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Enzymes and biological molecules


Contain 3 elements:

1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)

Carbohydrates are found in one of three forms:

1. Monosaccharides
2. Disaccharides (both sugars)
3. Polysaccharides

Disaccharides and glycosidic bonds

These are formed when two monosaccharides are condensed together. One…

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Lipids are made up of the elements carbon, hydrogen and oxygen but in different
proportions to carbohydrates. The most common type of lipid is the triglyceride Lipids can
exist as fats, oils and waxes. Fats and oils are very similar in structure (triglycerides).


These are…

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Hydrolysis is the opposite of condensation and is the breaking of a peptide bond using a
molecule of water.

Fibrous proteins are made of long molecules arranged to form fibres (e.g. in keratin). Several
helices may be wound around each other to form very strong fibres.


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2. pH
3. Enzyme Concentration
4. Substrate Concentration


Most enzymes require additional help from cofactors, of which there are 2 main types:

1. Coenzymes - these are organic compounds, often containing a vitamin molecule as
part of their structure.
2. Metal ions - most speed up…

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Infection and disease

Your immune system is made up of cells that work with the body's physical and chemical
barriers. It helps prevent any pathogen (disease-causing organism) entering your body, and
your body therefore becoming infected. Note: Harmful bacteria is an example of a pathogen.
If the…

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Inflammation happens because cells damaged by invading pathogens and particular white
blood cells release 'alarm' chemicals which makes blood vessels enlarge (vasodilate) and the
capillaries more 'leaky'.

Attack no 2: Phagocytes and lymphocytes

Inflammation attracts white blood cells to the area. The three types of white blood…

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Suppressor T cells

Memory cells

Humoral response (B cells)

As with T cells, a B cell will form a clone if it comes into contact with a complementary
shaped antigen. The clone contains mostly plasma cells for immediate use and some
memory cells for use in the…

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These are a result of an overreaction of the immune system to a harmless antigen, as in
asthma, hay fever and eczema. They are caused by allergens - for example, pollen, dust,
particles of animal skin, dustmites and their faeces.

Health and disease

Health can be…

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Lung disease
After heart disease and strokes, this is the most common cause of illness and death in the
Chronic bronchitis
Tar stimulates goblet cells and mucus glands to enlarge, producing more mucus. It destroys
the cilia inhibiting the cleaning of the airways and mucus…

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blood pressure rises. This makes it difficult for the heart to receive the extra nutrients and
oxygen it requires during exercise.
Three forms exist: Angina, Heart Attacks, Heart Failure
These occur if an artery in the brain burstsand blood leaks into the brain tissue or when…


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