cells

• nucleus controls genetic information and controls cell activities
• cell membrane controls the movement of substances in and out of cells
• cell wall is made of cellulose to strengthen the cell
• chloroplasts is the site of photosynthesis
• mitochondria is the site of aerobic respiration and energy release
• ribosome is protein synthesis
• permanent vacuole is filled with cell sap to keep cells rigid
• cytoplasm is a gel like substance where chemical reactions take place
• types of microscopes

  • transmission electron
  • scanning electron
  • light
• light microscope

  • x1500 magnification
  • 200nm resolution
  • alive specimens
• transmission electron microscope

  • x500k
  • 0.1nm resolution
  • dead specimens
• scanning electron microscope

  • x100k magnification
  • 0.1nm resolution
  • dead specimens
  • 3d
• magnification is the number of times larger an image appears compared to the size of the object
• resolution is the ability to distinguish between two separate points
• cm -> mm = x10

  mm -> μm = x1000

  μm -> nm = x1000
• magnification = image size x real size of object
• mitosis process

  1. normal cell with a nucleus and string like dna
  2. dna condenses and chromosomes form
  3. nuclear membrane disappears and spindle 5 is formed and attaches to chromosomes
  4. chromosomes line up at the middle of the cell
  5. chromosomes split and are pulled to opposite sides of the cell
  6. two new nuclei are formed around 2 sets of dna
  7. cytoplasm and cell membrane split and 2 new genetically identical cells are formed
• mitosis takes place in

  • embryo development
  • seed germination
  • growing regions of plants
  • cells of skin and bone marrow replacing lost blood cells
  • repair of tissues
• egg cell/ovum

  • function is to be fertilised by sperm cell
  • lots of mitochondria for energy
  • nucleus contains half of mothers genes
• sperm cell

  • function is to fertilise the egg cell
  • flagellum for swimming
  • acrosomes to digest the cell membrane of egg cell
• red blood cell

  • function is to collect oxygen for respiration and carbon dioxide to be removed
  • haemoglobin to stick to oxygen molecules
  • biconcave shape to travel through small blood vessels
• nerve cell

  • function is to send and receive electrical messages to and from the brain and nervous system
  • long thin shape so it is faster to send electrical messages
  • myelin sheath helps messages travel faster
• muscle cell

  • when it contracts it gets smaller, when it relaxes it gets longer
  • lots of mitochondria for energy
• palisade cell

  • function is to carry out photosynthesis for the plant
  • many chloroplasts where photosynthesis takes place
  • tall thin shape
  • top half of the leaf
• root hair cell

  • function is to absorb water and nutrients from the soil for the plant
  • large surface area for absorbing water and nutrients
  • thin cell wall so water can easily pass through
  • large vacuole to store water
• ciliated epithelial cell

  • function is to help move things
  • tiny hairs that move and help carry things