Chloroplast and photosynthesis Flashcards
photosynthesis description
main source of new energy
efficiency 4.5% max and 1-2% actual
energy cycle
water with solar energy + photosynthesis light reaction and leaving oxygen
=4H+ + 4e- organic molecule
energy cycle reverse
4H+ + 4e- go to combustion and respiration and oxygen and leaving energy
overall equation in energy cycle
CO2 + 2H2O -> (CH2O) + O2 + H2O
light reaction use..
intermediate store of energy - C reaction
intermediate energy
ATP and NADPH
light reaction z-scheme
converting light (photons) - chemical energy process of electron movement from PSII to PSI
PSII function
donation of electron to quinone result in charge separation across membrane - splitting water
electrons in PSII
reduce oxidised chlorophyll from charge separation
reaction centre in PSII
light excites electrons to primary electron acceptor
quinone in PSII
become strong reducing agent (electron donor)
chlorophyll in PSII
strong oxidising agent (electron acceptor)
organisation in PSII
reaction centre pair of chl a with slightly lower energy
held by D1/D2
D1/D2 protein in PSII
damaged therefore it is constantly replaced
parts of electron transport chain
pheophytin
plastoquinone
cytochrome b{E}f complex
Plastocyanin(PC)
pheophytin
modified chlorophyll (no Mg)
plastoquinone
small lipid soluble molecule
cytochrome b{e}f complex
2 beta-type + f cytochromes and Fe-S protein
chlorophyll - ground state
energy in Chl captured
PSII found in
chloroplast and cyanobacteria = oxygenation of planet
PSI
takes electron from PSII - used to generate energy rich compound - NADPH
PSI - ferredoxin
small, water soluble, Fe-S protein
feed electrons to FNR
FNR
ferredoxin-NADP+ reductase
FNR function
enzyme, reducing NADP+ - NADPH
plastocyanin - PSI
passes electron to P700
phosphorylation
light dependent ATP generated via formation of electrochemical H+ proton
H+ travel down gradient generate ATP (use ATP synthase)
light reaction of photosynthesis - antenna complex
light-harvesting antenna complex
increase efficiency
action spectrum
how efficient wavelength of light are absorbed
more pigments
increases range of wavelength of light are absorbed
reaction of centre function - pigment
absorb only 1 photon/sec
not enough for charge separation and photosynthesis
received extra energy from other molecules - stages
carotenoid to chlorophyll b to chlorophyll a to P680*
function stages in received extra energy
pass resonance energy transfer to P680
structure- tetrapyrrole
has a lipid attached so they are able to sit in thylakoid membrane
ATP synthase
CF{0}-CF{1}
large enzyme complex
CF{0}
in membrane - spins
CF{1}
out of membrane
ATP synthase production
4 protons per ATP
linear phosphorylation
have H+ during PSII and PSI
back though ATP synthase and used NADP and H+
what is required in Calvin/ Calvin-Benson cycle
13 steps
13 enzymes
what is required from CO2 to G3P
uses intermediate molecules ATP and NADPH
cycle of dark reaction
RuBP + C = 3 phosphoglycerate by Rubisco
ATP + 3 phosphoglycerate = 1,3-bisphosphateglycerate
+ NADPH = G3P - C is taken to make G3P sugar
G3P(5c) with ATP = RuBP
1 molecule of G3P requires
9ATP and 6NADPH
Rubisco
Ribulose bisphosphate carboxyl oxygenase
Rubisco function
converts 1,5-bisphosphate to 3-phosphoglycerate
ability to use oxygen and carbon dioxide
rubisco - structure
8 large (56kDa) subunit 8 small (14kDa) subunit
large subunit encoded
by plastid
small subunit encoded
by nuclear genomes
problem of rubisco
able to use oxygen instead of carbon dioxide
recovering oxygen - energetically costly
Rubisco when temperature increase
increase problem
why it increase temperature is bad
stomata close prevents water loss = decrease gas exchange and availability of carbon dioxide
decrease gas exchange and availability of carbon dioxide causes
increase in rubisco activity but affinity of carbon dioxide decrease - more oxygen used
in Maze
has C4
store carbon dioxide in leaves therefore more efficient
