pratical 5

Created by

Lily P

Cards (21)

Place a test tube rack containing a boiling tube 10 cm away from the light source, measured using the ruler.
Fill the boiling tube with a fixed volume of 0.2% sodium hydrogen carbonate solution.
Place the cut pondweed into the boiling tube with the cut end at the top.
Gently push the pondweed down with the glass rod.
Leave the boiling tube to rest for 5 minutes.
Start the stopwatch and count the number of bubbles produced in one minute.
For each light intensity/distance, repeat the count twice more and take a mean.
Record in a table as seen below.
Repeat steps 1-7 for 3 more distances (20, 30, 40 cm) of the boiling tube from the light source.
Plot a graph of the rate of photosynthesis (given by the number of bubbles) against light intensity (using the inverse square law, light intensity ∝ 1/distance2 between pondweed and light source).
Place a test tube rack containing a boiling tube 10 cm away from the light source, measured using the ruler.
Fill the boiling tube with a fixed volume of 0.2% sodium hydrogen carbonate solution.
Place the cut pondweed into the boiling tube with the cut end at the top.
Gently push the pondweed down with the glass rod.
Leave the boiling tube to rest for 5 minutes.
Start the stopwatch and count the number of bubbles produced in one minute.
For each sodium hydrogen carbonate concentration, repeat the count twice more and take a mean.
Record in a table as seen below.
Repeat steps 1-7 for 3 more concentrations of sodium hydrogen carbonate solution.
Plot a graph of the rate of photosynthesis (given by the number of bubbles) against sodium hydrogen carbonate concentration.
chlorophyll
Use a variegated leaf (with green parts and white parts).
Immerse the leaf in boiling water for 30 seconds.
Carefully spread onto a white tile so the colour change can be accurately seen.
Use a dropping pipette to add iodine solution to the leaf.
The green parts of the leaf should turn blue-black due to the presence of starch the whiteareas should not.