simplified equation of photosynthesis
H2O + CO2 + light → O2 + glucose + H2O
Enzymes
made up of proteins that acts as a catalyst - does not get consumed
sometimes needs ATP
do not change the free energy
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simplified equation of photosynthesis
H2O + CO2 + light → O2 + glucose + H2O
Enzymes
made up of proteins that acts as a catalyst - does not get consumed
sometimes needs ATP
do not change the free energy
active site
lock and key: where catalysis occurs - substrates binding exactly
induced fit: substrates bind and active site changes shape
conditions
pH: optimal 6-8
temperature: higher temp speeds up reactions but too hot will denature proteins
cofactors: non proteins helpers for catalytic activity (organic = coenzymes)
concentration of substrate and concentration of enzyme
inhibitors
competitive and non competitive, substances that decrease enzyme activity
competitive inhibition
looks simialr to the substrate
binds to active site
no reaction takes place because active site taken up
non-competitive inhibiton
binds to allosteric site (away from active site) and changes shape to change function and stop enzyme from working
forms of energy
kinetic: motion
heat/thermal: random movement of atoms or molecules
potential: location/structure
chemical: to release in reaction
laws of thermodynamics
1st: energy cannot be created or destroyed
2nd: every energy transfer increases the entropy
endergonic vs exergonic reactions
ender: energy absorbed
exer: energy released
ATP
energy for cellular processes
ribose, adenine, 3 phosphates
unstable, stored when stable ADP (phosphorylation)
OILRIG
oxidation is lost, reduction is gained
chloroplast
thylakoid membrane: light dependent reactions, first stage of photosynthesis, have grana
stroma: light independent reactions, calvin cycle
pigment
absorbs light at a particular wavelength
chlorophyll, carotenoids, and phycobilins
stomata & transpiration
stomata: CO2 enters, water vapor and O2 leave
transpiration: plants lose H2O from their leaves by evaporation
plants close stomata to conserve water but also closes off CO2 and locks too much O2 in
Autotroph
self nourishing, producers
Bundle sheath cells
cells tightly wrapped around veins of a leaf
site for calvin cycle in C4 plants
C4 plants
adapted plant to hot and dry conditions
mesophyll & mesophyll cells
mesophyll: interior tissue of leaf
mesophyll cells: contain many chloroplasts and host majority of photosynthesis
photosytems
photosystem II = P680
photosystem I = P700
light dependent reactions (noncyclic) - sequence of events
photon strikes PII
captured by primary electron acceptor
water split into 2H and O, electrons go to PII
travels through ETC, creates ATP through active transport w/ cytochrome protein pump
5. photon strikes PI
2 electrons reduce NADP+ to NADPH
photolysis
water is broken up into hydrogen ions and oxygen during light dependent reactions
photophosphorylation
ATP produced during light dependent reactions
chlorophyll a and chlorophyll b
a: major pigment, passes excited electrons to primary electron acceptor
b: accessory pigment
oxygen from plants
produced from the intake of water (H2O), not CO2
cyclic light reaction
no water split
no oxygen produced
no NADPH
still produces ATP
just uses PI and recycle electrons in ETC
hydrogen ion gradient
made by cytochrome, used to power ATP synthase
H+ move from stomata to thylakoid
light-independent reactions (calvin cycle)
occur in stomata
inputs: ATP and NADPH from light dependent, CO2
outputs: sugar, ADP, NADP+
carbon fixation
carbon from CO2 + RuBp to form 3-phosphoglycerate (3-PGA) through the enzyme Rubisco
photorespiration
Rubisco uses oxygen instead of CO2, no sugar produced
happens on hot dry days when stomata is closed
oxaloacetate
instead of two 3PGA molecules, produces one 4 carbon molecule, oxaloacetate during carbon fixation for C4 plants
CAM (Crassulacean acid metabolism)
water storing plants, desert plants
stomata open at night to avoid transpiration
Calvin cycle occurs during day when CO2 is released