Communication and Homeostasis | OCR A-Level Biology A (H420)
Communication and Homeostasis
- 32 questions
- 3 subtopics
- Module 5: Communication, homeostasis and energy
- Component 01 and Component 03
Communication and homeostasis opens Module 5, examined on Biological Processes.
It covers why a multicellular organism needs a communication system, cell signalling, the receptors and effectors that make up a homeostatic loop, negative and positive feedback, and how endotherms and ectotherms hold body temperature steady.
Sample questions from Communication and Homeostasis
Answer each one closed book first, then open the answer.
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Cell signalling and communication systems
How do communication systems help multicellular organisms interact with their surroundings?
Show the answer
They allow organisms to respond to changes in the external environment. -
Cell signalling and communication systems
Define cell signalling.
Show the answer
The process by which cells communicate with each other. -
Homeostasis, negative and positive feedback
What is the functional difference between receptors and effectors?
Show the answer
Receptors detect changes in conditions, whereas effectors carry out responses to restore conditions. -
Homeostasis, negative and positive feedback
Give an example of positive feedback in the body.
Show the answer
The release of oxytocin during labour, which strengthens contractions and causes more oxytocin to be released. -
Thermoregulation in endotherms and ectotherms
What happens to blood flow in the skin when arterioles vasodilate, and how does this affect heat loss?
Show the answer
Vasodilation increases blood flow to the skin surface, increasing heat loss. -
Thermoregulation in endotherms and ectotherms
How does basking in sunlight help an ectotherm regulate its body temperature?
Show the answer
It allows the ectotherm to absorb heat from the sun, raising its body temperature.
The 3 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Cell signalling and communication systems | Why a multicellular organism needs coordination, and how cells signal to one another whether they are touching or far apart in the body. | 8 |
| Homeostasis, negative and positive feedback | Homeostasis and the receptors and effectors that carry it out, and how negative feedback restores a set point while positive feedback drives further away from it. | 10 |
| Thermoregulation in endotherms and ectotherms | Peripheral receptors and the hypothalamus, vasodilation, sweating, erector pili muscles and shivering, and the behavioural responses an ectotherm relies on. | 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 sections
OCR A-Level Biology A Active Recall Guide
Every section, not just this one. 1,833 questions with their answers.