viruses

Question 1

What is a virus?

Answer 1

An infectious, obligate intracellular parasite comprised of genetic material (DNA or RNA) surrounded by a protein coat (and sometimes a membrane)

Question 2

what does the structure of a virus consist of

Answer 2

viruses consists of a nucleic
acid surrounded by a protein coat

Question 3

viruses depend on host cells for…

Answer 3

depend on host cell for ATP, amino
acids, nucleotides, etc.

Question 4

what are three functions that viruses DONT have..

Answer 4

▪ Do not grow or divide
▪ Do not have ribosomes
-Or the genetic info to make them
▪ Do not have metabolic pathways

Question 5

5 characteristics of living entities

Answer 5

▪ Energy processing
▪ Growth and development
▪ Response to environment
▪ Regulation
▪ Reproduction

Question 6

out of the 5 characteristics of living entities.. which ones do viruses adhere to.

Answer 6

▪ Energy processing - no
▪ Growth and development - no
▪ Response to environment - no
▪ Regulation - no
▪ Reproduction- yes (sort of)

Question 7

what is the nucleic acid inside a virus is made out?

Answer 7

DNA or RNA

Question 8

what is the protein coat of a virus made of?

Answer 8

called a capsid; encloses the viral
genome; made of protein subunits called capsomeres

Question 9

what are the different structures that a virus can be

Answer 9

9Helical capsid- Ex. Tobacco Mosaic Virus)
(Polyhedral with glycoprotein spikes-Ex. Adenovirus)
(Heads that enclose DNA and Protein tail with fibers- Ex. Bacteriophage)
(Membranous envelope with glycoproteins-Ex. Zika Virus, Coronaviruses, Influenza Viruses)

Question 10

viral life cycle

Answer 10

▪ Infect a host
-Host range is determined by how the virus recognizes the host cell
▪ Reproduce (replicate)
▪ Ensure that progeny are transmitted

Question 11

the replicative cycle of a Retrovirus

Answer 11

Retrovirus: a virus that inserts a DNA copy of its RNA genome into the DNA of the host cell that it invades, changing the genome of that cell

Retroviruses have the enzyme
reverse transcriptase that
converts their RNA into DNA

The new viral DNA gets
incorporated into the host cell DNA = called a provirus

Question 12

what the 2 Replicative Cycles of Phages called and what they do.

Answer 12

▪ Lytic cycle (produces new phages and lyses the
host)
▪ Lysogenic cycle (produces new phages without
destroying the host)

Question 13

explain the steps of the Lytic cycle

Answer 13

Question 14

explain the steps of the lysogenic

Answer 14