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Unformatted text preview: e wav elengths , we c an as s ume that red light is not effec tiv e.
One c annot tell from this graph, but bec aus e c hlorophy ll a does abs orb red light, we c an predic t that it would be effec tiv e in driv ing
photos y nthes is . Correct Part E
If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm ) be effective in driving photosynthesis?
The graph indic ates that c hlorophy ll a abs orbs v ery little blue light, s o we c an predic t that blue light would not be effec tiv e.
The peak abs orption for c hlorophy ll b is c los e to this wav elength, s o we c an predic t that blue light would be effec tiv e.
One c annot tell from this graph. Correct Part F
An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of
about 490 nm is effective in driving photosynthesis. Based on this inform ation and the absorption spectra shown at left, what role m ay
chlorophyll b and carotenoids play in photosynthesis?
Thes e pigments are able to abs orb more wav elengths of light (and thus more energy ) than c hlorophy ll a alone c an abs orb. As part of light
harv es ting c omplex es in photos y s tems , they broaden the range of light that c an be us ed in the light reac tions .
Thes e pigments probably play only a photoprotec tiv e role (abs orbing ex c es s light energy that c ould damage c hlorophy ll a) and a role in
produc ing the c olors of fall foliage.
Bec aus e c hlorophy ll a is found in the reac tionc enter c omplex es of both photos y s tems II and I, we c an as s ume that thes e other pigments
play no role in photos y nthes is . Correct Photosynthesis (2 of 3): The Light Reactions (BioFlix tutorial)
In the light reac tions of photos y nthes is , energy in s unlight is c onv erted into c hemic al and redox energy in the form of ATP and NADPH. This tas k is
ac c omplis hed by two photos y s tems that power linear elec tron flow from water to NADP+, while generating a proton gradient that is us ed to mak e ATP.
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This document was uploaded on 02/17/2014 for the course BIOCHEMIST 2550 at Ohio State.
- Spring '14