Question

fill in the blank.
complete these statements about the light reactions.

1. they occur in the
2. the source of energy for these reactions is
3. they use and release
4. the 2 high - energy products are &.

complete these statements about the calvin cycle.

1. occurs in the of the chloroplast.
2. requires the products of the light reactions and from the air.
3. one molecule of is produced by each turn of the cycle.

multiple choice.

1. which of the following statements about photosystems is not true?

a. there are 2 photosystems built into the thylakoid membrane
b. composed of chlorophyll and other molecules arranged in clusters
c. the light reactions start when photosystem i absorbs light energy
d. the primary electron acceptor passes excited electrons to an electron transport chain

1. which of the following statements about the electron transport chains is not true?

a. electrons increase in energy as they pass through the etc
b. h+ ions are pumped across the membrane
c. h+ ions diffuse back through the membrane during chemiosmosis
d. the etc after psii produces atp; the etc after psi produces nadph

Explanation:

1. The light reactions of photosynthesis occur in the thylakoid membranes of chloroplasts.
2. The source of energy for light reactions is sunlight (solar energy).
3. Light reactions use water (\(H_2O\)) and release oxygen (\(O_2\)).
4. The two high - energy products of light reactions are ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate).
5. The Calvin cycle occurs in the stroma of the chloroplast.
6. The Calvin cycle requires the products of the light reactions (ATP and NADPH) and carbon dioxide (\(CO_2\)) from the air.
7. One molecule of glyceraldehyde - 3 - phosphate (G3P) is produced by each turn of the Calvin cycle.
8. For question 8:

• Option a: There are two photosystems (PSII and PSI) built into the thylakoid membrane. This is true.
• Option b: Photosystems are composed of chlorophyll and other molecules arranged in clusters. This is true.
• Option c: The light reactions start when Photosystem II (not PSI) absorbs light energy. So this option is not true.
• Option d: The primary electron acceptor passes excited electrons to an electron transport chain. This is true.

1. For question 9:

• Option a: Electrons lose energy as they pass through the ETC (electron transport chain), not increase. So this option is not true.
• Option b: During electron transport, \(H^+\) ions are pumped across the membrane. This is true.
• Option c: \(H^+\) ions diffuse back through the membrane during chemiosmosis. This is true.
• Option d: The ETC after PSII produces ATP; the ETC after PSI produces NADPH. This is true.

Answer:

1. thylakoid membranes
2. sunlight (solar energy)
3. water (\(H_2O\)); oxygen (\(O_2\))
4. ATP; NADPH
5. stroma
6. ATP, NADPH; carbon dioxide (\(CO_2\))
7. glyceraldehyde - 3 - phosphate (G3P)
8. C. The light reactions start when Photosystem I absorbs light energy
9. A. Electrons increase in energy as they pass through the ETC