topic 1 lifestyle, health and risk

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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= slightly positive charge
o Oxygen= slightly negative charge (electrons are more concentrated at this end)
Positively charged end of water molecule is attracted to the negative ends of surrounding molecules
Hydrogen bonding:
o Holds the water molecules together
o Results in water being liquid at room temperature
Solvent properties
Chemicals easily dissolve in water= biochemical reactions can occur in cytoplasm of cells
Dissolved substances can be transported around organisms
o E.g. in animals via the blood and lymph systems
o E.g. in plants via the xylem and phloem
Polar molecules dissolve easily in water molecules
Polar groups e.g. ­OH become surrounded by water and go into solution
Polar substances= hydrophilic= water attracting
Hydrophobic= non-polar , e.g. lipids do not dissolve in water> allows transport in blood
A large amount of energy needed to break hydrogen bonds in water
o a large input of energy causes only a small increase in temperature= water warms up and cools down
1.3 Distinguish between monosaccharides, disaccharides and polysaccharides (glycogen and starch ­ amylose and
amylopectin) and relate their structures to their roles in providing and storing energy (-glucose and cellulose are not
required in this topic). P30-35
Monosaccharides are single sugar units Glucose
formula (CH 2O)n
main sugar used by cells for
have between 3-7 carbon atoms respiration
examples= glucose, galactose and glucose subunits joined together
fructose>are known as hexose sugars starch + glycogen
starch + glycogen digested
can provide rapid source of energy o can be absorbed and
Are also readily absorbed and require little transported in
change before being used in cellular bloodstream to cells
part of disaccharide sugar
lactose>found in milk

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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 is Sugar that is transported
released around a plant
Glycosidic bond forms between two
2 glucose molecules= M
Maltose is an example of a disaccharide
Produced when amylase
Glycosidic bond broken by hydrolysis…read more

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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 is found in liver and muscles
Is a dietary fibre and is aka non-starch polysaccharide
Made up of glucose molecules that are joined together= straight chain with no branches
Glucose molecules have a slightly…read more

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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).…read more

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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 once for each complete circuit of the body
Birds and mammals
The right ventricle of the heart pumps deoxygenated blood to the lungs where it receives
The oxygenated blood then returns to the heart…read more

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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 up and into arteries
In diastole, elastic recoil as the heart relaxes = causing low pressure in the heart.…read more

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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 their steady flow of blood contraction of skeletal
elastic walls In capillaries this allows muscles during movement
stretch to exchange between the of limbs and breathing
accommodate blood and surrounding Low pressure when
for the…read more

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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.…read more

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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.…read more

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



Absolute lifesaver!! THANKYOU!

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