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5 Unit 5: Exercise and Coordination


Muscles and movement

Muscles, joints and movement
Bones can move in relation to one another at joints. Different types of joint allow
different degrees of movement. Ligaments are made of elastic connective tissue.
They hold bones together and restrict the amount of movement possible…

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Topic 7: Run for your life 5

Myosin filaments have flexible `heads' that can change their orientation, bind to actin
and hydrolyse ATP (using ATPase). Actin filaments are associated with two other
proteins, troponin and tropomyosin, that control the binding of the myosin heads to
the actin filaments.

When a…

Page 3

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5 Unit 5: Exercise and Coordination


Energy and the role of ATP in respiration

All living organisms have to respire. There are two different ways in which they do this
­ aerobic respiration (using oxygen) and anaerobic respiration (without oxygen).
Both of these processes make the energy stored in glucose…

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Topic 7: Run for your life 5

Anaerobic respiration allows animals to make a small amount glucose lactate pathway
of ATP. It is an inefficient process but it is rapid and can supply
muscles with ATP when oxygen is not being delivered quickly
2ADP
enough to cells.
+2P i
2H…

Page 5

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5 Unit 5: Exercise and Coordination


Krebs cycle and the electron transport chain

In aerobic respiration, the pyruvate (from glycolysis) is completely oxidised into carbon
dioxide and water using oxygen.
Aerobic respiration takes place in two stages:
Many of the reactions involved in · First pyruvate is oxidised into carbon…

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Topic 7: Run for your life 5

Each molecule of the 2-carbon acetyl coenzyme A from the link reaction is used to generate:
· three molecules of reduced NAD
· one molecule of reduced FAD
· two molecules of CO2
· one molecule of ATP by substrate-level phosphorylation (synthesised directly…

Page 7

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5 Unit 5: Exercise and Coordination
LA
3
LV

RV 4

The heart, energy and exercise
1
non-conducting layer
in 2
heart wall between
atria and ventricles 4
RA


3
LV The control of the cardiac cycle
RV 4
The impulse to contract originates within the heart itself from the…

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Topic 7: Run for your life 5

The heart rate can be affected by hormones (e.g. adrenaline) and nervous control. The
cardiovascular control centre in the medulla of the brain controls the sinoatrial
node via nerves. The sympathetic nerve speeds up the heart rate in response to falls
in pH…

Page 9

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5 Unit 5: Exercise and Coordination


Homeostasis

Homeostasis is the maintenance of a stable internal environment, within a narrow
limit, of the optimum conditions needed by cells so they can function properly. A
homeostatic system therefore requires:
· receptors to detect the change away from the norm value (stimulus)
·…

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Topic 7: Run for your life 5

heat loss heat loss
centre in centre in
detected detected effectors effectors
hypothalamus hypothalamus
by receptors send by receptors sends send react sends react
impulses impulses
impulses impulses
mperature rises temperature rises temperature falls temperature falls

et point set point set point set…

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