biology paper 1 required practicals

• microscope experiment!

  1)spread the cells on a slide.add a dye(iodine)to stain the cells and place a cover slip on top.

  2)place the slide on the stage and use grips to keep in place

  3)select the lowest magnification objective lens to view cells

  4)use the coarse focus wheel,then the fine focus wheel to focus the image

  5)draw the image using pencil(and no shading).label the parts you see and write the magnification on the image.

  6)change the lens to a higher magnification and re-focus the image
• osmosis experiment!

  1)cut the potato images into approximately the same size and shape

  2)using a balance,weigh each vegetable piece and record this in a table

  3)add one potato piece into 200ml of 0ml/dm sugar solution,another 0.5 mol/dm sugar solution

  4)leave solution in for 24 hours

  5)remove each vegetable piece,pat dry on a piece of paper and re-weigh using a balance

  6)calculate the percentage change in mass for each potato
• enzyme expirement!

  1)heat a water bath to 37°C and place a boiling tube containing 7cm³ of amalyse and 25cm³ of pH 3 buffer

  2)prepare a spotting tile by dropping a few drops of iodine into each well

  3)add 5cm³ of starch to the boiling tube and immediately start a stop watch

  4)Every 30s,remove a small sample of mixture in the boiling tube using a pipette and add a couple of drops to one well on the spotting tile

  5)repeat the previous step until the colour of the well remains orange.Stop the stopwatch and record the time

  6)Repeat the experiment for different pH buffers(e.g ph,5,8,13)
• food tests expirement!


  starch:iodine

  protein:biuret

  sugar:benedict's solution

  lipid:ethanol
• food test expirement(2)!!


  1)crush food using pestle and mortar

  2)mix with a little water in a test tube to make a food solution

  test:iodine

  positive result:orange--->black

  test:benedict's solution(in a water bath)

  positive result:blue---->orange

  test:biuret's solution

  positive result:blue--->light purple
• measuring the rate of photosynthesis experiment!!


  1)cut 10cm³ of pond weed and submerge this in water in a boiling tube

  2)clamp the boiling tube to a clamp stand

  3)measure 50cm from the clamp stand using a ruler and place a lamp here directed at the pondweed

  4)turn on a stopwatch.record the number of bubbles produced by the pondweed in one minute

  5)Repeat this experiment for the following distance(40,30,20,10cm)

  6)each time recording the number of bubbles produced by the pondweed in one minute
• variables of the photosynthesis expirement?


  indepent variable:distance between lamp and pondweed

  dependent variable:number of bubbles per minute

  control variable:type pondweed and length
• investigating the effect of antibiotics on bacterial growth!!

  1)lift lid of petri dish towards flame(to sterlisie air by moving microbes away/killing them)

  2)put drop of culture on agar/spread evenly

  3)put drops/discs of antibiotics on culture if needed

  4)few bits of tape(to allow areobic respiration),incubate at 25°C

  5)measure size of cultue/areas with no bacteria with π r²