Food Supply, Plant Growth And Productivity Part B Flashcards
What is light energy absorbed by
Light energy is absorbed by photosynthetic pigments to generate ATP and for photolysis.
What happens when light energy is not absorbed?
Light energy that is not absorbed is transmitted or reflected.
What are the 3 pigments
- Chlorophyll A
- Chlorophyll B
- Carotenoids
Absorption spectra…
Of chlorophyll a and b and carotenoids compared to action spectra for photosynthesis.
What do carotenoids do?
Carotenoids extend the range of wavelengths absorbed and pass the energy to chlorophyll for photosynthesis.
What does each pigment absorb?
Each pigment absorbs a different range of wavelengths of light.
What does absorbed light energy do?
Absorbed light energy excites electrons in the pigment molecule. Transfer of these electrons through the electron transport chain releases energy to generate ATP by ATP synthase.
What is energy also used for?
Energy is also used for photolysis, in which water is split into oxygen, which is evolved, and hydrogen ions, which are transferred to the co-enzyme NADP.
What happens in carbon fixation stage?
The enzyme RuBisCO fixes carbon dioxide by attaching it to RuBP.
What happens to the 3PG produced in the carbon fixation stage?
The 3PG produced is phosphorylated by ATP and combined with hydrogen ions from NADPH to form G3P.
What is G3P used for in the carbon fixation stage?
G3P is used to regenerate RuBP and for the synthesis of glucose.
What can glucose may be used as?
Glucose may be used as a respiratory substrate, synthesised into starch or cellulose or passed to other bio synthetic pathways.
What can biosynthetic pathways lead to?
Biosynthetic pathways can lead to the formation of a variety of metabolites such as DNA, protein and fat.
Absorption spectra
The degree of absorption at each wavelength of light
Action spectrum
Shows the rate of photosynthesis of the plant
