Photosynthesis Flashcards
Redox Rxn
Photosyn: H2O oxidized to 02, CO2 reduced to glucose
Cell Resp: O2 reduced to H20, glucose oxided to CO2
LDR
In thylakoid membranes
Photosystem ll- sun excites e- in chlorophyll & travel in ETC
ll gains e- from H20, releases oxygen
acidic due to H+ so ATP synthase diffuses H+ into the low conc, when it spins it makes ATP
Photosystem l
e- from ETC enters and travel to NADP+
accepts e- & hydrogen so becomes NADPH
NADPH & ATP then go to calvin cycle
Calvin Cycle 3 steps
Carbon fixation, reduction, regeneration
Carbon Fixation
Rubisco takes each CO2 and makes 2 molecules of 3PGA
Reduction
ATP & NADPH from LDR convert 3PGA into G3P, can be used to make carbs
Regeneration
some G3P form RuBp so cycle can continue (needs ATP so RuBp can get CO2)
Production of glucose
need 2 spins of the calvin cycle to make glucose, 2 G3P’s will be used for it
To synthesize one glucose molecule, the Calvin cycle uses how many molecules of CO2, ATP, & NADPH
6CO2, 18 ATP, 12 NADPH
Oxidize & reduce
Oxidize- lose electrons
Reduce- gain electrons
Glycolysis
Cytoplasm
Enzymes oxidize glucose to 2 pyruvates, NAD+ reduces into 2 NADH (e- carrier) No net ATP energy inv uses 2 ATP payoff gives 2 ATP
Link Rxn
Mitochondrial matrix
Decarboxylation & oxidation of 2 pyruvates forms 2 CO2, 2 NADH, 2 acetyl CoA
Krebs Cycle
Matrix
2 turns for 2 acetyl CoA Produces 2 ATP, 6 NADH, 2 FADH2, 4 CO2
Electron carriers go to ETC
ETC/ Oxidative Phosphorylation
Inner mitochondria membrane
e- carriers transport e- through proteins at the end O2 takes e- and H+ making H2O
makes ATP with ATP synthase
cytochromes- proteins helping transfer e-
Pathway of H+ Ions in Oxidative Phosphorylation
E- carriers transfer e- to proteins, movement of e- makes high conc H+ in inner membrane
ATP synthase moves H+ into matrix and forms around 30-38 ATP
Depends on energy from H+ gradient
Chemiosmosis & Energy coupling Mechanism
Chemiosmosis- movement of ions across a semipermeable membrane through gradient
Energy made in rxn drives another rxn
Chemiosmosis uses energy from H+ gradient to make ATP
Anaerobic Resp. & Fermentation
Don’t require O2 to make ATP
Since O2 isn’t present ETC won’t happen
Glycolysis pairs with AR & ferm. to make ATP
Anaerobic Respiration
Uses ETC with final e- aceptor instead of O2 like sulfate to make small amounts of ATP
Fermentation
Uses substrate level phosphorylation to make small amounts of ATP
Alcohol fermentation
Yeast
Pyruvate is decarboxylated to acetaldehyde, NADH reduced acet. into ethanol
Lactic acid fermentation
Animals (muscle cells), bacteria (in dairy)
Pyruvate gets reduced from NADh producing lactate
Most primative pathway
Glycolysis because it can occur with/without O2 and in the cytoplasm of any cell
Light spectrum & pigments
Violet (400) high energy, red (700) low energy
Primary- chlorophyll a (all but green)
2nd- chlorophyll b (blue) & carotenoids (blue green)
Better to have multiple pigments because plants could absorb more sunlight to start photosynthesis, more food & energy made
Engelman Experiment
Algae used diff wavelengths during photosynthesis to make O2
bacteria depended on the algae producing O2 because it grew near those areas
didn’t grow near green because the algae reflected this wavelength not absorbed it for photosynthesis
