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Topic 1: Lifestyle health and risk

1.2 Importance of water as a solvent in transport, including its dipole nature. P8

Water is a polar molecule = it has an unevenly distributed chemical charge
o The two hydrogens are pushed towards each other forming a V shaped molecule
o Hydrogen=…

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-OH groups on carbon 1 + 4 lie on
opposite side of ring compared to

Sugar that occurs naturally in fruit,
honey + some vegetables

Disaccharides Two single sugar units join together in a Sucrose
condensation reaction disaccharide glucose + fructose= S
Condensation reaction = water molecule…

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Spiral structureand insolublenature
o It doesn't diffuse across cell membranes
o Has very little osmotic effectwithin the cell
Is a major source of energy for the diet


A polymer compound of glucose molecules
Has numerous side branches = can be rapidly hydrolysed=easy access to stored energy
In humans…

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Fats provide a source of
essential fatty acids

6 Explain why many animals have a heart and circulation (mass transport to overcome limitations of diffusion
in meeting the requirements of organisms). P6-7

Why have a heart and circulation?

The purpose of the heart and circulation is to move substances…

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There is diffusion of carbon dioxide from the blood into the water that surrounds the gills, and
diffusion of oxygen from this water into the blood
The blood leaving the gills then flows around the rest of the body before returning to the heart
Blood flows through the heart…

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Elastic recoilof heart wall= lowers pressure in atriaand ventricles> closes the semilunarvalves=
prevents backflow
Coronary arteries fill>low pressure in atria= helps draw blood into heart< from veins


In atrial systole the atria contract , forcing blood into the ventricles
In ventricular systole the ventricles contract , pushing blood…

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tough and strong to
withstand high pressure

No valves valves

How does blood move through the vessels?
Arteries Capillaries Veins

When blood reaches
During systole blood is smaller arteries and In veins blood flow is
forced into arteries capillaries = there is a assisted by the
o This makes…

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5. Platelets stickto damaged wall and to each other forming a platelet plug
6. Fibrin mesh traps blood cells , forming a clot
7. Prothrombin thrombin is an enzyme that catalyses the conversion of soluble fibrinogen to insoluble

Only arteriesget atherosclerosis because blood is under high pressure= high…

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Mutations in genes that affect relative
HDL:LDL levels in the blood

There are many correlations between dietary
diet habits and level of CVD e.g. saturated fat,
cholesterol and lipoprotein level
Some evidence that these correlations are
causal , particularly for blood cholesterol
Non- starch polysaccharides lower blood

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1.13 Describe the benefits and risks of treatments for CVD (Antihypertensives, plant statins, anticoagulants and
platelet inhibitory drugs).

Drug treatment Mode of action Risk/side effects
Diuretics Increase volume of urine; Occasional dizziness,
(antihypertensive) lowers blood volume and nausea, muscle cramps
Beta blockers Block response of heart to Possible…




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