influenza

Question 1

what are the glycoproteins present in the envelope of influenza?

Answer 1

• hemagglutinin and neuraminidase

Question 2

what does hemagglutinin do

Answer 2

it is a protein that functions in the attachment of the virus to a host cell and entry of the viral genome into the target cell

Question 3

what does neuraminidase do

Answer 3

it facilitates the release of newly produced virus particles from the host cell by cleaving sialic acid which binds to the hemagglutinin on emerging viral particles

Question 4

what does the influenza genome have?

Answer 4

it is organised into eight pieces (-) sense ssRNA (single stranded RNA)

Question 5

how does the influenza virus start the life cycle?

Answer 5

it enters the epithelial cells lining the respiratory tract

Question 6

adsorption

Answer 6

hemagglutinin on the virus binds to the sialic acid (glycoprotein receptor) on the cell’s membrane

Question 7

penetration

Answer 7

is taken into the cell by receptor-mediated endocytosis within a vesicle

Question 8

replication

Answer 8

the (-) sense viral genome acts as a template for the synthesis of complementary (+) sense RNA strands by viral genome and a template for synthesis of new viral proteins

the new viral genomic RNAs become associated with nucleoproteins and exist the nucleus via the nucleus pores

at the same time, haemaglutinin and neuraminidase are incorporated into the host cell’s membranes

Question 9

maturation

Answer 9

individual ribonucleoprotein segments associate together to form the helical nucleocapsid.

haemagglutinin and neuraminidase have at this point coated the surface of the cell membrane

Question 10

release

Answer 10

neuraminidase facilitates the release of the virus particles by cleaving sialic acid which binds to haemagglutinin on emerging virus particles

• it is then bud off by evagination of the cell