General Key Points in Photosynthesis

Question 1

What is the direction of proton movement during photosynthesis?

What does this achieve, exactly?

Answer 1

H+ is concentrated in the Lumen, and it is transported out of the Stroma.

This creates a gradient helping generate ∆p, or Proton Motive Force (PMF)

Question 2

What direction do protons migrate in ATP synthesis through ATP Synthase, and through what residues?

What does this achieve?

Answer 2

They flow through critical residues (xyz) which overall results in the transfer of protons with the gradient, into the Stroma (from the Lumen).

This movement of protons enables harvesting of energy held in the gradient into chemical energy stored the high-energy phosphate bond of ATP.

Question 3

What is the (general) Redox Z-Scheme?

Answer 3

H2O –> P700 –> P700* –> PQ (Plastoquinone/ol) –> CytB6f –> Pc (Plastocyanin) –> P680 –> P680* –> Fd (Ferredoxin) –> NADP+

Question 4

What is the Proton Motive Force, PMF, or ∆p composed of?

Answer 4

It is composed of the sum of the charge gradient and the pH gradient. It can be expressed mathematically as follows:

∆p = ∆pH + ∆Psi

This means they could either work together, or counteract each other, in theory.

(Psi can’t be typed but it’s the trident thing)