EVERYDAY SCIENCE

Detailed explanation-1: -An icosahedron is a three-dimensional shape made up of 20 equilateral triangles. Viral structures are built of repeated identical protein subunits, making the icosahedron the easiest shape to assemble using these subunits.

Detailed explanation-2: -Most viruses have icosahedral or helical capsid structure, although a few have complex virion architecture. An icosahedron is a geometric shape with 20 sides, each composed of an equilateral triangle, and icosahedral viruses increase the number of structural units in each face to expand capsid size.

Detailed explanation-3: -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-4: -Viruses can be simple or complex in shape. The different virus shapes include helical or cylindrical, polyhedral (icosahedral and prolate), spherical, and complex shapes.

Detailed explanation-5: -A protective protein shell, or capsid. A nucleic acid genome made of DNA or RNA, tucked inside of the capsid. A layer of membrane called the envelope (some but not all viruses)