Viruses

Question 1

Describe genome of influenza virus.

Answer 1

-negative sense RNA (complementary to mRNA)
-8 different segments of single stranded RNA associated with nucleoproteins
-Each RNA segment is packed with 3 polymerase proteins which come together to form an RNA-dependent RNA polymerase enzyme complex which replicates and transcribes the viral genome in the host cell

Question 2

Describe genome of HIV virus.

Answer 2

-(+) strand RNA
-viral genome has the same sequence as viral mRNA
-2 identical copies of single stranded RNA bound to nucleocapsid proteins

Question 3

Describe attachment of influenza virus.

Answer 3

Hemagglutinin binds to complementary sialic acid receptor on host cell (e.g. epithelial cells in respiratory tract) membrane.

Question 4

Describe penetration of influenza virus.

Question 5

Describe how viral nucleic acid of bacteriophage enters a bacterial cell

Answer 5

1. When tail fibres of T4/Lambda bacteriophage attaches to receptors on bacterial cell wall,
2. Lysozyme is released which digests the bacterial cell wall releasing molecules, causing conformational change in base plate
3. This causes the tail sheath to contract and thrust the hollow tube through the cell wall
4. Viral DNA genome is injected into the bacterial cell through the hollow tube.