Quiz 10

In this figure, Lacl is acting as a(n) repressor/activator that inhibits/activates transcription.

1. repressor

2. inhibits

In this figure, allolactose is acting as an inducer/copressor _ that inhibits/activates transcription.

1. inducer

2. activates

In this figure, tryptophan is acting as a(n) corepressor/inducer that __inhibits /activates_ transcription.

Answer 1:

corepressor

Answer 2:

inhibits

Genes that are constitutively expressed are operons/conditionally needed/needed for essential functions and sometimes on, always "on" .

Answer 1:

needed for essential functions

Answer 2:

always "on"

The papillomavirus infects keratinocytes that are not actively dividing. What does this virus do to gain nucleotides to support viral replication?

 

It stimulates the cell to enter into “S-phase” of the cell cycle.

 

It contains genes that encode for enzymes for nucleotide synthesis.

 

It degrades the nuclear DNA of the host cell to release free nucleotides.*

 

It stimulates the cell to enter into apoptosis.

 

It lyses the cell to release nucleotides.

 

It stimulates the cell to enter into “S-phase” of the cell cycle.

Match to following definitions

• provirus

• reverse transcriptase

• RNA-dependent RNA polymerase

• integrase

• Provirus — Viral genome incorporated into host genome

• Reverse transcriptase — Viral enzyme that converts the single-stranded RNA genome into double-stranded DNA

• RNA-dependent RNA polymerase — Viral polymerase that produces RNA from an RNA template

• Integrase — Viral enzyme that ifacilitates incorporation of viral genome into host genome

Which one of the following is an example of a virus known to undergo evolutionary change by reassortment?

Papilloma virus

Influenza virus

Hepatitis type B virus

Herpes virus

Adenovirus

Influenza virus

A non-enveloped virus will have its attachment proteins present in its ______________

envelope spikes

capsid spikes

cell wall spikes

cytoplasm

plasma membrane

capsid spikes

Obviously, host cells do not “want” to be infected by viruses, yet they contain receptors that allow viral entry. Why can’t host cells eliminate the receptors to prevent viral attachment?

• The receptors are integral to the host genome

• Most host cell receptors are embedded in the cell wall

• Most host cell receptors serve a critical cellular function

• The receptors are integral to the structural integrity of the cell

• Host cells rely on the immune system to destroy viruses

Most host cell receptors serve a crtiical cellular function