Question

Chemiosmosis in Photosynthesis

Photophosphorylation.

Where is the location of the ETC? What is the original source of the Hydrogen Electrons given to the etc? Where do the Hydrogen electrons end up when they leave the ETC? What specific location becomes acidic/ low pH (has higher H⁺ concentration)? What specific location becomes basic/high pH (has lower H⁺ concentration)?

Answer 1

Chemiosmosis is the process of ion whre ions are moved down the electrocheimcal gradient crossing a semipermeable barrier or membrane. During photosynthesis, ATP is generated by this process through the movement od hydrogen ion.

During photosynthesis, in the presence of light, ADP is phophorylated to prodcue ATP with the help of ATP synthase enzyme and this process is called photophosphorylation. During this process light is used as energy source.

Electron trnsport chain or ETC is a process where electrons are transfred from donar to acceptor by redox reaction and this transfer is occured simultaneously with hydrogen ion (H+) transfer accross a membrane.In eukaryotes ETC is found in the innermembrane of mitochondria. In prokaryotes, ETC is found in the thylakoid membrane of the chloroplast.

During ETC, a gradient is created between mitochondrial matrix and inner membrane space. The Hydrogen ion is pumped out from the matrix of mitochondria to innermembrane space of mitochondria. As the concentration of H+ ion is higher outside the matrix, the innermebrane space becomes acidic with low pH, whereas the matrix becomes basic with higher pH values.

In prokaryotes, the proton or H+ ion is transported from stroma of thylakoid to lumen of thylakoid membrane and thus lumen has more H+concentration and lower pH. Whereas stroma has less hydrogen ion concentration and basic in nature having higher pH.