Clinically significant viruses

Question 1

What is the importance of viruses in the environment and its impacts on health

Question 2

What are the key components of a virus (Structure)

Answer 2

Capsid, Lipid Envelope, Spikes,

Question 3

What are the key components of a virus (genome)

Answer 3

GENOME: A single molecule of DNA or RNA BUT NEVER BOTH
Nucleic acid may be:
-single stranded (ss)
-double stranded (ds)
-partially double stranded (eg HBV partially ss and mainly dsa DNA)

Viruses can have different genome

Question 4

What are the key components of a virus (shape)

Answer 4

SHAPE: Viruses generally fall into 2 morphological groups Helical or Isometric/Icosahedral

Question 5

Identify some diseases infections caused by viruses

Question 6

Define Genome

Question 7

Define Capsid

Answer 7

Coat Protein - surrounding genetic material and made up of a discrete and standard number of units(capsomeres) which are generally specific for a virus type

Question 8

Define peplomer

Answer 8

AKA spikes
Glycoproteins present on the outside of viral capsid or envelope
Important for attachment to specific host tissues
Changes in spike proteins can result in new variants
Can also be categorized by other characteristics:
HA : Haemagglutinin (allows attachment)
NA: Neuraminidase (allows exit)

Question 9

Define envelope

Answer 9

Lipid Envelope: +/- eg HSV
When present, surrounds capsid
Made from the host cell membrane and some viral glycoproteins
Glycoproteins on surface of lipid envelope allow attachment to specific receptors on host cell
Aids in penetration of host cell by fusing with cell membrane

Question 10

Describe the steps in viral reproduction

Answer 10

Six steps in the replication of most viruses
1. Adsorption
2. Penetration
3. Uncoating
4. Replication
5. Maturation/assembly
6. Release