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Formula for photosynthesis
6 CO2 + 12 H2O + Light Energy --> C6H12O6 + 6 H2O
Molecule that can absorb light energy
What are the two stages of Photosynthesis and where do they take place?
- 1. Light Reactions - occurs in the thylakoid membrane
- 2. Calvin Cycle - occurs in the stroma
Explain Light Reactions and what it produces
- -Light energy is transformed into electrochemical energy, and the energy gets stores in chemical bonds
- - Produces ATP, NADPH, and O2
What does Calvin Cycle do?
Uses ATP and NADPH to incorporate CO2 into Carbohydrates
Define Noncyclic Electron Flow
Electrons from photosystem II follow a pathway along an ETC in the thylakoid membrane. This path generates an H+ chemical gradient that is used to make ATP. In addition, light energy striking PSI boosts electrons to a very high energy level that allows the synthesis of NADPH.
Define Cyclic Electron Flow
Electrons are activated in PSI and flow through the ETC back to PSI. This cyclic electron route produces an H+ gradient that is used to make ATP.
Define Z Scheme
Proposes that an electron absorbs light energy twice at both PSII and PSI, losing some of that energy as it flows along the ETC in the thylakoid membrane.
Explain Photosystem II and it's primary roles
- It is the initial step in photosynthesis
- Primary roles: Oxidize water which generates O2 and H+ / Releases energy in ETC / Energy used to make H+ electrochemical gradient
Explain Photosystem I and it's primary roles
- Primary role is to make NADPH
- Addition of H+ to NADP+ contributes to H+ gradient by depleting H+ from the stroma.
How much energy is required for the Calvin Cycle?
for every 6 CO2 molecules incorporated, 18 ATP and 12 NADPH are used
What are the three phases of the Calvin Cycle?
- Phase 1: Carbon fixation
- Phase 2: Reduction and Carb Production
- Phase 3: Regeneration of RuBP
What is Rubisco
- the enzyme which catalyzes the first step in the Calvin cycle in which CO2 is incorporated into an organic molecule
- Functions as carboxlyase in photorespiration. Can also be oxygenase.
What is PEP Carboxlyase?
An enzyme in C4 plants that adds CO2 to phosphoenolpyruvate (PEP) to produce the four carbon compound exaloacetate.
Difference(s) between C3 plants and C4 plants
- -C4 plants conserve water and prevent photorespiration in warm/dry climates.
- -In cooler climates, C3 plants use less energy to fix CO2
Define Carbon Fixation
A process in which Carbon from inorganic CO2 is incorporated into an organic molecule such as a carbohydrate.