5.3.3 Photosystem 2

Question 1

photosystem 2

Answer 1

• an electron is excited by light and passed to the primary electron acceptor, which passes it down an
  electron transport chain and leads to the synthesis of ATP
• an electron in chlorophyll a is excited and passed to the primary electron acceptor. The electron is passed down a chain of proteins from the primary electron
  acceptor. As the electron is passed, it loses energy. The
  energy lost from the electron is used to pump protons (H+) into the lumen of the thylakoid. The proton gradient created is used to fuel the production of ATP via the enzyme complex ATP synthase.
• The final acceptor of the electron from photosystem 2 is the chlorophyll a that lost its electron in photosystem 1.
• As electrons are lost from photosystem 2, electrons from the splitting of water replace them. Water is split into two hydrogen ions and an oxygen atom. The oxygen atom combines with another oxygen to form O2
  .

Question 2

photosystem 1

Answer 2

• has lost an electron to make NADPH, it receives an electron from the electron transport chain of
  photosystem 2.

Question 3

photolysis

Answer 3

• or the splitting of water, takes place in order to provide electrons to photosystem 2 (since chlorophyll a from photosystem 2 loses excited electrons).

Question 4

light reactions

Answer 4

• The end products of the light reactions (the reactions of photosystem 1 and photosystem 2) are ATP, NADPH + H+, and O2

Question 5

Which of the following does not take place during cyclic photophosphorylation?

Answer 5

• Water provides electrons to photosystem I.

Question 6

A major difference between cyclic and noncyclic photophosphorylation is

Answer 6

• cyclic photophosphorylation produces no NADPH

Question 7

An electron from Photosystem II is lost when it is excited by a photon of light. Photosystem II is supplied with another electron from

Answer 7

• water

Question 8

Which of the following takes place as a result of photosynthetic electron transport?

Answer 8

• A proton gradient is established across the thylakoid membrane

Question 9

Where is ATP produced in the light reactions?

Answer 9

• in the stroma

Question 10

How is photosystem II linked to photosystem I?

Answer 10

• An electron from photosystem II is passed to photosystem I