Introduction to viruses

Question 1

What size are viruses

Answer 1

Small: 20 – 400 nm diameter

Question 2

What is the 3 structure of viruses

Answer 2

Icosahedral: 20 faces equilateral triangle
Helical: protein binds round DNA/RNA in a helical fashion
Complex: neither

Question 3

What does it mean that viruses are Obligate intracellular pathogens

Answer 3

can only replicate inside host

Question 4

What is the order of taxonomy

Answer 4

Order
Family 
genus 
species 
(oh my freaking god sarah)

Question 5

Viral families classified by

Answer 5

shape/symmetry
envelope
genetic structure
mode of replication

Question 6

What do they spiral infections do for the virus

Answer 6

provide natural immunity

Question 7

What is a virus composed of

Answer 7

nucleic acid
Lipid envelope
Protein capsid
Virion associated polymerase

Question 8

Process of viral replication

Answer 8

attaches, uncoats RNA, replication of virus RNA in MRNA synthesis, virus protein synthesised, budding and related on the surface

Question 9

What are the different viral transmissions

Answer 9

Blood borne
Sexual
Droplet 
Airborne 
Close contact 
Vector borne 
Zoonotic (Animals)

Question 10

What isa droplet transmission; example

Answer 10

Large particle with small projection; Influenza,

Question 11

What is a airborne transmission; example

Answer 11

Particle transferred in the air environment; Measels, chicken pox

Question 12

What does coinfection of human and animal or bird lead to

Answer 12

may lead to recombination and generation of a new strain

Question 13

Novel virus

Answer 13

Virus that has not be seen before

Question 14

What does a clearance of viral infection mean

Answer 14

you don’t get any immunity e.g. influenza

Question 15

What immunity does Measels have

Answer 15

Long term immunity

Question 16

What infection is HIV, hepatitis B, hepatitis C

Answer 16

Chronic infection

Question 17

What is viral latency

Answer 17

Virus lies dormant, then something triggers the virus

eg. immune system supresors/ stress etc.

Question 18

What is viral transformation

Answer 18

long term viral infection that alters gene expression e.g. cancer

Question 19

Example of viral infections that cause transformation i.e. cancer

Answer 19

Epstein-Barr Virus — glandular fever
Human Papillomavirus — causes cervical cancer
Hepatitis B/C : hepatocellular carcinoma
Human T-cell Lymphotropic Virus: Adult T-cell leukaemia/lymphoma

Question 20

What viruses are latent

Answer 20

Herpes Simplex Virus (coldsore)

Varicella Zoster Virusm (chicken pox)

Question 21

How does viral infections cause cancer

Answer 21

Modulate cell cycle control
Modulating apotosis
Promote oxidation
(some persistent viral infections can cause persistent inflammatory processes which lead to cancer)

Question 22

How do you detect a whole virus organism

Answer 22

electron microscopy or grown in cell culture

Question 23

How do you detect part of virus organism (antigen, nucleic acid)

Answer 23

antigen detection detected from viruses immune response
DNA/RNA replication from PCR
Amplification of region target organism genome

Question 24

What is antiviral therapy

Answer 24

treating viruses by binding to cell and preventing viral replication

Question 25

Antivirals are used for

Answer 25

Prophyaxis - prevent disease
Pre-emptive therapy - treat before symptoms
Overt disease
Suppressive therapy - keep viral replication below the rate that causes tissue damage in an asymptomatic infected patient

Question 26

How do you prevent viral infection

Answer 26

immunisation - vaccination

Antenatal screening

Question 27

Human virus passage to animal is called

Answer 27

coinfection