Question

Give a brief account on TMV.

Answer 1

Hint: TMV is a virus, a virus consists of a protein coat and genome which can be RNA or DNA, the virus genome can be single-stranded, double-stranded. They have a very strong virulence and are known for causing various life-threatening diseases. TMV is the first virus to be discovered by the scientist named Ivanoski.

Complete answer:
Tobacco mosaic virus is known as TMV which is semi helical with rod shape.
Together with centrally positioned single-stranded RNA (5.6 percent) enveloped via a protein coat (94.4 percent). The rod is considered to be 3,000 angstrom in length and about a hundred and eighty angstrom in diameter.

The protein coat is technically known as ‘capsid’. R. Franklin estimated 2,130 sub-units, specifically, capsomeres in a whole helical rod and forty-nine capsomeres on every 3 turns of the helix; thus there might be approximately a hundred thirty turns in keeping with the rod of TMV.

Plant viruses like TMV penetrate and input the host cells into toto and their replication completes inside such infected host cells. Inside the host cell, the protein coat dissociates and viral nucleic acid turns into free in the mobile cytoplasm.

Although the sites for exceptional steps of the viral multiplication and formation of latest viruses have now not but been decided with absolute reality, the research proposes a regulation turning into free within the cellular cytoplasm the viral-RNA movements into the nucleus (probably into the nucleolus).

The viral-RNA first induces the formation of precise enzymes called ‘RNA polymerases’ the unwinded-stranded viral-RNA synthesizes an additional RNA strand called replicative RNA.

Note: The single-stranded RNA consists of 7300 nucleotides with a molecular weight of RNA to be 25,000 daltons, it consists of a protein coat which was the basis of experiments of Fraenkel-Cornet and Williams in 1955, It comes under rod-shaped with a helical structure. All the experiments and discovery of the virus starts from the TMV.