Lecture 8-Photosynthesis Flashcards
autotrophs
use inorganic carbon as C source to fix C into organic compound
photoautotroph
use light energy to fix C
chemoautotroph
use redox energy to fix C
heterotrophs
use organic C as both C source and energy source
chemoheterotrophs
use organic C as main nutirent
photoheterotroph
use light energy and organic C
where does light reactions occur
thylakoid membrane
where does calvin cycle occur
stroma
redox reaction of photosynthesis
carbon dioxide is reduced and water is oxidized to produce oxygen and glucose
function of light reactions
use energy carried by light and convert it into chemical energu in the form of ATP and NADPH that will be used to power the calvin cycle
what happens to the light that is absorbed?
-absorbed by pigments and used as energy source
photosystems function
sit in thylakoid membrane and contain pigments to absorb light
-pigments within the photsystem can absorb light, excite e-, and pass those e- thru the photosystem
ETC (election transport chain)
a set of increasing strength of e- acceptors to allow energy from excited e- to be converted into H gradient and released in small discrete steps
three methods of energy conversion
- convert light energy into chem. energy in the form of an excited e-
2.excited e- is passed down ETC and releases energy to pump H into thylakoid gradient - excited e- from P1 is used to reduce NADP+
chemiosmosis
formation of ATP using a H concentration gradient and ATP synthase
photophosphorylation
if energy source for H gradient is light
oxidative phosphorylation
if energy source for H gradient is oxidation of a nutirent
ATP synthase
an enzyme complex that couples ATP synthesis (endergonic) with the dissipation of H gradiant (exergonic)
what is NADPH?
an election carrier b/w redox reaction of light reactions to calvin cycle
-electon is used to reduce C
calvin cycle/dark reaction function
to fix C from atmospheric form to organic C
-use energy from light reactions (ATP and NADPH) to convert CO2 to sugar
-endgergonic
carbon fixation phase of calvin cycle
one CO2 is added per turn of cycle therefore the cycle must turn three times to get one product (G3P)
-enzyme=rubisco
reduction phase of calvin cycle
the NADPH from light reactions are used to reduce the fixed C
regeneration phase of calvin cycle
RuBP is regenerated
-a set of complex rxns requiring ATP
net inputs of calvin cycle
9 ATP, 6 NADPH, 3 CO2= 1 G3P
