Question

QUESTION 1

1. Viruses are important in ecological processes in directly stimulating which process?

   	A.	Uptake of nitrogen to make amino acids and other organic N compounds
   	B.	Nitrification
   	C.	Nitrogen fixation
   	D.	Nitrogen mineralization

2 points   

QUESTION 2

1. One difference between SARS-CoV-2 and influenza viruses is that SARS-CoV-2

   	A.	is a retrovirus
   	B.	infects through respiratory droplets
   	C.	has a single molecule encoding its genome
   	D.	embeds spike proteins in the host cell membrane before new virion budding
   	E.	has an animal reservoir

2 points   

QUESTION 3

1. Why are flu vaccines required every year?

   	A.	Antigenic shift results in new combinations of flu genes that have not been encountered before
   	B.	Immune memory is not lifetime for vaccinated individuals
   	C.	Mutations accumulate in human strains of the flu genome
   	D.	All of the above

2 points   

QUESTION 4

1. Which virus has the highest case fatality rate despite a long latency period?

   	A.	SARS-CoV-2
   	B.	Measles
   	C.	HIV
   	D.	Influenza

2 points   

QUESTION 5

1. Which of the following types of viruses require a nucleotide polymerase (an RNA polymerase or reverse transcriptase) to be included in the virion? (choose any number of options 0-5)

   	A.	Positive strand RNA virus
   	B.	Retrovirus
   	C.	Negative strand RNA virus
   	D.	Double stranded RNA virus
   	E.	DNA virus

Answer 1

Answer 1-c) nitrogen fixation

Answer 2- c) has a single molecule encoding its genome.

Rest all the statements are common to the influenza virus

Answer 3- d) all of the above

Answer 4- c) HIV virus

Fatality rate of HIV is 80-90% where as influenza =60%, measles= 1-3% & SARS-CoV-2 =11%

Answer 5- c) negative strand RNA virus

Negative strand RNA is complementary to mRNA and thus RNA polymerase is required to convert it in positive strand RNA before translation.