Light is one of the many faction which effect the rate of li

Light is one of the many faction which effect the rate of light intercity is measured study the graph and answer the question light below. Describe the relationship between light intensity and the rate of photosynthesis. Recall that photosynthesis is a series of chemical reactions catalyzed by enzymes List some photosynthesis possible reasons why the rate of photosynthesis levels off at higher light intensities. Did the results of your carbon dioxide uptake experiment from Section 3 support or reject your predictions? Explain the color change in the bromthymol blue after the Elodea was added.

Solution

a. Photosynthesis is the synthesis of food materials in plants using sunlight, CO₂ and water. Photosynthesis is light dependent reaction. Light intensity from low to high gradually increase the rate of photosynthesis when there is sufficient supply of other factors. When the other factors are limiting or depleting high ligh intensities decrease the rate of photosynthesis and therefore, there is straight plateau observed in the graph after increase for some time.

b. At high light intensities some factors required in photosynthesis may be limiting and high light intensity may damage the chlorophyll. As a result, at high light intensities the rate of photosynthesis exhibitsa level off forming a lineatr plateau.

2a. Carbondioxide is a requisite factor for photosynthesis. The requirement of carbondioxide and light for photosynthesis are tested using a color indicator like bromothymol blue and an alga Elodea. In presence of light and carbondioxide the color of indicator was changed gradually and the experiment supported the prediction.

2b. Light and carbondioxide are required for photosynthesis. Carbon dioxide dissolves in water and the pH of water becomes slightly acidic. The addition of bromothymol blue indicator detects the change in pH by change in the color of the indicator. When the Elodea was added to tube containing water, CO₂ , bromothymol blue, initially the color was green/ yellow indicating acidic pH. In presence of light, Elodea taken up the CO₂ occuring in the tube as part of photosynthesis. The pH is changed to neutral and the color was turned to blue. This proves that plants uptake CO₂ in presence of light to carryout photosynthesis.