photosyntheiss stuff! Flashcards
which spectrum(s) of light does chlorophyll absorb? A red B orange C green D blue E purple
red and blue!
they relfect the freen light so thats why they are green!
> caratenoids do blue so they look red!
name 3 membrane bound compartments inside a chloroplast
> not organelles!
intermembrane space
stroma
thylakoid lumen
what three membranes make up a chloroplast
Outer envelope
inner envelope
thylakoid memebrane
does PS|| have
P680 or P700?
PS|| has P680
this is the reaction centre whre electrons are accepted/ lost
what is the name of the chlorophyll compartment that is the site of photolysis?
the manganese cluster
which electron carrier (intermediate) carries e- from cytochrome b6f complex to PS|? A zeaxanthin B plastoquinol C plastoquinone D plastocyanin E pheophytin
OPTION D
plastocyanin has a Cu+ that is easily reduced which carries the electron
… docks at a postivie area on PS|
What are the pathways of electron transport through cytochrome b6f complex? A Linear and cyclic B Cyclic only C Linear only D Reverse and linear
Linear and cyclic
HAPPEN at the same time - this is too replenish the plastaquinol-H+
which compound is in a reduced state
A plastiquinol
B plastiquinone
plastiquinol is in a reduced state
it gets oxidised by PS||
> quiNONE has no H+`
How does the photolysis of water support the process of electron transfer?
A Releases electrons that replenish the electron lost in PSII
B Helps use up excess water
C Releases electrons that replenish electron lost in PSI
D Provides H+ ions for ETC
OPTION A
helps to replenish the electrons lost in PS||
why and what occurs in cyclic photophosphorlyation
if there is too much sunlight then NADPH precursor becomes limiting there can be a backlog of e-
chlorplast recycles the e- back through cytb6f and can
make more plastiquinol too (to be split again through b6f)
> also extra e- used to create more of a proton gradient
How do you differentiate between grana and lamellae in chloroplasts.
Lamellae are unstacked, strips of memebrane.
Grana are stacks of appressed thylakoid membranes
carrier protein order in light dependent reaction?
Pheophytin to plastiquinone to plastiquinol then transfers electrons to Cytochrome b6f
plastocyanin carries electorn to PS1 then ferredxin helps with NADPH production
What is the role and cause of cyclic photophosphorylation?
Role = Speed up light reactions
Cause = Decreased light availability (shade, winter/autumn, night)
Role = Slow down light reactions to conserve energy Cause = Decreased light availability (shade, winter/autumn, night)
Role = Increase efficiency Cause = Not enough resources (low H+ availability)
Role = Prevent build up of high energy electrons Cause = Too little sunlight
Role = Prevent build up of high energy electrons Cause = Too much sunlight (energy, excited electron
OPTION E
If build up of e- happens, chloroplast switch to cyclic pathway to build up more of a H+ gradient.
Electrons from PSI go back to cytochrome b6f (through Fd) to create a greater H+ gradient
How does LHCII work to balance/regulate the activity of PSII and PSI?
A LHCII is phosphorylated in response to photosystem activity through enzymes that “sense” the Q:QH2 ratio.
B LHCII regulates activity through sensing electron movement
C LHCII regulates activity through sensing the light wavelength and determining what photosystem is best to go to.
D LHCII regulates activity enzymes that sense the amount of products of b6f complex reactions
OPTION A
LHC dissociates from PS2 and asscoicates with PS1 to upregulate it.
more plastiQuinome made which activates phosphatase so now LHC dissociates from PS1
> more plastiquinol QH2 = kinase activated
which habitiats does C4 p/s take place? can you name any examples of crops
dry arid areas
maize, corn , sugar cane!
