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Course: Edexcel A Level Biology A (SNAB) 9BI0
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Edexcel A Level Biology A (SNAB) 9BI0

Topic 1 · Lifestyle, Health and Risk

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Topic 2 · Genes and Health

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Topic 3 · Voice of the Genome

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Topic 4 · Biodiversity and Natural Resources

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Topic 5 · On the Wild Side

0/72

Topic 6 · Immunity, Infection and Forensics

0/41

Topic 7 · Run for your Life

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Topic 8 · Grey Matter

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Quiz

Response to the Environment – Check yourself

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Response to the Environment IAL Modular Biology check yourself quiz: free practice for IAL Edexcel Modular. Work through this Response to the Environment IAL Modular Biology check yourself quiz and get instant feedback on every answer. If you get stuck, review the 5.5 Response to the Environment — IAL Biology Notes lesson. More practice: IAL Edexcel Modular — all units. Syllabus: Pearson Edexcel International A Levels.

  • Questions count: 11
  • Passing grade: B
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1.

Phytochrome is

an animal hormone
a neurotransmitter
a plant pigment that exists in two interconvertible forms, P_r and P_fr
an enzyme in the retina
2.

In sunlight, phytochrome is mainly in the form

P_r
P_fr
neither
both equally
3.

IAA (auxin) causes a shoot to bend towards light because

it is destroyed by light on the shaded side
cells on the lit side elongate more
it accumulates on the shaded side, where cells elongate more
it stops cell division
4.

In a rod cell in the dark

sodium channels are closed
the cell is hyperpolarised
sodium ions flow in through open channels and the cell is depolarised, releasing glutamate
rhodopsin is bleached
5.

When light hits rhodopsin

sodium channels open
it breaks down into retinal and opsin, sodium channels close and the rod cell hyperpolarises
more glutamate is released
the rod cell depolarises
6.

An action potential begins when

potassium ions enter
sodium ions are pumped out
sodium ion channels open and Na⁺ diffuses into the axon
calcium leaves
7.

A myelin sheath speeds up conduction because

it carries ions
it widens the axon
the impulse jumps from node to node (saltatory conduction)
it makes neurotransmitter
8.

At a synapse, neurotransmitter is released when

calcium ions enter the presynaptic knob
sodium ions leave
potassium ions enter
the vesicles are destroyed
9.

Nervous coordination differs from hormonal coordination in being

faster, shorter lasting and more localised
slower
longer lasting
carried in the blood
10.

The pupil reflex in bright light involves

contraction of the circular muscles of the iris, making the pupil smaller
contraction of the radial muscles
relaxation of all muscles
widening of the pupil
11.
IGCSE Biology 14.3 Synapse - Question 1
IGCSE Biology 14.3 Synapse - Question 1
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Part of Topic 8 · Grey Matter — see every lesson and quiz in this unit.
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