Transport Systems in Plants | OCR A-Level Biology B (Advancing Biology) (H422)
Transport Systems in Plants
- 79 questions
- 5 subtopics
- Further biology content, examined on all three papers
- Component 01, Component 02 and Component 03
Transport Systems in Plants is examined in all three written papers — the specification states that Components 01, 02 and 03 can each assess content from any of the five modules, so nothing is confined to one paper.
It covers the need for transport systems in plants, vascular tissue in roots, stems and leaves, water uptake and movement through the plant, transpiration and Its Measurement and translocation in the Phloem.
Sample questions from Transport Systems in Plants
Answer each one closed book first, then open the answer.
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The need for transport systems in plants
Explain why roots need substances to be transported to them.
Show the answer
Roots are underground and contain no chloroplasts, so they cannot photosynthesise and must receive sugars made in the leaves. -
The need for transport systems in plants
Why can a moss survive without vascular tissue?
Show the answer
It is only a few cells thick and grows very close to the ground, so water and solutes only have to travel short distances and diffusion is fast enough. -
Vascular tissue in roots, stems and leaves
State two adaptations of a companion cell to its function.
Show the answer
It has dense cytoplasm with many mitochondria to supply ATP for active loading, and numerous plasmodesmata linking it to the sieve tube element. -
Vascular tissue in roots, stems and leaves
Classify wheat, carrot and potato as monocotyledonous or dicotyledonous crop plants.
Show the answer
Wheat is a monocotyledonous cereal, while carrot and potato are dicotyledonous broad-leaved crops. -
Water uptake and movement through the plant
Describe the symplast pathway.
Show the answer
Water passes through the cytoplasm of the cortex cells, moving from one cell to the next through the plasmodesmata. -
Water uptake and movement through the plant
What is the transpiration pull?
Show the answer
It is the tension created when evaporation from the mesophyll cell walls lowers the water potential in the leaf, drawing the whole column of water up the xylem behind it. -
Transpiration and Its Measurement
What effect does air movement have on the rate of transpiration, and why?
Show the answer
Wind increases the rate, because it blows away the humid layer of air held next to the leaf surface and so keeps the diffusion gradient steep. -
Transpiration and Its Measurement
How is the rate of water uptake calculated from the movement of the bubble in a potometer?
Show the answer
Measure the distance the bubble travels in a known time, multiply that distance by the cross-sectional area of the capillary tube to give a volume, then divide the volume by the time.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| The need for transport systems in plants | Recall questions on why large plants need transport systems, surface area to volume ratio and metabolic rate, why roots need sugars and leaves need water and mineral ions, what xylem and phloem carry, why mosses manage without vascular tissue, tall trees, support, and daily changes in water demand. | 13 |
| Vascular tissue in roots, stems and leaves | Recall questions on xylem vessels and their lignin patterns, sieve tube elements and companion cells, the arrangement of vascular tissue in roots, stems and leaves of monocotyledonous and dicotyledonous crops, and preparing, staining with phloroglucinol and drawing plant sections. | 18 |
| Water uptake and movement through the plant | Recall questions on root hair cells and water entry by osmosis, the apoplast, symplast and vacuolar pathways, the Casparian strip, root pressure, cohesion, adhesion and transpiration pull, the water potential gradient through the plant, and the evidence for the cohesion-tension theory. | 17 |
| Transpiration and Its Measurement | Recall questions on why transpiration is unavoidable, how light, temperature, humidity and air movement change its rate, what a potometer actually measures, and comparing shoots of different sizes. | 17 |
| Translocation in the Phloem | Recall questions on sources and sinks, how sucrose is loaded at a source, what drives mass flow, why sucrose rather than glucose is carried, and the evidence from aphids. | 14 |
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
OCR A-Level Biology B (Advancing Biology) Active Recall Guide
Every topic, not just this one. 2,895 questions with their answers.