photosynthesis. Explain how the following parts of the leaf are adapted for photosynthesis.
palisade mesophyll layer
spongy mesophyll layer
guard cells
A student uses this method to show that starch is produced during photosynthesis. Step 1 put a potted plant in a dark cupboard for 24 hours Step 2 then put the plant in bright sunlight for 12 hours Step 3 remove a leaf from the plant and put it in a beaker of boiling water for 30 seconds Step 4 put the leaf in a boiling tube containing hot ethanol for 10 minutes Step 5 wash the leaf in cold water and put it on a white tile Step 6 add enough iodine solution to cover the leaf and observe the change in colour
Explain why the student put the plant in a dark cupboard for 24 hours in step 1.
Describe how the student could carry out step 4 safely.
State the colour of the leaf observed in step 6.
The student concludes that starch is produced by photosynthesis in the leaf. State a suitable control that she should use to make her conclusion valid.
Plants need to absorb mineral ions from the soil to enable them to produce other biological molecules. Complete the table by giving the missing information.
| Mineral ion absorbed | Biological molecule produced |
| magnesium | |
| protein |
A student uses a microscope to look at some cells from an organ found in a plant. The diagram shows what the student observes through the microscope. One cell has been labelled X.
Name the organ that the student observes.
What is meant by the term organ ?
Draw a labelled diagram of cell X.
The diagram shows a cross section through a leaf.
Each part of the leaf is adapted for a specific function. Name each part of the leaf and explain how it helps the leaf in photosynthesis.
Layer A
Layer B
Layer C
Structure D
Water lilies float on the surface of ponds. Structure D is found on the upper surface of a water lily rather than the lower surface. Suggest a reason for this adaptation.
A student examined the upper and lower surfaces of a leaf from a land plant using a microscope. This is her diagram of the lower surface.
How many stomata are shown in the diagram?
Suggest how the upper surface of the land plant would differ from this diagram.
Memes
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