Process
OCR A-Level Biology H420
Cell Structure
Biological Molecules
Nucleotides and Nucleic Acids
Enzymes
Biological Membranes
Cell Division, Cell Diversity and Cellular Organisation
Exchange Surfaces
Transport in Animals
Transport in Plants
Communicable Diseases, Disease Prevention and the Immune System
Biodiversity
Classification and Evolution
Communication and Homeostasis
Excretion as an Example of Homeostatic Control
Neuronal Communication
Hormonal Communication
Plant and Animal Responses
Topic overviewTropisms and plant responses to stress and herbivoryPlant hormones and their commercial usesThe nervous system and the brainReflex actions and the knee jerk reflexFight or flight and the control of heart rateThe structure of skeletal muscleThe neuromuscular junction and the sliding filament model
Photosynthesis
Respiration
Cellular Control
Patterns of Inheritance
Manipulating Genomes
Cloning and Biotechnology
Topic overviewNatural plant cloning and taking cuttingsMicropropagationAdvantages and disadvantages of plant cloningAnimal cloning: embryo twinning and nuclear transferAdvantages and disadvantages of animal cloningMicroorganisms in food productionAseptic techniqueFermentation and its conditionsThe microbial growth curveImmobilised enzymes
Ecosystems
Populations and Sustainability
Practical Skills and Mathematical Requirements
Communication and Homeostasis
- 3 subtopics
- 6 things to know
- Components 01 and 03
What Communication and Homeostasis covers
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.
Where it is assessed
Components 01 and 03
Module 5 is examined on Biological Processes, then the unified paper.
Check the OCR specification ↗The 3 subtopics
Each one has its own page.
- Cell signalling and communication systemsWhy a multicellular organism needs coordination, and how cells signal to one another whether they are touching or far apart in the body.Open →
- Homeostasis, negative and positive feedbackHomeostasis 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.Open →
- Thermoregulation in endotherms and ectothermsPeripheral receptors and the hypothalamus, vasodilation, sweating, erector pili muscles and shivering, and the behavioural responses an ectotherm relies on.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Compare negative and positive feedback.
Key term
Define cell signalling.
Process
How does negative feedback differ from positive feedback in terms of stability?
Process
How does an endotherm respond to a rise in body temperature?
Process
How does an ectotherm regulate its body temperature?
Take Communication and Homeostasis further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Negative feedback vs Positive feedback
Negative feedback: response that reverses deviation and restores conditions towards a set point. Positive feedback: response that amplifies deviation and moves conditions further from a set point.
Questions from this topic
Each one with the model answer underneath.
- 1
Why do multicellular organisms require communication systems?
Model answer
Because different parts of the body must work together in a coordinated way.
- 2
What internal changes can communication systems allow multicellular organisms to respond to?
Model answer
Changes in the internal environment, such as fluctuations in blood glucose concentration, pH, or temperature.
- 3
How do communication systems help multicellular organisms interact with their surroundings?
Model answer
They allow organisms to respond to changes in the external environment.
- 4
What role do communication systems play in relation to different organs?
Model answer
They coordinate the activities of different organs so they function together effectively.
- 5
Do plants require communication systems, or only animals?
Model answer
Both animals and plants need to respond to environmental changes and coordinate organ activities.
- 6
Define cell signalling.
Model answer
The process by which cells communicate with each other.
What is inside Levo
Six ways to work the same material.
Communication and Homeostasis revision questions
- What does Communication and Homeostasis cover in OCR A-Level Biology?
- 3 subtopics: cell signalling and communication systems, homeostasis, negative and positive feedback and thermoregulation in endotherms and ectotherms. Each one has its own page with questions and model answers.
- How is Communication and Homeostasis organised?
- By the OCR H420 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Communication and Homeostasis, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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