Question 1

Which of the following is a source of electrons that plants use for reduction reactions during photosynthesis?

Accepted Answer

Water (H2O) is the source of electrons that plants use for reduction reactions during photosynthesis. When water is split during the light-dependent reactions, electrons are released and then used in the light-independent reactions to reduce carbon dioxide into glucose.

Question 2

The ATP and NADPH synthesized during the light reactions are

Accepted Answer

The ATP and NADPH synthesized during the light reactions of photosynthesis are moved to the stroma of the chloroplast, where they are used in the Calvin cycle to synthesize glucose from carbon dioxide.

Question 3

What is produced in the electron transport system associated with photosystem II?

Accepted Answer

The answer of What is produced in the electron transport...

Question 4

The energy of the movement of electrons down a concentration gradient via electron transport within chloroplasts and mitochondria is used to generate

Accepted Answer

The energy from the movement of electrons down a concentration gradient in both chloroplasts and mitochondria is primarily used to generate ATP through a process known as chemiosmosis.

Question 5

From where does the O2 released during the light reactions of photosynthesis come?

Accepted Answer

The oxygen released during the light reactions of photosynthesis comes from the splitting of water (H2O) molecules, not from carbon dioxide (CO2) or any other source. This process is known as photolysis, where water molecules are split into hydrogen ions, electrons, and oxygen in the presence of light.

Question 6

The role of water in photosynthesis is to

Accepted Answer

Water in photosynthesis is split during the light-dependent reactions, providing electrons that are essential for the electron transport chain, which ultimately leads to the production of ATP and NADPH necessary for the Calvin cycle.

Question 7

The light reactions of photosynthesis result in which of the following?

Accepted Answer

The light reactions of photosynthesis involve the absorption of light by chlorophyll and the use of that energy to produce ATP (and NADPH), which are then used in the Calvin cycle to fix carbon dioxide into sugars.

Question 8

The NADPH required for carbon dioxide fixation during the Calvin cycle is formed

Accepted Answer

NADPH is produced during the light reactions of photosynthesis, where light energy is used to generate ATP and reduce NADP+ to NADPH.

Question 9

Which process of photosynthesis is directly linked to the production of ATP?

Accepted Answer

Photosystem II is directly involved in the photophosphorylation process, where light energy is used to pump protons across the thylakoid membrane, creating a proton gradient that drives ATP synthesis through ATP synthase.

Question 10

Which sequence accurately describes the flow of electrons in photosynthesis?

Accepted Answer

In photosynthesis, electrons flow from water (H2O) to photosystem II, then to photosystem I, and finally to NADP+ to form NADPH. This sequence is part of the light-dependent reactions of photosynthesis.

Question 11

Hydrogen ions cross the thylakoid membranes from the stroma by

Accepted Answer

Hydrogen ions (protons) are transported across the thylakoid membrane from the stroma into the thylakoid lumen by active transport, utilizing energy from light-driven electron transport. This process is essential for the establishment of a proton gradient used in ATP synthesis during photosynthesis.

Question 12

You are carrying out an experiment on several aquatic plants in your fish tank. You decide to expose two of the plants to green light and two to blue light. You want to determine which type of light is best for the light reactions, so to reach your conclusions, you decide to record the amount of oxygen bubbles produced. Which of the following results would be expected?

Accepted Answer

Plants generally absorb blue and red light more efficiently than green light for photosynthesis. Since the amount of oxygen produced is an indicator of the rate of photosynthesis, plants exposed to blue light would be expected to produce more oxygen (and thus more bubbles) than those exposed to green light.

Question 13

The energy of the movement of electrons down a concentration gradient via electron transport within the thylakoid membrane is used to generate

Accepted Answer

The energy derived from the movement of electrons down a concentration gradient in the thylakoid membrane during photosynthesis is primarily used to generate ATP, which is a form of chemical energy used by cells.

Question 14

Light reactions produce

Accepted Answer

Light reactions of photosynthesis produce ATP and NADPH, which are used in the Calvin cycle to synthesize glucose, and O2 as a byproduct of splitting water molecules.

Question 15

Which of the following statements is TRUE about the light reactions?

Accepted Answer

Photosystem II is primarily involved in water splitting and the generation of a proton gradient used for ATP synthesis, while photosystem I is mainly responsible for the reduction of NADP+ to NADPH.

Question 16

Suppose you are studying photosynthesis in a research lab. You grow your plants in a chamber with a source of water that has a radioactively labeled oxygen atom. What photosynthetic product will be radioactive?

Accepted Answer

During photosynthesis, the oxygen atoms in water molecules are used to produce O2 gas as a byproduct of the light-dependent reactions. When water with radioactively labeled oxygen is used, the O2 gas released will contain the radioactive label.

Question 17

Which of the following provides O₂ as an end product?

Accepted Answer

Light reactions, which occur in the chloroplasts during photosynthesis, produce oxygen (O2) as a byproduct when water is split to provide electrons for the photosynthetic electron transport chain.

Question 18

Which of the following statements about the light reactions of photosynthesis is FALSE?

Accepted Answer

In the light reactions of photosynthesis, NADP+ becomes reduced to NADPH, not the other way around. This process involves the addition of electrons (and a proton) to NADP+, forming NADPH, which is then used in the Calvin cycle for the synthesis of glucose.

Question 19

The primary function of the light reactions of photosynthesis is to

Accepted Answer

The light reactions of photosynthesis convert solar energy into chemical energy in the form of ATP and NADPH, which are then used in the Calvin cycle to synthesize glucose from carbon dioxide.

Question 20

During the process of photosynthesis, solar energy is converted to

Accepted Answer

During photosynthesis, plants convert solar energy into chemical energy, which is stored in the bonds of sugar molecules they produce.

Quiz 7: Capturing Solar Energy: Photosynthesis