Dark reactions Flashcards
What are the three phases of the Calvin Cycle? Describe them.
1) carboxylation phase: CO2 + Rubisco –> RuBP
2) reduction phase: 3-PG + NADPH + ATP –> G3P
3) regeneration phase: 5 G3P + 3 ATP –> RuBP
How much ATP and NADPH does it take to fix one CO2 molecule? How about for one GLC?
CO2 : 2 NADPH + 3 ATP
GLC: 18 ATP and 12 NADPH
How many runs of photosystem one does it take to make enough product to run CBC once?
one complete run of the light rxn. This means two waters were used in order to get one electron completely down the chain
How many protons does it take to make one ATP molecule from ATPase?
4 H+
What are the four sites in the cell where photorespiration takes place?
Chloroplast, the mitochondria, the peroxisomes, and the cytoplasm
What were the findings of CO2 enrichment in plants?
-short-term growth followed by stagnation/decline
-long-term protein deficiency
- elevated free nitrogen and malic acid in the plant
Which pathway does Mn2+ rubisco favor? Which one does Mg2+ favor?
When associated with Mg2+, carbon fixation is preferred
When associated with Mn2+, photorespiration is prefered
Which metal (Mg, or Mn) can participate in redox chemistry and why?
Mn2+ has a less stable shell, with five unpaired electrons, so it can participate in redox chem
What are the five difference between NH4+ and NO3- in the soil?
NH4+: low concentrations, toxic in tissues, less mobile, preferred for microbes, higher oxidation state (+3)
NO3-: high concentrations, benign in tissues, mobile in soil, undesirable for microbes, and low oxidation state (-5)
What is the difference between translocation and passive transport?
Translocation: over long distances (i.e. hormones)
transport: movement across a memebrane (i.e. ions)
Which use passive transport and which use active?: pumps, channel proteins and carrier proteins
active : pumps
Compare and contrast carriers from channels (speed and mechanism)
Carriers: slow and function via protien conformations
channels: fast and function via increasing membrane permeability
What are the five steps in photosynthesis?
1) blue light hit receptor in guard cell
2) ATPase is activated and H+ start to be pumped out of the cell (creates a pmf)
3) pmf causes k+ channels to open, and allow for K+ to enter the cell
4) K+ influx causes start to be degraded into malate in the cytoplasm (negative charged)
5) Malate and K+ causes Cl-, K+, and Malate to enter the valuole, which drops the water potential and causes
Why is cyclic electron flow nessisary for photosynthesis?
CBC needs an extra ATP (3 ATP to 2 NADPH) in order to run once. Linear photosythsis only makes 2 ATP and 2 NADPH, but when using cyclic electron transport, a third ATP can be made without needing to make another NADPH
