Effects of different colors of light on the photosynthesis rate.

Aim: We will be trying to see if light intensity has an effect on the rate of photosynthsis.

Low light intensity lowers the rate of photosynthesis

Glycerate 3-phosphate is reduced during the reduction reactions to a three-carbon sugar called triose phosphate. Energy and hydrogen is needed for the reduction and these are supplied by ATP and NADPH + H+ (both produced during light-dependent reactions) respectively. Two triose phosphate molecules can then react together to form glucose phosphate. The condensation of many molecules of glucose phosphate forms starch which is the form of carbohydrate stored in plants. However, out of six triose phosphates produced during the reduction reactions, only one will be used to synthesise glucose phosphate. The five remaining triose phosphates will be used to regenerate RuBP.

Photosynthesis need light to work, so light therefore should speed up the rate of photosynthesis.

The Effect Of Substrate Concentration On The Activity …

Photosynthesis occurs inside chloroplasts. Chloroplasts contain chlorophyll, a green pigment found inside the thylakoid membranes. These chlorophyll molecules are arranged in groups called photosystems. There are two types of photosystems, Photosystem II and Photosystem I. When a chlorophyll molecule absorbs light, the energy from this light raises an electron within the chlorophyll molecule to a higher energy state. The chlorophyll molecule is then said to be photoactivated. Excited electron anywhere within the photosystem are then passed on from one chlorophyll molecule to the next until they reach a special chlorophyll molecule at the reaction centre of the photosystem. This special chlorophyll molecule then passes on the excited electron to a chain of electron carriers.

Aim: To see if raising the light intensity increases the rate of photosynthesis.

The colour of the lamp will stay the
same (yellow) as to plants Chlorophyll easily absorbs blue light,
however it does not easily absorb green or yellow light, rather it
reflects it, this decrease's the rate of photosynthesis.

Free rate of photosynthesis papers, essays, and research papers.


Input - Light intensityis to be varied by increasing and decreasing
the distance from the light source to the plant

Output - The rate of photosynthesisis to be measured by counting the
bubbles of oxygen produced by the plant every two minutes, and
therefore finding the rate of photosynthesis

Control - The amount of water available to the Elodea will stay the
same level in the 400 cm3 beaker.

Photosynthesis Science Fair Projects and Experiments

Background information: Photosynthesis Photosynthesis is the process of autotrophs turning carbon dioxide and water into carbohydrates and oxygen, using light energy from sunlight.

Glossary of Biological Terms ← BACK

I think this because the plant may use up all of the carbon dioxide (Sodium hydro carbonate) and the plant can have as much light as it needs but if it does not have any carbon dioxide it will not be able to photosynthesise....

Chemistry for Biologists: Photosynthesis

The Effect of the Type of Soil on the Amount of Chlorophyll in Bean PlantsThe Effects of Wavelengths of Light on Plant Food ProductionEffect of different colors of light on the growth of plants Do plants need sunlight to be green?

IB Biology Notes - 8.2 Photosynthesis

The effects of various pH levels on the photosynthesis process of the aquatic plant elodeaThe effects of phosphorous on the photosynthesis of aquatic plantsDoes light affect stem growth?

As the intensity is increased the rate also increases


Distance (cm)

Number of bubbles counted (every two minutes)























My graph shows that the closer the distances of the light source the
higher the rate of photosynthesis.