rpas

• photosynthesis rpa

  1. set up test tube rack 10cm away from light source
  2. fill boiling tube with sodium hydrogen carbonate (increases conc of co2 to stop it being a limiting factor)
  3. add piece of pondweed to boiling tube
  4. leave for 3 minutes to allow pondweed to adjust to new light intensity
  5. start stop watch and count number of bubbles produced in 1 minute
  6. write down results and repeat to calculate mean and cancel anomalies
  7. repeat at distances of 20cm and 30cm from light source
• microscope rpa

  1. drop water using pipette on microscope slide
  2. peel thin layer of epidermal tissue
  3. use forceps to place layer on slide
  4. add 2 drops of iodine using pipette
  5. lower coverslip
  6. place slide on stage
  7. lowest power objective lens
  8. turn coarse adjustment knob for distance
  9. turn fine adjustment for focus
  10. make clear labelled drawing of cells
• osmosis rpa

  1. cork borer to cut 5 potato cylinders of same diameter
  2. trim length of cylinders to 3cm
  3. dry potato carefully by blotting it with a paper towel
  4. accurately measure and record mass and length of each potato
  5. measure 10cm³ of 1.0m, 0.75m, 0.5m and 0.25m of sugar solution into boiling tubes (label)
  6. 5th boiling tube should have just water to act as a control
  7. add one potato into each boiling tube
  8. leave overnight
  9. remove and dry
  10. remeasure length and mass
  11. calculate % change
• enzymes rpa

  1. 1 drop of iodine into each well on spotting tile
  2. place labelled test tubes containing buffered pH solution, amylase solution and starch solution into waterbath
  3. add 2cm³ of one of the buffered solutions into test tube
  4. add 2cm³ of amylase
  5. start stop clock
  6. mix using glass rod
  7. after 20 seconds remove drop of the mixture and add to 1st well of the spotting tile using a pipette
  8. repeat adding a drop every 20seconds
  9. continue until iodine on spotting tile stays orange
  10. repeat with different pH solutions
• petridish rpa

  1. disinfect work bench
  2. underneath plate, divide into 4 sections using wax pencil
  3. set up bunsen burner
  4. on blue flame, sterilise neck of bottle
  5. collect 1ml of bacterial culture, lift lid of plate at an angle and add bacterial
  6. sterilise loop using blue flamed bunsen burner and spread the bacterial around the plate. sterilise loop after use
  7. use forceps to place filter discs soaked in antiseptic onto plate in each section
  8. secure with two pieces of tape
  9. incubate in 25 degrees for 48 hours
• part 1

  1. sterilise petri dish and agar gel in an autoclave

  • kill any bacteria that are present in the solution or on the Petri dishes.

  1. Pour the sterile agar plates and allow to set fully.

  • provides selected bacterium with all nutrients needed to grow.

  1. Sterilise inoculating loop using blue flame

  • kills bacteria present on loop.

  1. Dip the inoculation loop into bacterial solution and spread evenly

  • allows the bacteria to spread and grow across the whole plate.