light dependent reactions

Question 1

Where are electrons released from water molecules?

Answer 1

On the inner thylakoid side of photosystem 2.

Question 2

When electrons are released from water molecules, what other products are formed?

Answer 2

O2 and hydrogen ions.

Question 3

The light-dependent reactions of photosynthesis include three major processes:

Answer 3

A. Excited electrons leave chlorophyll and reduce NADP+ into NADPH.
B. Excited electrons moving through the electron transport chain provide the free energy needed to pump hydrogen ions into the inner thylakoid.
C. Hydrogen ions flowing out of the thylakoid via a protein channel provide the free energy
needed to convert ADP to ATP

Question 4

How does the electron transport chain system work?

Answer 4

The electron transport chain uses the energy from excited electrons to move hydrogen ions (H+) across the thylakoid membrane in a direction that is against the concentration gradient. This produces a high
concentration of H+ inside the thylakoid membrane.

Question 5

Name the embedded protein complex found in the thylakoid membrane that uses excited
electrons to reduce NADP+ into NADPH

Answer 5

photosystem 1

Question 6

Name the embedded protein complex found in the thylakoid membrane that provides excited
electrons to the electron transport chain

Answer 6

photosystem 2

Question 7

Name the embedded protein complex found in the thylakoid membrane that converts ADP
to ATP using free energy from a flow of hydrogen ions.

Answer 7

ATP synthase.

Question 8

Once a chlorophyll molecule has released electrons it is no longer useful until those electrons are
replaced. What is the source of replacement electrons for those released from
photosystem I?

Answer 8

Electrons that have completed the electron transport chain.

Question 9

What is the source of replacement electrons for those released from
photosystem II?

Answer 9

Electrons from the splitting of water.

Question 10

Is carbon dioxide involved in the light-dependent reaction?

Answer 10

No

Question 11

welve water molecules are shown as reactants, but
six water molecules are shown as products. Are any of the twelve water molecules products of
the light-dependent reactions?

Answer 11

No

Question 12

Calculate the total number of oxygen, NADPH, and ATP molecules that are produced when
twelve water molecules complete the light-dependent reactions.

Answer 12

6O2 + 12NADPH + 18ATP

Question 13

Where do the ATP and NADPH produced during the light-dependent reactions go when the
process is complete?

Answer 13

calvin cycle