PAPER 1_Biology PRACTICALS

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Cards (8)

  • microscopy

    1) use stain to make organelles visible.
    2) clip onto stage.
    3) turn nosepiece on low-power objective.
    4) use coarse adjustment knob to raise stage until just below lens.
    5) look into eyepiece and turn coarse adjustment knob until image is in focus.
    6) turn nosepiece to a high-power objective.
    7) turn fine adjustment until image is in focus.
  • osmosis

    1) cut 5 equally shaped cylinders of potato.
    2) measure and record the mass of each cylinder.
    3) measure 10cm3 of 1M sugar solution and transfer to first boiling tube.
    4) repeat with different concentrations.
    5) add one potato cylinder to each boiling tube.
    6) leave cylinders overnight.
    7) remove cylinders and blot them dry with paper towel.
    8) measure mass and calculate percentage change.
  • Iodine food tests

    1) put some of food sample into test tube.
    2) add a few drops of iodine solution.
    3) will turn brown to blue black.
  • Benedict food test

    1) add excess of Benedict's solution.
    2) place in a hot water bath for a few mins.
    3) will turn brick-red.
  • protein food test

    1) add a few drops of Biuret's.
    2) shake solution to mix and wait.
    3) will turn to purple.
  • lipid food test

    1) add ethanol.
    2) white emulsion is formed on surface of mixture.
  • enzymes

    1) add drop of iodine solution to each well in a tile.
    2) add 2cm3 of buffer solution using a syringe into each labeled test tubes. (with pH ranging from 3-7)
    3) put test tubes and starch solution and amylase solution into water bath at 25 degrees.
    4) add 2cm3 into a test tube, then add 2cm3 of starch into the same test tube and start timer.
    5) use syringe to transfer a drop into a well on tile.
    6) repeat every 30 seconds until idoine solution remains brown.
    7) calculate rate of reaction by using 1/time taken for idioine solution to remain brown.
    8) repeat steps 4-7 with different pH values.
  • photosynthesis

    1) place a boiling tube 10cm from a light source.
    2) add sodium hydrogen carbonate to boiling tube.
    3) add pondweed.
    4) count number of bubbles for 1 minute.
    5) repeat process but increase distance each time.