Photosynthesis and Eukaryotic Cells Quiz

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What is the role of Photosystem II in the light reactions of photosynthesis?

Donates high energy electrons to an electron transport chain (ETC).

Which high energy electron carrier is reduced by PQ in the thylakoid membrane?

Cytochrome complex.

What is the final step in the electron transport chain in the light reactions?

Reducing PC.

What is the function of Photosystem I in the light reactions of photosynthesis?

Accepts low energy electrons from PC and re-excites them. Signup and view all the answers

Which enzyme is responsible for reducing NADP+ to produce NADPH in photosynthesis?

NADP+ reductase. Signup and view all the answers

What is the role of feridoxin (FD) in the light reactions of photosynthesis?

Delivers high energy electrons to NADP+ reductase. Signup and view all the answers

Describe the movement of electrons through the components of the light reactions, and relate these steps to the energy levels of the electrons.

The electrons released during photolysis are initially at a low energy level. They are then energized by the Photosystem II (PSII) complex, which uses light energy to excite the electrons to a higher energy state. These high-energy electrons are then passed through the electron transport chain, which includes the cytochrome complex and Photosystem I (PSI). As the electrons move through these components, they lose energy in a stepwise manner, ultimately reaching a lower energy state. The energy released during this process is used to pump protons (H+) across the thylakoid membrane, creating a proton gradient that drives ATP synthesis. Signup and view all the answers

Explain the role of photolysis in the light reactions of photosynthesis and its significance.

Photolysis refers to the splitting of water molecules by the Photosystem II (PSII) complex during the light reactions. This process releases electrons, hydrogen ions (H+), and oxygen gas as by-products. The release of electrons is crucial as it initiates the electron transport chain, which ultimately drives the synthesis of ATP and NADPH. The oxygen gas released is a by-product of photosynthesis. Signup and view all the answers

Explain how ATP is synthesized during the light reactions of photosynthesis.

The proton gradient created by the movement of electrons through the electron transport chain is used to power the enzyme ATP synthase. As protons flow down their concentration gradient from the thylakoid lumen to the stroma, ATP synthase uses this energy to phosphorylate ADP, producing ATP. This process is known as photophosphorylation and is the primary mechanism for ATP synthesis during the light reactions of photosynthesis. Signup and view all the answers

Name and describe the major function of each phase of the Calvin Cycle.

The Calvin Cycle consists of three major phases: 1) Carbon fixation phase: In this phase, CO2 is covalently bonded to the 5-carbon molecule ribulose-1,5-bisphosphate (RuBP) by the enzyme Rubisco, generating two 3-carbon organic molecules. 2) Reduction phase: The 3-carbon molecules are reduced to form glyceraldehyde-3-phosphate (G3P) using the energy and reducing power from ATP and NADPH, respectively, generated in the light reactions. 3) Regeneration phase: Some G3P molecules are used to regenerate RuBP for the next cycle, while the remaining G3P molecules are exported for the synthesis of other organic compounds. Signup and view all the answers

Define the products of the light reactions and explain what they will be used for in subsequent processes.

The main products of the light reactions are ATP and NADPH. ATP is a high-energy molecule that provides the energy required for various cellular processes, including the Calvin cycle in photosynthesis. NADPH is a reducing agent that provides the electrons needed for the reduction of carbon dioxide (CO2) to organic compounds during the Calvin cycle. Signup and view all the answers

Explain how the G3P produced during photosynthesis is utilized for the synthesis of other organic molecules, and provide examples of these molecules.

The glyceraldehyde-3-phosphate (G3P) produced during the Calvin Cycle can be used as a precursor for the synthesis of various organic molecules. Some examples include: 1) Fatty acids: G3P can be converted into pyruvate, which can then enter the citric acid cycle to produce acetyl-CoA, a precursor for fatty acid synthesis. 2) Amino acids: G3P can be converted into 3-phosphoglycerate, which can then enter the glycolytic pathway and eventually lead to the production of various amino acids. 3) Nucleic acids: G3P can be converted into ribose-5-phosphate, which is a precursor for the synthesis of nucleotides and, subsequently, nucleic acids like DNA and RNA. Signup and view all the answers

What is the primary function of the electron transport chain in the light reactions of photosynthesis?

To generate a proton gradient across the thylakoid membrane (D) Signup and view all the answers

Which of the following is the correct sequence of electron flow through the components of the light reactions?

Photosystem II -> PQ -> Cytochrome complex -> PC -> Photosystem I -> FD -> NADP+ reductase (C) Signup and view all the answers

What is the role of Photosystem I in the light reactions of photosynthesis?

To reduce NADP+ to NADPH (B) Signup and view all the answers

What is the function of the cytochrome complex in the light reactions of photosynthesis?

To pump hydrogen ions across the thylakoid membrane (A) Signup and view all the answers

What is the role of plastocyanin (PC) in the light reactions of photosynthesis?

To accept electrons from the cytochrome complex and transfer them to Photosystem I (A) Signup and view all the answers

What is the role of ferredoxin (FD) in the light reactions of photosynthesis?

To transfer electrons from Photosystem I to NADP+ reductase (A) Signup and view all the answers

What is the primary function of the thylakoid membrane in the light reactions of photosynthesis?

To synthesize ATP through the process of chemiosmosis (A) Signup and view all the answers

What is the role of NADP+ reductase in the light reactions of photosynthesis?

To reduce NADP+ to NADPH (A) Signup and view all the answers

What is the primary role of the stroma in the light reactions of photosynthesis?

To provide the enzymes and substrates for the Calvin cycle (A) Signup and view all the answers

What process results in the formation of ATP in the stroma during photosynthesis?

Photophosphorylation (C) Signup and view all the answers

In photosynthesis, what is covalently bonded to the 5C molecule RuBP by the enzyme Rubisco?

CO2 (C) Signup and view all the answers

What is the product of the reduction phase in photosynthesis?

G3P (B) Signup and view all the answers

What is the role of electrons obtained through water splitting in photosynthesis?

Resupply PSII (B) Signup and view all the answers

Which molecule is exported after one cycle of the Calvin Cycle?

G3P (C) Signup and view all the answers

What is the primary function of G3P produced during photosynthesis?

Make other organic molecules (B) Signup and view all the answers

During photosynthesis, what is not required for the process but is a by-product?

Oxygen (B) Signup and view all the answers

Which enzyme is responsible for fixing CO2 by bonding it to RuBP during photosynthesis?

Rubisco (D) Signup and view all the answers

What is the initial electron donor in the light reactions of photosynthesis?

Photosystem II (B) Signup and view all the answers

Which component is responsible for pumping hydrogen ions into the thylakoid lumen during the light reactions?

Cytochrome complex (B) Signup and view all the answers

What is the primary function of Photosystem I in the light reactions of photosynthesis?

Reducing ferredoxin (D) Signup and view all the answers

Which molecule serves as the final electron acceptor in the light reactions of photosynthesis?

NADP+ (C) Signup and view all the answers

What is the role of PQ in the thylakoid membrane during photosynthesis?

Donating high energy electrons (D) Signup and view all the answers

During photosynthesis, what does NADP+ reductase do?

Reduces ferredoxin back to high energy level (A) Signup and view all the answers

What is the primary role of plastocyanin (PC) in the light reactions of photosynthesis?

Donating high energy electrons to Photosystem I (D) Signup and view all the answers

What is the primary function of the electron transport chain in the light reactions of photosynthesis?

To generate a proton gradient that powers ATP synthase (D) Signup and view all the answers

Which enzyme is responsible for covalently bonding CO2 to the 5C molecule RuBP during the Calvin Cycle?

Rubisco (B) Signup and view all the answers

What is the primary role of photolysis in the light reactions of photosynthesis?

To split water molecules and release electrons, protons, and oxygen (B) Signup and view all the answers

What is the primary function of the G3P (glyceraldehyde-3-phosphate) produced during the Calvin Cycle?

To be exported out of the chloroplast for use in other metabolic processes (C) Signup and view all the answers

Which of the following is the correct sequence of electron flow through the components of the light reactions?

PSII -> PQ -> Cyt b6f -> PC -> PSI -> FD -> NADP+ reductase (B), PSII -> PQ -> Cyt b6f -> PC -> PSI -> FD -> NADP+ reductase (D) Signup and view all the answers

What is the role of NADP+ reductase in the light reactions of photosynthesis?

To reduce NADP+ to NADPH using electrons from the electron transport chain (C) Signup and view all the answers

Which molecule is exported from the chloroplast after one cycle of the Calvin Cycle?

G3P (D) Signup and view all the answers

What is the primary function of the thylakoid membrane in the light reactions of photosynthesis?

To generate a proton gradient that powers ATP synthase (B) Signup and view all the answers

What is the role of plastocyanin (PC) in the light reactions of photosynthesis?

To transfer electrons from Photosystem II to the cytochrome b6f complex (C) Signup and view all the answers

What is the primary function of Photosystem I in the light reactions of photosynthesis?

To reduce NADP+ to NADPH using high-energy electrons from the electron transport chain (B) Signup and view all the answers

Photosynthesis and Eukaryotic Cells Quiz

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Questions and Answers

What is the role of Photosystem II in the light reactions of photosynthesis?

Which high energy electron carrier is reduced by PQ in the thylakoid membrane?

What is the final step in the electron transport chain in the light reactions?

What is the function of Photosystem I in the light reactions of photosynthesis?

Which enzyme is responsible for reducing NADP+ to produce NADPH in photosynthesis?

What is the role of feridoxin (FD) in the light reactions of photosynthesis?

Describe the movement of electrons through the components of the light reactions, and relate these steps to the energy levels of the electrons.

Explain the role of photolysis in the light reactions of photosynthesis and its significance.

Explain how ATP is synthesized during the light reactions of photosynthesis.

Name and describe the major function of each phase of the Calvin Cycle.

Define the products of the light reactions and explain what they will be used for in subsequent processes.

Explain how the G3P produced during photosynthesis is utilized for the synthesis of other organic molecules, and provide examples of these molecules.

What is the primary function of the electron transport chain in the light reactions of photosynthesis?

Which of the following is the correct sequence of electron flow through the components of the light reactions?

What is the role of Photosystem I in the light reactions of photosynthesis?

What is the function of the cytochrome complex in the light reactions of photosynthesis?

What is the role of plastocyanin (PC) in the light reactions of photosynthesis?

What is the role of ferredoxin (FD) in the light reactions of photosynthesis?

What is the primary function of the thylakoid membrane in the light reactions of photosynthesis?

What is the role of NADP+ reductase in the light reactions of photosynthesis?

What is the primary role of the stroma in the light reactions of photosynthesis?

What process results in the formation of ATP in the stroma during photosynthesis?

In photosynthesis, what is covalently bonded to the 5C molecule RuBP by the enzyme Rubisco?

What is the product of the reduction phase in photosynthesis?

What is the role of electrons obtained through water splitting in photosynthesis?

Which molecule is exported after one cycle of the Calvin Cycle?

What is the primary function of G3P produced during photosynthesis?

During photosynthesis, what is not required for the process but is a by-product?

Which enzyme is responsible for fixing CO2 by bonding it to RuBP during photosynthesis?

What is the initial electron donor in the light reactions of photosynthesis?

Which component is responsible for pumping hydrogen ions into the thylakoid lumen during the light reactions?

What is the primary function of Photosystem I in the light reactions of photosynthesis?

Which molecule serves as the final electron acceptor in the light reactions of photosynthesis?

What is the role of PQ in the thylakoid membrane during photosynthesis?

During photosynthesis, what does NADP+ reductase do?

What is the primary role of plastocyanin (PC) in the light reactions of photosynthesis?

What is the primary function of the electron transport chain in the light reactions of photosynthesis?

Which enzyme is responsible for covalently bonding CO2 to the 5C molecule RuBP during the Calvin Cycle?

What is the primary role of photolysis in the light reactions of photosynthesis?

What is the primary function of the G3P (glyceraldehyde-3-phosphate) produced during the Calvin Cycle?

Which of the following is the correct sequence of electron flow through the components of the light reactions?

What is the role of NADP+ reductase in the light reactions of photosynthesis?

Which molecule is exported from the chloroplast after one cycle of the Calvin Cycle?

What is the primary function of the thylakoid membrane in the light reactions of photosynthesis?

What is the role of plastocyanin (PC) in the light reactions of photosynthesis?

What is the primary function of Photosystem I in the light reactions of photosynthesis?

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