Edexcel IGCSE Biology 2.86 Homeostasis
Practise comparing nervous and hormonal communication using body systems, response speed data, hormones and behaviour contexts.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Exam points
- distinguish nervous and hormonal control by signal type, target cells and response duration
- calculate speed ratios after converting units between centimetres, metres, seconds and minutes
- link adrenal glands or neurotransmitters to behaviour through adrenaline or nerve signalling
2.86 Nervous and hormonal communication question 1
[Maximum number: 3]
Fur colour in rats is controlled by a gene with two alleles.
One allele codes for black fur colour. The other allele codes for agouti fur colour.
Several female rats with agouti coloured fur are mated with several male rats with black coloured fur.
All of the offspring have agouti coloured fur.
Scientists observed that genes that control fur colour in rats can affect rat behaviour, such as how tame they are.
Other genes that control the size of the adrenal glands and the production of neurotransmitters also affect rat behaviour.
Scientists also noticed that coat colour is associated with differences in anatomy and physiology, such as the size of the adrenal glands and the production of neurotransmitters.
Explain why the size of the adrenal glands and the production of neurotransmitters would affect rat behaviour.
An explanation that makes reference to three of the following:
- more adrenaline produced / affects amount of adrenaline produced / eq
- affects heart rate / fear response / fight or flight idea /eq
- neurotransmitter levels affects synapses / eq
- quicker reflex / reaction time / quicker response / more responsive / eq
allow converse for smaller adrenal and less neurotransmitter
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