viruses, bacteria, pathogens, protists and fungi ..

1) viruses are not cells- they are much smaller, about 1/100th the size of a bacterium

2) they can reproduce rapidly inside your body

3) they live inside your cells and replicate themselves using the cells' machinery to reproduce many copies of themselves

4) the cell will usually then burst, releasing all the new viruses

5) this cell damage is what makes you feel ill

1) bacteria are very small living cells (about 1/100th the size of your body cells), which can reproduce rapidly inside your body

2) they can make you feel ill by producing toxins (poisons) that damage your cells and tissues

1) pathogens are microorganisms that enter the body and cause disease

2) they cause communicable (infectious) diseases- diseases that can spread easily

3) both plants and animals can be infected by pathogens

4) pathogens can be bacteria or viruses, or protists or fungi

1) there are lots of different types off protists. but they're all eukaryotes and most of them are single-celled

2) some protists are parasites. Parasites live on or inside other organisms and can cause them damage. They are often transferred to the organism by a vector, which doesn't get the disease itself- e.g. an insect that carries the protist

1) some fungi are single-celled

2) others have a body which is made up of hyphae (thread like structures)

3) these hyphae can grow and penetrate human skin and the surface of plants, causing diseases

4) the hyphae can produce spores, which can be spread to other plants and animals

symptoms: purple or black spots that develop on the leaves or rose plants. the leaves can turn yellow then fall off

methods of transmission: spreads through the environment in water or by the wind

treatment: the disease can be treated by using fungicides and by stripping the plant of its affected leaves.

symptoms: causes flu-like symptoms for a few weeks. then symptoms arent usually experienced for a few years.

method of transmission: the virus is spread by sexual contact or by exchanging bodily fluids such as blood.

control: there is no initial cure but antiretroviral drugs can help to stop the virus replicating in the body.

symptoms: a red skin rash is developed, and they show signs of a fever

methods of transmission: it is spread by droplets from an infected persons sneeze or cough.

prevention: you can be vaccinated against measles when you are young

it causes a mosaic pattern on the leaves of plants- parts of the leaves become discoloured. this effects how the plant carrys out photosynthesis, so the virus effects growth

symptoms: infected people can suffer from fever, stomach cramps, vomiting and diarrhoea

method of transmission: you can get salmonella from eating food that's been contaminated with salmonella bacteria

control: keep raw meat away from food eaten uncooked

symptoms: a person with gonorrhoea will experience pain when they urinate. another symptom is thick yellow or green discharge from the vagina or penis

methods of transmission: gonorrhoea is a sexually transmitted disease (STD), so is passed on by sexual contact e.g unprotected sex

treatment: gonorrhoea is normally treated with antibiotics, called penicillin

control: to prevent the spread of gonorrhoea , people can be treated with antibiotics and should use barrier methods of contraception e.g. condoms

symptoms: malaria causes repeating episodes of fever. It can be fatal

methods of transmission: when mosquito's fead on other animals, it infects it by inserting the protist into the animal's blood vessels

prevention: people can be protected from malaria/ mosquitos using insecticides or mosquito nets

skin: waterproof, impermeable, pH 5.5 (acidity prevents bacteria and fungi from growing)