Photosynthesis Flashcards
What is the main function of photosynthesis?
Producing carbohydrates
Sunlight is what type of energy?
Electromagnetic
All the energy from sun is used during photosynthesis.
False. 60% is out of the visible range and unavailable for plants to use. The rest of it is lost to other processes such as photorespiration.
Where are Chloroplasts located?
Mesophylls
Where will the light dependent and dark reactions occur in the chloroplast?
Light dependent will happen in the thykaloid lumen and dark reactions (Calvin Cycle) will happen in the stroma
What is the photosynthesis equation?
6CO2 + 6H2O + light → C6H12O6 + 6O2.
Cite the processes involved in the light dependent reaction, in order:
Photosystem II Electron Transport Chain I Photosystem I Electron Transport Chain II ATP synthesis
What is the role of the light dependent reaction?
To generate chemical energy from light and water
Cite the order of events responsible for charging NADP:
Light - H2O oxidation - PSII - Pq - Cy - Pc - Light - PSI - Fe - NADP reductase
What is the electron energy being used for during the light dependent reaction?
To create a proton gradient in the thykaloid lumen; it is pumping protons into the cell
What is the main difference between PSI and PSII?
PSI is about charging NADP+ and PSII is about creating a proton gradient
What is ATP synthase’s main function?
It phosphorylates ADP, trapping the energy in there, creating ATP
What will cause the protons to flow through ATP synthase?
The proton gradient
What is the Calvin Cycle main function?
To create 3-carbon sugars from carbon dioxide and ATP/NADPH
What are the steps for the Calvin Cycle?
Carbon fixation (carboxylation), reduction of 3-PGA to G3P, regeneration of CO2 acceptor (RUBP)
What is the carboxylation (carbon fixation) phase?
It is where 3 molecules of CO2 are bound to RuBP (ribulose biphosphate) with the help of Rubisco
What is the reduction phase?
In the reduction phase we transform the compound created during carboxylation into glyceraldehyde-3-phosphate (G3P), which is the basic sugar.
What happens in the regeneration phase?
Some of the G3P created is used to regenerate RuBP in order to keep the cycle happening.
What is photorespiration?
It is when Rubisco accidentally accepts oxygen to RuBP instead of carbon dioxide.
Suppose you discovered a mutant strain of spinach in which the thykaloid membranes were slightly permeable to protons and thus allowed a slow leakage of protons. How would this leakage affect the yield of ATP and/or NADPH from the light dependent reactions?
ATP yield would decrease
Which is the role of Rubisco in the Calvin Cycle?
To incorporate CO2 from the atmosphere into an organic molecule.
What is another vital function of Cytochrome b6f?
It couples the transport of electrons with the pumping of protons from the stroma into the thylakoid lumen
What is the energy in NADPH and ATP being used for during the light independent cycle?
To assemble carbohydrates in the stroma
