Definition. Region in San Francisco, California that is considered to be the technology hub of the United States. The region is made up a number of computer companies and computer chip manufactures. The region gets its nickname from the silicon that is used in computer chips.Due to the demand for space in Silicon Valley, real estate and other property is very expensive and hard to find.he region is made up a number of computer companies and computer chip manufactures. The region gets its nickname from the silicon that is used in computer chips. Due to the demand for space in Silicon Valley, real estate and other property is very expensive and hard to find.
A substitution is a mutation that exchanges one base for another (i.e., a change in a single chemical letter such as switching an A to a G). Such a substitution could: 1  change a codon to one that encodes a different amino acid and cause a small change in the protein produced. 2  For example, sickle cell anemia is caused by a substitution in the beta-hemoglobin gene, which alters a single amino acid in the protein produced.
Point mutation. Definition. noun, plural: point mutations. A mutation in DNA or RNA molecule involving a change of only one nucleotide base.Supplement. This type of mutation occurring in noncoding sequences often does not result in an altered amino acid sequence during translation.f a mutation in the promoter sequence of a gene occurs, the effect may be apparent since the expression of the gene may cause changes in the amino acid sequence, as well as the structure and function of the protein product. Point mutations may be classified based on functionality: 1  nonsense mutation. 2  missense mutation.