Photosynthesis Flashcards
Excitation of energy by light
The process where light energy is absorbed by pigments, causing electrons to move from their ground state to an excited state.
Deactivation of excited state
The return of excited electrons to their ground state, releasing excess energy as heat or light (photoluminescence), which includes fluorescence and phosphorescence.
Linear Electron Flow vs Cyclic Electron Flow
Linear electron flow involves both PSII and PSI and produces ATP and NADPH. Cyclic electron flow involves only PSI and produces ATP but not NADPH.
What is an “electron flow”?
A pathway for movement of electrons during photosynthesis
Light harvesting
The process where pigments in photosystems capture light energy
Photochemical reaction
A reaction in which absorbed light energy drives the water-splitting reaction in PSII, releasing oxygen, electrons, and protons.
Electron transport
The movement of electrons through a series of protein complexes, creating a flow of electrons and protons.
Meaning of ATP
Adenosine triphosphate
Name the three electron carriers involved in Light Dependent Reactions.
Plastoquinone, Plastocyanin, Ferredoxin
The complex between PS II and PS I
Cytochrome b6-f Complex
What Other Living Organisms are Capable of Photosynthesis?
Cyanobacteria
Location of Light-dependent reactions and the Calvin Cycle
In the Thylakoid membrane, In the Stroma of the chloroplast
What Reactions Occur During Photosynthesis
Absorption of light energy by chlorophyll, the splitting of water molecules, the production of ATP and NADPH, and the fixation of CO2 to form glucose
Chemical equation of Photosysnthesis
6CO2 + 6H20 –(Chlorophyll & Sunlight)—–> C6H12O6 + 6O2
Alternative name for the Calvin Cycle
Photosynthetic Carbon Reactions
What is the role of Carotene?
Carotene absorbs green light which chlorophyll cannot. It also has strong antioxidant properties and can dissipate excess energy as heat.
Why are C3 plants most popular?
C3 plants are common due to their adaptability to diverse habitats and the trade-off between efficiency and energy investment.
What is the CO2 acceptor?
RuBP (1-Ribulose, 5-biphosphate)
How many CO2, ATP and NADPH are needed to make one glucose molecule?
6 CO2 molecules, 18 ATP molecules, and 12 NADPH molecules are needed
What is the enzyme that catalyzes the reaction?
RuBisCO
What are the 3 phases of the C3 pathway?
Carbon fixation, reduction of PGA to G3P, and regeneration of RuBP
What is the first stable product of the C3 pathway?
3-phosphoglycerate (3-PGA)
What is the product of the C3 pathway?
glyceraldehyde-3-phosphate (G3P)
What is the role of Rubisco?
It is an enzyme responsible for both carbon and oxygen fixation.
What is the function of Photorespiration?
It is considered wasteful as it consumes energy and reduces the efficiency of photosynthesis. It possibly prevents damage from reactive oxygen species and preserves redox balance.
Advantages of C4 Pathway
Reduces photorespiration and increased efficiency of carbon fixation. C4 plants thrive in specific hot and arid environments.
Advantages of CAM plants
They are adapted to arid environments where water is scarce, they open stomata at night to take in CO2 and release it in the day -great at conserving water.
Meaning of CAM
Crassulacean acid metabolism
Light Saturation Point
The light saturation point is the maximum light intensity at which photosynthesis reaches its peak rate.
Carbon Dioxide compensation point
The CO2 concentration at which photosynthesis equals respiration, resulting in no net change in CO2 levels.
Water
Hydrolysis
Temperature
Photosynthesis increases with temperature up to a point (around 30-35°C), then declines due to enzyme denaturation.
Nutrients
Nitrogen, Magnesium, Calcium, Iron
