B1

• Light microscope are cheap to make, they let you see the outline of cells. Electron microscopes allow you to visualise inner cells including organelles because of the higher resolution. All human cells have 23 chromosomes pairs (diploid) expect gametes they only have 23(haploid). New diploid cells are made by mitosis for growth and repair. The genetic material is duplicated and the number of ribosomes in mitochondria is doubled as well. The nucleus breaks down and one set of each chromosome pair is pulled to opposite sides of the cell.
• Stem cells

  Cells that are not yet specialized
• Stem cells


  • Found in human and animal embryos
  • Found in the meristem of plants
• Embryo cloning


  1. Make a clone of a person

  2. Harvest stem cells from the clone
• Using stem cells from a clone

  Helps prevent rejection in the patient's body
• Diffusion

  Movement of particles from a high concentration to a low concentration
• Factors affecting diffusion rate


  • Difference in concentrations
  • Surface area
  • Temperature
• Osmosis


  Movement of water from a less concentrated area to a more concentrated area through a partially permeable membrane
• Osmosis practical

  1. Weigh and place identical cylinders and the same vegetable in sugar solutions of varying concentrations

  2. After set time, remove excess water and calculate percent change in mass
• Active transport

  Movement of particles across a membrane
• Microscopes practical: first place a drop of water onto the middle of a clean slide. Then cut up an onion and peel of one layer. After that use tweezers to peel of the epidermal tissue of the bottom of the layer. Then place a cover slip on top. After this clip the slide onto the stage of the light microscope. Then make sure to use the objective lens and adjust it to the lowest magnification. Then use the coarse adjustment knob to move the stage just below the objective lens.