Photosynthesis Flashcards
What are the two stages of photosynthesis
Light dependent stage and Light independent stage
What is the process of cyclic photophosphorylation in LDS
- Photon of light hits PS1 and 2e- become excited
- 2e- are passed along electron carrier chain
- Small amounts of ATP are made by phosphorylation by chemiosmosis
- Electrons passed back to PS1
What is the process of non-cyclic photophosphorylation in LDS
- Photolysis of water make 2H+ + 1/2 O2
- Photon of light hits excited and leave Chlorophyll A
- The 2e- pass along a chain of electron carriers and ATP is made by photophosphorylation
- Light has also struck PSI and 2e- are lost
- These 2e- join with 2H+ and NADP to become reduced NADP in the presence of NADP reductase
- 2e- from PSII replace those lost from PSI
- 2e- from water go to PSII
- ATP made from chemiosmosis - helped by H+
9/ 1/2 O2 released
What photosystems is involved in which part of LDS
In cyclic - PSI
Non cyclic - PSI and PSII
Where is photolysis involved in LDS
Non-cyclic
What happens to the electrons in Cyclic photophosphorylation
Returns to PSI after going through the electron carrier system
What happens to the electrons in non-cyclic photophosphorylation
Join H+ to make NADPH2
Products of Cyclic photophosphorylation
ATP
Products of non-cyclic photophosphorylation
1/2 O2
Reduced NADP
Where does the Light Independent stage take place
Stroma
How is CO2 absorbed for LIS
Absorbed by spongy mesophyll then passed along to palisade
Stages of the Calvin Cycle/LIS
CO2 diffuses into stroma
Co3 combines with RuBP(5C) - catalysed by Rubisco to form an unstable 6C
Unstable 6C breaks down into 2xGP
2GP is reduced to 2TP (3C)using ATP and reduced NADP
5 of the 6Cs in 2TP are recycled to form RuBP using ATP
How many times is the Calvin cycle repeat to form 1 hexose sugar
6
What molecules can be made from 2TP
Hexose sugars: Glucose, fructose
Sucrose
Starch
Cellulose
Glycerol
What molecules can be made from 2 GP
Amino acids
Fatty acids
Lipids
What are the limiting factors of Photosynthesis
CO2 conc
Light intensity
Temperature
What is an accessory pigment
A light harvesting cluster of photosynthetic pigment
What is the Endosymbiotic theory
The theory that mitochondria and chloroplasts were once aerobic bacteria that were ingested by early eukaryote cells
What are the parts of the chloroplast
Lamellae
Thylakoids
Intermembrane space
Granum
Intergranal lamellae
Stroma
DNA Loop
Ribosome
What are primary pigments
the reaction centres where electrons are excited
What is the absorption peak of photosystem I
P700nm
what is the absorption peak of photosystem II
P680nm
How is thin layer chromatography used in identifying photosynthetic pigments
Dots of pigments are added to the bottom of the TLC plate above solvent
Mobile phase (solvent) moves through stationary phase (silica) and carries components of the mixture
Different components travel at different rates
Find retention factor of components and compare it against a database to identify factors
what is the effect of increasing light intensity
Excites more electrons
Splits more water
opens stomata
More reduced NADP and ATP
