noun. 1  a mutation occurring in a somatic cell, resulting in a change in the morphology or some other aspect of one part of an organism (usually a plant). 2  It may be maintained by vegetative propagation but not by sexual reproduction.oun. 1  a mutation occurring in a somatic cell, resulting in a change in the morphology or some other aspect of one part of an organism (usually a plant). 2  It may be maintained by vegetative propagation but not by sexual reproduction.
Protein has a range of essential functions in the body, including the following: 1  Required for building and repair of body tissues (including muscle). 2  Enzymes, hormones, and many immune molecules are proteins. 3  Essential body processes such as water balancing, nutrient transport, and muscle contractions require protein to function. 4  Protein is a 5  ... P Enzymes, hormones, and many immune molecules are proteins. 2  Essential body processes such as water balancing, nutrient transport, and muscle contractions require protein to function. 3  Protein is a source of energy. 4  Protein helps keep skin, hair, and nails healthy.
Many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle.