Photosynthesis Flashcards
What is the overall equation for photosynthesis?
The overall equation for photosynthesis is: [ 6CO_2 + 6H_2O \xrightarrow{light} C_6H_{12}O_6 + 6O_2 ] (Carbon dioxide + water → glucose + oxygen).
What are the two stages of photosynthesis?
The two stages of photosynthesis are the light-dependent reaction and the light-independent reaction (Calvin cycle).
Where do the light-dependent and light-independent reactions occur?
The light-dependent reactions take place in the thylakoid membranes of the chloroplasts, while the light-independent reactions occur in the stroma.
What is the role of chlorophyll in photosynthesis?
Chlorophyll absorbs light energy, mainly in the blue and red regions of the light spectrum, and converts it into chemical energy.
What is photolysis?
Photolysis is the splitting of water molecules using light energy during the light-dependent reactions, producing oxygen, protons (H+), and electrons.
What is the role of NADP in photosynthesis?
NADP (nicotinamide adenine dinucleotide phosphate) acts as an electron carrier, accepting electrons and protons to form NADPH, which is used in the Calvin cycle.
What is ATP synthesis in the light-dependent reaction?
ATP is synthesized from ADP and inorganic phosphate (Pi) by ATP synthase, using energy from the flow of protons (H+) through the enzyme, a process called photophosphorylation.
What happens during the Calvin cycle?
In the Calvin cycle, carbon dioxide is fixed into an organic molecule (RuBP), and through a series of reactions, glucose is synthesized. The cycle involves ATP and NADPH.
What is RuBP, and what is its role in the Calvin cycle?
RuBP (ribulose bisphosphate) is a 5-carbon molecule that combines with CO2 in the Calvin cycle to form two molecules of 3-phosphoglycerate (3-PGA).
What is the role of the enzyme Rubisco in photosynthesis?
Rubisco (ribulose bisphosphate carboxylase/oxygenase) catalyzes the reaction between RuBP and CO2 in the Calvin cycle, facilitating carbon fixation.
What is the importance of the proton gradient in the light-dependent reaction?
The proton gradient (across the thylakoid membrane) is used to power ATP synthase to produce ATP during chemiosmosis in the light-dependent reactions.
What is the function of the thylakoid membrane in photosynthesis?
The thylakoid membrane hosts the photosystems and ATP synthase, where light energy is captured and used to produce ATP and NADPH.
What are the products of the light-dependent reaction?
The light-dependent reaction produces oxygen (from photolysis), ATP (for energy), and NADPH (for reducing power) used in the Calvin cycle.
How does light intensity affect the rate of photosynthesis?
As light intensity increases, the rate of photosynthesis increases, up to a certain point. Beyond that point, the rate levels off due to other limiting factors.
How does carbon dioxide concentration affect the rate of photosynthesis?
An increase in CO2 concentration increases the rate of photosynthesis, as more carbon is available for fixation in the Calvin cycle.
How does temperature affect the rate of photosynthesis?
Temperature affects enzyme activity; as the temperature rises, the rate of photosynthesis increases up to a point. After that, the enzymes denature, and the rate decreases.
What is the role of water in photosynthesis?
Water is the source of electrons and protons in the light-dependent reactions, and its splitting during photolysis releases oxygen as a by-product.
What are the two types of phosphorylation in photosynthesis?
The two types of phosphorylation are cyclic and non-cyclic photophosphorylation. In non-cyclic, both ATP and NADPH are produced, while in cyclic, only ATP is produced.
What is the importance of the electron transport chain in photosynthesis?
The electron transport chain transfers electrons from photosystem II to photosystem I, driving the proton pump, which creates the proton gradient for ATP synthesis.
What are the factors that limit the rate of photosynthesis?
Factors include light intensity, carbon dioxide concentration, temperature, and the availability of water.
