B1

• Prokaryotic cells


  Bacteria: smaller and simpler
• Eukaryotic cells


  Animals & plants: bigger & complex
• Cell components


  • DNA (floating free)
  • Plasmids
  • Cytoplasm
  • Membrane
• Light microscopes


  • Invented 1590
  • Cheap & portable
  • Easy to prepare living specimen
• Electron microscopes


  • Invented 1930s
  • Expensive & not portable
  • Hard to prepare only dead specimen
• Specimen preparation


  1. Pipette to place a drop of water on a clean slide

  2. Use tweezers to put a thin slice of specimen

  3. Stain if needed

  4. Place cover slip on top, press down gently with needle to remove air bubbles
• Viewing preparation


  1. Clip the slide onto the stage

  2. Select the lowest powered objective lens

  3. Use coarse adjustment to move the stage up

  4. Look through the eyepiece and adjust the focus with the fine adjustment knob
• Magnification


  Total magnification = eyepiece magnification x objective lens magnification
• Chromosome


  Long molecules of coiled up DNA containing genes
• Polymer


  Large, complex molecules made of chains of monomers joined together
• Nucleotides


  Join together in a long chain to make DNA, each containing a base: Adenine, Thymine, Cytosine, Guanine
• Respiration


  1. Process of transferring energy from the breakdown of glucose

  2. Exothermic reaction controlled by enzymes

  3. Affected by temperature and pH
• Types of respiration


  • Aerobic (with oxygen - 32 ATP)
  • Anaerobic (no oxygen - 2 ATP)
• Aerobic respiration


  Glucose + oxygen → carbon dioxide + water
• Anaerobic respiration (animals)


  Glucose → lactic acid
• Anaerobic respiration (plants)


  Glucose → ethanol + carbon dioxide
• Enzymes


  • Biological catalysts that speed up reactions
  • Affected by temperature and pH
  • Have an optimum temperature and pH
• Enzyme denaturation occurs when temperature is too high or pH is too high/low, breaking bonds and changing the enzyme's shape
• The more enzyme molecules present, the more likely a substrate molecule will collide with and react with an enzyme