In this article we will discuss about the changes in chromatin structure during transcription. Displacement of nucleosomes: During transcription, some changes in the chromatin structure occur in the region of transcription. RNA polymerase is comparatively larger in size than the nucleosomes. The molecular weight of RNA polymerase is about 5,00,000 Daltons, while that of nucleosome is about 2,60,000 Daltons. Lewin [...]
In this article we will discuss about:- 1. Coiled DNA Model 2. Nucleosome-Solenoid Model of Chromatin Fibres. Coiled DNA Model: This model of chromatin structure was proposed by DuPraw in 1965. As per this model, DNA molecule is associated with three classes of proteins: (i) Lysine rich histories: They are common to both A and B type fibres and are [...]
In this article we will discuss about the cell division and cell cycle in prokaryotes. Bacterial cell division is also termed as fission. The bacterial chromosome is circular and attached to the plasma membrane at a specific point. Its replication starts from an initiation point. Both the copies of the chromosome are attached to the plasma membrane, close to each [...]