NEET BIOLOGY

Detailed explanation-1: -In general, the shapes of viruses are classified into four groups: filamentous, isometric (or icosahedral), enveloped, and head and tail. Filamentous viruses are long and cylindrical. Many plant viruses are filamentous, including TMV (tobacco mosaic virus).

Detailed explanation-2: -Viruses may also be classified according to the structure of the virus particle, or virion. The three major shapes seen are spherical, filamentous, and complex.

Detailed explanation-3: -Helical. This virus structure has a capsid with a central cavity or hollow tube that is made by proteins arranged in a circular fashion, creating a disc like shape. The disc shapes are attached helically (like a toy slinky) creating a tube with room for the nucleic acid in the middle.

Detailed explanation-4: -In a helical virus, the viral nucleic acid is in the shape of a helix. The capsid proteins wind within or outside the nucleic acid. The nucleic acid along with the capsid makes the nucleocapsid. They have a long tube or rod-like structure.