Photosynthesis Flashcards
Describe the light-dependent
reaction
- Chlorophyll absorbs light energy & Excites electrons
- electrons removed (Oxidation of chlorophyll) via photoionisation;
- Electrons move along carriers/electron transport chain releasing energy (Series of REDOX reactions)
- Energy released (by electrons) used to form proton gradient;
- H+ ions move through ATP synthase;
- providing energy to join ADP and Pi to form ATP;
- Photolysis of water produces 2 protons, 2 electrons and ½ oxygen;
- NADP reduced by electrons / electrons and protons / hydrogen;
Describe the light independent reaction
- Carbon dioxide combines with ribulose bisphosphate/RuBP;
- Produces two glycerate (3-)phosphate/GP;
- GP reduced to triose phosphate;
- Using reduced NADP;
- Using energy from ATP;
- Triose phosphate converted to glucose/hexose/RuBP/ named organic substance;
ATP is produced in the light dependant reaction, suggest why this is not their (plants) only source of ATP.
- Plants don’t photosynthesis in the dark;
- Not all the parts of the plants photosynthesise;
- Plants require more ATP than is produced in the light dependant reaction;
- ATP used in Active Transport (accept other named processes)
Describe the effect of introducing a herbicide/inhibitor on the electron transport chain (4)
- Reduced transfer of protons across thylakoid membrane
OR - Reduced chemiosmotic gradient/proton gradient across thylakoid membrane;
- (So) less ATP produced;
- (So) less reduced NADP produced;
- (So) light-independent reaction slows/stops
OR - Less reduction of GP to triose phosphate;
Describe what happens during photoionisation in the light dependent reaction.
- Chlorophyll absorbs light
OR
Light excites/moves electrons in chlorophyll; - Electron/s are lost
OR
(Chlorophyll) becomes positively charged;
Accept electrons go to electron transport/carrier chain for ‘electrons lost’.
When producing a chromatogram explain why the origin is marked using a pencil rather than ink.
- Ink and (leaf) pigments would mix
OR - (With ink) origin/line in different position
OR - (With pencil) origin/line in same position
OR - (With pencil) origin/line still visible;
While making a chromatogram, describe the method used to separate the pigments after the solution of pigment had been applied to the origin.
- Level of solvent below origin/line;
- Remove/stop before (solvent) reaches top/end;
Suggest and explain the advantage to plants of having different colour pigments in leaves.
- Absorb different/more wavelengths of light for photosynthesis;
Name the two products of the light-dependent reaction that are required for the light-independent reaction
1) ATP
2) Reduced NADP
where precisely is rubisco found in a cell?
Stroma
Explain why scientists measure the rate of production of oxygen in this investigation (rate of photosynthesis)
- Oxygen production in the light-dependent reaction
- the faster (oxygen) is produced, the faster the light-dependent reaction
Explain why plants that have more chlorophyll will grow faster than plants with less chlorophyll
- have faster production of ATP and reduced NADP
- so faster/ more light-independent reaction
- so produce more sugars that can be used in respiration
- so have more energy for growth
- have faster / more synthesis of new organic materials
Explain the relationship between stomatal opening and photosynthesis
- stomata allow uptake of carbon dioxide
- Carbon dioxide used in / required for photosynthesis
ATP is useful because…
- Releases energy in small manageable amounts
- Broken down in one single step
- Immediate energy available
- Phosphorylates other compounds
5.makes more reactive
6.reformed
The light independent reaction involves a series of reactions which is called…
…the Calvin cycle
