light dependant reaction

Question 1

where does the light dependant reaction occur

Answer 1

thylakoid membranes

Question 2

what are the two types of reactions that occur during the light dependant stage

Answer 2

cyclic photophosphorylation
non cyclic photophosphorylation

Question 3

what absorbs light energy

Answer 3

photosystem II

Question 4

what happens when PSII absorbs light energy

Answer 4

electrons in the chlorophyll get excited and move to a higher energy level

Question 5

when electrons have more energy where do they travel to

Answer 5

move along the electron transport chain to PSI

Question 6

what happens after the electrons from PSII travel to PSI

Answer 6

photolysis of water

Question 7

what is the equation for photolysis of water

Answer 7

H2O -> 2H+ and 1/2O2

Question 8

what is photolysis

Answer 8

splitting of water by light energy into protons, electrons and oxygen

Question 9

what is the purpose of photolysis

Answer 9

replace the electrons that have left PSII

Question 10

what happens as electrons move along the electron transport chain

Answer 10

lose energy

Question 11

what is the energy, lost by the electrons, used for

Answer 11

transport proteins into the thylakoid membrane

Question 12

how are proteins transported into the thylakoid membrane

Answer 12

via membrane proteins called proton pumps

Question 13

what is the purpose of protein pumps

Answer 13

ensures that the thylakoid has a higher concentration of protons than the stroma to create a proton gradient across the membrane

Question 14

as protons enter the thylakoid, what happens

Answer 14

move down and across their gradient

Question 15

how do the proteins in the thylakoid enter the stroma

Answer 15

via an enzyme called ATP synthase

Question 16

what happens as the proteins pass through ATP synthase

Answer 16

the energy from the movement combines ADP + Pi to form ATP

Question 17

what happens after the protons reach the stroma

Answer 17

light energy excites electrons in PSI to an even higher energy level, where they are then transferred to NADP along with the protons from the stroma to form reduced NADP (NADPH)

Question 18

in what ways does cyclic photophosphorylation differ from non cyclic photophosphorylation

Answer 18

cyclic only uses PSI
no reduced NADP

Question 19

why is cyclic photophosphorylation described as being cyclic

Answer 19

electrons from the chlorophyll in PSI are not passed to NADP but instead passed back to PS1 via electron carriers