cell functions

• Animal and plant cells

  • They are eukaryotic, which means they have a cell membrane, cytoplasm, and a nucleus containing DNA
• Bacteria cells


  • They are prokaryotic and contain a cell wall
• Nucleus


  Contains DNA in a nuclear membrane
• Cytoplasm


  Substance where chemical reactions occur
• Cell membrane


  Controls what enters and leaves the cell
• Mitochondria


  Site of aerobic respiration
• Ribosomes


  Site of protein synthesis
• Chloroplast


  Where photosynthesis takes place, contains chlorophyll
• Vacuole


  Contains cell sap
• Cell wall


  Made from cellulose, strengthens and supports the cell
• Flagella


  Tails on bacteria that allow them to move
• Root hair cells


  • Take up water by osmosis
  • Take up mineral ions by active transport
• Root hair cells


  • Have large surface area to allow more water movement in
  • Have mitochondria to provide energy for respiration and active transport
• Xylem cells


  • Transport water and mineral ions up the plant from roots to shoots
  • Have lignin in spirals to withstand pressure
  • Have lignin that kills cells and makes them hollow so they can join end-to-end
• Phloem cells


  • Carry products of photosynthesis (food) to all the cells
  • Have sieve plates that allow movement of substances from cell to cell
• Sperm cells


  • Carry male DNA to the egg
  • Have a long tail and streamlined head to help them swim
  • Have lots of mitochondria to provide energy to swim
  • Have a haploid nucleus (23 chromosomes)
• Egg cells

  • Accept a single sperm cell to form an embryo
  • Have lots of mitochondria to provide energy
  • Have a special membrane that only accepts one sperm cell
  • Are large in size and have a lot of cytoplasm to allow quick, repeated division
• Ciliated epithelial cells

  • Are specialised to waft bacteria to the stomach
  • Have long, hair-like cilia that waft bacteria
  • Have mucus that traps the bacteria and transports them to the stomach
• enzymes


  Break up small molecules
• Light microscope invented


  1665
• Electron microscope invented


  1930's
• image


  Produced by microscope
• uper part of microscope to focus

  Used to focus the image
• Changing magnification


  Turret rotated to change magnification
• Preparing a slide


  1. Take thin layer of cells

  2. Add stain to make cells more visible

  3. Add to slide

  4. Place coverslip on top
• Enzymes


  Break up small molecules
• Lock and key method

  Shape of substrate is complementary to shape of the active site
• Optimum temperature for enzymes is 37°C
• Enzymes denature once the optimum temperature is exceeded
• Active site changes shape at optimum temperature
• Optimum pH affects the forces that hold amino acid chains in protein together
• Optimum concentration is different for every enzyme
• Carbohydrates


  Simple sugars
• Carbohydrate digestion


  1. Produced in pancreas

  2. Produced in small intestine
• Protein digestion


  1. Produced in stomach (pepsin)

  2. Produced in pancreas
• Lipid digestion


  1. Produced in pancreas

  2. Produced in small intestine
• Lipids are broken down into fatty acids and glycerol
• Starch + iodine solution = blue-black
• Reducing sugars + Benedict's solution (water bath) = reddish-brown
• Non-reducing sugars + Benedict's solution (water bath) = blue