2jStructures and Functions in Living Organisms
Co-ordination and response — Edexcel Linear - OL Revision Notes & Topical Questions
5 min read 7 parts Lesson 10 of 25 2 quizzes
Lesson summary
Co-ordination and response Edexcel O Level Linear Biology notes: understand how organisms are able to respond to changes in their environmentMyelin sheath speeds up impulses.Adrenaline prepares the body for fight or flight.Auxin moves to the shaded side of a shoot.understand how …
- Co-ordination and response Edexcel O Level Linear Biology: what to do next
- Sensory neuron
- Motor neuron
- Reflex arc
- Endocrine gland
- Give / State / Name
Part 1 of 6Key ideas
Key ideas
Myelin sheath speeds up impulses.
Adrenaline prepares the body for fight or flight.
Auxin moves to the shaded side of a shoot.
Part 2 of 6Syllabus points
1
understand how organisms are able to respond to changes in their environment
2
understand that homeostasis is the maintenance of a constant internal environment, and that body water content and body temperature are both examples of homeostasis
3
understand that a co-ordinated response requires a stimulus, a receptor and an effector Flowering plants
4
understand that plants respond to stimuli
5
describe the geotropic and phototropic responses of roots and stems
6
understand the role of auxin in the phototropic response of stems
7
describe how nervous and hormonal communication control responses and understand the differences between the two systems
8
understand that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves
9
understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses
10
understand the role of neurotransmitters at synapses
11
describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
12
describe the structure and function of the eye as a receptor
13
understand the function of the eye in focusing on near and distant objects, and in responding to changes in light intensity
14
describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation
15
understand the sources, roles and effects of the following hormones
- adrenaline
- insulin
- testosterone
- progesterone and oestrogen
Part 3 of 6Process & sequence
- Stimulus
- Receptor
- Sensory neuron
- Relay neuron (spinal cord)
- Motor neuron
- Effector
- Response
Plant responses
Phototropism – shoots grow towards light (auxin)
Gravitropism – roots grow down
Thigmotropism – response to touch
Part 4 of 6Summary
Summary
A reflex arc passes through the spinal cord.
Hormones travel in the blood.
Part 5 of 6Keep going
Co-ordination and response Edexcel O Level Linear Biology: what to do next
These Co-ordination and response Edexcel O Level Linear Biology notes covered the key ideas, worked examples and exam technique for this topic. Check your Co-ordination and response Edexcel O Level Linear Biology understanding with the practice questions below, then reread any Co-ordination and response Edexcel O Level Linear Biology point you were unsure about before moving on.
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Previous lesson: 2i Excretion — Notes
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Next lesson: 3a Reproduction — Notes
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Course: Edexcel Linear - OL — all units
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Official syllabus: Pearson Edexcel International GCSEs
Part 6 of 6Compare: Compare
| Feature | Nervous system | Endocrine system | Signal | Speed | Example |
|---|---|---|---|---|---|
| Signal type | Electrical impulses | Hormones | — | — | — |
| Transmission | Neurons | Blood | — | — | — |
| Speed | Very fast | Slower | — | — | — |
| Duration | Short | Long-lasting | — | — | — |
| Target | Specific muscles/glands | Target organs with receptors | — | — | — |
| Example | Withdrawal reflex | Insulin, adrenaline, thyroxine | — | — | — |
Key terms
Command terms
Command terms
Give / State / Name
Recall a fact; one idea per mark.
Define
Give the exact meaning using the specification keywords.
Describe
Give an account of what happens / the pattern in data, quoting values; no reasons needed.
Explain
Give reasons with linked statements (cause → effect). Each linked step is usually a separate marking point.
Suggest
Use knowledge in a new context; more than one answer may be accepted.
Compare
Similarities and differences; each point must refer to both items.
Calculate
Show working; include units; check significant figures. Method marks are given even if the final answer is wrong.
Discuss
Explore the issue from different angles and link the points.
Evaluate / Assess
Weigh strengths and weaknesses and reach a supported judgement.
Deduce
Draw a conclusion from the information given.
Justify
Support a statement/choice with evidence.
Exam technique
Keywords the mark scheme looks for in this lesson
Keywords the mark scheme looks for in this lesson
Neuron · Sensory neuron · Motor neuron · Synapse · Reflex arc · Hormone · Endocrine gland · Tropism
Learn each definition in the Key words tab exactly; a missing keyword in a definition usually loses the mark.
How to get full marks (examiner guidance)
How to get full marks (examiner guidance)
Use specification keywords exactly (e.g. eukaryotic/prokaryotic, enzyme–substrate complex, active site, complementary).
Link ideas
Link ideas for “explain” each marking point is usually a cause → consequence step; unlinked facts often score nothing.
Use the information in the question
“discuss/evaluate” answers must use the data provided and match the number of marks.
Convert units carefully (mg → g, cm³ → dm³) and show working for calculations.
Avoid vague words
“it”, “stuff”, “things”, “goes up”, “energy is made”. Name the substance and the process.
Do not extrapolate a graph line beyond the data or to zero unless asked.
Six-mark extended responses are marked on content AND a logical, linked line of reasoning.
Marked practiceQuizzes for this lesson
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