Lecture 8 - Viruses

Question 1

What is a Virus?

Answer 1

Non-living structure formed from proteins an nucleic acids

Question 2

There is a variety of viruses, what is a Caspid?

Answer 2

Caspid is made of identical protein sub-units called capsomeres.

Two types: Caspid (e.g. rabies)
and Icosophedral (polio) and herpes)

Question 3

What is the purpose of Caspid?

Answer 3

Protecting the viral genome and can aid attachment to host cell

Question 4

What are the properties of Viral Genome?

Answer 4

Can be RNA or DNA
Single or Double Stranded
Segmented or Non- segmented
Diploid or Haploid

Question 5

What is genome?

Answer 5

Amount of genetic material

Question 6

How is Viral replication occurred? 7 Steps

Answer 6

1. Adsorption: Virus binds to the host cell
2. Penetration: Virus inject its genome into the host cell
3. Disassembly: Release of nucleic acid from protein coat
4. Viral genome replication: (Transcription)
5. Assembly (Translation)
6. Maturation: Viral components assemble and viruses fully develop
7. Release: Newly produced viruses are expelled from the host cell.

Question 7

How is RNA virus replicated such as Influenza Virus

Answer 7

1. Virus binds to cell and virus enters through endocyotosis
2. Virus releases RNA strands (Influenza has 8) which enter the host cell’s nucleus
3. Viral RNA replicated in host cell nucleus, then in cytoplasm the RNA is packed into capsid and glycorproteins produced
4. Capsid acquired phospholipid coat from host cell membrane with viral glycoprotein “pegs” added
5. Assembled virus leaves host cell - eventually host cell is destroyed

Question 8

How does a DNA virus e.g. HPV infect

Answer 8

1. Virus binds to cell and enters through endocytosis
2. Virus dissembles and releases into cell nucleus
3. Transcription to produce mRNA and Viral DNA is replicated
4. Capsid proteins are made and coat DNA, other proteins are (translated) assembly occurs in nucleus.
5. If a virus is coated it will acquire phospholipid coat, with associated viral glycoproteins on surface.
6. Assembled virus leaves host cell - eventually host cell is destroyed

Question 9

How does a Retro Virus such as HIV infect?

Answer 9

1. Virus binds to cell enters through endocytosis
2. Releases RNA strands
3. Reverse transcritpase from virus converts viral RNA into Viral DNA
4. Viral DNA enters host cell nucleus and combines with its DNA, host cell no produces viral RNA coated in capsid proteins.
5. Host cells ribosomes produces viral protein. VIral RNA coated in capsid proteins
6. Acquire phospholipid coat, with associated viral glycoproteins on surface
7. Assembled Virus leaves host cell, eventually host cell is destroyed

Question 10

What kinda virus is Ebola?

Answer 10

A RetroVirus (RNA)

Question 11

What pathogen causes Ebola?

Answer 11

Ebola Virus

Question 12

What is the disease caused of Ebola

Answer 12

Ebola Hemorrhagic Fever

Question 13

What Resrvoir is Ebola in

Answer 13

Fruit Bats, non-primates

Question 14

How is ebola transmissted

Answer 14

Direct contact with body fluids (blood, sweat, urine, vomit, breast milk, semen, and faeces through broken skin or mucous membranes

Question 15

How long does Ebola incubate for?

Answer 15

2-21 days