The action spectrum of photosynthesis shows a high light absorption for violet/blue and orange/red and a low a

Question

low absorption for green/yellow. If we were to set up an experiment where narrow bands of unicolored light were shown on an aquatic plant such as Elodea, and we counted the number of bubbles of oxygen produced as an indicator of photosynthetic rate how would the graph appear?

A Just like the action spectrum with peaks at violet/blue and orange/red and a trough at yellow/green

B Exactly inveerted from the action spectrum with a peak for yellow/green

C perfectly flat because many wavelenghts are used by chlorophyll

D A descending line because ultra-violet has more energy than infra--red

E. There is no way to guess without actually running the experiment.

Answer 1

The answer is A. Assuming that Elodea has chlorophyll as its primary light capturing pigment, the plant would have high rates of photosynthesis at the blue and red regions. The light regions where the chlorophyll absorption is the most are the same regions where photosynthesis takes place.

The action spectrum is basically a measure of how much photosynthesis takes place at particular regions of light. Low rates of photosynthesis occur in the green and yellow regions, and high at blue and red.