Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can be later released to fuel the organisms' activities.owever, not all organisms that use light as a source of energy carry out photosynthesis, since photoheterotrophs use organic compounds, rather than carbon dioxide, as a source of carbon. In plants, algae and cyanobacteria, photosynthesis releases oxygen.
Describe the mechanism of clonal selection. The binding of an antigen receptor to an epitope initiates events that activate the lymphocyte. Once activated, a B or T cell undergoes multiple cell divisions. For each activated cell, the result of this proliferation is a clone.ntibodies and B cell receptors. Antibodies have the same Y-shaped organization as B cell antigen receptors, but they are secreted rather than membrane bound. It is the antibodies, rather than the B cells themselves, that actually help defend against pathogens.
This accumulation, which we have termed memory âinflation,â was not uniform. CD8 + T cells specific for IE1/pp89 and for m164 clearly showed this phenomenon, but frequencies of cells specific for other viral epitopes did not increase.nfections with herpesviruses are usually controlled by a broad array of immune effector mechanisms. Of these, the antiviral CD8 + T cell response has been shown to be important to limit acute CMV disease and reactivation of latent infection in both humans and mice (2, 3, 4).