PHOTOSYNTHESIS
Group 4
Bello, Dela Cruz, Laguyo, Torres
Photosynthesis
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People: Eating
Plants: Photosynthesis
Production of glucose in
plants which later converts as
ATP which gives chemical
energy to the plants.
Uses light energy, water and
carbon dioxide (provided by
us).
Byproduct is oxygen which we
use, in return.
OBJECTIVES
Objectives
1. To determine the why plants need the process of
photosynthesis.
2. To measure the rate of photosynthesis as affected by
some factors such as light, carbon dioxide, and
3. To obtain and identify the pigments involved in
photosynthesis through the experiments performed.
METHODOLOGY and
RESULTS AND DISCUSSION
Light as a Requirement for Photosynthesis
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2 Mayana leaves were each placed in a dark place and the other under
direct sunlight for 48 hours.
This test will determine the leaves’ starch component.
Boiling the leaves using distilled water should remove most of its
pigment.
After removing most of the pigment, the leaves were immersed in 95%
ethyl alcohol and boiled in a water bath.
After boiling in 95% ethyl alcohol solution, iodine solution was added.
Light as a Requirement for Photosynthesis
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The first boiling of the leaves with distilled water
removed most of its piment showing the leaves
naked form. On the second boil, the leaves were
immersed in 95% ethyl alcohol which made the
solution more green than its starting color and left
the leaves less green. We may assume that some of
the pigment that weren’t removed by the distilled
water is now removed by the alcohol solution.
Adding iodine determines the presence of starch
which is indicated by a bluish black color.
After adding iodine and leaving it for 10 mins, the
results show that the mayana leaf that was exposed
under direct sunlight has starch.
Light Intensity and the Rate of Photosynthesis
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5 test tubes labeled A to E were prepared and each filled with 1%
NaHCO3 (sodium bicarbonate) solution almost completely.
Each test tube was immersed with a 8 cm long healthy Hydrilla sprig
from under water and covered with a stopper.
Test tube A was placed in the dark while test tubes B to E were placed
in front of a light source 20cm, 40cm, 60cm, and 80cm away
respectively. All test tubes were placed in their following positions for a
total of 1 ½ hours.
Afterwards, all test tubes were observed for the formation of bubbles.
Light Intensity and the Rate of Photosynthesis
All test tubes did not contain any bubbles due to the poor condition of the Hydrilla plant.
According to the laboratory technician, the condition of the Hydrilla plant was not good
because of the bad weather that it grew in.
Carbon Dioxide as a Requirement for
Photosynthesis
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3 test tubes were labeled with A, B and C and filled halfway with
phenol red solution
In test tubes A and B, a straw is used to blow gently in the test tubes
until the solution became pale orange
Afterwards, test tubes B and C were each placed with a Hydrilla plant
and all 3 test tubes were set in a bright light and observed changed for
2 hours.
Carbon Dioxide as a
requirement
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The carbon dioxide provided by the experimenters
turned the solution orange; absence of carbon dioxide
was shown by the red solution.
Ideally: Test tube B was supposed to turn back to red
(like in test tube C) since the hydrilla was supposed to
use up the oxygen
Actual: The hydrilla was not in the best condition due
to the weather, which in retuern was not able to utilize
the carbon dioxide present in the test tube.
Separation of Chloroplast
PIGMENT EXTRACTION: Green vs
Variegated leaf
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5.
10g cut into small pieces
Crush with 5mL acetone using
blender
Add 3mL acetone
Squeeze using cheese
Collect extract with a dropper
PAPER CHROMATOGRAPHY
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2.
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5.
Cut a filter paper in a shape of a pen
Place the drop of the extract 1 inch from
the tip of the paper that would touch the
solution
Place 1:9 acetone:petroleum ether on a
beaker (not too many. Approximately 10 cm
from the base of the beaker
Place the filter paper in the beaker, allowing
only the tip to touch the solution
DONT LET THE EXTRACT TOUCH THE
SOLUTION
Wait for 15-30 minutes before taking off
the filter paper and observing color bands
produced
Separation of
Chloroplast
After the 30 minute waiting period, both leafs had
clear yellow band produced clearly, while a very
light green band can be seen at the bottom.
Carotene: involved in the primary light absorption
Chlorophyll a: is the pigment that makes plants
and algae green.
CONCLUSIONS
Light and Carbon Dioxide are two key factors in the
process of photosynthesis, although given the condition,
we weren’t able to manifest the importance of it in the
experiment.