Viral Structure/Replication

Question 1

What impact has molecular biology has on understanding of viruses?

Answer 1

Basis for classification
Understanding replication and pathogenesis
Development of antiviral drugs/novel vaccines
Molecular epidemiology of viruses

Question 2

How do viruses depend on their host?

Answer 2

Dependent as a source of energy / to provide raw materials

Use host cell machinery to replicate their genome / to synthesise new protein

Question 3

Describe the small virus genome.

Answer 3

Few genome protein components

No genes for energy metabolism / lipid or amino acid synthesis

No protein synthesis enzymes or ribosomes

Less non-coding DNA, few or no introns

Question 4

What three kinds of RNA genome can a virus have?

Answer 4

+ve sense single-stranded RNA

-ve sense single-stranded RNA

Double-stranded RNA

Question 5

What is the structure of a virus?

Answer 5

Virus nucleic acid enclosed in a capsid made of multiple protein subunits called capsomers

Nucleic acid and capsid together form the nucleocapsid.

Question 6

Define peplomers.

Answer 6

Membrane-anchored glycoprotein sugars added by host cell enzymes in the Golgi apparatus.

Question 7

Briefly describe viral replication.

Answer 7

Attachment to plasma membrane -> entry into cytoplasm/nucleus -> uncoating of virus particle -> synthesis of mRNA and protein -> replication of nucleic acid -> virus assembly -> exit of virus from cell