Quinone A, Quinone B, Ubiquinone, Plastoquinone: whats the difference?

I am getting very confused about this. My understanding so far is that ubiquinone is used as an electron (and proton) carrier in oxidative phosphorylation in the mitochondria whereas plastoquinone is the carrier in the light dependent reaction in photosynthesis in chloroplasts. My guess is that these carriers are similar because it is a highly conserved carrier that was present in many of the original life forms (including those that formed chloroplasts and mitochondria).

My first questions are:

• is the above distinction correct?

• do we find ubiquinone and plastoquinone elsewhere in cells, other than in mitochondria and chloroplasts, or in other prokaryotes?

Then I am not sure about quinone a and b. My lecturer said that quinone b is present in photosystem II and it accepts the two electrons from the lysis of H₂O and then it accepts two H⁺ ions from the stroma to enter the membrane of the thylakoid

But I have also read that it is plastoquinone which shuttles the H⁺ ions in the thylakoid membrane in the form of plastoquinol. So could it be that quinone B turns into plastoquinone on accepting the electrons, and plastoquinone accepts two H⁺ ions to form plastoquinol?

If so, how is the quinone B from photosystem II replenished?