Photosynthesis Flashcards
How are photosynthesis’s and respiration related
CO2 and H2O are the raw material for photosynthesis and the products of respiration
O2 and glucose are raw materials for photosynthesis and the products of respiration
Describe structure of chloroplast
-disc shaped
-double membrane (envolope)
-thylakoids flattened disc stacked yo form grana
-intergranal lamellae thbbuler extentions joining the grana
-stroma fluid filled matrix with high enzyme and substrate conc and own loop of dna
Where does the light dependent reaction occurat
Thylakoids
Where does the light independent reaction occure
Stroma
What is the role of photosynthetic pigments? 2 examples
Absorbe different wavelengths of light to maximise photosynthesis
- primary pigment: chlorophyll a and chlorophyll b in photo systems
- accessory pigments: carotenoids ,xanthophylls light harvesting system
Name the processes of light dependent reaction
Cyclic :
-photoionisation
-electron transport chain
-chemosmosis
Non-cyclic:
-reduction of NADP
- photolysis
Role of photoionisation
Chlorophyll a molecules absorbes energy from photons of light
This then excites 2 electrons which are then causses the electrons to be emmited from photosystems
What happens in the ECT
Electrons released from chlorophyll a move down series of carrier proteins embedded in the thylakiod membrane and hnder go series of redox reactions which release energy
How does chemiosmosis produced atp in light dependent reaction
Some energy released from etc is coupled to active transport of H+ ions from stroma into thylakoid space
H+ ions move down the conc gradient from thylakiod space into stroma via transmembrane channell protien ATP synthase
ADP + Pi ——> ATP
Describe non cyclic photophosphorylation
Used photosystem 1 and 2 excites electrons which enter etc producing atp .NADP acts as a finall electron acceptor and its reduced .water is photolysed to release electrons to replace those lost in photosystem 2
Purpose to produce ATP and NADPH for calvin cycle
Describe cyclic photophosphorylation
Used Ps1 excites electrons which enter etc to produce atp the return to ps1
Purpose to produce atp to meet surplus energy demands
name the three stages of light independent reaction
1) carbon fixation
2) reduction
3) regeneration
what happens during carbon fixation
reaction between CO2 and RuBP catalysed by rubisco
forms a stabel 6C intermediate that breaks down into GP
what happens during reduction in the light indopendent reaction
2 GP are reduced to 2 TP requires 2 NADPH and 2 ATP
forms 2 NADP and ADP
