Group 10: Cyclic and Non-Cyclic Electron Flow

Question 1

(True or False) Light dependent reaction take place in the stroma.

Answer 1

FALSE. Light dependent reaction takes place in the thylakoids

Question 2

(True or False) Light dependent reaction occurs during day and night.

Answer 2

FALSE. Light dependent reactions occur only during the day when the sun is present.

Question 3

It is a process that results in the movement of the electrons in a non-cyclic way to synthesize the ATP molecules by using the energy from the excited electrons that are provided by Photosystem II.

Answer 3

Non-cyclic electron flow.

Question 4

(True or False) Photosystem I and II harvest electrons to charge up energy-carrying molecules that will power the dark reaction.

Answer 4

FALSE. They harvest photons for the Calvin Cycle.

Question 5

Why is Non-cyclic flow important?

Answer 5

ATP and NADPH are molecules needed for the next step of photosynthesis, which is the Calvin Cycle.

Question 6

What protons are produced when the water molecules split up and that results in reducing NADP into NADPH?

Answer 6

The electrons combined to protons H+ to reduce NADP into NADPH.

Question 7

Each photoexcited electron passes from the
primary electron acceptor of PS II to PS I via an
__________.

Answer 7

Electron Transport Chain

Question 8

What makes up the electron transport chain between PS II and PSI?

Answer 8

An electron carrier plastoquinone (Pq), a cytochrome complex, and a protein called plastocyanin (Pc).

Question 9

What catalyzes the transfer of electrons from Fd to NADP+?

Answer 9

The enzyme NADP+ reductase.

Question 10

refers to the use of light energy to ultimately provide the energy to convert ADP to ATP, thus replenishing the universal energy currency in living things.

Answer 10

Photophosphorylation

Question 11

What is involved in the Cyclic electron flow?

Answer 11

Photosystem I and Chlorophyll P700

Question 12

(True or False) The cyclic electron flow produces NADPH and O2.

Answer 12

False. It only produces ATP.

Question 13

Why is cyclic photophosphorylation important?

Answer 13

The cyclic photophosphorylation is required all the time as it can generate ATP at a low cost. It provides ATP which is non-sufficiently produced in non–cyclic process.

Question 14

What captures the photons of the sun that is used as energy in the cyclic electron flow?

Answer 14

antenna complex (light absorbing pigments)

Question 15

In what evidence did the idea that cyclic electron flow may be photoprotective come from?

Answer 15

This came from the idea that mutant plants that are not able to carry out cyclic electron flow are capable of growing well in low light, but do not grow well where light is intense.

Question 16

(True or False) In non-cyclic electron flow, Electrons from Photosystem I are accepted by
NADP and it does not return back.

Answer 16

True

Question 17

(True or False) In cyclic electron flow, both ATP and NADPH molecules get formed.

Answer 17

False. Only ATP molecules are generated in cyclic electron flow.

Question 18

In which process does photolysis occur?

Answer 18

Non-cyclic electron flow and thus, water is needed in the process.

Question 19

What are the 3 similarities of the Cyclic and Non-cyclic Electron Flow?

Answer 19

1. ) Both are light-dependent reactions
2. ) Both occur in the thylakoid membrane of the chloroplasts.
3. ) Both are electron transport systems