5.7 Photosynthesis Flashcards
Describer the function of a chloroplast
- Absorbs light for photosynthesis to produce carb/glucose
What kind of membrane structure does a chloroplast have
- Double membrane
- Inner and outer membrane
What is the cytoplasm like structure in the chloroplast and what is its function
- Stroma
- Jelly like matrix which fills the organelles
- Light independant stage occurs here
What is a thylakoid and what is its function
- Membrane disc that contains chlorophyll and stalked particles for atp synthesis
What is a granum
- Stack of thylakoids
What is the intergranal lamallae
- Membranes that connect adjacent granum
Where does the light dependant stage take place
- Thylakoid membrane
What are the products of the light dependant stage >
- Reduced NADP
- ATP
State the difference between the absorption spectrum and the action spectrum
- Absorption shows absorption of light at different wavelengths
- Action shows the rate of PS at each wave length
Where does the light dependent stage take place
Thylakoid membranes in the choloroplast
What are the products of the light dependent reaction
- ATP
- Reduced NADP
Explain the stages in cyclic phosphorylation
1 - Photon of light hits chlorophyll molecule
2 - Causes electrons to become excited
3 - Electrons are taken up by ETC, as electrons move down chain energy is lost which synthesizes ATP
4 - Electrons return back to PS1`
Explain the stages in non cyclic phosphorylation
- Photon of light hit electrons in PSII
- This causes a pair of electrons to get excited
- Electrons are then emitted from the photosystem and taken up by ETC
- ATP is produced
- Photon of light hits PSI and electrons are excited again and taken up by ETC
- Electrons are accepted by NADP to make reduced NADP
- Photolysis occurs to replace the electrons lost in PSII
Explain how oxygen is produced during the light independent reactions of photosynthesis
1 - Energy from light causes photolysis of water
2 - This makes a pair of electrons and oxygen
Describe the structures in a chloroplast which that are involved in the light dependent reaction
1 - Takes place on thylakoid membrane
2 - Which is made of inner membrane
3 - Which contains chlorophyll
What are the products of light independent reactions
- ATP, REDUCED NADP AND OXYGEN
Where does the light independent stage take place
- Occurs in the stroma of chloroplast
State where carbon fixation takes place in the chloroplast
- Stroma
Name the enzyme involved in carbon fixation
- Rubisco
Explain the steps in the light independent stage ( Calvin Cycle )
- 5C molecule (RUBP) turned into a 6C Molecule via addition of a carbon from CO2, this process catalysed by rubsico
- 6C molecule formed, unstable and splits into 2x GP
- GP is reduced via NADP, turning into reduced NADP and ATP is hydrolysed to create energy
- GALP formed, 5 out of 6 carbons will be reused in the cycle however one carbon will be used to make a 6C glucose
Explain how GP, product of carbon fixation can be used to synthesize starch
1 - GP is converted into GALP
2 - Using reduced NADP and ATP
3 - GALP is then converted into glucose
4 - Which is formed by glycosidic bonds
5 - These are 1-4 and 1-6 glycosidic bonds
Explain why the rate of carbox fixation increases at higher temperatures
- High temperatures causer particles to have greater kinetic energy
- This leads to higher enzyme substrate complexes being made
Explain the affect of co2 conc on the production of RUBP
- As CO2 decreases, RUBP increases intially
- This is because less carbon is being fixed to RUBP
- RUBP increases because it is being regenerated
- Decreases as it is being used to fix to co2
What are the limiting factors of photosynthesis
- Light intensity
- Temperature
- CO2 conc
How does light intensity affect the rate of photosynthesis
- Low levels of light will reduce the amount of reduced NADP and ATP produced in the light independent stage
How does CO2 CONC affect the rate of photosynthesis
- Lack of CO2 will mean there is less conversion of RUBP into GP into GALP (less carbon fixation)
How does temperature affect the rate of photosynthesis
- High temperatures causer particles to have greater kinetic energy
- This leads to higher enzyme substrate complexes being made
- However temperatures above the optimum , enzymes will denature
