Cell Structure

Cell Structure

Microscopes
1. Light
  1. Uses glass lenses to refract light and increase magnification
    1. Light is focused on object using condenser lens
      1. Passed through specimen and refracted by objective lens
        Reaches eyepiece lens, where image is flipped right way up
  2. Resolution tends to be low
    1. Resolution is degree of detail
    2. Magnification is increases apparent size
  3. Stains tend to be chemicals that react with chemicals found in sample or attach to cellular parts
2. Electron
  1. Tranmission Electron Microscope
    1. Passes electrons through object
  2. Scanning Electron Microscope
    1. Bounces electrons off object
  3. Stains tend to be heavy metal ions
    1. Ions are positive and stop electrons passing, causing a darkening effect in final image
Eukaryotic Organelles
1. Animal Specific
  1. Centrioles
    1. Make microtubules
      1. Then orders them to make spindle for mitosis
2. Plant Specific
  1. Chloroplasts
    1. Membranes called grana form stacks of thylakoids
      1. Light is used to split water into hydrogen ions
        Used to make ATP
  2. Cell Walls
    1. See Cell Membranes Mind Map
3. Nucleus
  1. The Nucleus houses the chromosomes, which contain the DNA of the cell
    1. It is surrounded by a nuclear envelope
      1. This has nuclear pores to allow mRNA in and out
4. Endoplasmic Recticulum
  1. Rough
    1. Covered in ribosomes
      1. Place of protein synthesis
  2. Smooth
    1. Various uses
  3. Membrane that separates cisternae from cytoplasm
    1. Synthesisied proteins stored in cisternae
5. Golgi Apparatus
  1. Combines small molecules to make bigger ones
    1. Bigger molecules packaged to make vesicles
      1. Sent out of cell or stored
  2. Makes Lysosomes
6. Lysosomes
  1. Bags of digestive enzymes
    1. Sperm cells have specialised lysosomes
7. Mitochondria
  1. Site of aerobic respiration
  2. Has a double membrane
    1. Inner makes cristae
      1. ATP formed here
        ATP= Energy currency
    2. Background material called matrix
8. Cell Membrane
  1. See Cell Membranes Mind Map
9. Cilia and Flagella
  1. Cilia= Short structures
  2. Flagella= Long structures
  3. Can be used to move cell
    1. Arranged with two microtubules in the centre and 9 pairs circling
      1. Called 9+2
10. Vacuoles
  1. Storage for food in liquid form
    1. Larger in Plants and used for sap
Prokaryotic cells
1. No Nucleus
  1. Chromosomes present but not as we know them
    1. Circular and not associated with histones
2. No Mitochondria
3. No Chloroplasts
4. Ribosomes about 2/3rds smaller
5. No Cytoskeleton
6. Has Cell walls but not as we know it
7. Flagella only, and different structure

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