Photosynthesis Overview

Flashcards covering key concepts of photosynthesis including its stages, processes, and important molecules.

What is the main function a of photosynthesis?

To convert light energy into chemical energy in the form of glucose.

Where does photosynthesis occur in plant cells?

In chloroplasts.

What are the two main stages of photosynthesis?

Light-dependent reactions and Light-independent reactions (Calvin Cycle).

What is produced during the light-dependent reactions?

ATP and NADPH.

What is photolysis?

The process in which water is broken down by light in the thylakoid membrane.

What waste product is generated during photolysis?

Oxygen.

What happens to excited electrons in Photosystem II (PSII)?

They are transferred to an electron transport chain.

What is the role of ATP synthase in photosynthesis?

It synthesizes ATP from ADP and inorganic phosphate (P) as protons flow back into the stroma.

What is created by the proton gradient during light-dependent reactions?

ATP, through chemiosmosis.

What is the process of combining re-energized electrons and H+ with NADP+ called?

Reduction, forming NADPH.

What is the significance of NADP+ in photosynthesis?

It is an electron acceptor that becomes reduced to NADPH.

What occurs during the carbon fixation stage of the Calvin Cycle?

RuBisCO enzyme attaches CO2 to RuBP to form an unstable 6-carbon compound.

How many turns of the Calvin Cycle are needed to produce one glucose molecule?

Six turns.

What does RuBisCO stand for?

Ribulose-1,5-bisphosphate carboxylase/oxygenase.

What are PGAL molecules?

Glyceraldehyde 3-phosphate, which is the first true product of photosynthesis.

What is the main purpose of light-independent reactions?

To convert energy stored in ATP and NADPH into glucose.

What are the three stages of the Calvin Cycle?

Carbon fixation, Reduction, and Regeneration.

What is created when an electron acceptor gains electrons?

A reduced molecule.

What do chlorophyll and carotenoid pigments do?

They absorb light to facilitate photosynthesis.

What is a photosystem?

A cluster of pigments in the thylakoid membrane that absorbs light energy.

What is a redox reaction?

A reaction that involves the transfer of electrons between molecules.

What is the main energy currency made during the light-dependent reactions?

ATP (adenosine triphosphate).

Where does the Calvin Cycle take place within the chloroplast?

In the stroma.

What compounds are created from the light-dependent reactions?

ATP and NADPH are produced, and oxygen is released as waste.

What does LEO the lion says GER stand for?

LEO (Lose Electrons = Oxidation) and GER (Gain Electrons = Reduction).

What is the role of electron transport chain (ETC) in photosynthesis?

To transfer high-energy electrons from PSII to PSI and to contribute to proton transport.

What happens to the electrons lost from Photosystem I?

They are replaced by electrons from Photosystem II.

What is the function of H+ ions in photosynthesis?

They create a proton gradient that is used to synthesize ATP.

What is absorbance spectrum in relation to pigments?

It refers to the specific wavelengths of light absorbed by pigments during photosynthesis.

What is the main goal of reduction phase in the Calvin Cycle?

To convert PGA into PGAL using energy from ATP and NADPH.

What component is essential for the regeneration stage of the Calvin Cycle?

RuBP (Ribulose-1,5-bisphosphate).

What does NADPH provide for the Calvin Cycle?

Reducing power needed to convert PGA into PGAL.

What does the breakdown of water supply during photosynthesis?

Electrons, protons, and oxygen.

What is the final product of the Calvin Cycle?

Glucose, which serves as an energy storage molecule.

How does light energy contribute to photosynthesis?

It excites electrons in pigments, initiating the electron transport chain.