Lecture 11 - Carbohydrate Anabolism 2

Question 1

What are some differences between a mitochondria and chloroplast?

Answer 1

• 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

Question 2

Is a bacterium (ex: E. coli) more similar to a mitochondria or chloroplast with respect to the flow of protons to make ATP?

Answer 2

Mitochondria

Question 3

How many photons and electrons are produced for every 2 NADPH?

Answer 3

2 H2O give up 4 electrons, which are each excited twice, producing 8 photons

Question 4

Where do the 12 protons that are pumped into the thylakoid membrane come from?

Answer 4

• 4 H+ are produced from OEC

- 8 H+ pumped across membrane by Cyt bf-quinone complex

Question 5

What occurs in complex 1 (OEC) of thylakoid ATP generator?

Answer 5

• 4 H+ pumped from stroma to thylakoid vesicle (1 H+ per electron)
• In the lumen, 2 H2O is converted to O2 + 4 H+

Question 6

What occurs in complex 2 (PS 2) of thylakoid ATP generator?

Answer 6

4 photons enter (light energy)

Question 7

What occurs in complex 3 (cyt bf) of thylakoid ATP generator?

Answer 7

8 H+ pumped from stroma to thylakoid vesicle (2 H+ per electron)

Question 8

What occurs in complex 4 (PS 1) of thylakoid ATP generator?

Answer 8

• 4 photons enters (light energy)

- In the stroma, 2 NADP+ + 2 H+ is converted to 2 NADPH

Question 9

What occurs in the ATPase of thylakoid ATP generator?

Answer 9

• 12 H+ pumped from thylakoid vesicle to stroma

- 3 ADP + 3 Pi -> 3 ATP + 3 H2O

Question 10

Does the stroma or thylakoid vesicle have a higher pH?

Answer 10

Stroma

Question 11

Does the stroma or thylakoid vesicle have a positive charge?

Answer 11

Thylakoid vesicle

Question 12

How many ATPs can a chloroplast produce per 12 H+?

Answer 12

1 ATP per 4 H+, so 12 will produce 3 ATP

Question 13

Define photophosphorylation

Answer 13

The production of ATP from light energy

Question 14

How many ATPs are produced for every 2 NADPH?

Answer 14

3

Question 15

Describe the quantum yield

Answer 15

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

Question 16

Describe cyclic electron flow

Answer 16

Electrons from PS 1 are passed to Fe-S protein -> ferridoxin -> plastoquinone -> cytochrome bf -> plastocyanin -> P700

Question 17

What is the purpose of cyclic electron flow?

Answer 17

To generate more ATP

Question 18

Cyclic electron flow is independent of ____ and _____

Answer 18

O2 evolution and NADPH production

Question 19

Why is cyclic electron flow carried out?

Answer 19

ATP is used in CO2 assimilation as a higher ratio than NADPH, so extra ATP is made to meet this ratio

Question 20

Where are PS 1 and ATPase found?

Answer 20

In the unstacked lamella, giving them easy access to NADP+ in the stroma as well as ADP and Pi

Question 21

Where is PS 2 found?

Answer 21

In the tightly packed grana, as well as the Cyt-bf complex

Question 22

What is plastoquinone?

Answer 22

A soluble protein that carries electrons between cyt-bf and PS 1

Question 23

What is another name for dark reactions?

Answer 23

Calvin cycle

Question 24

What is needed for 2 C3 to produce glucose?

Answer 24

12 NADPH and 18 ATP

Question 25

What are the 2 stages of dark reactions?

Answer 25

1) Fixation stage

2) Rearrangement stage

Question 26

In what stage of dark reactions are the NADPH and ATP used?

Answer 26

Fixation stage

Question 27

What reaction occurs in the fixation stage?

Answer 27

• 3 C5 + 3 CO2 -> 6 C3

- Cofactor = 6 NADPH + 9 ATP -> 6 NADP+ + 9 ADP

Question 28

What reaction occurs in the rearrangement stage?

Answer 28

5 C3 -> 3 C5