Microscopic fungi

• Unicellular organisms


  Microorganisms
• 5 kingdoms of organisms

  • Animals
  • Plants
  • Fungi
  • Protoctists
  • Prokaryotes (bacteria)
• Viruses are not classed as living things because they cannot carry out the life processes without being in a living cell
• Fungi


  • They are typically multicellular (made of many cells)
  • Fungi cells have nucleus, cytoplasm, cell membranes, mitochondria and cell walls however they do not contain chloroplasts
  • They are also examples of microorganisms
• Yeast


  The most common example of a fungi
• Fungi can cause diseases but they also have practical uses
• Ringworm


  A common skin disease that is caused by fungi
• Ringworm discovered when David Gruby used a microscope to look at the rings on a patient's skin


  1840s
• Ringworm is just one of many diseases caused by microorganisms
• Fungi Reproduction


  1. Budding

  2. Asexual reproduction

  3. Daughter cell grows out of a parent cell
• Budding can be seen under a microscope in a yeast cell
• Fungi Respiration


  1. Anaerobic – without oxygen

  2. Aerobic – with oxygen
• Discovered by scientist Louis Pasteur


  19th century
• Yeast


  An example of a fungi that can be used in the fermentation process as well as baking
• Baking


  1. Yeast undergoes aerobic respiration

  2. Releases more energy for yeast cells

  3. Produces much more carbon dioxide

  4. Bread dough is stretched and folded to get air in to it

  5. Yeast cells in the mixture respire aerobically, making bubbles of gas causing the mixture to rise
• Brewing


  1. Anaerobic respiration of microorganisms is called fermentation

  2. Air is deliberately left out of the juice mixture to make sure it ferments correctly
• Growth Curves


  • For yeast cells to grow and reproduce, they need warmth, moisture and sugar
  • A few yeast cells will very quickly reproduce to become millions but eventually the population will stop growing
  • This is because the sugar eventually all reacts and runs out
  • Something that slows down or stops a process like this is known as a limiting factor