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CAMBRIDGE GCSE BIOLOGY Y10

By KenTheGreatSir

Edmodo group code: 27ip42

Human Biology & Living Organisms Key Notes

Our energy is derived from food - whereas plants can produce their own energy

from sunlight, we must consume food.

This food is our raw material - needed to make new substances for: -

_____________________ (movement etc)

_____________________

_____________________

A balanced diet contains the different nutrients in the correct amounts, keeping us

healthy

Certain foods are not necessarily 'bad' for us, but eating too much of them could

be

Foods contain nutrients: these are substances which provide raw materials for the

body (we need nutrients, along with fibre and water for a healthy diet)

There are ___________________ different nutrients, and some foods are

particular rich in certain nutrients: -


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Different foods contain different substances - there is no one food that contains

all the substances the body needs. Instead you must eat a wide variety of foods -balancing your diet

Different people need different amounts of food. You need more food if you are

particularly active, are pregnant etc (the amount of energy food contains is

measured in _____________ (_______) - if you are more active, your kJ intake

needs to be greater )

If we eat too little food, we will use up our store of fat and become too thin. If we

eat too much food, especially foods rich in sugar and fat, we will increase our store

of fat and become too fat

If you have too little of a particular nutrient, we say that you have a deficiency in

that nutrient, e.g. fibre deficiency can lead to constipation

Mineral deficiencies - e.g. iron deficiency can lead to________________(too

few red blood cells); iodine deficiency can lead to a swelling in the neck called a

_______________

Vitamin deficiencies - e.g. vitamin A deficiency can cause _______________;

vitamin C deficiency can cause ______________ (makes the gums bleed); and


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vitamin D deficiency can cause _______________ (legs bow outwards in growing

children)

A healthy diet contains all the different nutrients in the correct amounts, and

provides the right amount of energy for each individual

An unbalanced diet can lead to a person becoming malnourished they may be too

thin or too fat as a result, and they may suffer from deficiency diseases

___________________ is the _______________ that allows cells to release

energy from food the _______________ rate is the speed at which such

chemical reactions take place in the body

_________________ rate is the rate at which your body burns calories

Basal metabolic rate (BMR) is the rate when resting (you can inherit a high BMR)

You can also increase your BMR with more exercise (increasing your muscle to fat

ratio)

Malnourishment is a person with an unbalanced diet these diseases are due to

malnourishment: -

Anaemia lack of ______________

____________________ too much fat

____________________ too much carbohydrate and no protein

____________________ too little food

RDA is the amount of a specific nutrient which is recommended for consumption

per day food packaging must clearly show this for each nutrient

A balanced diet should contain fats, proteins and carbohydrates in roughly these

amounts: carbohydrates, fat and protein


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Food labels on products show the RDA of different nutrients within the food,

usually per 100g and per serving of food

Overweight people may suffer from health problems, including: -

Diabetes (type 2) - an illness in which the body is unable to control the

amount of sugar in the blood

Arthritis - an illness in which the joints become worn, inflamed and painful

High blood pressure

Heart disease

BMI (body mass index) is a scale to determine your ideal weight the calculation is

your weight (kg) height2(m)

Blood pressure is the force ________________ on the blood vessel walls from

circulating the blood

___________________ can lead to heart disease by straining the heart and

damaging the blood vessels


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Normal blood pressure is ______________ overweight people and those who eat

too much ________________- often have high blood pressure

The heart is an organ that needs its own supply of blood to keep it working if the

blood supply is reduced, the heart muscle will not work properly and will become

weaker

A heart attack happens when part of the heart does not get any blood because of a

blocked _______________

Table salt is ____________________too much salt in the diet can lead to high

blood pressure, which in turn leads to an increased risk of heart disease and

strokes

Salt is found naturally in many kinds of food, but more is added by food

manufacturers - and many people add even more when they are eating

Processed foods often have a high proportion of salt and fat

Salt added to food during processing accounts for about two-thirds of the average

salt intake

____________________-- (C27H46O) is a substance found in the blood it is

made in the liver and is needed for healthy cell membranes

Too much cholesterol in the blood increases the risk of heart disease, and of

diseased arteries

Cholesterol is important for a variety of body functions, including: -


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________________________

________________________

________________________

________________________

The bloodstream transports cholesterol around the body attached to proteins

The combination of cholesterol and protein is called lipoprotein, and there are two

type: -

Low-density lipoproteins (LDLs) - carry cholesterol from the liver to the

cells

High-density lipoproteins (HDLs) - carry excess cholesterol back to the

liver

LDLs are often called 'bad' cholesterol because they lead to fat building up on

artery walls, which causes heart disease 70% of cholesterol consisting mostly of

fat

HDLs are often called good cholesterol because they help to stop fat building up

in the arteries 20% of cholesterol consisting mostly of protein

Monounsaturated and polyunsaturated oils (found in vegetable oils) help to reduce

cholesterol levels in the blood, and also increase the proportion of HDLs compared

with LDLs

Molecules of vegetable oils consist of glycerol and fatty acids

Glycerol has 3 carbon atoms and fatty acids have long chains of carbon atoms


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The fatty acids in some vegetable oils are saturated, and only have single bonds

between their carbon atoms

_____________ oils tend to be solid at room temperature, and are sometimes

called vegetable fats instead of oil

The fatty acids in some vegetable oils are unsaturated, and have double bonds

between some of their carbon atoms

Unsaturated oils tend to be liquid at room temperature, and are useful for frying

food they can be divided into two categories: -

Monounsaturated fats have one double bond in each fatty acid

Polyunsaturated fats have many double bonds

The carbon-carbon double bonds in unsaturated oils can be detected using the

elements bromine or iodine

These elements react with the double bonds in the oils, and the more double bonds

there are, the more bromine or iodine is used up

Bromine water is a dilute solution of bromine, which is normally orange-brown in

colour it becomes colourless when shaken with an alkene, or with unsaturated fats

(when shaken with alkanes or saturated fats, its colour remains the same)

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