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UNIT 1: TOPIC 1: LIFESTYLE, HEALTH AND RISK

ELEMENTS:
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are units of pure substance making up our world
there are 4 main elements needed for living organisms
C, H, N, O, P
H, O : water
C, H, O: Carbohydrates / lipids
C, H, O, N, (P) : Proteins

GENERALLY ABOUT WATER:
∑ Is the medium in which all reactions take place in cells (is a SOLVENT)
∑ Is also an excellent transport medium

∑ Is a major habitat for living organisms

CHEMISTRY OF WATER:
∑ Ratio of 2:1 (H:O)
∑ Each water molecule is slightly polarized (charged)
...
5°
between H’s and O’s

BE CAREFUL: DO NOT CONFUSE THE TERMS SOLVENT AND SOLUTE
∑ Solvent is the medium (in biology is always water, in chemistry is usually an
organic one such as ethanol) in which various substances- SOLUTES- can be
dissolved –found
...
Water is the solvent, sugar is the solute

PROPERTIES OF WATER:
∑ Unusual excellent solvent
o Many polar substances will dissolve in it
o Non-polar substances form colloids(solute particles larger than
solvent)
o Insoluble particles form emulsions or suspensions –mixtures
∑ Excellent transport medium due to properties such as being highly adhesive
and cohesive
o Adhesion: being able to stick on surfaces, for example on the xylem
of the plants
o Cohesion: being able to stick very close to one another due to
hydrogen bonds
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These properties
High specific heat capacity
prevent
o It means it takes a lot of energy to warm it up again due to H temperature
bonds
fluctuations in
High latent heat of vaporization
living organisms

o It takes a lot of energy to turn it into gas
∑ High surface tension
o Is a property in which some liquids behave as if their surface is
covered by a thin elastic skin
o In water again this is due to H bonds
o It is a very important property in plant transport systems and affects
life in lakes, ponds
∑ Is amphoteric
o It means it acts both as an acid and as a base
o It can equally donate and receive protons
o This makes it an ideal medium for reactions since it acts as a buffer

CARBOHYDRATES, LIPIDS, PROTEINS
CARBON:
∑ is a small element
∑ it usually forms and is found in organic compounds with the exceptions of
CO2, HCO3, CaCO3
o those are inorganic compounds that C is found
∑ it forms 4 strong / stable covalent bonds
∑ it reacts with other C atoms to form chains (straight and branched) and
rings
∑ It binds with O, H, N, S
∑ Is found in Carbohydrates, Lipids, Proteins
o In those, small molecules known as monomers bind with many other
similar units to make a very large molecule called a polymer
A
...
BE CAREFUL since the
arrangement of the atoms on the side chains make a significant
difference to the way in which the molecule can be used in the body
...
gmuscles, liver
∑ Has more 1-6 glycosidic, as well as 1-4 glycosidic bonds

Type of carbohydrate Examples
(how many
saccharides?)
Glucose
Monosaccharides
(one saccharide)
Galactose
Fructose
sucrose
Disaccharide (two
saccharides)

lactose

maltose

Polysaccharides
(many saccharides)

amylose

Notes
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amylopectin

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glycogen

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Main substrate for respiration
Soluble, osmotic effect
Soluble, osmotic effect
‘fruit’ sugar
Soluble, osmotic effect
Glucose + fructose
Main transport sugar in plants
soluble
‘milk’ sugar
Glucose + galactose
soluble
glucose + glucose
soluble
found in starch – energy storage
molecule in plants
α –glucose molecules in tight
spirals so compact
insoluble, no osmotic effect
found in starch – energy storage
molecule in plants
branched chains of α –glucose
molecules – lots of terminal ends
so digested more rapidly than
amylose
insoluble, no osmotic effect
energy storage molecule in
animals, bacteria and fungi
branched chains of glucose
molecules
compact, insoluble, no osmotic
effect

B
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It is NOT a
saturated fat but instead it is made in the liver from saturated fats
absorbed from food
...
PROTEINS
∑ Are large molecules – polymers
∑ Are made from smaller monomer units known as amino acids (there are 20
different types of amino acids in nature)
∑ Contain the elements C, H, O, N, S, P
∑ Form hair, skin, nails, enzymes, hormones, antibodies
AMINO ACIDS:
∑ Have a central C atom
∑ An amino group (-NH2)
∑ A carboxyl group (-COOH)
∑ A H atom
∑ A variable side group known as R-group, which can represent any of the 20
different amino acids (the simplest R is glycine, the most complex is
tryptophan)
∑

Amino acids are joined together in condensation reactions to form
ß dipetides,
ß tripeptides
ß polypeptides
∑ water is once again removed from the formation of the
above and the bond is called peptide bond

Other types of bonds found in proteins are
∑ Hydrogen
∑ Sulfur bridges
∑ Ionic
Those bonds are very important in the formation of the 3 dimensional
structure of a protein

LEVELS OF PROTEIN STRUCTURE:
The shape of a protein is important in the properties and the role of a protein in a
cell
...

A mass transport system (example heart and circulation) moves the exchanged
materials around the body
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Most deaths are due to atherosclerosis
ATHEROSCLEROSIS: is the progressive degeneration of the artery walls
∑ Athero = artery
∑ Sclerosis = hardening
It usually happens in arteries because blood flows there under high pressure, fast,
so there is more strain on the endothelium

STEPS IN ATHEROSCLEROSIS
Damage to endothelial lining
of artery (by smoking, high
blood pressure)

Raised blood pressure

Increased risk of blood clotting
in the artery

Inflammatory
response, where WBC
move into the artery

Narrowing of the artery

There are various types of cardiovascular diseases, all
caused as a result of atherosclerosis

Cholesterol builds up, leading to
formtion of atheroma (fatty
yellowish deposits in the
endothelium)

Build up pf calcium salts
and fibres leading to
plaque formation

∑ Endothelial damage: fat collected under endothelium from lipoproteins
and cholesterol

∑ Raised blood pressure: fats cause high blood pressure, loss of elasticity of
walls, narrowing of coronary arteries, so less oxygen reaches the heart
cells, which leads to severe chest pain known as angina

∑ Lession formation: the smooth lining of the vessels breaks, so blood gets in
contact with fat (known as atheromatic plaque), blood platelets collect,
clotting takes place, the clot formed is called thrombus
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∑ Embolus leading to myocardial infarction: the embolus might get in a small
artery or arteriole and cause blockage
...
If the aneurysm
bursts…
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o Also, Y chromosome is linked to high incidence of CHD (in males)
...
(see
below)

o Those not stored have to be transported around the body as
respiratory substance to lead to the production of hormones and
assist in the repair of membranes
o However, they are insoluble in water, so they are transported in
association with proteins
ß LDL: Low Density Lipoproteins which make bad*cholesterol
ß HDL: High Density Lipoproteins which make good* cholesterol
∑ Good and bad cholesterol are no different to each other
chemically, it is the way the cholesterol is carried in the
blood that differ

∑ Alcohol:
o Increases blood pressure
o Damages heart as it leads to irregular beats
o Causes high LDL’s
o Leads to certain cancers –liver, stomach, gut

∑ Physical inactivity / obesity / being overweight
o BMI and body shape

∑ Diabetes

∑ Dietary issues:
o Salt consumption (?)
o Lipid-based diets?
o Meat consumption?

RISKS:
What is a risk?
∑ It describes a probability that a particular event will take place OR
∑ Is the likelihood or a chance of the event happening, calculated
mathematically
∑ Eaxmple in dice: 1 in 6, 1/6, 1:6, 0
...
People smoking and having a high fat, high salt diet
appear perfectly ok so evidence from stats seems insignificant
o Actual Risks are sometimes ignored in the light of vanity (example
continue smoking in order to not be fat)
o Fatalism:the idea that whatever is going to happen will happen and
we will all die one day…
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Cholesterol facilitates the formation of plaques; this is
the causal link
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Cholesterol is a water soluble lipid
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ANTIOXIDANTS
∑ Our bodies produce substances known as ‘’free radicals’’
o For example one oxygen atom with unpaired e- becomes O2(superoxide) which is a highly destructive compound
Antioxidants
∑ Supply H+ to our body cells and stabilise the unstable free radicals so they
become less reactive with cell membranes

TREATMENT OF CVD’s
∑ Lifestyle changes:
o Stopping smoking
o Moderate exercise several times a week
o Stopping over consumption of alcohol
o Dietary changes especially lowering cholesterol and saturated fat
intake

∑ Medical treatments:
o Drugs to control blood pressure (known as anti-hypertensives)
ß Diuretics:
∑ Increase the volume of urine
∑ Increase removal of salts/fluids so it decreasees blood
volume
∑ Therefore, if less blood is pumped, less blood pressure
∑ Risks: very occasional dizziness, nausea, muscle cramps
ß β - blockers:
∑ reduce heart rate by making heart muscle less
responsive to hormones
∑ contractions are not that strong and frequent
∑ reducesbloodpressure
∑ Risks: possiblelinktodiabetes
ß ACE inhibitors:
∑ Block the production of angiotensin which causes
arterial constriction and a rise in blood pressure
∑ So vasodilation takes place and there is more room for
blood to circulate so pressure drops
∑ Risks: cough, dizziness, heart arrhythmia, impaired
kidney function
ß Calciumchannelblockers:
∑ Similar as ACE inhibitors, but here they block calcium
channels
Overall risks: falls, injuries, accidents, tiredeness,
impotence, ankle swelling

∑ Drugs to reduce cholesterol levels:
o Statins: are a group of drugs
ß Block enzyme which is found in liver and is responsible for
synthesis of cholesterol (LDL)
ß Improve balance of LDL to HDL
ß Reduce inflammation in arteries
ß Side effects: muscle inflammation (death), nausea,
constipation and diarrhoea, liver failure, stop eating a healthy
diet leaving it all to the statins (indirect side effect)
o Plant statins:
ß Found in spreads and yoghurts eg
...

∑ Describe the cardiac cycle (atrial systole, ventricular systole and diastole);
the structure and operation of the mammalian heart related to its function
The mammalian heart:
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Is the size of a clenched fist
Is found in thorax between the lungs and beneath breast bone (sternum)
Is a hollow organ
Has muscular wall
Is surrounded by a thin membrane which forms a strong non-elastic sac
known as the pericardium
∑ Is separated in left and right sides
o Each side has upper and lower chambers
ß Upper chambers are called atria, they are thin walled and they
receive blood from organs
ß Lower chambers are called ventricles, are thick – walled and
they pump blood out of the heart
∑ Has heart cells which receive oxygenated blood via the coronary arteries
∑ Has valves which prevent blood from going backwards
o Atrioventricular valves
ß Are located between the atria and the ventricles
ß On the right side called tricuspid, on the left side bicuspid
ß Prevent backflow from the ventricles to the atria
ß Their edges are supported by tendons
o Semi-lunar
ß Are present in pulmonary artery and in aorta
ß They prevent blood from going backwards in ventricles

The cardiac cycle:
The cardiac muscle makes 2 movements
∑ Contraction (known as systole)
o Atrial and ventricular
∑ Relaxation (known as diastole)
o Atrial and ventricular
In contraction:
∑ The volume of that chamber decreases,
∑ So pressure goes up, remember PV=nRT
∑ So blood is forced to a region where pressure is lower
The heart is continuously contracting and then relaxing, and the follwing is the
sequence of events on the left side of the heart during one beat
1
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Raising of the blood pressure in the left atrium, forces the left atrioventricular valve to open
3
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As soon as the left atrial systole is over, the left ventricular muscles start to
contract
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Blood then leaves the left ventricle along the aorta
Similar events take place at the same time on the right side
Then at diastole, ventricles and atria relax
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Blood is drawn into the heart from the
arteries and veins, closing the semilunar valves
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We can study the functioning of the heart in an organism in which the heart is
visible without the need for damaging and invasive procedures, such as the water
flea, Daphnia sp

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