5.6/5.7 Photosynthetic Pigments Flashcards
What is the equation for photosynthesis
6H2O +6CO -> 6O2 + C6H12O6
Water + carbon dioxide -> oxygen + glucose
Explain the structure of the chloroplast
Site of photosynthesis containing stacks of thylakoids called grana storing photosynthetic pigments such as chlorophyll, stroma is the membrane and contains enzymes needed for light independent stage of photosynthesis.
Chloroplast pigments
Chlorophyll a- reflected green-blue
Chlorophyll b - reflected yellow - green
Carotenoids - orange
Xanthophylls- yellow
Flavonoids - yellow
Explain the stages of photosynthesis
In the light dependant reaction electrons get excited
Action spectra
The rate of photosynthesis measured against wavelength of light
Absorption spectra
The wavelength a cell can absorb
Light dependent reaction( non-cyclic phosphorylation)
In the light dependant reaction electrons get excited in PSII raising to a higher energy level by the energy being trapped in the thylakoid membrane and are then passed down an electron transport and the electrons get excited again forming reduced NADP and ATP generated through chemiosmosis in a process called photophosphyrylation. The electrons are then passed too PS I . Because the pair of electrons that left PS II have not returned to PS II photolysis happens and water splits the produced 2 electrons that enter PS II and the process happens and produces oxygen again the
Evidence of pigments
Similar shapes - proof that that wavelength must be used in photosynthesis when it is absorbed
Evidence of pigments
Similar shapes - proof that that wavelength must be used in photosynthesis when it is absorbed
cyclic phosphorylation
Light energy is absorbed by PS I causing a pair of electrons to be excited passing through the electron transport chain generating ATP and the electron pair returns too PS I. Only happens when the chloroplast needs an increased amount of ATP.
Compare cyclic and non - cyclic
Both produce atp
Involves electron transport chain
Energy of electrons pumps protons from the stroma into thylakoid membrane
During non - cyclic a proton is removed from the stroma and added too NADP to make reduced NADP lowering concentration in stroma
During photolysis protons are reduced from water water in the thylakoid membrane both enhancing proton gradient used to generate AR
Light dependent reaction(Calvin cycle)
In the stroma light Independent reaction use ATP and reduced NADP produced by LDR and carbon dioxide is used to make glucose(don’t require light). RUbisCO reacts with carbon dioxide catalysed by the enzyme RUbisCO making 2 molecules of GP each GP molecule has 3 carbon atoms each molecule of GP is reduced using reduced NADP and ATP forming GALP used by the plant too make glucose and other molecules. RUbisCO is regenrated using ATP allowing the cycle too continue.
Has too turn 6 times too make 1 molecule of glucose as it only produces 1 carbon dioxide
