Photosynthesis Flashcards
(8 cards)
explain the structure of chloroplasts
- they have 3 membranes
- outer
- inner
- thylakoid - have 3 compartments
- intermembrane space
- stroma
- thylakoid space
what are the 2 reactions of photosynthesis
- the light reactions occurs in the thylakoid membrane - water is split to give oxygen, and ATP & NADPH is generated
- the Calvin cycle or carbon fixation occurs in the stroma - the ATP & NADPH produced in light reaction are used to fix CO2 and produce carbohydrates
what happens during the first reaction of photosynthesis - part 1
light energy is absorbed
- in the thylakoid membrane there are protein complexes called photosystems that contain chlorophyll
- chlorophyll absorbs light energy
- light energy is passed to electrons and high energy electrons leave the photosystem
what happens during the first reaction of photosynthesis - part 2
- high energy electrons move through the photosynthetic electron transport chain (the protein complexes: photosystem II, cytochrome complex and photosystem I)
- the photosynthetic electron transport chain produces a NADPH, H+ and oxygen gradient
what happens during the first reaction of photosynthesis - part 3
the H+ gradient is used to generate ATP, as the protons move through the ATP synthase the energy is used to generate ATP
what happens during the second reaction of photosynthesis - part 1
fixation
- 3 CO2 molecules are fixed to 3 - 5C molecules and 6-3C low energy molecules are produced
what happens during the second reaction of photosynthesis - part 2
reduction
- the 6 - 3C molecules are converted into a different type of 3C molecules using the energy from the ADP and NADPH as high energy molecules
- one of these 3C molecules are released, and as the cycle happens twice the product will be glucose
what happens during the second reaction of photosynthesis - part 3
regeneration
- ATP is then used to convert the remaining 5 - 3C high energy molecules into 3 -5C molecules, and the whole cycle repeats.
