© Oxford University Press a Types of microbes The blue sausage and the yellow spheres are bacteria..... but the big green cells are a type of fungus called yeast. They look a bit like bacteria but yeast cells have a nucleus and bacteria don’t.

© Oxford University Press 2009 Other fungi are made of long thin threads….. so when lots grow together they make a dense fluffy mat. All this fungus grew from one microscopic spore. Spores blow around in the air, so a fungus can spread over large areas quickly. 2.1a Types of microbes

© Oxford University Press 2009 These microbes came from someone’s mouth......but bacteria survive in amazing places, like hot springs where the water is almost boiling. When scientists melted a 32,000 year-old ice cube, the bacteria inside it sprang back to life. 2.1a Types of microbes

© Oxford University Press 2009 Bacteria look a bit like miniature plant cells because… They look a bit like miniature animal cells because… What makes them different from both of these is that… Bacteria can be sausage-shaped or spherical, but they all have similar parts. 2.1a Types of microbes Genes made of DNA

© Oxford University Press 2009 Bacteria look a bit like miniature plant cells because…..they have cell walls. They look a bit like miniature animal cells because…..they have no chloroplasts and no vacuole. What makes them different from both of these is that…..they have no nucleus. Their DNA is loose in the cytoplasm. 2.1a Types of microbes

© Oxford University Press 2009 Bacteria are living things because they have all the life processes: Movement Reproduction Sensitivity Growth Respiration Excretion Nutrition 2.1a Types of microbes

© Oxford University Press 2009 These purple bacteria will not harm the pink skin cell. There are trillions of bacteria in the world – and most are harmless. Many are very useful, both inside and outside our bodies. A few cause disease. If they get inside us, they make toxic chemicals and destroy cells. 2.1a Types of microbes

© Oxford University Press 2009 Viruses are not cells and don’t carry out most life processes. They do not feed, respire or excrete. But they have genes and can reproduce. A virus is just an outer coat wrapped round a set of genes. Like a computer virus, it’s just a set of instructions. 2.1a Types of microbes Genes

© Oxford University Press 2009 These viruses detected a white blood cell and stuck to it. Their genes will enter it and force the cell to make new virus particles. A virus can’t reproduce by itself. 2.1a Types of microbes

© Oxford University Press 2009 Eventually the cell dies. Virus particles burst out through its membrane and then spread to new cells. 2.1a Types of microbes

© Oxford University Press 2009 Which life processes does the virus carry out? Movement Reproduction Sensitivity Growth Respiration Excretion Nutrition       2.1a Types of microbes

© Oxford University Press 2009 Viruses make cells construct miniature motors to pack new virus genes into their coats. Some can hide in your cells for years. Cold sore viruses hide in nerve cells. They can pop out to cause an infection whenever you are feeling a bit run down. 2.1a Types of microbes

© Oxford University Press 2009 There are trillions of viruses in the world. This one attacks bacteria. Most are harmful to living things. Can you explain why? 2.1a Types of microbes Virus Bacterial cell Bacterial genes Viral genes