Plant Structures and Their Functions | Edexcel GCSE Combined Science Biology, Higher tier (1SC0)
Plant Structures and Their Functions
- 104 questions
- 6 subtopics
- Paper 2
- Paper 2
Plant Structures and Their Functions is examined in Paper 2, Biology 2.
It covers photosynthesis and its limiting factors, light intensity and the inverse square law, root hair cells, xylem and phloem, transpiration and translocation, and the factors affecting transpiration and the potometer.
Sample questions from Plant Structures and Their Functions
Answer each one closed book first, then open the answer.
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Photosynthesis as an endothermic reaction
Explain why animals depend on photosynthetic organisms for their food.
Show the answer
Animals cannot make their own food, so they must obtain it by eating producers or by eating other animals that ate producers. -
Photosynthesis as an endothermic reaction
Name the pigment that absorbs light for photosynthesis and state where it is found.
Show the answer
Chlorophyll, which is held inside the chloroplasts of plant and algal cells. -
Limiting factors in photosynthesis
Explain why the rate of photosynthesis falls sharply above about 45 °C.
Show the answer
The enzymes controlling photosynthesis denature, so their active sites change shape and can no longer catalyse the reactions. -
Limiting factors in photosynthesis
The rate of photosynthesis is measured against light intensity at 15 °C and at 25 °C. Explain why the line for 25 °C levels off at a higher rate.
Show the answer
At the higher temperature the enzymes work faster, so photosynthesis can reach a greater rate before another factor becomes the one in short supply. -
Light intensity and the rate of photosynthesis
Describe two ways of improving the quality of results in an investigation of light intensity and photosynthesis.
Show the answer
Repeat each distance at least three times and calculate a mean, and collect the gas in a capillary tube so its volume can be measured precisely. -
Light intensity and the rate of photosynthesis
In dim light, doubling the brightness doubles how fast a plant photosynthesises. Explain why.
Show the answer
Light is the factor in shortest supply, so every extra unit of light energy absorbed produces a matching increase in the rate. -
Root hair cells, xylem and phloem
Explain how having a thin surface layer helps a root hair cell absorb substances.
Show the answer
The short distance to cross means water and mineral ions enter the cell quickly. -
Root hair cells, xylem and phloem
Explain the advantage of xylem vessels having no cytoplasm or organelles inside them.
Show the answer
The empty lumen lets water flow through with very little resistance.
The 6 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Photosynthesis as an endothermic reaction | Producers, biomass and why animals depend on photosynthetic organisms, the word and balanced symbol equations for photosynthesis, why it is endothermic, chlorophyll in chloroplasts, where the raw materials come from, and how a plant uses the glucose and oxygen it makes. | 13 |
| Limiting factors in photosynthesis | What a limiting factor is, how light intensity, temperature and carbon dioxide each set the rate of photosynthesis, and reading graphs of rate against light under different conditions. | 14 |
| Light intensity and the rate of photosynthesis | Measuring the rate of photosynthesis in pondweed, the variables and controls in the lamp-distance investigation, improving on counting bubbles, the inverse square relationship and calculating relative light intensity as 1 ÷ distance², why light limits the rate in dim light, and hypotheses, predictions and whether data support them. | 24 |
| Root hair cells, xylem and phloem | How root hair cells absorb water by osmosis and mineral ions by active transport, why salty water makes a plant wilt, how dead, lignified xylem vessels carry water, and how phloem sieve tubes and companion cells use energy to move sucrose up and down the plant. | 15 |
| Transpiration and translocation | Transpiration and the path of water from soil to air, how evaporation pulls water up the xylem, stomata and how guard cells open and close them, wilting, and the translocation of sucrose in the phloem from the leaves to growing regions and storage organs using energy from respiration. | 14 |
| Factors affecting the rate of transpiration | How light, wind, temperature and humidity affect water uptake, setting up and using a potometer, why uptake only estimates transpiration, calculating rates per minute, per hour, by volume and per unit of leaf area, and plotting graphs, lines of best fit, gradients, intercepts and y = mx + c. | 24 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel GCSE Combined Science Biology, Higher tier Active Recall Guide
Every topic, not just this one. 968 questions with their answers.