33. Viruses II

Question 1

Pseudo Types are formed when ……

A. genome of one virus randomly incorporated in capsid composed from a different virus.
B. Minor changes to genome year to year.
C. nucleocapsid of one virus acquires envelope from another virus type
D. Reassortment of RNA segments between two different viruses making a pathogenic strain

RFA

Answer 1

Ans. C

A. is the definition for Phenotypic mixing or transcapsidation

B. is the definition for Genetic drift

D. is the definition for Genetic shift.

Question 2

A researcher is investigating a newly discovered virus and has fun that is posses RNA-Dependent DNA polymerase . Under which viral group would with be classified?

A. IV
B.VII
C. I
D. III
E. V

RFA

Answer 2

Ans. B. VII, VI both possess RNA Dependent DNA Polymerase

VI is RNA retroviruses

VII is DNA virus that goes to RNA then back to DNA

Question 3

A 25 year old male presents with fever, lymphadenopathy, and blistering sores on his penis after having sex with several women he met dancing Soca at Bananas. This is a dsDNA virus which utilizes both DNA-Dependent Polymerase and DNA-Dependent RNA polymerase. According to Baltimore Classification this virus falls into which group?

A. I
B. II
C. IV
D. V
E. VII

SZ

Answer 3

Ans. A Group I

The man has herpes which is a Group I virus.

Group II is a ssDNA. Group IV and V are both RNA. Group VII is dsDNA which utilizes Reverse Transcriptase.

Question 4

Hepatitis D is defective and requires Hepatitis B to act as a “helper-virus.” It utilizes the Hep B glycoproteins/antigens to infect the host. This is an example of which of the following?

A. Antigenic Shift
B. Complementation
C. Antigenic Drift
D. Phenotypic Mixing

SZ

Answer 4

Ans. B Complementation

Hep B rescues the defective Hep D so they can both act on host at different gene locations.

Choice A: Antigenic Shift is when segmented viruses undergo reassortment.
Choice C: Slower than antigenic shift, antigenic drift is when evolution causes small changes in the genome sequence.
Choice D: Phenotypic mixing is when the genome of one viruses is randomly incorporated into the capsid from a different viruses, or combination of two viruses.