Deck 18: Genetics of Viruses and Bacteria

Question 1

The bacterial genetic material is

A) held within a membrane-bound nucleus.
B) localized to a nucleoid region.
C) circular and loosely packed.

Answer 1

localized to a nucleoid region.

Question 2

f an E. coli strain typically has 50 loop domains, how many total base pairs might this bacteria have in its chromosome?

A) 500-2,000
B) 5,000-20,000
C) 50,000-80,000
D) 200,000-450,000
E) 5 billion

Answer 2

200,000-450,000

Question 3

The chromosome must be ___________ in order to fit into the bacterial cell.

A) supercoiled by topoisomerases
B) supercoiled around histone proteins
C) organized into loop domains by topiosomerases
D) compacted into a nucleosome
E) both organized into loop domains and supercoiled by topoisomerases

Answer 3

supercoiled by topoisomerases

Question 4

Bacteria contain plasmids because

A) they are essential for growth.
B) they provide genes that allow the bacteria to grow and thrive in the presence of potential toxins.
C) they are essential for cellular respiration.
D) humans artificially created plasmids and then inserted them into bacteria.
E) they are essential for chromosome replication and binary fission.

Question 5

The two daughter cells that are formed as a result of binary fission

A) each have about half the number of plasmids as the mother cell.
B) are members of the same colony.
C) have genetically identical chromosomes.
D) Two of the answers are correct. They are members of the same colony and have genetically identical chromosomes.
E) All of these statements are correct.

Question 6

How does the reproduction of HIV and lambda phage differ?

A) HIV contains reverse transcriptase enzyme, while lambda phage does not.
B) Immediately after HIV enters the cell, reverse transcriptase RNA is transcribed into DS DNA. Lambda phage reverse transcriptase DNA is integrated immediately into the host genome
C) HIV contains integrase, while lambda phage does not.
D) HIV attaches to specific proteins on the cell surface, while lambda phage does not.
E) Lambda phage attaches to specific proteins on the cell surface, while HIV does not.

Question 7

Viral release from a eukaryotic cell

A) requires the production of lysozyme encoded by the viral genome.
B) requires the production of lysozyme encoded by the eukaryotic genome.
C) is essential to envelope formation.
D) kills the infected cell.
E) requires the production of lysozyme encoded by the viral genome and kills the infected cell.

Question 8

Which of the following is not an emerging virus?

A) HIV
B) SARS
C) influenza
D) Epstein Barr
E) All of these choices are emerging viruses.

Question 9

Which of the following hypotheses proposed to explain the evolutionary origin of viruses does not assume the pre-existence of living cells?

A) Viruses evolved from macromolecules.
B) Viruses evolved from plasmids that acquired genes for their own replication.
C) Viruses evolved by losing all the genetic information that is not absolutely required for reproduction.
D) The precursors of cellular DNA genomes may have been RNA molecules.
E) Viruses evolved from chromosomal elements.

Question 10

A drug researcher has developed a macromolecule that can bind to scrapie and thus change the prion's conformation. What effect might this have on the actions of scrapie?

A) The shape change could prevent the scrapie protein from converting normal proteins to scrapie proteins.
B) The shape change could induce scrapie protease activity.
C) The shape change could stop the transcription of scrapie RNA.
D) The shape change could stop the replication of scrapie DNA.
E) The shape change could block the translation of scrapie RNA.

Question 11

Which of the following does not contribute to the infectious ability of prions?

A) Prion proteins are not digested.
B) Prion proteins can induce the misfolding of normal proteins.
C) Prion proteins can enter the bloodstream.
D) Prion proteins are deposited as aggregates.
E) Prion diseases progress slowly.

Question 12

Viroids have a genome but do not translate any of it to protein.

Question 13

Horizontal gene transfer occurs when one species of bacteria takes up the DNA of another species that released the DNA when it died.

Question 14

The ability to transfer DNA via conjugation is a universal feature of E. coli strains.