What are micro-organisms?

Microbes –Microbes are single celled organisms –Too small to be seen with the naked eye –They are found practically EVERYWHERE on earth –Also commonly known as bugs, germs and microbes –Generally divided into 3 different groups Bacteria Virus Fungi

Bacteria –Obtain nutrients from their environments in order to live. In some cases that environment is a human body –Most are helpful or harmless. But some cause disease –Bacteria can reproduce outside of the body or within the body as they cause infections –Some bacteria are good for our bodies: Good bacteria live in our intestines and help us use the nutrients in the food we eat and make waste from what's left over. –They are found everywhere on earth, in the ocean, in rocks, in volcanoes, in our bodies and in the soil

Bacterial Structure Chromosome: DNA material of the cell Cell wall:Composed of peptidoglycan the cell wall maintains the overall shape of a bacterial cell Cell membrane:Lining the inside of the cell wall it provides a boundary for the contents of the cell and a barrier to substances entering and leaving. Cytoplasm: Describes the inside of the cell and the contents Chromosome Cell Membrane Cytoplasm Cell wall

Bacterial Shapes There are 3 different shapes of bacteria Spirals (Campylobacter) Rods (Lactobacillus) Balls or cocci (Staphylococcus)

Viruses –Viruses are even smaller than bacteria and can sometimes live INSIDE bacteria –Most viruses make us ill –Diseases like CHICKENPOX and the FLU are caused by viruses. –Viruses are easily spread from one person to another. –Viruses cannot reproduce by themselves. They infect other cells and take over their reproductive machinery in order to reproduce. –They multiply inside the ‘host’ cell and when they have used all the cells reproductive machinery, thousands viral cells burst out of the cell. The host cell is completely destroyed.

Viral Structure Envelope Double lipid layer holding the cells genetic material. Glycoproteins These serve 2 purposes Anchor the virus to the host cell. Transport genetic material from the virus to the host cell. Nucleic acid Either DNA or RNA material, but virus cells rarely contain both. Most viral cells contain RNA material. Complex (Bacteriophage – a virus which infects bacteria) Envelope Nucleic acid Glycoproteins

Viral Shapes Icosahedral (Influenza) Complex (Bacteriophage – a virus which infects bacteria) Helical (Tobacco mosaic virus) There are 3 different shapes of Virus

Fungi –The largest and most versatile of all microbes –Large plant like structures which lack chlorophyll –Need to absorb nutrients from whatever they are growing on –Fungi can be very helpful and humans have used them in –The food industry - brewing beer, making bread rise –Medicine – making antibiotics –They can also be harmful if they steal nutrients from another living organism. Examples include, mould on bread and athletes foot which is caused by a group of fungi known as dermatophytes –Fungi can be found in the air, on plants and in water

Fungal Structure Sporangia: Spore producing body. Sporangiophore: Filamentous stalk on which the sporangium forms. Rhizoids: The sub-surface hyphae are specialized for food absorption. Sporangiophore Sporangia Rhizoids