The morphologic characteristics of chromosomes are best studied during metaphase and anaphase of cell division. The chromosome was supposed to be covered by a membranous Pellicle. Electron microscope studies later showed that there is no definite membranous pellicle surrounding the chromosomes. A matrix of some sort, possibly protein, lipid, may be present. Other structures present in the chromosome include the [...]
In this article we will discuss about the mechanism for the replication of DNA. The mechanism for the synthesis of DNA proposed by Watson and Crick offered the important advantage of explaining how new DNA molecules could be exact replicates of the old. According to Watson and Crick, each single strand is a template on mold for its complement, and [...]
In this article we will discuss about the structure of lac operon in E. coli. The lac operon comprises three structural genes (z, y & a) and produces a polycistronic mRNA (Lac mRNA). This messenger RNA codes for β-galactosidase, lac permease and transacetylase. The lac permease is a single unit protein that acts as a carrier for the entrance of [...]