Cell Biology - Biology Paper 1

• Nucleus


  Genetic material, controls cell activity
• Cytoplasm


  Where chemical reactions take place, controlled by cell membrane
• Cell membrane


  Controls what goes in and out, contains enzymes
• Mitochondria


  Site of respiration
• Ribosome


  Site of protein synthesis
• Cell wall


  Provides strength and shape, made of cellulose
• Chloroplasts


  Contain chlorophyll, site of photosynthesis
• Vacuole


  Contains cell sap, keeps cell turgid
• Sperm cell


  • Streamlined head
  • Tail for swimming to the egg
  • Lots of mitochondria to generate energy to swim
• Nerve cell


  • Long and thin to cover distances
  • Branches to connect to other cells
  • Makes signals faster
• Muscle cell


  • Long to have space to contract
  • Lots of mitochondria to generate energy for contraction
• Total magnification


  objective lens x eye piece
• Magnification = image size ÷ actual size
• Egg organism development

  1. After fertilisation the zygote divides again and again through mitosis until it becomes a ball of cells

  2. The cells diffrentiate into specialised cells like blood, nerve and muscle cells

  3. Cells form an embryo

  4. As the cells diffrentiate more tissues and organs are formed to make a foetus
• Microscope practical


  1. Place specimen on slide

  2. Add drop of stain (methylene blue or iodine)

  3. Place coverslip on specimen

  4. Place slide onto stage of microscope

  5. Turn on the light source

  6. Set the objective lens to lowest power

  7. Look through eyepiece and adjust coarse focusing wheel for a clear image

  8. Increase the power of objective lens to increase magnification