Photosynthesis Flashcards
describe structure of chloroplast
double membrane
stroma contains thylakoid membrane, 70s ribosomes, circular dna and starch granules
lamella is the thylakoid linking grana
and grant are stacks of thylakoids
photoionisation
chlorophyll absorbs light energy exciting electrons to a higher energy level
so electrons are released from chlorophyll and chlorophyll becomes positively charged
what happens after photoionisation
some energy from electrons released in photoionisation conserved to produce ATP and reduced NADP
electrons move along ETC releasing energy
energy used to actively pump protons from stroma to thylakoid
protons move via FD down electrochemical gradient into stroma via ATP synthase
energy used to join ADP AND PI to form ATP
NADP accepts a proton and electron to become reduced NADP
photolysis of water
water splits to produce protons electrons and oxygen
electrons replace those lost from chlorophyll
light independent reaction
in stroma
co2 reacts with RUBP which is catalysed by rubisco
forming GP reduced to TP
using products from LDR reduced NADP and energy from ATP
some TP converted to useful organic substances
some TP used to regenerate RuBP in Calvin cycle using energy from ATP
how does temp affect rate of photosynthesis
temp increase rate increases
as enzymes gain KE
so more E-S
above optimum rate decreases as enzymes denature as h bonds in tertiary structure break so fewer enzyme substrate complexes
how does light intensity affect rate of photosynthesis
increases rate does too
LDR increases so more photoionisation so more ATP and reduced nadp produced
so more LIR as more gp reduced to TP and more TP to regenerate rubp
but as certain light intensity something else becomes a limiting factor like temp or co2 conc
how does co2 conc affect rate of photosynthesis
as co2 increases rate increases
LIR increases as more co2 combines with RuBP to form GP so more GP reduced to TP and more TP is converted to organic substances and more RuBP regenerated
