Lecture 1 - Introduction

Question 1

Define a virus

Answer 1

A virus is an infectious, obligate intracellular parasite comprising genetic material surrounded by a protein coat and sometimes a lipid membrane.

Question 2

What are the 5 goals that need to be met by a virus’s morphology?

Answer 2

1) Protect and deliver genome into cell
2) Economy: maximize functionality with minimal structure and genome requirements
3) Stability to survive harsh environments encountered during infection
4) Specificity of viral genome to cell type
5) Flexibility or metastability to uncoat and deliver genome within the cell

Question 3

What are the 3 types of virus capsids?

Answer 3

Icosahedral, helical and complex

Question 4

What is the difference between a structural and non-structural protein?

Answer 4

Structural proteins are proteins found within the virion (even if they don’t play a structural role)
Non-structural proteins are made in the infected cell but not incorporated into the virion (may still be essential to viral life cycle)

Question 5

Define the nucleocapsid

Answer 5

Nucleocapsid is the internal core of the virus and consists of the viruses nucleic acid surrounded by a protein coat called the capsid

Question 6

Define an icosahedron

Answer 6

Icosahedrons are 3-dimensional structures with 20 triangular faces and 12 vertices related by 2-, 3- and 5-fold rotational axes of symmetry.

Question 7

Define capsomere

Answer 7

Viral protein subunits of capsids