cells

• Function of a vacuole

  contains cell sap and keeps cell rigid and firm
• Function of chloroplasts

  contains chlorophyll, where photosynthesis takes place to produce glucose by absorbing light energy
• Function of cell wall

  gives cell structure and support
• Function of cytoplasm

  jelly like substance, where chemical reactions take place
• Fucntion of cell membrane

  controls what goes in and out of a cell
• Function of a ribosome

  where protein sythesizes
• Function of mitochondria

  where respiration takes place and releases energy
• Function of nucleus

  contains DNA and controls cell activities
• Function of plasmid DNA

  provides genetic variation for bacteria
• Function of chromosomal DNA

  controls activity of the cell
• Eukaryotic cells


  have a nucleus, have membrane bound organelles, ribosomes are large
• Prokaryotic cells

  no nucleus, no membrane bound organelles, ribosomes are small
• Mitosis

  .2 daughter cells produced

  .diploid number of chromosomes

  .genetically identical cells

  .makes body cells for growth and repair

  .asexual reproduction
• Meiosis

  -4 daughter cells produced

  -haploid number of chromosomes

  -not genetically identical

  -makes gametes

  -sexual reproduction
• Describe mitosis(3 marks)

  -2 daughter cells

  -diploid

  -genetically identical
• What should happen when cells are dividing by mitosis to make body cells?


  the cells produced at the end must have a diploid number of chromosomes
• Explain why sperm cells cannot be produced using the cell cycle(2 marks)

  sperm cells are a haploid however the cell cycle produces diploid cells
• What is cancer?

  when a mutated cell divides uncontrollably by mitosis to form a lump of cells called a tumour.
• Describe how to produce a microscope slide to view onion cells

  -cut a thin layer of onion

  -place the layer onto the slide

  -add one drop of a stain using iodine

  -place cover slip over the specimen at an angle

  -place slide onto the stage and secure with stage clips
• How to prepare a slide to view an onion cell

  -peel thin layer of the onion (allows light to go through)

  -place the layer onto a slide

  -stain the cells with iodine (to make the cells more visible)

  -place a cover slip over the cells
• Describe how to use a light microscope

  -place the slide onto the stage of the microscope and secure with stage clips.

  -select lowest magnification of objective lens

  -look through the eyepiece

  -turn the focusing wheels to make the image clearer

  -select the next highest objective lens

  -refocus