vircus

• Bacteria


  Smallest living organisms
• Bacteria


  • Lots of shapes and sizes
  • Cannot see without using microscope
  • Each bacterium is a single cell
• Bacterial cell


  • Lack a nucleus and membrane-bound organelles
  • Have circular DNA
  • Have smaller ribosomes
• Bacterial cell

  Different to plant and animal cells<|>Don't have proper nucleus<|>Have a loop in the cytoplasm that carries all the information (genetic information)<|>Have other small pieces of genetic information called plasmids

  
• Bacteria


  • Take in food and respire
  • Excrete carbon dioxide and other waste products
  • Can grow and reproduce by splitting in half
  • Some bacteria split in half every 20 minutes
  • Some have flagella to move themselves
• Useful and harmful bacteria

  • Some bacteria cause diseases in human and other organisms
  • Many bacteria are harmless and some are very useful
• Useful and harmful bacteria

  • Salmonella bacteria cause stomach upsets
  • Bean blight is caused by bacteria
  • Bacteria help to decay the bodies of plants and animals
  • Bacteria in the guts and skin help to keep healthy
  • Use bacteria to make cheese, yoghurt, wine and vinegar
  • Treating human sewage
• Growing bacteria

  1. On special jelly that contains all the nutrients

  2. They form colonies

  3. Can been seen without microscope
• Growing bacteria

  • Take great care when culture bacteria
  • Carefully to avoid any risk from harmful bacteria
• Fungi

  Mushrooms and puffballs are the parts that uses for reproduction<|>Spread out in the soil as very thin, thread-like structures are called hyphae
• Fungi

  • All fungi get their food from dead or other living organisms
  • Some of them cause a lot of damage
  • Digest crops and food and make them rot
  • Usually need moist conditions to grow
• Yeast

  Single-celled organisms<|>Found all around us<|>Grow on the skin of fruits, feeding on sugar in the fruit<|>Usually respire using oxygen but they can respire without oxygen<|>It has nucleus, cytoplasm and a membrane with cell wall<|>Reproduce by budding (a small new yeast cell forming from old one)
• Yeast

  • Some used to make bread and drinks (beer and wine)
  • Different yeast cells can also cause diseases of the skin, the lungs and brain
• Mould


  Made up of tiny thread-like structures called hyphae<|>Hyphae are not made up of individual cells<|>Moulds need oxygen to respire<|>Get their food by digesting it outside their bodies<|>Moulds reproduce, make little fruiting bodies that are full of spores<|>Each spore can grow into new mould
• Differences between yeast and mould

  • Multicellular (multiple celled)
  • Unicellular (one celled)
  • Filamentous fungi, Thread-like
  • Round or oval in shape
  • Respire oxygen
  • Respire with/ without oxygen
  • Microscopic filaments called hyphae
  • Do not have true hyphae
  • Sexually and asexually (spore) reproduce into multi-cellular form
  • They reproduce mostly asexually (budding)
  • Moulds are very colorful compared to yeast
  • Yeast are less colorful compared to molds (colorless)
• Fungi has all the characters of living things as movement, respiration, sensitivity, growth, reproduction, excretion and nutrition
• Mold

  • Requires water, food, and oxygen to grow
  • Grows best in humid and warm environments
  • Can survive on foods with a high acid content, such as fruits, pickles, jams, salt meats, and tomatoes
• Procedure to examine fungi under microscope

  1. Place the specimen on a clean glass slide

  2. Add 1 drop of 20% KOH (Potassium hydroxide)

  3. Place the cover glass on top of the slide and gently press to get rid of any air bubbles

  4. Place slide on the microscope stage and start with a low-power (10 ×) examination

  5. Examine for fungal structures such as hyphae or yeast
• Virus

  Doesn't respire, move, excrete or any sensitivity<|>Can reproduce by taking over other organisms<|>Very small, about 0.0001mm<|>Reproduce only inside the cells of another living organism (an animal or a plant)<|>Can be seen as strange shapes<|>Made of protein and genetic material
• Viruses

  Cannot move themselves from one organism to another<|>They have found ways of spreading around in different ways
• HIV (Human Immunodeficiency Virus)


  AIDS (Acquired Immunodeficiency Syndrome)
• Parasites

  • Animals, such as tapeworm and thread worms
  • Bacteria, such as Mycobacterium leprae, which cause leprosy
  • Fungi, such as Candida, which causes thrush
• Viruses as parasites

  • Most parasites rely on host for food and protection
  • Viruses get into the body invade the cells
  • Protein coat of the virus stays outside the cell but the genetic materials is injected through the cell membrane
  • Genetic material of the virus takes control of the nucleus of the host cell
  • Make lots of new viruses
  • Spread through the body and infect more cells
  • Leave the body and infect someone