Q: Chlorophyll b, chlorophyll a and carotene are all key pigments in the photorespiration process. a) Explain the role of pigments in the production of ATP [3], b) Explain the role of ATP in the cellular processes of plants [1], Why is it advantageous for plants leaves to contain more than one pigment? [2]
a)
Light is absorbed by chromophore regions on the pigment molecules, contained within photosystems.
PSI + PSII are the light harvesting photosystems essential to photosynthesis.
Absorption of light at the photosystems excites electrons to a higher energy level
These excited electrons are released from chlorophyll a and used to drive a proton gradient, with the diffusion of H+ along this gradient generating ATP via ATP synthase.
b)
ATP is the energy currency that allows the plant cells to do work.
c)
Use of several pigments allows photons to be absorbed over a range of wavelengths
This increases the number of photons available for the light dependent stage, increasing product formation
This in turn increases the rate of photosynthesis.