biology rp p1

• microscopy practical

  • Put the slide on the microscope stage. Turn the nose piece to select the lowest power objective lens
  • Turn the coarse adjustment knob to move the lens towards the slide.
  • Now look through the eyepiece. Slowly turn the coarse adjustment knob in the direction to increase the distance between the objective lens and the slide.
  • Do this until the cells come into focus.
  • Slightly turn the fine adjustment knob to bring the cells into a clear focus. When you have found some cells, turn the nose piece to switch to a higher power lens
  • Make a clear, labelled drawing of some of the cells. Make sure that you draw and label any component parts of the cell. Use a pencil to draw the cells. Write the magnification underneath your drawing.
• microbiology -aseptic

  • Spray the bench where you are working with disinfectant spray.
  • . divide the plate into three equal sections and number them 1, 2 and 3 around the edge
  • Put a different antiseptic onto each of the three filter paper discs, being careful to shake off excess liquid
  • Carefully lift the lid of the agar plate at an angle . Do not open it fully. Use the forceps to carefully put each disc onto one of the dots you drew on with the wax pencil.
  • Secure the lid of the agar plate in place using two small pieces of clear tape.
  • Incubate the plate at 25 °C for 48 hours. Measure the diameter of the clear zone around each disc.
• osmosis practical

  • Use a cork borer to cut five potato cylinders of the same diameter.
  • trim each potato cylinder so that they are all the same length. Accurately measure the mass of each potato cylinder.
  • Accurately measure the length of each cylinder.
  • Measure 10 cm3 of each concentration of sugar or salt solution and put into boiling tubes.
  • . Measure 10 cm3 of the distilled water and put into the fifth boiling tube.
  • Leave the potato cylinders in the boiling tubes for a chosen amount of time. Remove the potato cylinders from the boiling tubes and carefully blot them dry with the paper towels.
  • Measure the new mass and length of each potato cylinder again.
• food tests

  Benedicts

  • Set up your traditional water bath set up using a Bunsen burner. Put some of the food sample into a test tube Add a few drops of Benedict’s solution to the sample in the test tube. Put the test tube in the water bath at a minimum of 80 °C for about 5 minutes.
  • Put some of the food sample into a test tube. Add a few drops of Iodine solution.
  • Put some of the food sample into a test tube. Add a few drops of distilled water. Add a few drops of ethanol. Care: Ethanol is highly flammable. Keep the solution away from any flames. Shake the solution gently.
  • Put some of the food sample into a test tube. Add 1 cm3 of Biuret solution A and 1 cm3 of Biuret solution B to the test tube. Care: Biuret solution contains copper sulphate, which is poisonous, and sodium hydroxide, which is corrosive.
• enzyme practical

  • Heat your water bath to 35 °C. Put 2 cm3 of each buffered solution into individual, separate test tubes.
  • Label each tube with the pH of the solution. add 4 cm3 of starch solution into each tube. Put a thermometer in one of the starch test tubes
  • Add 10 cm3 of Amylase solution into another test tube. Put all the test tubes into the water bath.
  • put one drop of Iodine solution into each hole on your spotting tile.
  • take one of the tubes of starch from the water bath and add the 2 cm3 of your first pH buffered solution.
  • .add 2 cm3 of amylase solution to the mixture. Start the stop clock ,Keep stirring the mixture with the glass rod.
  • After 10 seconds, remove one drop of the mixture with a glass rod. Put this drop on the second depression of your spotting tile. . Every 10 seconds, use the glass rod to remove one drop of the mixture.
• photosynthesis

  • Put your 10 cm piece of pond weed into a beaker of water.
  • . Cover the pondweed with an funnel –
  • Fill the measuring cylinder with water
  • position the beaker of pondweed 1 metre away from the light source Start the stop watch and count number of bubbles released in three minutes and b. the volume of gas produced in the same three minutes.
  • Move the light source so that the pondweed beaker is 80 cm away. Refill the measuring cylinder with water .repeat for different distances