Practicals

Question 1

Describe the experiment for amylase at different temps (9)

Answer 1

1. 5cm³ of starch into B.T using a pipette
2. 5cm³ of amylase into dif B.T using dif pipette
3. B.Ts placed into R.T water bath (5mins)
4. amylase poured into starch and left in bath
5. Immediately remove sample of mixture with pipette and place onto dropping tile
6. add iodine and record colour
7. continue every 30s for 1 mins until stops turning black
8. repeat with dif temp water baths
9. repeat for reliability

Question 2

Describe the experiment for heat produced by respiration (8)

Answer 2

1. soak batch of peas for 24hrs so they start germinate
2. boil 2nd batch to kill
3. wash batches in bleach to kill bacteria then rinse in distilled water to rid of bleach
4. place batches into vaccum flask (provides insulation)
5. place cotton wool at bottom so CO² can escape
6. leave for days
7. measure temp
8. repeat for reliabilty

Question 3

Describe the experiment to demonstrate diffusion (jelly) (5)

Answer 3

1. get agar jelly, died with potassium permanganate
2. cut 3 cubes with side lengths of 2, 1, 0.5 cm
3. cubes into HCL
4. time taken for cubes to go colourless
5. repeat for reliability

Question 4

Describe the experiment for effect of exercise on breathing rate (6)

Answer 4

1. subject relaxes for 5 mins
2. subject counts B.R
3. subjects carries out exercise for 3 mins
4. subject counts B.R
5. subject continues every min until B.R returns to normal
6. repeat for reliability

Question 5

Describe test for starch (3)

Answer 5

1. place sample in dropping tile
2. add drop of iodine
3. if starch present, iodine turns blue-black

Question 6

Describe test for glucose (4)

Answer 6

1. place sample into test tube
2. add drops of benedicts solution
3. place tube into water bath
4. if glucose present, will turn blue to green to yellow to brick red

Question 7

Describe an experiment to measure the energy in food (7)

Answer 7

1. weigh mass of food with balance
2. add 20cm³ of water to a B.T and place onto clamp stand
3. measure water temp
4. spear food on mounted needle and light with a B.B
5. hold under boiling tube
6. measure temp of water
7. repeat for reliability

Question 8

Describe the test for starch in leave (6)

Answer 8

1. place one plant in light for 24hrs and another in dark
2. take leaf from each plant and boil for 30s
3. place leaves in B.T with ethanol and leave in water bath for 10 mins
4. rinse leaves
5. place on white tile and add iodine (blue-black if present)
6. repeat for reliability

Question 9

Describe the test for effect of light on gas exchange by leaf (6)

Answer 9

1. 10cm³ of hydrocarbon indicator at bottom of 4 B.Ts
2. add leaf to 3 of them and seal all 4 with a bung
3. place one tube in light, one in dark (covered with silver foil) and third in dim light (translucent material) and leave fourth without leaf as a control
4. four tubes set up under bright light for hours
5. colour of indicator recorded
6. repeat

Question 10

Describe the test for rate of photosynthesis using pond weed (6)

Answer 10

1. place pondweed upside down in test tube (cut bottom)
2. place test tube into water bath to keep temp constant
3. place lamp 5cm away
4. count number of bubbles released during 5 mins
5. repeat with lamp futher away
6. repeat

Question 11

Describe potato tuber tissue osmosis test (7)

Answer 11

1. fill boiling tube with water, another with sucrose solution and third empty
2. cut potato into three equal chips (5x1x1cm) with no skin
3. weigh mass using scales
4. place chips into B.Ts
5. after 30 mins remove chips, bot to remove excess water and weigh
6. calculate change in mass
7. repeat

Question 12

Describe test to demonstrate products of anaerobic respiration in yeast (7)

Answer 12

1. add 100ml of glucose to B.T
2. add 100ml of yeast to same tube
3. place in water bath and attach bung with deliver tube into limewater
4. leaver for 2 hours
5. check if limewater goes cloudy
6. repeat for reliability
7. you can repeat with dif temps or concentrations of sugar

Question 13

Describe rate of transpiration test (8)

Answer 13

1. place whole apparatus into sink of water and remove all air
2. cut end of a shoot at angle
3. push stem into rubber tubing
4. remove water and use Vaseline to seal
5. place lamp 5cm away
6. time movement of water in capillary tube
7. repeat wit light placed further away
8. repeat for reliability