Core Practicals Flashcards
(32 cards)
What Is A Control Variable?
The things you keep the same
What Is An Independent Variable?
The thing you change
What Is A Dependent Variable?
The thing you measure
What Are The Control Variables In The Daphnia Practical?
- Daphnia size
- Amount of caffeine solution
- Time
What Is The Independent Variable In The Daphnia Practical?
Caffeine concentration
What Is The Dependent Variable In The Daphnia Practical?
Heart rate
Describe The Method For The Daphnia Practical?
- Place a Daphnia on a microscope slide
- Rinse with distilled water and leave for 5 mins
- Count the heart beats in 30 secs and X2 (beats per min)
- Repeat with various caffeine solutions on different Daphnia
What Are The Control Variables For The Vitamin C Practical?
- Amount of DCPIP
- DCPIP concentration
- No. of times the tube is shaken
What Is The Independent Variable For The Vitamin C Practical?
Type of fruit juice
What Is The Dependent Variable For The Vitamin C Practical?
Volume of juice to decolourise DCPIP
Describe The Method For The Vitamin C Practical?
- Pipette 1cm3 of DCPIP into a test tube and add drops of fruit juice
- Shake tube gently after each drop
- Keep doing so until it’s no longer blue
- Record volume of fruit juice used once no longer blue
- Repeat with different juices
What Calculations Are Useful For The Vitamin C Practical?
Mass in 1cm3= 10mg X Vol to decolourise DCPIP
Mass in sample= Mass of juice to decolourise divided by volume to decolourise
What Are The Control Variables For The Membrane Practical?
- Vol. of water
- Time beetroot is in water
- Beetroot size
What Is The Independent Variable For The Membrane Practical?
The temperature of the water
What Is The Dependent Variable For The Membrane Practical?
% transmission of light through solution
Describe The Method For The Membrane Practical?
- Cut up 1cm long beetroot cylinders
- Rinse in distilled water over night
- Prepare 8 tubes of different water temps.
- Add beetroot and leave for 30 mins
- Remove and shake to create dye
- Set colour meter to % absorbance (green/blue filter)
What Calculations Are Useful For The Membrane Practical?
100-% absorbance
What Are The Control Variables For The Enzyme Rate Of Reaction Practical?
- Enzyme vol.
- Substrate concentration
- pH
- Temperature
What Is The Independent Variable For The Enzyme Rate Of Reaction Practical?
Enzyme concentration
What Is The Dependent Variable For The Enzyme Rate Of Reaction Practical?
Time taken for enzyme to break down substrate
Describe The Method For The Enzyme Rate Of Reaction Practical?
- Create different enzyme concentrations using distilled water
- Use different syringes to avoid cross contamination
- Set up water bath to constant temperature
- 1 test tube of 5cm3 casein solution
- 1 test tube of 2cm 0.2% trypsin
- Leave 3 mins then mix together until transparent and time this
What Calculations Are Useful For The Enzyme Rate Of Reaction Practical?
Rate= 1 divided by time
Describe The Method For The Mitosis Practical
- Test tube of 2cn3 1m HCL and place in 60 degree water bath
- Cut 1-2cm off tip of garlic and place in 2cm3 of acetic alcohol for 12 mins
- Repeat with ice cold distilled water
- Leave For 5 mins then place in heated HCL
- Break up under microscope with needle and stain with or orcein ethanoic blue
What Calculations Are Useful For The Mitosis Practical?
Mitosis Index= no. of cells with chromosomes divided by total no. of cells
