Question

differentiate between action spectrum and absorption spectrum with respect to photosynthesis

Answer 1

                                     Absorption Spectrum vs Action Spectrum

Absorption Spectrum

Action Spectrum

1. Absorption Spectrum is the graphic representation of the different wavelengths of light absorbed by the different pigments in a leaf during photosynthesis

1.Action Spectrum is the graphic representation of the effectiveness of different wavelengths of light in photosynthesis


2.Plot showing intensity of light absorbed relative to its wavelength


2.Plot showing relative efficiency of photosynthesis produced by light of different wavelengths

3.Explains the relationship between quality of light and absorbing capacity of pigments

3.Explains the relationship between photosynthetic activity in relation to different wavelengths of light

4.Chlorophyll absorb blue and red light

Carotenoids absorb violet and blue light

4.The maximum photosynthesis occurs in blue and red light

5.Absorption of different wavelengths of light by pigments can be measured using spectrophotometer.

5.In action spectrum, the rate of photosynthesis is measured as amount of carbon dioxide fixation, oxygen production, NADP+ reduction etc.

Answer 2

Absorption spectrum:

Absorption spectrum with respect to photosynthesis is defined as ability of a pigment to absorb light of certain wavelength.

Both chlorophyll a and b shows maximum absorption in violet and orange red region of visible spectrum.

Visible spectrum:

On the other hand, action spectrum shows the effectiveness of different wavelengths of light in photosynthesis.

In action spectrum, the rate of photosynthesis is measured in amount of carbon dioxide fixation, oxygen production and NADP and reduction etc.