Required Practicals (Paper 1)

Question 1

Describe an experiment to measure the effect of light intensity on the rate of photosynthesis of pondweed. [6]

Answer 1

• Add Sodium hydrogencarbonate solution to the water [1]
• Place a bright lamp 10cm away from the pondweed. [1]
• Record the number of bubbles produced in 1 minute. [1]
• Repeat the count 5 times. [1]
• Calculate the mean amount of bubble produced [1]
• Repeat experiment by moving lamp 10cm further away. [1]

Question 2

(Photosynthesis RQP)

State 2 factors which should be kept constant during the experiment. [2]

Answer 2

• Same pondweed [1]

- Temperature [1]

Question 3

(Photosynthesis RQP)

What is the independent variable in this experiment? [1]

Answer 3

Distance from lamp to pondweed [1]

Question 4

(Photosynthesis RQP)

How can you test for oxygen presence in the tube? [2]

Answer 4

• Use a glowing splint. [1]

- Splint will relight in oxygen presence [1]

Question 5

(Photosynthesis RQP)

How can a student be more accurate in the investigation? [1]

Answer 5

Measure the volume of bubbles collected in a set time [1]