MicroOrganisms Chapter 20 MicroOrganisms Microorganisms are very small

Micro-Organisms Chapter 20

Micro-Organisms • Micro-organisms are very small organisms. • Most are to small to see with the naked eye and we need a microscope. • Micro-organisms are found almost everywhere air, water, our skin and our gut.

Micro-organisms • There are 3 types of micro-organism – Viruses – Bacteria – Fungi

Viruses

Viruses • Viruses are the smallest of the microorganisms. • They cannot be seen with a microscope. • Viruses are a chemical surrounded by a protein coat. • Viruses do not feed, respire, grow or move they only reproduce.

Viruses

Viruses • Viruses only reproduce by invading living cells, which they take over and kill. • Therefore all viruses are harmful and cause disease to plants and animals. • Viruses are parasites.

Illness caused by viruses • Cold sore • Flu • Chicken pox http: //i. ehow. com/images/Global. Photo/Articles/ 2041461/cold-sore-crop_Full. jpg • AIDS • Measles http: //cache. eb. com/eb/image? id=82674&rend. Type. Id=4

Bacteria http: //www. bact. wisc. edu/themicrobialworld/C. bot. Spores. jpg

Bacteria are simple living cells. Bacteria feed, move, respire and reproduce. Bacteria live almost everywhere. Most bacteria are harmless they even do us good. • Other bacteria is harmful and causes disease. • •

Benefits of Bacteria • Soil Nutrients – Soil bacteria decompose the remains of dead plants and animals, this releases nutrients back into the soil. • Decay of wastes - Bacteria are used in sewage treatment to break down wastes and make them harmless. • Cheese and yogurt - bacteria are used in the making of cheese and yogurt.

Benefits of Bacteria • Silage – Bacteria break down grass into silage which is used for feeding cattle.

Harmful Effects of Bacteria • Disease – bacteria causes diseases such as food poisoning, pneumonia, meningitis and appendicitis. • Food spoilage – • Tooth Decay –

Fungi • 3 Types –Yeast (single cell) –Bread mould (long threads) –Mushrooms (large structures)

Fungi • Most fungi live on dead organisms bread and fruit • Some fungi are parasites and cause disease.

Benefits of Fungi • Some large fungi are edible (Food) • Brewing – Yeast is used to make alcohol. • Baking – Yeast is added to dough in baking. • Antibiotics – The fungus penicillium is used to make penicillin.

Harmful effects of Fungi • Disease – some fungi cause disease e. g. athletes foot and ringworm. • Food Spoilage – some fungi cause food to spoil e. g. bread mould. • Poisonous – Some fungi are poisonous i. e. certain toadstools.

Soil Micro-organisms • Some micro-organisms break down the dead remains of plants and animals and release nutrients back into the soil. • These are known as decomposers.

Biotechnology • Biotechnology involves using living things like micro-organisms to make substances useful to humans. • Examples Industry: – Yeast in baking and brewing. – Bacteria in cheese and yoghurt. • Examples in medicine: – Bacteria to make insulin – Penicillium to make penicillin.