ZOOLOGY BOTANY CHEMISTRY

● This type of termination occur in Prokaryotes for termination of transcription.  ◇ Transcription = Synthesis of RNA from DNA. ● Dna which have such a termination sequence which terminates the transcription only in presence of rho factor are called rho dependent termination. ● This termination sequence is rich in C but devoid of G .This types of sequence is necessary for function rho protein .  ● Rho protein binds with mRNA which is elongated by rna polymerase at rut site (rho utilization site) and then rho protein moves from 5' to 3' end . ● When RNA polymerase reaches rho dependent termination sequence then rho protein shows its helicase activity and unwind DNA-RNA hybrid. ● This will disrupt and terminate transcription bubble and new synthesized mRNA is released.  (Helicase is a enzyme that can unwind the dna strand or we can say breaks H bonds present in between the double helix of DNA )

We have seen earlier that the continuance of the information flow to progeny and somatic cells is maintained by the DNA. This task is accomplished by the meticulous plan of DNA replication. Since DNA makes its own copies using the pre-existing DNA, the synthesis of DNA is referred as replication. Since only one strand of the double stranded DNA is newly synthesized, therefore, its replication is called as semi-conservative. However, in terms of contents, the resulting two helices are exactly identical with the original helix. The two strands of DNA double helix are united by hydrogen bonds between purine and pyrimidine base pairs. The initiation of the replication is marked by a cut or nick made by endonuclease on one of the strands of DNA. For replication, DNA binding proteins and DNA gyrase open up the DNA helix. Gyrase binds on a single strand and initiates uncoiling of coiled strands. The unwinding of strands results in the development of strain in the remaining helix and is reliev...