b1

• eukaryotic cells- have a cell membrane, cytoplasm, nucleus, mitochondria and ribosomes and a plant cells has all of them and a cell wall, chloroplasts and a vacuole
• prokaryotic cells- cell wall, cell membrane, plasmid, cytoplasm and doesn’t have a true nucleus
• start with the lowest objective lens- to get a wider field of view or easier to focus
• light microscope advantages and disadvantages- cheap, view live samples and has a lower magnification and resolution
• electron microscope advantages and disadvantages- higher resolution, higher magnification and it’s expensive
• microscope equation- magnification = image size / actual size
• cell cycle-

  1. cell grows and DNA doubles
  2. one set of chromosomes goes to each end of cell
  3. 2 sets of cells are made and cytoplasm and cell membrane are doubled and divided
• mitosis- identical cells, 46 chromosomes each, divides once, asexual reproduction and it is used for growth and repair
• stem cell- unspecialised cell that can divide to produce more cells of the same type
• therapeutic cloning- cells is stimulated to divide, after 4-5 days stem cells are removed, stem cells are altered from embryos for therapeutic cloning use
• positives of therapeutic cloning- treat diseases and can differentiate into any cell
• negatives of therapeutic cloning- shortage of donors and has a low success rate
• advantages of embryonic stem cells- it isn’t a painful process and the cells differentiate into any type of cell
• nerve cell- it is for rapid signalling

  • long - to cover large distances
  • branches- to form a network of connections
• villi function- absorbs glucose into bloodstream