GLOSSARYAbundance of an mRNA is the average number of molecules per cell
Abundant mRNAs consist of a small number of individual species, each present in a large number of copies per cell
Acceptor splicing site—see right splicing junction
Acentric fragment of a chromosome (generated by breakage) lacks a centromere and is lost cell division
Acrocentric chromosome has the centromere located nearer one end than the other
Active site is the restricted part of a protein to which a substrate binds
Allele is one of several alternative forms of a gene occupying a given locus on a chromosome
Allelic exclusion describes the expression in any particular lymphocyte of only one allele coding for the expressed immunoglobulin
Allosteric control refers to the ability of an interaction at one site of a prot