Photosynthesis Flashcards
2 uses of ATP in cells
1.Phosphorylation by binding to enzyme and making them more reactive
2.Provides energy for active transport
Why is ATP useful ?
- Release energy instantaneously in small packs so less heat loss
- Can be easily resynthsisesd in one step
- Phosphorylates compounds making them more reactive
- Large so doesn’t diffuse out the cell
- Can be easily reformed
uses of NADP
- Essential molecule which acts as a hydrogen acceptor becoming reduced NADPH
- NADPH is a reducing agent which means it can donate hydrogen molecules during redox reactions
4.NADPH is a coenzyme which means it can aid the function of an enzyme
OILRIG
Oxidation loss of electrons / hydrogen
Reduction gain of electron/ hydrogen
Structure of a chloroplast
Granum = stacks of thylakoid membrane
Thylokoid membrane = contains ATP synthase for ATP production and chrlophyl for photosynthesis
Stroma where photosynthetic reactions occur
Its own 70s ribosomes and DNA
Has starch grains which provide energy
Double membrane
Equation for photosynthesis
Carbon dioxide + water = glucose + oxygen
What is required for the light independent reaction to occur
ATP and NADPH
Name the 2 processes of photosynthesis
Light dependent reaction
Light independent reaction
Where does the light dependent reaction occur
Thylakoid membrane in the Granum
Process of light dependent reaction - photoionisation
Chlorophyll absorbs light energy
This excites the electrons to be higher energy level and electrons leave the chlorophyll. Chlorophyll is now Oxidised.
Electrons passed down the electron transfer chain by a series of redox reaction reactions
Energy released is used to pump protons across the thyroid membrane into the thylokoid forming a proton electrochemical gradient
Process of light dependent reaction- photophosphorylation
- Energy released by the electrons is used to pump protons across the thyroid membrane into the thylokoid forming a
- Protons diffuse down the electrochemical gradient through ATP synthase catalysing condensation reaction forming ATP from ADP and PI
Process of light dependent reaction- photolysis
- Light split water into two hydrogen molecules, two electrons and half a oxygen molecule
- Electrons replace electrons in chlorophyll and become reduced
- The H+ and an associated electron (e-) are used to reduce a hydrogen carrier NADP to form NADPH.
4.Oxygen is expired out as a useful waste product
Occurs in the dial cord space
Why does the light independent reaction occur?
Stroma
Suggest why respiration and photosynthesis are used in plants
- Plants do photosynthesis in the dark.
- Not all parts of the plant photosynthesise
- Plants require more ATP than is produced in the light dependent reaction
- ATP is used in active transport
Describe the effect of introducing a herbicide on the electron transport chain ?
Reduce transfer of protons across the thylakoid membrane.
so less ATP produced
so less reduced NADP produced
so less light independent reaction
Where does the light independent reaction occur?
In the stroma and requires ATP and NADPH
What are the three stages in the light Independent reaction?
- Carbon fixation.
- Reduction
- Regeneration
Process of the light independent reaction
- The enzyme RuBisCO catalyses carbon dioxide combining with RUBP.
- This forms an unstable molecule which splits into 2GP molecules
- GP is reduced using NADPH to triose phosphate which requires energy from ATP hydrolysis
- Some of the triose phosphate is converted into useful organic compounds
- Most of triose phosphate is used to regenerate RUBP using PI from ATP
What are the factors affecting photosynthesis?
- Carbon dioxide concent.
- Light intensity and wavelength
- Temperature
Commercial glass houses
Glasshouses can be used to grow crops in areas that they would not grow and allow them to be grown all year around with no limiting factors
Such as artificial light may be used to increase light intensity , carbon dioxide levels can be increased by burning fossil fuels or pumping carbon dioxide, heaters can be used to raise the temperature to optimum level
