Photosynthesis- the Synthesis of ATP in the Chloroplast

Question 1

What is the source of energy for ATP synthesis during the light dependent reactions?

Answer 1

A gradient of protons established between the lumen of the thylakoid and the stroma of the chloroplast.

Question 2

How are protons provided for the synthesis of ATP in the chloroplast?

Answer 2

Proton pumps in the thylakoid membrane pump protons from the stroma into the lumen of the thylakoids using energy that is released during electron transport along the thylakoids (electron transport chains).
Additionally, the photolysis of water also provides protons for this purpose. Each time that a water molecule is photolyzed, two protons remain in the thylakoid space.

Question 3

The high concentration of protons in the lumen of the thylakoid and the lower concentration of protons in the stroma establish what?

Answer 3

An electrochemical gradient across the thylakoid membrane.

Question 4

What type of energy is there a large amount of in the lumen of the thylakoid?

Answer 4

Potential energy

Question 5

What can the protons use to move into the stroma from the thylakoid membrane?

Answer 5

Channel proteins

Question 6

Due to the many channel proteins in the thylakoid membrane, as protons move into the stroma, what is released?

Answer 6

Energy as they move along the channels.

Question 7

What is this energy used for

Answer 7

The energy is used to synthesize ATP from ADP and inorganic phosphate.

Question 8

What enzyme needs to be present in order for the synthesis of ATP from ADP and inorganic phosphate to take place?

Answer 8

ATP synthase enzyme which is attached to the channel proteins.