8.2

Question 1

Identify where in the chloroplast the light reactions occur.

Answer 1

thylakoids

Question 2

Explain how the light reactions generate ATP and NADPH.

Answer 2

photophosphorylation for ATP
reduction reaction to turn NADP+ to NADPH

Question 3

Describe how some bacteria use only one photosystem for cyclic photophosphorylation.

Answer 3

Some bacteria only use one photosystem because they don’t produce oxygen

Question 4

Compare the functions of the two photosystems in green plants.

Answer 4

Photosystem I
- Reaction center of chlorophyll a of PS I is called P700
- Best at absorbing wavelength of 700nm
Photosystem II
-functions first
-the reaction-center chlorophyll a of PS II is called P680
-best at absorbing a wavelength of 680nm

Question 5

Identify the wavelength of light that is absorbed by each photosystem.

Answer 5

• Photosystem I
   700nm
• Photosystem II
   680nm

Question 6

Describe the linear flow of electrons through photosystem II

Answer 6

Photon received from light excites reaction center P680, oxidizing it to P680+ -> Water is split, replaces lost electrons in P680+ to reduce it back to P680 -> oxygen is released-> electrons are passed to B6-f complex -> proton pump to created H+ gradient (Used to generate ATP) -> passes electrons to plastocyanin

Question 7

Describe the linear flow of electrons through photosystem I.

Answer 7

Photon received from light excites reaction center P700, oxidizing it to P700+ -> accepts an electron from plastocyanin (from PS II) to reduce back to P700 -> passes electrons to ferredoxin and finally to NADP+ to form NADPH

Question 8

chemiosmosis in the mitochondria and chloroplasts

Answer 8

 Chemical energy from food and turns into ATP
 Protons pumped into intermembrane space and drive ATP synthesis as they diffuse back into mitochondrial matrix

Question 9

chemiosmosis in the chloroplasts

Answer 9

 Transforms light energy into ATP
 Protons pumped int Thylakoid space and drive ATP synthesis as they diffuse back into stroma