Photosynthesis Flashcards
What is photosynthesis
Process of which plants derive complex molecules eg glucose from light energy
What is an autotroph
An organism that has photosynthesis
What is a heterotroph
An organism that derives complex molecules from eating other organism
What is the fromula for photosynthesis
6CO2 + 6H20 -> C6H12O6 + 6O2
Photosynthesis facts about chloroplasts
-Location of photosynthesis
- Network of membranes for high SA:VOL
- thylakoids(flattened sacs of membranes) stack together to make a granum
- granum joined together membrane channels called lamellae
- light absorbed by pigments in thylakoids (eg cholorphyll a/b which absorb higher WL of light)
-Fluid called stroma where most of the chemical reactions occur
Double membrane
4 main pigments and what do they do
Chlorophyll A/B, cartenoids and xanthophyll which all absorb different WL of light(light harvesting) then transfer photons to reaction centres(Photosystems)
What does non cyclical phosphorylation produce
Photons used to produce ATP an NADPH
What does Calvin cycle produce
Organic molecules like glucoseN
What is non cyclical phosphorylation
PSI absorbs light at a higher WL than PSII (700nm) to (680nm). The photon then excites an eletron at the reaction centre of the photosystems.
Excited electron of PSII is then passed across the ETC which produced ATP via chemiosmosis
What is then broken down to replace the lost electrons by photolysis
Excited electrons in PSI passed down the ETC producing ATP lost electrons are replaced by electrons from PSII. Electrons from ETC of PSI are accepted with a hydrogen by NADP to form NADPH which is used in calvin cycle
Photolysis
Water molecules split into 2h+ 1/2 O2 and 2e-
electrons replace PSII
Oxygen evolving complex catalyses the photolysis of water
O2 is a byproduct of reaction
H+ ions released into lumen of thylakoids to increase H+ ions for ATP production/ bind to NADP to make NADPH
cyclic phosphorylation
When electrons from PSI go across ETC then return to PSI meaning ATP can be made continously without electrons from PSII
Calvin cycle
CO2 and RuBP molecule bind together with the enzyme Rubisco to make an unstable hexose molecule(carbon fixation) which then breaks down into GP. GP is then reduced by NADP with energy from ATP to produce TP which is a carbohydrate that can be used to make organic molecules. 6 turns of the calvin cycle produce 1 molecule of glucose
Explain pigments in chloroplasts
Photosynthetic pigments are coloured substances that absorb light energy, the pigments are found in the thylakoid membranes attached to proteins together called (photosystem). Primary pigments where electrons are excited and accessory pigments make up light harvesting system that transfer light energy to reaction centres
What is chromatography
Used to seperate different pigments in plants based on solubility. Mobile phase mixture of pigments and stationary phase is thin layer of silica gel. Pigments interact with stationary phase based on solubility causing them to move at different rates.
RF value
RF = Distance moved by component/ distance moved by solvent
