5A - Photosynthesis Light dependant stage

Question 1

What are the two distinct stages of photosynthesis?

Answer 1

The two stages are light-dependent reactions and light-independent reactions.

Question 2

Where do the light-dependent reactions occur?

Answer 2

The light-dependent reactions take place across the thylakoid membrane within the chloroplast.

Question 3

Where do the light-independent reactions occur?

Answer 3

The light-independent reactions occur in the stroma of the chloroplast.

Question 4

What is photolysis?

Answer 4

Photolysis is the process where water molecules are split in the light-dependent reactions, producing hydrogen ions (protons), electrons, and oxygen.

Question 5

What happens to the oxygen produced during photolysis?

Answer 5

Oxygen is released as a waste product into the atmosphere.

Question 6

What is the role of NADP in photosynthesis?

Answer 6

NADP is a coenzyme that transfers hydrogen from one molecule to another, becoming reduced NADP (NADPH) when it gains hydrogen.

Question 7

What is the relationship between reduction and oxidation?

Answer 7

Reduction is the gain of electrons or hydrogen, while oxidation is the loss of electrons, hydrogen, or gain of oxygen.

Question 8

How are ATP and NADPH transferred to the light-independent reactions?

Answer 8

The useful products, ATP and NADPH, generated in the light-dependent reactions are transferred to the light-independent reactions within the chloroplast.

Question 9

What is photophosphorylation?

Answer 9

Photophosphorylation is the process of producing ATP by adding a phosphate group to adenosine diphosphate (ADP) using light energy.

Question 10

What are the two types of photophosphorylation?

Answer 10

The two types are non-cyclic photophosphorylation and cyclic photophosphorylation.

Question 11

What is chemiosmosis?

Answer 11

Chemiosmosis is the process where H+ ions are actively pumped across a membrane, creating a concentration gradient, which drives ATP production.

Question 12

How is ATP produced in non-cyclic photophosphorylation?

Answer 12

Light energy excites electrons in photosystems I and II, leading to the production of ATP through the electron transport chain and chemiosmosis.

Question 13

What happens during cyclic photophosphorylation?

Answer 13

Light energy excites electrons in photosystem I, and ATP is produced through the electron transport chain and chemiosmosis, without the production of NADPH.

Question 14

Where does non-cyclic photophosphorylation occur?

Answer 14

Non-cyclic photophosphorylation involves both photosystem I and photosystem II and occurs in the thylakoid membrane.

Question 15

Where does cyclic photophosphorylation occur?

Answer 15

Cyclic photophosphorylation occurs only in photosystem I and takes place in the thylakoid membrane.

Question 16

What are the products of non-cyclic photophosphorylation?

Answer 16

The products are ATP, NADPH, and oxygen.

Question 17

What is the role of photosystem II in non-cyclic photophosphorylation?

Answer 17

Photosystem II absorbs light energy and initiates the electron transport chain by replacing its lost electrons with electrons from water during photolysis.

Question 18

What is the role of photosystem I in non-cyclic photophosphorylation?

Answer 18

Photosystem I absorbs light energy and further energizes electrons, which combine with hydrogen ions and NADP to form reduced NADP (NADPH).

Question 19

What is the role of ATP in the light-independent reactions?

Answer 19

ATP produced during the light-dependent reactions provides energy for the light-independent reactions, also known as the Calvin cycle.

Question 20

What is the purpose of cyclic photophosphorylation?

Answer 20

Cyclic photophosphorylation produces ATP but does not produce NADPH, and it functions to provide additional energy for cellular processes.