Question

name class date
electron carriers

1. when sunlight excites electrons in chlorophyll, how do the electrons change?
2. what is a carrier molecule?
3. circle the letter of the carrier molecule involved in photosynthesis.

a. h₂o c. co₂
b. nadp⁺ d. o₂

1. how does nadp⁺ become nadph?

light - dependent reactions

1. circle the letter of each sentence that is true about the light - dependent reactions.

a. they convert adp into atp.
b. they produce oxygen gas.
c. they convert oxygen into carbon dioxide.
d. they convert nadp⁺ into nadph.

1. where do the light - dependent reactions take place?
2. circle the letter of each sentence that is true about the light - dependent reactions.

a. high - energy electrons move through the electron transport chain from photosystem ii to photosystem i.
b. photosynthesis begins when pigments in photosystem i absorb light.
c. the difference in charges across the thylakoid membrane provides the energy to make atp.
d. pigments in photosystem i use energy from light to reenergize electrons.

1. how does atp synthase produce atp?

Explanation:

1. When sunlight excites electrons in chlorophyll, the electrons gain energy and move to a higher energy level.
2. A carrier molecule is a molecule that can accept and carry electrons or other chemical groups.
3. In photosynthesis, \(NADP^{+}\) (nicotinamide adenine dinucleotide phosphate) acts as a carrier molecule. It accepts electrons and hydrogen ions to form NADPH.
4. \(NADP^{+}\) becomes NADPH by accepting electrons and a hydrogen ion (\(H^{+}\)).

10.

• a. Light - dependent reactions convert ADP into ATP through chemiosmosis.
• b. They produce oxygen gas as a by - product of water splitting.
• d. They convert \(NADP^{+}\) into NADPH.

1. Light - dependent reactions take place in the thylakoid membranes of chloroplasts.

12.

• a. High - energy electrons move through the electron transport chain from photosystem II to photosystem I.
• c. The difference in charges (proton gradient) across the thylakoid membrane provides the energy to make ATP.
• d. Pigments in photosystem I use energy from light to reenergize electrons.

1. ATP synthase produces ATP by using the energy from the proton gradient (flow of hydrogen ions \(H^{+}\)) across the thylakoid membrane. As \(H^{+}\) flow through ATP synthase, it catalyzes the addition of a phosphate group to ADP, forming ATP.

Answer:

1. The electrons gain energy and move to a higher energy level.
2. A molecule that can accept and carry electrons or other chemical groups.
3. b. \(NADP^{+}\)
4. By accepting electrons and a hydrogen ion (\(H^{+}\)).
5. a. They convert ADP into ATP; b. They produce oxygen gas; d. They convert \(NADP^{+}\) into NADPH.
6. In the thylakoid membranes of chloroplasts.
7. a. High - energy electrons move through the electron transport chain from photosystem II to photosystem I; c. The difference in charges across the thylakoid membrane provides the energy to make ATP; d. Pigments in photosystem I use energy from light to reenergize electrons.
8. By using the energy from the proton gradient (flow of \(H^{+}\)) across the thylakoid membrane. As \(H^{+}\) flow through ATP synthase, it catalyzes the addition of a phosphate group to ADP, forming ATP.