Human cloningHuman cloning is the creation of a genetically identical copy of a human. The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural conception and delivery of identical twins. The possibilities of human cloning have raised controversies. These ethical concerns have prompted several nations to pass laws regarding human cloning. Two commonly discussed types of human cloning are therapeutic cloning and reproductive cloning.
Extracellular signal-regulated kinasesIn molecular biology, extracellular signal-regulated kinases (ERKs) or classical MAP kinases are widely expressed protein kinase intracellular signalling molecules that are involved in functions including the regulation of meiosis, mitosis, and postmitotic functions in differentiated cells. Many different stimuli, including growth factors, cytokines, virus infection, ligands for heterotrimeric G protein-coupled receptors, transforming agents, and carcinogens, activate the ERK pathway.
DesquamationDesquamation occurs when the outermost layer of a tissue, such as the skin, is shed. The term is . Keratinocytes are the predominant cells of the epidermis, the outermost layer of the skin. Living keratinocytes reside in the basal, spinous, or granular layers of the epidermis. The outermost layer of the epidermis is called the Stratum corneum and it is composed of terminally differentiated keratinocytes, the Corneocytes. In the absence of disease, desquamation occurs when corneocytes are individually shed unnoticeably from the surface of the skin.
