OCR Biology F215 - Responding to environment (animals) exam questions

tricky questions and answers

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Describe and explain how an impulse in a motor neu

entry of Calcium ions through gated channels

Vesicles fuse with membrane via exocytosis

neurotransmitter released into the cleft

binds to repressor site on post-synaptic membrne

depolarisatin opens Na+ channels

impulse teavels into T-tubules

sarcoplasmic reticulum releases calcium ions

  • ions bind to troponin
  • tropopmyosin moves
  • reveals myosin bindng sites on actin/thin fillament
  • movement og myosin heads

mitochindria produce atp (at junction/in muscle)

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Suggest how nicotine may act at a neuromuscular ju

Mimics neurotransmitter ACh

causes calcium channels to open

nicotine binds to receptor sites on post-synaptic membrane

complementary shapes

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i) explain what is meant by innate behaviour

Genetically programmed/inherited, not learnt, instinctive

ii) state the actions of the sympathetic nervous system in the flight or flight response on the heart and the digestive system

Heart: Increased heart rate, stroke vol and cardiac output

digestive system: reduced smooth muscle action, sphincter muscles/arterioles contract

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Suggest why conc insulin falls and conc adrenaline

Operate conditioning can be used to train the animal to increase the temp

cold/stress causes release of adrenaline

stimulation of glycogen breakdown in liver cells

raised glocose conc

antaginises insulin

insulin secretion hinhibited

  • adrenaline levels fall as animal learns to control environment
  • no reason to secrete adrenaline
  • insulin stimulates uptake of glucose into cells
  • glucose converted to glucagon storage
  • negative feedback
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Compare the different types of muscles

Voluntary  Involuntary  Cardiac

cellular Striated unstriated striated

structure multi-nucleate uninucleate uninucleate

cylindrical cells spindle-shaped cells branched cells

Function move limbs/ control diameter of contract heart to

skeleton/ bones arteries/bronchi pump blood


control pupil size

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For each type of muscle identity where in the thor

Voluntary: intercostal, diaphragm

Involantary: bronchi, bonchioles, arteries, artereoles, aorta, oesophagus

Cardiac: heart/wall of atria 

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Suggest why Monkeys rather than lab rats were used

Monkeys are closer related to humans than rats: share more genes/common ancestor

They are both primates

Similar brain/ body/ physiology/ behaviour

Monkey has bigger brain than rat


Can save human lives/ alleviate human suffering

Causes monkey harm/pain/distress/stress

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Describe & explain how activation of 'fight or fli

  • Sympathetic nervous system stimulated
  • noradrenaline released at neuromuscular junctions 
  • adrenaline secreted from adrenal glands/medulla
  • binds to receptor on target tissue

Cardiac: heart beats faster and with more force

Smooth (involuntary):

  • Increased BP (arterioles constrict)
  • Reduced blood flow to skin/gut, reduced gut secretions and makes skin pale
  • Smooth muscle in gut and airways relax
  • Pupils dilate


  • Breathing (intercostal muscles and diaphragm) fasater
  • More blood flow to skeletal muscles
  • Muscle primed for action
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Explain why a grasshopper provides more food energ

Grasshopper is a herbivor/primary consumer and at a lower trophic level

more food available

less energy lost through food chain, fewer steps

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