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.
Overview. Receptors are nature's transducersâthey detect circulating hormones or substances released by nerve activity and elicit a biological response. Our research centers on specialized types of receptors called synaptic receptors, found on the surfaces of cells in close proximity to nerve terminals.f the receptor is located on a muscle cell, the impulse triggers contraction. Whereas if it is on a nerve cell, it causes release of transmitter substance on yet another cell. In this way, excitable cells communicate throughout the body by means of specialized pairs of neurotransmitter substances and receptors.