Lecture 11 - Carbohydrate Anabolism 2 Flashcards
What are some differences between a mitochondria and chloroplast?
- Mitochondria has a matrix; chloroplast has a thylakoid lumen on the inside
- Mitochondria has a intermembrane space; chloroplast has a stroma on the outside
- In the mitochondria, protons are pumped from matrix to intermembrane space, and then back to the matrix where ATP synthase is
- In the chloroplast, protons are pumped from stroma to thylakoid lumn and then back to stroma where ATP synthase is
Is a bacterium (ex: E. coli) more similar to a mitochondria or chloroplast with respect to the flow of protons to make ATP?
Mitochondria
How many photons and electrons are produced for every 2 NADPH?
2 H2O give up 4 electrons, which are each excited twice, producing 8 photons
Where do the 12 protons that are pumped into the thylakoid membrane come from?
- 4 H+ are produced from OEC
- 8 H+ pumped across membrane by Cyt bf-quinone complex
What occurs in complex 1 (OEC) of thylakoid ATP generator?
- 4 H+ pumped from stroma to thylakoid vesicle (1 H+ per electron)
- In the lumen, 2 H2O is converted to O2 + 4 H+
What occurs in complex 2 (PS 2) of thylakoid ATP generator?
4 photons enter (light energy)
What occurs in complex 3 (cyt bf) of thylakoid ATP generator?
8 H+ pumped from stroma to thylakoid vesicle (2 H+ per electron)
What occurs in complex 4 (PS 1) of thylakoid ATP generator?
- 4 photons enters (light energy)
- In the stroma, 2 NADP+ + 2 H+ is converted to 2 NADPH
What occurs in the ATPase of thylakoid ATP generator?
- 12 H+ pumped from thylakoid vesicle to stroma
- 3 ADP + 3 Pi -> 3 ATP + 3 H2O
Does the stroma or thylakoid vesicle have a higher pH?
Stroma
Does the stroma or thylakoid vesicle have a positive charge?
Thylakoid vesicle
How many ATPs can a chloroplast produce per 12 H+?
1 ATP per 4 H+, so 12 will produce 3 ATP
Define photophosphorylation
The production of ATP from light energy
How many ATPs are produced for every 2 NADPH?
3
Describe the quantum yield
For 8 photons 2 NADPH and 3 ATP are produced, which is the amount of energy needed to fix 1 molecule of CO2 into organic form
Describe cyclic electron flow
Electrons from PS 1 are passed to Fe-S protein -> ferridoxin -> plastoquinone -> cytochrome bf -> plastocyanin -> P700
What is the purpose of cyclic electron flow?
To generate more ATP
Cyclic electron flow is independent of ____ and _____
O2 evolution and NADPH production
Why is cyclic electron flow carried out?
ATP is used in CO2 assimilation as a higher ratio than NADPH, so extra ATP is made to meet this ratio
Where are PS 1 and ATPase found?
In the unstacked lamella, giving them easy access to NADP+ in the stroma as well as ADP and Pi
Where is PS 2 found?
In the tightly packed grana, as well as the Cyt-bf complex
What is plastoquinone?
A soluble protein that carries electrons between cyt-bf and PS 1
What is another name for dark reactions?
Calvin cycle
What is needed for 2 C3 to produce glucose?
12 NADPH and 18 ATP
What are the 2 stages of dark reactions?
1) Fixation stage
2) Rearrangement stage
In what stage of dark reactions are the NADPH and ATP used?
Fixation stage
What reaction occurs in the fixation stage?
- 3 C5 + 3 CO2 -> 6 C3
- Cofactor = 6 NADPH + 9 ATP -> 6 NADP+ + 9 ADP
What reaction occurs in the rearrangement stage?
5 C3 -> 3 C5
