The rate of photosynthesis p2

Question 1

Read page 52 AQA

Answer 1

graphs showing more than one limiting factor

Question 2

What can be measured to measure the effect of light intensity on the rate of photosynthesis ??

Answer 2

Canadian pondweed. Rate at which pondweed produces oxygen corresponds to the rate at which its photosynthesising. - The faster the rate of oxygen production the faster the rate of photosynthesis

Question 3

PRACTICAL 1-2

Answer 3

1) A source of white light is placed at a specific distance from the pondweed

2) The pondweed is left to photosynthesis for a set amount of time. As it photosynthesises, the oxygen released will collect in the capillary tube.

Question 4

PRACTICAL 3-4

Answer 4

3) At the end of the experiment, the syringe is used to draw the gas bubble in the tube up alongside a ruler and the length of the gas bubble is measured. This is proportional to the volume of 02 produced.

4) For this experiment, any variables that could affect the results should be controlled e.g. temp and time the pond weed is left to photosynthesise

Question 5

PRACTICAL 5 -7

Answer 5

5) The experiment is repeated 2x with the light source at the same distance and the mean volume of o2 produced is calculated

6) Then the whole experiment is repeated with the light source at diff distance from the pondweed

7) The apparatus should be altered to measure the effect of temp or co2 on photosynthesis. e.g. test tube of pondweed can be put into water bath at set temperature or measured amount of sodium hydrogencarbonate dissolved in water. This experiment can then be repeated with diff temps of water/ conc of sodium hydrogencarbonate.