6.5: Core Practical – Light Intensity and Photosynthesis

Question 1

What is the set-up for the experiment?

Answer 1

Sealed flask with pondweed and water at room temperature, connected to a gas syringe.

Question 2

What is the first step in the experimental procedure?

Answer 2

Place pondweed 15 cm from the lamp and allow it to adjust for 10 minutes.

Question 3

How long should the gas syringe reading be recorded after placing the pondweed?

Answer 3

After 5 minutes.

Question 4

What should be done after recording the gas syringe reading at 15 cm?

Answer 4

Repeat at 10 cm intervals.

Question 5

What type of graph should be plotted from the results?

Answer 5

A graph of distance (x-axis) vs gas volume (y-axis).

Question 6

What trend is observed in the rate of photosynthesis as light intensity reduces?

Answer 6

The rate of photosynthesis decreases.

Question 7

Fill in the blank: The experiment involves measuring the _______ produced by pondweed.

Answer 7

oxygen