5.5 Photosynthesis - light dependant & independent Flashcards
(light dependant) 1. what does photosystem 2 (ps2) absorb and what effect does this have?
light
excites electrons
(light dependant) 2. excited electrons pass to where?
electron transport chain
(light dependant) 3. ATP is made in what process?
chemiosmosis
(light dependant) 4. electrons pass down the chain to where?
photosystem 1 (ps1)
(light dependant) 5. electrons lost from ps2 are replaced by what?
electrons from photolysis
(light dependant) 6. the electrons from ps1 pass to where?
electron transport chain
(light dependant) 7. in non cyclic photophosphorylation, where do the electrons that leave the ETC after ps1 go?
accepted by coenzyme NADP with a hydrogen ion
(light dependant) what does reduced NADP do?
provides the H+ in the light independent reaction
(light dependant) what occurs in cyclic photophosphorylation?
the electron is fed back into ps1
(light dependant) what is photolysis?
water split into H+, e- and O2 using energy from the sun
(light dependant) equation for photolysis:
H2O —>
2H+ + 2e- + 1/2 O2
(light dependant) what is the enzyme forming part of the ps2 catalysing the breakdown of water?
the O2 evolving complex
(light dependant) protons are released into the lumens of the thylakoids increasing what?
the proton concentration gradient across the membrane
(light dependant) protons diffuse back down an electrochemical gradient driving what?
the formation of ATP
(light dependant) what happens to the proton once it returns to the stroma?
combines with electron and NADP to form reduced NADP
(light dependant) the process removes protons from the stroma helping maintain what?
the proton gradient across the thylakoid membrane
can photosynthesis occur in the dark?
only the light independent stage
when will the light independent stage stop in the dark?
when there is no reduced NADP and ATP left over from the light dependent reaction
where does the light dependant stage take place?
within the grana
where does the light independent stage take place?
in the matrix
what pigments are embedded in the thylakoid membrane?
chlorophyll a
chlorophyll b
xanthophylls
carotenoids
pigments and other proteins form a light harvesting system called what?
the antennae complex
what is the role of the antennae complex?
to absorb/harvest light energy at different wavelengths & transfer energy to the reaction centre
what is located in the reaction centre?
chlorophyll
(pigment) what is a photosynthetic pigment?
coloured biological compound present in chloroplasts and photosynthetic bacteria which captures light energy for photosynthesis
what pigment gives plants their green colour?
chlorophyll - it reflects green light
what pigment gives plants a red - yellow colour?
carotenoids
(light independent) what is the light independent stage also known as?
the calvin cycle
(light independent) 1. CO2 diffuses into the leaf through what?
spongy mesophyll cells
(light independent) 2. from the spongy mesophyll CO2 diffuses where?
into the stroma of chloroplasts
(light independent) 3. what does CO2 combine with?
ribulose bisphosphate
this fixes the CO2
(light independent) how many carbons does ribulose bisphosphate have?
5
(light independent) 4. which enzyme catalyses CO2 combining with ribulose bisphosphate?
Rubisco
(light independent) 5. CO2 + Ribulose forms an unstable six carbon molecule which breaks down to form what?
2 Glycerate 3 phosphates
(light independent) 6. what are the glycerate 3 phosphates converted into?
2 triose phosphates
(light independent) 7. how are the glycerate 3 phosphates converted to triose phosphates?
using hydrogens from reduced NADP and energy from ATP
(light independent) 8. what is done with most of the TP?
recycled into RUBP
(light independent) 9. what happens to the rest of the TP not used to make RUBP?
used to make lipids, glucose and amino acids
(light independent) for one glucose to be made how many CO2 have to enter the calvin cycle?
6
(light independent) 6 full turns of the calvin cycle produces how many triose phosphates?
12
(light independent) of the 12 triose phosphates made in the calvin cylcle how many are removed to make glucose?
2
(light independent) how many triose phosphates are recycled to regenerate 6 RuBP?
10
