cell biology

• Location of DNA in animal and plant cells


  In the nucleus
• Function of cell membrane

  Controls movement of substances in and out of the cell
• Function of mitochondria


  Site of respiration to transfer energy for the cell
• Function of chloroplasts


  Contain chlorophyll to absorb light energy for photosynthesis
• Function of ribosomes


  Enable production of proteins (protein synthesis)
• Function of cell wall


  Strengthens and supports the cell
• Structure of main genetic material in prokaryotic cell


  Single loop of DNA
• Function of red blood cell

  Carries oxygen around the body
• Adaptations of red blood cell


  • No nucleus, contains a red pigment called haemoglobin, and has a bi-concave disc shape
• Function of nerve cell

  Carries electrical impulses around the body
• Adaptations of nerve cell


  • Branched endings, myelin sheath insulates the axon
• Function of sperm cell

  Fertilises an ovum (egg)
• Adaptations of sperm cell


  • Tail, contains lots of mitochondria
• Function of palisade cell

  Carries out photosynthesis in a leaf
• Adaptations of palisade cell


  • Lots of chloroplasts, located at the top surface of the leaf
• Function of root hair cell


  Absorbs minerals and water from the soil
• Adaptations of root hair cell

  • Long projection, lots of mitochondria
• The resolution of a device is the smallest change that the device can measure
• Selecting equipment with the appropriate resolution is important in scientific investigations
• If the resolution of a digital watch is one second, one second is the smallest amount of time it can measure
• Some stop clocks have smaller resolutions, for example a resolution of 0.01 seconds. This means that they can measure times of 0.01, 1.29 or 9.62 seconds, whereas a digital watch could not
• Resolution of a thermometer


  The smallest change that it can detect
• Resolution of a digital thermometer


  0.1°C, as it can measure readings such as 1.1°C, 8.9°C and 36.7°C
• Looking at cells using a light microscope


  1. Describe how to set up a microscope

  2. Label parts of a microscope

  3. Describe how to focus on a slide containing specimen

  4. Make a labelled scientific drawing of what you observe
• Determining the actual size of a cell observed under a microscope


  1. Determine the total magnification

  2. Use the equation: actual size of object = size of image / magnification

  3. Convert the answer to standard form
• You need to be able to apply your skills and knowledge to other practicals too