Light Dependent and Independent

Question 1

What wavelength does Photosystem II absorb light at?

Answer 1

P680 (680 nm)

Question 2

What process occurs in PSII to replace lost electrons?

Answer 2

Photolysis – splits water into O₂, electrons, and protons (H⁺)

Question 3

What are the products of photolysis?

Answer 3

O₂, electrons (e⁻), and protons (H⁺)

Question 4

Where do the excited electrons from PSII go first?

Answer 4

Pheophytin → then to Plastoquinone (PQ)

Question 5

What is plastoquinone reduced to?

Answer 5

Plastoquinol (PQH₂)

Question 6

What does the cytochrome b6f complex do?

Answer 6

Transfers electrons and pumps protons (H⁺) into the thylakoid lumen

Question 7

What mobile carrier transfers electrons from Cyt b6f to PSI?

Answer 7

Plastocyanin (Pc)

Question 8

What wavelength does Photosystem I absorb light at?

Answer 8

P700 (700 nm)

Question 9

What happens when PSI absorbs light?

Answer 9

Electrons are excited and passed to ferredoxin (Fd) and NADP+ for NADPH production

Question 10

What is the final electron acceptor in the light-dependent reactions?

Answer 10

NADP⁺, which is reduced to NADPH

Question 11

What creates the proton gradient used in ATP synthesis?

Answer 11

H⁺ pumped into lumen by PQ and Cyt b6f

Question 12

What enzyme makes ATP during photophosphorylation?

Answer 12

ATP Synthase

Question 13

What is cyclic electron transport?

Answer 13

Electrons from PSI are cycled back to Cyt b6f to make more ATP

Question 14

What is the purpose of cyclic electron flow?

Answer 14

To increase ATP production without making NADPH

Question 15

What is the function of photosystem II?

Answer 15

Protein complex in the thylakoid membrane that is responsible for splitting water during photosynthesis, releasing oxygen and providing electrons for the electron transport chain

Question 16

What is the function of Photosystem I?

Answer 16

Protein complex in the thylakoid membrane that is involved in the light-dependent reactions of photosynthesis, catalyzing light-driven electron transfer from plastocyanin to ferredoxin.

Question 17

What is the first phase of the Calvin cycle?

Answer 17

Carboxylation: CO₂ is incorporated by the enzyme Rubisco.

Question 18

What enzyme catalyzes the incorporation of CO₂ in the Calvin cycle?

Answer 18

Rubisco

Question 19

What is the intermediate molecule formed during carboxylation?

Answer 19

3-PGA (3-phosphoglycerate)

Question 20

What is the role of ATP in the reduction phase of the Calvin cycle?

Answer 20

ATP donates a phosphate group to 3-PGA.

Question 21

What does NADPH do in the reduction phase of the Calvin cycle?

Answer 21

NADPH transfers 2 electrons plus 1 proton to 3-PGA.

Question 22

How many ATP and NADPH molecules are required for each molecule of CO₂ in the Calvin cycle?

Answer 22

2 ATP and 2 NADPH

Question 23

What are the products of the reaction: 3-PGA + ATP?

Answer 23

1,3-BGP + NADPH

Question 24

What does 1,3-BGP get reduced to in the reduction phase of the Calvin cycle?

Answer 24

Triose phosphate + NADP⁺

Question 25

What is triose phosphate in the context of the Calvin cycle?

Answer 25

The building block of glucose.

Question 26

What is the purpose of the regeneration phase of the Calvin cycle?

Answer 26

To convert five 3-carbon triose phosphate molecules into three 5-carbon RuBP molecules.

Question 27

What enzyme is involved in the regeneration phase of the Calvin cycle?

Answer 27

Rubisco

Question 28

How many times must the Calvin cycle process occur to produce one glucose molecule?

Answer 28

Three times (to process 3 CO₂ molecules).

Question 29

What are the three stages of the Calvin cycle?

Answer 29

Carboylation, reduction and regeneration

Question 30

What is the function of the Regeneration phase in the Calvin cycle?

Answer 30

Reactions that turn five 3-carbon triose phosphate molecules into three 5-carbon RuBP molecules