Cells and Microscopes

• Cell membrane

  Controls what enters and leaves the cell
• Nucleus

  Contains genetic material
• Mitochondria

  Provide the energy cells need
• Ribosomes

  Translation of genetic material occurs
• Cytoplasm

  Gel-like substance where chemical reactions happen, enzymes
• Cell wall

  Made of cellulose, supports and strengthens cell
• Chloroplasts

  Contains chlorophyll, photosynthesis occurs, makes food for the plant
• Vacuole

  Maintains internal pressure to support cell
• Plant cells have all the parts that animal cells do
• Flagellum

  Moves cell away from harm and forwards bacteria
• Chromosomal DNA

  Controls cell activity and replication
• Plasmid DNA

  Small loops of DNA, can be passed between bacteria
• Ribosomes

  Translation of genetic material
• Egg cell

  • Cytoplasm contains nutrients to feed embryo
  • Membrane harder to stop other sperm cells entering
• Sperm cell

  • Long flagellum to swim to the egg
  • Lots of mitochondria for energy
  • Acrosome in its head containing enzymes to dig through membrane
• Light microscope

  • Lower resolution around 200 nm
  • Low magnification of x2000
  • Cheaper
  • Portable
• Electron microscope

  • Higher resolution
  • Higher magnification
  • More expensive
  • Requires dead specimens
  • Extensive training needed
• Using a microscope

  1. Place thin layer of specimen on glass slide

  2. Add coverslip

  3. Add stain if needed

  4. Place slide on stage

  5. Start on lowest power objective lens

  6. Increase magnification

  7. Refocus using focusing wheel
• Magnification

  Image size / Actual size
• Converting units

  1. Millimeter (mm) to micrometer (μm) x1000

  2. Micrometer (μm) to nanometer (nm) x1000

  3. Nanometer (nm) to picometer (pm) x1000
• Resolution

  The smallest distance between two points that can still be seen as two points
• Eukaryotic

  Contain a nucleus + membrane bound organelles, e.g. Animal cell
• Prokaryotic

  Doesn't contain a nucleus or membrane bound organelles, e.g. bacteria