Practical Skills Flashcards
Effect of caffeine on Daphnia heart rate.
Place Daphnia on cavity slide. Replace pond water with distilled water. Leave to acclimatise. Count heart rate under microscope for 30 seconds. Multiply by 2. Repeat with more Daphnia. Repeat with different concentrations of caffeine (5).
As caffeine increased, heart rate increased.
Measuing the content of Vitamin C in fruit juice
Pipette 1cm3 blue DCPIP into a test tube. Using a burette, add vitamin C drop by drop. Shake gently. Continue until blue colour goes. Record volume of solution needed. Repeat a further two times. Repeat with different fruit juices.
Effect of temperature on cell membranes.
Cut beetroot into 1cm lengths. Place in distilled water to remove any dye. Place 8 boiling tubes of distilled water into 8 water baths of different temperatures. Place beetroot into each boiling tube and leave for 30 minutes. Remove beetroot and shake to disperse dye. Set a colorimeter to absorbance on blue/green filter. Calibrate using distilled water in a cuvette. Then read the absorbance of the other boiling tubes.
As temperature increased, transmission increased, due to molecules gaining more heat energy.
Effect of changing enzyme concentration on rate of reaction.
Using initial concentration, place at desired temperature, alongside hydrogen peroxide. Set up gas syringe, set to zero. Add peroxide to yeast and attach the gas syringe. Read off volume every 10 minutes for 3 concordant readings. Repeat 3 times for each concentration of yeast.
Observing mitosis.
Test tube of HCl placed into 60C water bath. Cut off root tip of garlic. Place in watchglass of acetic alcohol for 12 minutes . Remove then place in watchglass containing ice cold distilled water. Place tips into HCl for 5 minutes. Repeat previous steps. Transfer 1 tip to a microscope slide, add a drop of orcein ethanoic stain. Add coverslip. View under microscope.
Totipotency and tissue culture.
Place seeds on a damp sponge and allow to germinate. When leaves begin to unfold, cut the tops off just below the shoot (the explants). Place into gel. Cover with clingfilm, place in sunlight.
Roots and leaves continue to grow.
Strength of plant fibres.
Plant material left to soak in water. Remove fibres and connect between two clamp stands. Gradually add mass to the middle until the fibre snaps.
Investigating plant mineral deficiencies.
Half fill a tube with ‘all nutrients’ solution. Cover with foil. Push roots through the hole so it is in the solution. Repeat with all solutions (lacking nitrogen, phosphate, potassium, magnesium or calcium). Wrap tubes in aluminium foil, place in sun.
Effect of garlic and mint on bacterial growth.
Pipette extract of plant material onto sterile paper disc on a sterile petri dish. Label agar plates, split into 4 sections. Place one disc in each quadrant. Close and tape. Incubate over night and observe zones of inhibition.
Observing patterns by ecological sampling.
Line transect. Tape measure laid along several zones to look at. Quadrats used to record data at regular intervals.
Effect of temperature on hatching success of brine shrimp.
Test at a range of temperatures. Place sea salt into a 100cm3 beaker. Add 100cm3 of dechlorinated water and stir until salt dissolves. Place a pinch of eggs onto a large sheet of paper. Wet the paper. Dab the paper onto the white sheet to pick up eggs. Put the paper into the beaker. Use forceps to remove the paper.
DNA gel electrophoresis.
Mix DNA with desired restriction enzyme and loading dye. Prepare agar and pour into mould. Fill with buffer solution. Load restriction ladder into well then DNA samples cute with restriction enzyme into other wells. Connect to electrical supply. Remove gel from tank. View under UV light.
DNA amplification using PCR.
DNA sample placed into thermocycler with nucleotides, primers and polymerase. Denatured, annealed, extended.
Effects of different antibiotics on bacteria.
Wash hands. Work in aseptic technique. Flame forceps, pick up mast ring. Place in centre of agar. Tape dish. Keep upside down. Measure size of zones of inhibition.
Measuring the rate of oxygen uptake.
Place maggots into tube. Place a drop of dye in gas tube. Mark starting position of fluid. Isolate the respirometer. Start the stop watch. Mark fluid at intervals of one minute. Measure distance travelled.
