Biology

Communicable and non communicable diseases

Non communicable

Communicable

Can be transferred from one person to another

Measles, food poisoning and malaria

Not transferred between other people

cancer, diabetes

Antibiotics

medicines that help to cure bacterial disease by killing infective bacteria inside the body, but cannot be used to kill viruses

Penicilin

First antibiotic discovered in 1928

How does it work

Antibiotics damage the bacterial cells but do not damage the host cells

Viral diseases

Viral diseases cannot be cured by antibiotics, as they reproduce inside the host cells.

Stem cells

Stem cells are cells that have not undergone differentiation .

Adult stem cells can be found in the:

Brain, eyes, blood, heart, liver, bone marrow, skin, muscle

to treat conditions in which the bone marrow is damaged and is no longer able to produce healthy blood cells.

Enzymes

Enzymes are biological catalysts that speed up reactions

Enzymes are proteins

Enzymes are required for most of the chemical reactions that occur in organisms

These reactions occur in the breakdown of chemical molecules, which we see in the digestive system

Factors affecting enzyme action

At low temperatures, the number of successful collisions between the enzyme and substrate is reduced because their molecular movement decreases. The reaction is slow.

Higher temperatures disrupt the shape of the active site, which will reduce its activity, or prevent it from working. The enzyme will have been denatured

Osmosis

Osmosis is the diffusion of water molecules

The absorption of water from the soil is due to osmosis

water molecules are in higher concentration, to a region where they are in lower concentration,

DIffusion

Particles (molecules and ions) in a liquid and a gas move continuously.

will move in both directions, but there will be a net movement from high to low concentration

will end up evenly spread throughout the liquid or gas, but will continue to move

A tea bag immersed in a cup of hot water will diffuse into the water and change its colour

DNA

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