DEPARTMENT OF BIOLOGY

FACULTY OF SCIENCE AND MATHEMATICS

UNIVERSITI PENDIDIKAN SULTAN IDRIS

SBU 3013

BIOLOGY 1

MINI PROJECT

EFFECT OF CARBON DIOXIDE ON THE RATE OF PHOTOSYNTHESIS AND THE EFFECT OF PHOTOSYNTHESIS ON PLANT GROWTH

GROUP A

SEMESTER 2, SESSION 2011/2012

NO STUDENT’S NAME MATRIC NUMBER

1. MUHAMMAD AZRIN BIN AZMAN D20101037531

2. MUHAMMAD AFIQ SYAHMI BIN PUAD D20101037534

3. MOHD NURUL AMRI BIN RODZI D20101037539

LECTURER’S NAME

DR. SOM CIT A/P SI NANG

EFFECT OF CARBON DIOXIDE ON THE RATE OF PHOTOSYNTHESIS AND

EFFECT OF PHOTOSYNTHESIS ON PLANT GROWTH

OBJECTIVE:

1. To determine the effect of carbon dioxide in photosynthesis on plant growth. ( Vigna radiate)

2. To determine the effect of carbon dioxide in production of starch during photosynthesis. (Vigna radiate)

INTRODUCTION:

Photosynthesis consist of two reaction, light reaction and dark reaction.The dark reaction takes

place in the stroma within the chloroplast, and converts CO2 to sugar. This reaction doesn't

directly need light in order to occur, but it does need the products of the light reaction (ATP and

another chemical called NADPH). In the light-independent or dark reactions the enzyme

RuBisCO captures CO2 from the atmosphere and in a process that requires the newly formed

NADPH, called the Calvin-Benson Cycle, releases three-carbon sugars, which are later

combined to form sucrose and starch. The overall equation for the light-independent reactions in

green plants is:

3 CO2 + 9 ATP + 6 NADPH + 6 H+ → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+ + 3 H2O

The dark reaction involves a cycle called the Calvin cycle in which CO2 and energy from ATP

are used to form sugar. To be more specific, carbon fixation produces an intermediate product,

which is then converted to the final carbohydrate products. The carbon skeletons produced by

photosynthesis are then variously used to form other organic compounds, such as the building

material cellulose, as precursors for lipid and amino acid biosynthesis, or as a fuel in cellular

respiration. The latter occurs not only in plants but also in animals when the energy from plants

gets passed through a food chain.

The fixation or reduction of carbon dioxide is a process in which carbon dioxide combines with a five-carbon sugar, ribulose 1,5-bisphosphate (RuBP), to yield two molecules of a three-carbon compound, glycerate 3-phosphate (GP), also known as 3-phosphoglycerate (PGA). GP, in the presence of ATP and NADPH from the light-dependent stages, is reduced to glyceraldehyde 3-phosphate (G3P). This product is also referred to as 3-phosphoglyceraldehyde (PGAL) or even

as triose phosphate. Triose is a 3-carbon sugar (see carbohydrates). Most (5 out of 6 molecules) of the G3P produced is used to regenerate RuBP so the process can continue . The 1 out of 6 molecules of the triose phosphates not "recycled" often condense to form hexose phosphates, which ultimately yield sucrose, starch and cellulose. The sugars produced during carbon metabolism yield carbon skeletons that can be used for other metabolic reactions like the production of amino acids and lipids.

The following experiments may be introduced as an example of hypothesis testing .The hypothesis is that plants combine carbon dioxide and water to make carbohydrates (glucose, sucrose or starch) with the aid of energy from sunlight and with chlorophyll to absorb the energy. Accordingly, “If photosynthesis uses the carbon dioxide energy for making starch, then depriving the plant of carbon dioxide will prevent starch formation”.

6CO2 + 6H2O C6H12O6 + 6O2

In this experiment, we will try to identifies the effect of carbon dioxide in photosynthesis based on production of starch during photosynthesis. That mean the more production of starch the more photosynthesis happen in the leaves. We also will try to compared the effect rate of photosynthesis in plant growth.

MATERIALS:

Vigna radiate seeds, Soil, Water, Cricket (carbon dioxide supplier) , Alcohol, Potassium hydroxide, Iodine solution, Methylated spirit,

APPARATUS :

Polybag, Beaker, Bunsen burner, Tripod stand, Test tube, Petri dish, Dropper, Plastic cover, clippers

Uptake of carbon dioxide Production

of starchOutput of oxygen

Absorption of energy from sunlight

Sunlight absorbed by chlorophyll

PROCEDURE A:

1. Place three Vigna radiate seed in four polybag.2. Wait until the three seed in each polybag germinate.3. Choose one the best germinated seed in each polybag and remove the other germinated

seed.4. Place two polybag in a sealed container.5. One container is place with crickets as the carbon dioxide supplier and the other one is

place with potassium hydroxide.6. The growth of each germinated seed is recorded for a week.

PROCEDURE B:

1. Place three Vigna radiate seed in four polybag.2. Wait until the three seed in each polybag germinate.3. Choose one the best germinated seed in each polybag and remove the other germinated

seed.4. Control the growth of each seed until it has many leaves.5. After that, place one polybag inside sealed container and the other one is place outside.6. One container is place with potassium hydroxide for carbon dioxide absorbtion. 7. After 24 and 48 hours, cut the leaves in each polybag and sealed the leaves using plastic

cover. Mark the leaf take within 24 hours and 48 hours.8. The leaves in each polybag now is tested for the presence of starch.

DECOLOURISING THE LEAF :

1. Put the leaf inside a test tube fill up with ethanol.2. The test tube then is boil inside a beaker fill with water.3. The flame use must set to non-luminous flame because ethanol vapour is very

flammable.4. Then transfer the leaf to another beaker of Methylated Spirit (colourless initially).5. The beaker then is bath in a hot water gently.

TESTING FOR STARCH :

1. After the leaf has been decolourise, immerse the whole leaf in cold water.2. Put the leaf in plastic petri dish.3. Add a few drop of iodine and observe for colour change.