Photosynthesis Flashcards
Photosynthesis meaning
absorb and convert light energy into stored chemical energy of organic molecules
Autotrophs
self-feeders
Photoautotrophs
the ones that use light to make food
Heterotrophs
need to consume foods
fossil fuels
formed by remains of past organisms
what is the ultimate energy for living things
the sun
Photosynthesis happens in what organelle
Chloroplast
Chlorphyll
is the green pigment,in chloroplasts mesophyll
anatomy of the chloroplast
Outer membrane
inner membrane-encloses the stroma
Stroma
fluid filled enzymes to make carbs
stomata
the microscopic pores in the leaves for gas exchanges in leaves (usually on the underside of the leafs)
thylakoids
pancake discs in the chloroplasts and surrounded by stroma
thylakoid lumen
fluid-filled space inside of thylakoid
grana
its the thylakoids stacks
mesophyll
tissue in the middle of the leaf tissues ( the top tissue is waxy and the bottom tissue if rough)
the chlorophyll is in the
thylakoids membrane
chlorophyll absorbs what type of light
blue/red wavelengths
what color is reflected from the chlorophyll
yellow and green light
the absorbed light is
used
the transmitted light (reflected light)
isn’t used and its what we can see
because of it diff color wavelengths_______
some plants have diff colors
what comes first photosystem 1 or 2
photosystem 2
in photosystem 1 there chlorophyll_____ and how much light does it absorb -_____
chlorophyll a / P700
in photosystem 2 there chlorophyll_____ and how much light does it absorb -_____
A / P680
the pigments absorb
light energy
how do chlorophyll pigments molecules reach there maximum amount of light they can absorb
energy is passed from 1 pigment molecule to another until it reaches P700 or P680 at the reaction center
step 1 in photosystem
light energy will hit one of the pigment molecules and bounces down
step 2 in photosystem
once the special pair of chlorphyll a molecules get the energy its electron will be raised to a higher energy level
step 3 in photosystem
once the e- has a higher energy level it will be donated to the primary electron acceptor
the main plant pigment is
chlorophyll a
what type of chlorophyll pigment is in the reaction center
chlorophyll a
noncyclic electron transport
not a cycle its a cont. linear process ( 1 way flow of e- from water to NADP+
the noncyclic Electron transport makes
ATP and NADPH
step 1 of photolysis
a photon hits a pigment and its energy is passed along pigment molecules until it excites P680
step 2 of photolysis
An excited electron from P680 is transferred to the primary electron acceptor once the electrons are donated the P680 gets a + temporarily
step 3 of photolysis
H2O is split by enzymes, and the electrons are transferred from the hydrogen atoms to P680+ thus reducing it to P680
what is released as a by product of step 3 of photolysis
O2
photolysis is
light splitting
during photolysis
every e- is donated to P680 and P+ are released and crating a chemical electrical gradient into the thylakoid lumen
for 1 oxygen to be released into the atmosphere how many waters need to be split
2
( 2 H20——>O2+4H+)
Photosynthesis formula
6 CO2 + 6 H2O + light –> C6H12O6 + 6 O2
photosynthesis has many _____ steps
complex
2 parts of photsynthesis
Light-dependant (photo)- thylakoids
carbon fixation ( synthesis) - stroma
photosynthesis _____ the direction of e- flow compared to _____
reverses / resperation
NADP+ to
NADPH
Reaction center +
many antenna complexes
antenna complexes
absorbs light energy and transfers it to reaction center
reaction center light energy—>
chemical energy be series of e- transfers
step 4 of photolysis
each electron “falls” down an ETC from the primary electron acceptor of PS 11 to PS 1
step 5 of photolysis
energy released by the fall drives the creation of a proton gradient across the thylakoid membrane. Diffusion of H+ (protons) across the membrane drive ATP synthesis
step 6 of photolysis
meanwhile in PS 1, juse lke PS 2 the transffered ligh energy excite P700 which loses e- to an electron acceptor. P700+ ( P700 that is missing an electron ) accepts an electron passed down from PS 2 via the ETC
step 7 of photolysis
each electron falls down an ETC from the primary electron acceptor of PS1 to the Protein ferredoxin (FD)
step 8 of photolysis
the e- are then transferred to NADP+ nad reduced to NADPH. The electrons of NADPH are available for the reactions of the calvin cycle.
chloroplasts and mitochondria both generate ATP by chemiosmosis but
use different sources of Energy
Mitochondria transfer chemical energy from food to ATP; chloroplast
transform light energy into the chemical energy of ATP
Spatial organization of chemiosmosis
differs and can be similar between both mitochondria and chloroplast
In mitochondria, protons are pumped to the intermembrane space and drive ATP synthesis as they diffuse back into the mitochondrial matrix
but in chloroplast
protons are pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma
By chemosmosis_____
ATP synthesis
some of the energy not released——>
Drives synthesis of ATP (endergonic)
The synthesis of ATP in chloroplasts, promoted by light, is called
photophosphorylation
the final acceptor in the photolysis
is NADP+—–>NADPH
the light reaction ( photolysis) products
ATP and NADPH
calvin cycle products
G3P
carbon fixation
The Calvin cycle begins with the incorporation of carbon dioxide from the air into organic molecules already present in the chloroplast.
carbon fixation direct light is or not needed
not
carbon fixation depends on
products of the light reaction
the c3 pathway
is a pathway where majority of plants create G3P as a first product of carbon dioxide fixation in the calvin cycle
the calvin cycle occurs in the
stroma and there are more than one reactions
3 phases ofcalvin cycle
-co2 uptake
-carbon reduction
-RuBP regeneration
how many reactions in Co2 uptake ( calvin cycle)
one
step 1 of Co2 uptake
the carbon dioxide will attach with RuBP (5c) with an enzyme
step 2 of Co2 uptake
the co2 and RuBP will become a short lived intermediate and then immediately it will become 2 PGA (3c each)
carbon reduction phase step 1
a phosphate is added to PGA which creates the molecule 1,3-bisphosphoglycerate
carbon reduction pase step 2
the 1,3-bisphosphoglycerate molecules are reduced (gain electrons). Each molecule receives two electrons from NADPH and loses one of its phosphate groups, turning into G3P
carbon reduction products
NADP+ and phosphate as a by product
for net synthesis for 1 g3p
the cycle must take place 3 times,fixing three molecules of co2
how many reactions are in the RuBP regeneration phase
10
in RuBP regeneration phase the 30 c (from the 10 G3P left from carbon reduction phase) rearranged into
6 ribulose phosphate (+P)—-> RuBP (5c where reaction started)
Inputs of carbon fixation
6 co2
p from ATP
e-(as hydrogen) from NADPH
end of carbon fixation
6c remaining G3P—–> makes RuBP which combines with more co2
