Lab photosynthesis

Question 1

granal membrane

Answer 1

stacked/ appressed portion of the granum that is hydrophobic

Question 2

stromal membrane

Answer 2

exposed/ unstacked portion of the granum

Question 3

How is PS1 and PS2 distributed?

Answer 3

PS! found in the stromal membrane, PS2 found in the granal portion

Question 4

How are protein complexes distributed?

Answer 4

unequally between the two membrane types

Question 5

Where is ATP synthase found?

Answer 5

almost entirely in the stromal membrane

Question 6

Where are electron carriers like PC found?

Answer 6

unequally between the two membranes, in the lumen

Question 7

lateral heterogeneity

Answer 7

uneven distribution of proteins

Question 8

Why is lateral heterogeneity important in the granum?

Answer 8

both photosystems are spatially separated from each other

Question 9

What does lateral heterogeneity allow?

Answer 9

long distance electron transfer

Question 10

Where is cytochrome b6f complex found?

Answer 10

distributed evenly in the granum

Question 11

What is LHC-2 and its function?

Answer 11

a light harvesting protein complex

auxilliary antenna for PS2

Question 12

Where is LHC-2 found?

Answer 12

exclusively in granal membrane

Question 13

How are cyanobacterial membranes formatted?

Answer 13

unstacked with no LHC-2 but can still transport electrons

Question 14

How are some mutant chloroplasts formatted?

Answer 14

unstacked with no LHC-2 but can still photosynthesize

Question 15

What does membrane stacking do?

Answer 15

efficient distribution of light between PS1 and PS2 complexes

Question 16

How does balanced excitation of the ps occur?

Answer 16

one photosystem not receiving preferential photon delivery

Question 17

How are the PS balanced?

Answer 17

spatial separation of the PS

Question 18

How does LHC-2 balance the PS?

Answer 18

associates with PS2 to regulate distribution of quanta between the photosystem?\

Question 19

What happens when light activates LHC-2?

Answer 19

phosphorylation changes surface charge

Question 20

What happens after phosphorylation?

Answer 20

LHC-2 becomes negatively charged and displaced from the hydrophobic core of the granal stack to the less hydrophobic stromal membrane

Question 21

What happens when LHC-2 migrates?

Answer 21

PS2 has decreased light absorption due to decreased antenna association, and granum becomes unstacked

Question 22

Why does granum become unstacked?

Answer 22

electrostatic repulsion of negatively charged LHC-2, causing migration of LHC2

Question 23

How does chloroplasts detect imbalance of excitation and activate PS2?

Answer 23

redox-activated kinase

Question 24

What does the redox-activated kinase do?

Answer 24

involved in phosphorylating LHC-2

Question 25

When does the redox-activated kinase activate?

Answer 25

when PC, which shuttles electrons between PS1 and PS2 is in a highly reduced state

Question 26

When is PC reduced?

Answer 26

when PS2 receives more light than PS1

Question 27

What happens when PC becomes oxidized?

Answer 27

kinase activity reduces

Question 28

What happens when PS1 outperforms?

Answer 28

PC oxidates and phosphatase activates

Question 29

What does phosphatase do?

Answer 29

allows LHC-2 to migrate back to the hydrophobic stacked region by hydrolyzing phosphate group

Question 30

structure of cyanobacteria?

Answer 30

prokaryotic, lacking cell membrane and nucleus.

thylakoid, cell wall, gas vesicles, plasma membrane, storage vesicles

Question 31

How do cyanobacteria and chloroplast differ in function?

Answer 31

cyanobacteria can self-sustain, while chloroplast is limited to the eukaryotic cell

Question 32

structural difference between cyanobacteria and chloroplast

Answer 32

cyanobacteria lack membrane-bound organelles, while chloroplast has a double membrane