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UNIT 5 TOPIC 7: Run For Your Life
The Heart

The location of the SAN is in the right atrium.

Describe the changes in the heart that bring about an increase in cardiac output during exercise
(4) *The heart rate, *stroke volume and *SAN activity increases whilst the *AVN time…

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Using the information in the table, describe the effect of an increase in heart rate on both the
ventilation rate and oxygen uptake by the blood, after the first ten seconds of exercise. (3)
*There is little difference in ventilation rate compared to the *oxygen uptake which increases.
*Credit use…

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*Absolutists say drugs should not be used at any time and that *athletes should not be allowed to
be pressured into using drugs. *Relativists say that drugs could be used under some circumstances
e.g. they could be used for medication. But *drugs in the body can be difficult to legislate…

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Using the information in the graphs, compare the effect of pH on slow twitch and fast twitch
fibres. (2)
*The lower the pH, the less sensitive both become to calcium ions, so more calcium ions are
needed for (50%) contraction. But *the effect on slow twitch is greater though the…

Page 5

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Suggest why using material from structure P to repair structure Q after it tore in a sporting
injury will mean that recovery will be quite slow and require careful physiotherapy. (2)
Because *lots of time will be needed to repair Q and P, recovery will be slow. *Physiotherapy may

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During this race, runner A lost 3.02 kg of water and runner B lost 2.43 kg of water. Using the
information in the question and your own knowledge, suggest reasons for the change in core
temperature of runner A after 120 minutes. (2)
*Runner A may have become dehydrated and…

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*Carbon dioxide/CO2, because *the C has been removed from C6 or C5 compound.
Using information in the diagram, suggest what would happen in the Krebs cycle if acetyl CoA
became unavailable. (3)
*The cycle would stop and the *4 carbon compound would accumulate but the *6 & *5 carbon

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*Electrons are passed along the electron transport chain *losing energy. This energy is *used to
add a phosphate to ADP to make ATP with the enzyme *ATPase. *Oxygen is the final acceptor
molecule, it accepts hydrogen. This process is called *chemiosmosis.

Describe how a spirometer trace recorded immediately after a…

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sprinter is using contain large concentrations of *fast twitch fibres and so will have a high *lactate
*Creatine phosphate may also be used to generate short bursts of energy quickly by providing a
phosphate ion for ATP.

Lactate (lactic acid) can build up in the muscles of a sprinter.…

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Explain how a high concentration of hydrogen ions (H+) is maintained in the intermembrane
space during chemiosis. (3)
*H+ ions from reduced NAD are *pumped into inter membrane space *using energy. The
*electrons move along the ETC *inner membrane/cristae to be combined later.

Describe the role of the hydrogen ion…




Excellent! Really helpful. 

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