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Edexcel IAL Biology Topic 8 Coordination and gene technology

Identify the stimulus, pathway or molecular tool, trace the named mechanism in sequence and use diagram, calculation or experimental evidence to support the conclusion.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
A2

Exam points

  • Interpret neurone, receptor and response diagrams using impulse direction and effectors.
  • Explain action potentials, synaptic transmission and drug effects through ion movement.
  • Apply behavioural or gene-technology evidence to experimental conclusions.

Covered syllabus points

8.1—Neurone structure and function8.2—Nervous system control of effectors8.3—Spinal reflex arc8.4—Action potential conduction8.5—Saltatory conduction8.6—Synapses, neurotransmitters and pupil response8.7—Drugs and nerve impulse transmission8.8—Rod cells and stimulus detection8.9—Habituation8.10—Central and peripheral nervous systems8.11—Plant responses: phytochrome, auxin and gibberellins8.12—Core Practical 18 - amylase in germinating cereal grains8.13—Coordination by nervous and hormonal control8.14—Human brain regions8.15—Medical imaging of the brain8.16—Brain chemicals, ill health and drugs8.17—Drug production using GM organisms8.18—Recombinant DNA production8.19—Inserting recombinant DNA into cells8.20—Microarrays and active genes8.21—Bioinformatics8.22—Risks and benefits of GM organisms

Topic 8 - Coordination, Response and Gene Technology question 1

[Maximum number: 9]

Many predatory animals produce toxins to disable their prey. Some of these toxins inhibit nervous communication.

Question (a)

(a)

Nerve impulses are transmitted along axons. Some axons are myelinated.

[ 2 ]

Question (i)

(i)

Which type of cell produces myelin?

A

neurone

B

rod cell

C

Schwann cell

D

lymphocyte

[ 1 ]

Question (ii)

(ii)

Which row correctly compares the conduction of an impulse along a myelinated neurone with conduction along a non-myelinated neurone?
□ A
□ B

Table for Question (ii) — Edexcel A-Level Biology A2
[ 1 ]

Question (b)

(b)

Describe the role of ion transport in maintaining the resting potential of a neurone.

[ 4 ]

Question (c)

(c)

The pufferfish produces a neurotoxin called tetrodotoxin (TTX).

The graph shows the effect of TTX on the nerve impulse in an axon.

Membrane voltage / mV

Deduce how TTX inhibits nerve impulses in an axon.

Figure for Question (c) — Edexcel A-Level Biology A2
[ 3 ]

Topic 8 - Coordination, Response and Gene Technology question 2

Motility is produced in the ENS through a reflex circuit involving the circular and longitudinal muscles. Nicotinic synapses between interneurons mediate the reflex circuits. When the circuit activates by the presence of a bolus, excitatory neurons in the circular muscle and inhibitory neurons in the longitudinal muscle fire producing a narrow section of bowel proximal to the bolus; this is known as the propulsive segment. Simultaneously, excitatory neurons in the longitudinal muscle and inhibitory neurons in the circular muscle fire producing the "receiving segment" of the bowel in which the bolus will continue. This process repeats with each subsequent section of the bowel.

Topic 8 - Coordination, Response and Gene Technology question 3

[Maximum number: 2]

Whales are large mammals.
The photograph shows a beluga whale and a human diver.

Figure for Question Topic 8 - Coordination, Response and Gene Technology question 3 — Edexcel A-Level Biology A2

Question (a)

(a)

A beluga whale can become habituated to human divers.

How many of the following statements about habituation are correct?
- habituation is an example of anatomical adaptation
- habituation is only observed in mammals
- habituation only occurs after repeated exposure to the same stimulus
- A 0
□ B 1
□ C 2
□ D 3

[ 1 ]

Question (b)

(b)

A beluga whale can respond to a stimulus using a spinal reflex arc.

Which row is correct?

Location of relay neurone

Location of cell body on
the sensory neurone

grey matter of spinal cord

at the end of the axon

grey matter of spinal cord

in the middle of the axon

white matter of spinal cord

at the end of the axon

white matter of spinal cord

in the middle of the axon

[ 1 ]
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