BIO 120 Lec - 4B pt. 2 (Calvin Cycle, Photorespiration, etc)

because a 3C compound is formed at the first part of the cycle

why is the calvin cycle also known as the c3 cycle

carbon fixation reactions (uses ATP for energy and NADPH for reducing power)

type of reactions that occur during the calvin cycle

CO2 molecules are fixed to ribulose-1,5-bisphosphate (RuBP) and combined to form molecules of 3-phosphoglycerate (3-PGA)

describe the fixation step in calvin cycle

ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO)

catalyst of fixation step in calvin cycle

rubisco

most abundant protein on earth

3-PGA is reduced to molecules of G3P using energy from ATP and electrons or reducing power from NADPH. G3P can then be used to synthesize glucose, sucrose, and starch

describe the reduction step in calvin cycle

using ATP, G3P is regenerated into RuBP

describe the regeneration step in calvin cycle

3CO2 + 9ATP + 6NADPH + water -> 1G3P + 9ADP + 8Pi + 6NADP+

net chemical reaction of calvin cycle

false, they are unable to form O2 but there is only one photosystem in bacteria

[true or false] the two photosystems in purple and green sulfur bacteria are unable to form O2

true

[true or false] the photosystems in bacteria are in the membrane

false, there is a linear scheme, not a z-scheme

[true or false] photophosphorylation in bacteria is similar to plants in that there is a z-scheme and a cyclic scheme

from cytosol to the periplasmic space

proton movement in bacteria

purple

[purple or green sulfur bacteria] P870 light harvesting complex

green sulfur

[purple or green sulfur bacteria] P840 lHC

green sulfur

[purple or green sulfur bacteria] ferredoxin and FNR

green sulfur

[purple or green sulfur bacteria] use H2S instead of water

purple

[purple or green sulfur bacteria] two quinones

false, at high O2 and low CO2

[true or false] rubisco facilitates oxidation instead of reduction at high CO2 and low O2

2-Phosphoglycolate (alongside 3-PGA)

formed by rubisco through oxidation which is useless

hot conditions and closed stomata, with low co2 to o2 ratio

conditions that promote photorespiration

no CO2 is fixed
salvaging C atoms from 2-phosphoglycolate consumes significant amts of energy
diverts reducing power of nadh
releases previously fixed C

why is the photorespiration process a problem

chloroplast
peroxisomes
mitochondria

three organelles involved in photorespiration

glycolate is transported to peroxisome where it reacts with O2 to form glyoxylate which is formed into glycine. glycine is transported to mitochondria where two of them are converted to serine with release of CO2

describe the salvage pathway

bundle sheath cells - acid synthesis
mesophyll - sugar synthesis

two cell types involved in C4 photosynthesis and what synthesis occurs in them

hatch-slack cycle

acid synthesis is also known as

rubp carboxylase and pep carboxylase

two fixation enzymes in c4 photosynthesis

c4 photosynthesis

process wherein the o2 generation is separated from rubisco, leading to reduction of photorespiration and increased co2 fixation