Pupil sheet · How plants make food
What the plant does with its sugar — questions
Name ______________________ Date ____________
Try every question before you use a nudge. Write in full sentences where you are asked to explain.
1. match
Match each substance made from glucose, or use of glucose, to what it does for the plant.
Write the number of the matching option.
- an energy store
- builds cell walls
- provides energy for the cells
- is transported in the phloem
- attracts insects for pollination
- Starch: ______
- Cellulose: ______
- Glucose used in respiration: ______
- Sucrose: ______
- Nectar: ______
Nudge (only if you are stuck): One is a store, one is building material, one releases energy, one travels and one is for reproduction.
2. explain
Why does a plant store its sugar as starch rather than as glucose?
Circle one answer.
- Starch is insoluble, so it does not draw water into the cells by osmosis.
- Starch contains more energy than the glucose it is made from.
- Starch is made in the roots, where it is needed.
- Glucose cannot be broken down again once it is stored.
Nudge (only if you are stuck): Which of the two dissolves in water, and what would a lot of dissolved sugar do to a cell?
3. complete
Complete the sentences about mineral ions.
Nitrate ions supply nitrogen to make …
which are joined together to make …
Magnesium ions are needed to make …
Nudge (only if you are stuck): Glucose holds only carbon, hydrogen and oxygen. Which element do proteins need, and which does chlorophyll need?
4. explain
A potato grows underground, in the dark, yet it fills with starch. Explain how. Include where the sugar is made, how it travels and what happens to it in the potato.
(a) Where the sugar is made
(b) How it travels
(c) What happens in the potato
Nudge (only if you are stuck): The potato cannot photosynthesise. Which part of the plant can, and in what form does sugar travel?
5. identify
Which statements about the glucose a plant makes are correct? Choose all that apply.
Tick every correct statement.
- Glucose is used in respiration in every living cell, day and night.
- Glucose is turned into sucrose for transport in the phloem.
- Glucose is used to make cellulose for cell walls.
- Flowers use sugar to make nectar, which attracts insects.
- Plants respire only at night.
- A potato stores its sugar as glucose.
Nudge (only if you are stuck): Check the time of day, the form of sugar and where each use happens.
6. explain
Explain why a plant grown without magnesium ions has yellow leaves and grows less than a plant given magnesium.
Nudge (only if you are stuck): Which substance contains magnesium, and what does that substance do?
7. explain
A plant short of nitrate ions can still photosynthesise for a while, yet it stays small and weak. Explain why.
Nudge (only if you are stuck): Glucose holds only carbon, hydrogen and oxygen. What else does a plant need to build proteins?
8. calculate
Seedlings of the same kind and size were grown in three solutions, five in each, with the same light, temperature and volume of solution. The table shows teaching-model data (made up for this question, not measured). Calculate the mean height of each group.
| Solution | Heights of the five seedlings after 4 weeks / cm | Leaves |
|---|---|---|
| complete (all the mineral ions) | 22, 25, 24, 23, 26 | all dark green |
| without nitrate | 9, 8, 10, 9, 9 | older leaves yellow |
| without magnesium | 17, 19, 18, 16, 20 | older leaves yellow between the veins |
Mean height, complete solution: ______________ unit ________
Mean height, without nitrate: ______________ unit ________
Mean height, without magnesium: ______________ unit ________
Nudge (only if you are stuck): The mean is the total of the heights divided by the number of seedlings in the group.
9. interpret / explain
Use the table of the seedling trial (teaching-model data). (a) Which group is the control, and why is it needed? (b) What do the results show about nitrate and magnesium? Use the mean heights (24.0, 9.0 and 18.0 cm) and the leaves. (c) Why were five seedlings used in each group, not one?
| Solution | Heights of the five seedlings after 4 weeks / cm | Leaves |
|---|---|---|
| complete (all the mineral ions) | 22, 25, 24, 23, 26 | all dark green |
| without nitrate | 9, 8, 10, 9, 9 | older leaves yellow |
| without magnesium | 17, 19, 18, 16, 20 | older leaves yellow between the veins |
(a) The control
(b) What the results show
(c) Five seedlings
Nudge (only if you are stuck): (a) Which group has nothing taken away? (b) Compare each group with the control, for height and for leaf colour. (c) Could one odd seedling mislead you?
10. suggest
Grasses are pollinated by the wind: their pollen is blown from flower to flower. Their small, green flowers make no nectar. Suggest why.
Nudge (only if you are stuck): What is nectar for? Does a wind-pollinated flower need that?
11. suggest / explain
A grower of lettuces in water culture sees that the older leaves have turned yellow between the veins, while the veins stay green. She adds more nitrate, but the leaves do not improve. (a) Suggest which ion is most likely short, and explain your choice. (b) Describe how she could test her idea fairly.
(a) Ion and reason
(b) Fair test
Nudge (only if you are stuck): (a) Which deficiency gives yellow between the veins? Did nitrate help? (b) Think of the seedling trial: what is the control?
12. explain
A bean seed is planted deep in dark, damp soil. For several days it grows a root and a shoot before any leaf reaches the light. (a) Where does the energy for this growth come from? (b) What do the new cells use to build their walls?
(a) Energy
(b) Cell walls
Nudge (only if you are stuck): The seed cannot photosynthesise in the dark. What did the parent plant store in it?