Photosynthesis

Question 1

What is the
photosynthesis word
equation?

Answer 1

carbon dioxide + water —light energy—> glucose + oxygen

Question 2

Which part of the plant cell
absorbs the light energy?

Answer 2

Chlorophyll inside the chloroplasts

Question 3

The rate of photosynthesis
may be limited by these
factors

Answer 3

Shortage of light, shortage of
chlorophyll due to shortage of Mg,
low temperature, shortage of CO2

Question 4

Plants use the glucose
produced during
photosynthesis …

Answer 4

To convert it into insoluble starch
for storage; for respiration; to
produce fat or oil for storage; to
produce cellulose to strengthen the
cell wall; to produce proteins

Question 5

What do plants need to
absorb from the soil to
produce proteins?

Answer 5

Nitrate ions

Question 6

How to test for starch in a
leaf

Answer 6

1. Remove a green leaf from the
   plant.
2. Boil the leaf in boiling water.
   This stops all enzymatic
   reactions within the leaf cells.
3. Place leaf into boiling tube and
   add ethanol. The ethanol
   extracts the chlorophyll because
   it dissolves the lipids in the cell
   membrane.
4. Return the leaf to hot water.
5. Remove the leaf and add
   iodine.

Question 7

How to investigate
how light intensity
affects the rate of
photosynthesis.

Answer 7

Set up a boiling tube containing sodium hydrogencarbonate solution. Allow the tube to stand for a few minutes and shake to disperse any air bubbles that might form.
Cut a piece of the pondweed.
Use forceps to place the pondweed in the boiling tube carefully.
Position the boiling tube so that the pondweed is 10 cm away from the light source. Allow the boiling tube to stand for five minutes. Count the number of bubbles emerging from the cut end of the stems in one minute.
Calculate the average number of bubbles produced per minute. Repeat the experiment at different distances away from the light source.