photosynthesis

Question 1

outline the light dependent reaction

Answer 1

occurs in the thylakoid
light energy captured by chloroplast pigments such as chlorphyll
water is split (photolysis) into H+ ions electrons and oxygen
some of the energy from the released electrons is used to add a phosphate group to ADP to make ATP
as well as reduce NADP to make reduced NADP

Question 2

outline the light independent reaction

Answer 2

occurs in stroma
relies on products of light dependent reaction
ATP and reduced NADP
provide energy and hydrogen to produce glucose from carbon dioxide

Question 3

what is the stroma

Answer 3

a fluid matrix in the chloroplast

Question 4

what is the thylakoid

Answer 4

fluid filled sacs

that stack together to form the grana

Question 5

what is the chloroplast envelope

Answer 5

it is a double membrane in the chloroplasts

Question 6

what is a co-enzyme

Answer 6

a molecule that aids the function of an enzyme

Question 7

what is the co-enzyme used in photosynthesis and what does it do

Answer 7

NADP

it transfers hydrogen from one molecule to another

Question 8

what is photophosphorylation

Answer 8

the adding of phosphate to a molecule using light

Question 9

what is photolysis

Answer 9

the splitting of a molecule using light energy

Question 10

what are the products of non-cyclic photophosphorylation

Answer 10

ATP
reduced NADP
oxygen

Question 11

what is the product of cyclic photophosphorylation

Answer 11

ATP

Question 12

what are the 4 stages of non-cyclic photphosphorylation

Answer 12

1. light energy excites the electrons in chlorophyll
2. photolysis of water produces protons electrons and oxygen
3. energy from excited electrons make ATP
4. energy from the excited electrons generates reduced NADP

Question 13

outline light energy exciting electrons in chlorophyll

Answer 13

light energy absorbed by PSII
the light energy excites in chlorophyll
these high energy electrons are released from chlorophyll and are accepted onto the ETC
they move down the ETC to PSI

Question 14

outline photolysis of water produces protons,electrons and oxygen

Answer 14

as excited electrons from chlorophyll leave PSII they must be replaced
light energy splits water into protons, electrons and oxygen this is photolysis

Question 15

outline energy from the excited electrons make ATP

Answer 15

excited electrons lose energy as they move down the ETC
this energy is used to transport protons into the thylakoid so that the thylakoid has higher conc of protons than the stroma
this forms a proton gradient across the thylakoid membrane
protons move down their conc gradient into the stroma via ATP synthase the energy from this movement combines ADP and Pi to form ATP

Question 16

outline energy from the excited electrons generates reduced NADP

Answer 16

light energy absorbed by PSI which excited electrons to even higher energy level
finally the electrons are transferred to NADP along with a proton from the stroma to form reduced NADP

Question 17

outline cyclic photophosphorylation

Answer 17

electrons aren’t passed onto NADP
passed back to PSI via electron carrier
electrons are recylced and can repeaditley flow through PSI
only produces small amounts of ATP

Question 18

what are three factors that affect the rate of photosynthesis

Answer 18

light intensity
temperature
carbon dioxide concentration

Question 19

what are the optimum conditions for photosynthesis

Answer 19

blue light wavelength
carbon dioxide at 0.4%
water
temperatures around 25 degrees celcius

Question 20

what is the saturation point

Answer 20

the point where a factor is no longer limiting the reaction