【Chris】評論

Genes  for  products  that  are  required  at  all  times,  such  as  those  for  the enzymes  of  central  metabolic  pathways,  are  expressed  at  a  more  or  less constant level in virtually every cell of a species or organism. Such genes are often referred to as housekeeping genes.For  other  gene  products,  cellular  levels  rise  and  fall  in  response  to molecular  signals;  this  is  regulated  gene  expression.  Gene  products  that increase  in  concentration  under  particular  molecular  circumstances  are referred  to  as ...