TOPIC 8.3 PHOTOSYNTHESIS

Question 1

Where does the light dependent reaction occur

Answer 1

In the thylakoid membrane

Question 2

Where does the light independent reaction occur

Answer 2

In the stroma

Question 3

Light dependent reaction- what triggers the release of high energy electrons

Answer 3

Chlorophyll in the Photosystems 1 and 2 absorb light which triggers the release of high energy electrons

Question 4

Light dependent reaction- Production of ATP via electron transport chain

Answer 4

Excited electrons from Photosystem 2 transferred between carrier molecules in electron transport chain

Electron transport chain translocate H+ ions from stroma to thylakoid

Protons return back to stroma via ATP synthase. Stroma synthesizes ATP

Question 5

Light Dependent reaction- Reduction of NADP+ and photolysis of water

Answer 5

Excited electrons from Photosystem 1 reduce NADP+ to form NADPH

Electrons from Photosystem 1 replaced by de-energized electrons from Photosystem 2
Electrons from Photosystem 2 replaced by photolysis of water

PRODUCTS (ATP AND NADPH) USED IN LIGHT INDEPENDANT REACTION

Question 6

Light independent reaction- Carbon Fixation

Answer 6

Ribulose bisphosphate is carboxylate by CO2 to form hexose bisphosphate compound

The hexose bisphosphate compounds breaks down into glycerate-3-phosphate

Question 7

Light independent reaction- Reduction of glycerate phosphate

Answer 7

Glycerate-3-phosphate is converted by ATP and NADPH into triose phosphate

Question 8

Light independent reaction- Regeneration of Ribulose Bisphosphate

Answer 8

Triose phosphate can be used to form organic molecules or recombined with ATP to reform RuBP

Question 9

Definition of Photophosphorylation

Answer 9

Reaction using light as an energy source

Question 10

Cyclic Photophosphorylation

Answer 10

Only Photosystem 1 is used (de energized electrons go back to photosystem)
Water isn’t required for photolysis
NADPH isn’t synthesized
Produces additional ATP to meet cell energy demand

Question 11

Non-Cyclic Photophosphorylation

Answer 11

Photosystem 1 and 2 used
Photolysis of water is required to replace photosystem 2 electrons
NADPH is synthesized
Products used for light independent reaction

Question 12

What do chloroplast do

Answer 12

Chloroplast convert light energy into chemical energy such as ATP or organic compunds

Question 13

DRAW THE STRUCTURE OF A CHLOROPLAST

Question 14

Lollipop experiment for Calvin Cycle

Answer 14

1) Radioactive Carbon 14 added to Green Algae
2) Light shone on Apparatus to induce photosynthesis
3)After different times algae run in heated alcohol
4)Samples of dead algae analyzed for radioactive samples
5) Different periods of light exposure allowed for the order of carbon compund generation to be determined