Ch 16: Viruses (Exam 2)

Question 1

Species from which human influenza viruses often evolve

Answer 1

pigs (swine flu), birds (avian flu)

Question 2

Common Viral Diseases

Answer 2

-influenza
-ebola
-smallpox
-common cold
-rabies
-polio
-chicken pox
-warts
-AIDS
-zika

Question 3

Type of form of genetic information found in viruses

Answer 3

Either DNA or RNA that carries the “recipes” for their proteins, either type of nucleic acid may be single or doubled stranded

Question 4

Bacteriophages

Answer 4

(phages) are viruses that infect bacteria
-some phages have parts that resemble tails, legs, and spikes (like a spacecraft)

Question 5

What role does a reservoir play in viral transmission?

Answer 5

the reservoir of the virus is the host that acts as a continual source of the viral infection for other host species
Ex: for many viruses that infect humans the reservoir is the host animal that may or may not show symptoms of infection
-wild birds (west nile, avian flu)
-rodents (hantavirus pulmonary syndrome)
-mosquitos (yellow fever)
-raccoons (rabies)

Question 6

Why do most scientist not consider viruses to be alive?

Answer 6

because a virus does not metabolize, respond to stimuli, or reproduce on its own

Question 7

Distinguish between a Lytic Infection and a Latent stage of infection

Answer 7

Lytic Infection-(Replicates) a virus enters the bacterium, immediately replicates, and causes the host cell to burst (lyse) as it releases a flood of new viruses

Latent Infection-(Does Not Replicate) viral genetic information inside and animal cell lies dormant, even as the infected host cell divides, new viruses are not produced, However the virus may be reactivated later.

Question 8

What is a retrovirus and how is HIV an example?

Answer 8

-Has an RNA genome (HIV)
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades.

Question 9

What type of cells does HIV infect?

Answer 9

CD4 cells and T cells (WBC)

Question 10

Explain the role of vaccinations in limiting the extent/severity of viral infections

Answer 10

introducing something called an antigen into the body which imitates the infection and primes the immune system to respond
-antibiotics can treat secondary bacterial infections, but the cant effect the underlying virus

Question 11

Why is it recommended to get a new flu vaccine every year?

Answer 11

because flu viruses mutate rapidly so the flu vaccine for this year will not be effective against next years strain