Question 1

The HIV genome can be characterized by all of the following EXCEPT

Accepted Answer

A)  5'-"cap." 
B)  3'-poly A-"tail." 
C)  a Lys-specific tRNA. 
D)  a DNA primer. 
E)  a coated nucleoprotein. 
A)  5'-"cap." 
B)  3'-poly A-"tail." 
C)  a Lys-specific tRNA. 
D)  a DNA primer. 
E)  a coated nucleoprotein.

Question 2

The causative agent of chickenpox is

Accepted Answer

A)  herpes simplex virus 1. 
B)  herpes simplex virus 2. 
C)  varicella-zoster virus. 
D)  Epstein-Barr virus. 
E)  HIV. 
A)  herpes simplex virus 1. 
B)  herpes simplex virus 2. 
C)  varicella-zoster virus. 
D)  Epstein-Barr virus. 
E)  HIV.

Question 3

What regulatory elements of herpes genes do NOT resemble those of eukaryotic genes?

Accepted Answer

A)  Each gene has a promoter with control sequences such as a TATA box. 
B)  Genes are transcribed individually. 
C)  Different gene classes have their own specific regulatory elements. 
D)  tegument 
E)  Genes are translated individually. 
A)  Each gene has a promoter with control sequences such as a TATA box. 
B)  Genes are transcribed individually. 
C)  Different gene classes have their own specific regulatory elements. 
D)  tegument 
E)  Genes are translated individually.

Question 4

What is the cause for cloudy centers appearing in lambda plaques on an Escherichia coli confluent plate?

Accepted Answer

A)  A low multiplicity of infection prevents the appearance of large numbers of lysed cells. 
B)  Cell debris forms a physical barrier between uninfected cells and virions. 
C)  Compounds in agar or nutrient medium protect bacterial cells from infection. 
D)  A large number of infected cells become resistant to bacteriophage infection. 
E)  Some infected cells become lysogens and start growing up where the infection began. 
A)  A low multiplicity of infection prevents the appearance of large numbers of lysed cells. 
B)  Cell debris forms a physical barrier between uninfected cells and virions. 
C)  Compounds in agar or nutrient medium protect bacterial cells from infection. 
D)  A large number of infected cells become resistant to bacteriophage infection. 
E)  Some infected cells become lysogens and start growing up where the infection began.

Question 5

Which host protein cleaves CI and triggers up to 100% lysis after lysogenic Escherichia coli cells are exposed to ultraviolet light?

Accepted Answer

A)  primase 
B)  DNA polymerase III 
C)  RecA 
D)  terminase 
E)  Lon protease 
A)  primase 
B)  DNA polymerase III 
C)  RecA 
D)  terminase 
E)  Lon protease

Question 6

Endogenous retroviruses (ERVs) express viral components, including reverse transcriptase, as part of the host cell normal functions. What role do ERVs play in mouse B-cell immune response to carbohydrate antigens?

Accepted Answer

B-cell antigen receptors are antibody-li

Question 7

RNA synthesis of influenza virus is primed by 7-methylguanine fragments of host mRNA, obtained by

Accepted Answer

A)  telomerase activity. 
B)  the rolling-circle mechanism. 
C)  endocytosis. 
D)  exocytosis. 
E)  cap-snatching. 
A)  telomerase activity. 
B)  the rolling-circle mechanism. 
C)  endocytosis. 
D)  exocytosis. 
E)  cap-snatching.

Question 8

Viruses that specifically infect and lyse tumor cells are called

Accepted Answer

A)  transfer vectors. 
B)  temperate. 
C)  lytic. 
D)  lysogenic. 
E)  oncolytic. 
A)  transfer vectors. 
B)  temperate. 
C)  lytic. 
D)  lysogenic. 
E)  oncolytic.

Question 9

What is the mechanism by which the viriotherapeutic agent T-VEC specifically kills hard-to-treat tumors?

Accepted Answer

T-VEC-infected tumor cells release fragm

Question 10

The capsid of the bacteriophage lambda is composed of two types of protein subunits, namely, D and E, arranged in a(n)________ shape.

Accepted Answer

A)  icosahedral 
B)  rhomboidal 
C)  pyramidal 
D)  triclinic 
E)  cubic 
A)  icosahedral 
B)  rhomboidal 
C)  pyramidal 
D)  triclinic 
E)  cubic

Question 11

Which are the main open reading frames (ORFs) present in all retroviruses, including HIV?

Accepted Answer

A)  vif, vpi, vpu 
B)  env, pol, gag 
C)  tat, nef, rev 
D)  vif, pol, tat 
E)  tat, nef, vpu 
A)  vif, vpi, vpu 
B)  env, pol, gag 
C)  tat, nef, rev 
D)  vif, pol, tat 
E)  tat, nef, vpu

Question 12

The figure below shows a partial map of the lambda DNA genome (23-48 kb). The early left and right operons as well as the late operon are indicated. Which gene or gene set is mislabeled?

Accepted Answer

A)  A-integration to host chromosome 
B)  B-lysis/lysogeny switch 
C)  C-DNA replication 
D)  D-lysis 
E)  E-terminase 
A)  A-integration to host chromosome 
B)  B-lysis/lysogeny switch 
C)  C-DNA replication 
D)  D-lysis 
E)  E-terminase

Question 13

Which of the following is FALSE regarding the establishment of lysogeny?

Accepted Answer

A)  Lambda phage DNA integrates as a prophage in the host genome at the att site by site-specific recombination. 
B)  Rolling-circle replication generates multiple genomes in tandem, which are eventually cleaved by the enzyme terminase. 
C)  Production of the repressor CI by the integrated prophage prevents superinfection by other lambda phages. 
D)  A CI lambda repressor dimer binds to the major groove of a specific DNA sequence in the bacterial host, preventing the transcription of lytic promoters. 
E)  Once integrated in the host's DNA, gene expression from the prophage is limited to a few proteins, including the repressor C1. 
A)  Lambda phage DNA integrates as a prophage in the host genome at the att site by site-specific recombination. 
B)  Rolling-circle replication generates multiple genomes in tandem, which are eventually cleaved by the enzyme terminase. 
C)  Production of the repressor CI by the integrated prophage prevents superinfection by other lambda phages. 
D)  A CI lambda repressor dimer binds to the major groove of a specific DNA sequence in the bacterial host, preventing the transcription of lytic promoters. 
E)  Once integrated in the host's DNA, gene expression from the prophage is limited to a few proteins, including the repressor C1.

Question 14

What is the Escherichia coli protein used by bacteriophage lambda as a receptor? Why has this protein not been lost in the process of evolution?

Accepted Answer

Escherichia coli can feed off short-chai

Question 15

Why do highly virulent strains of the influenza virus appear periodically? Give one example.

Accepted Answer

The influenza virus genome is organized

Question 16

The lambda genome is replicated by a rolling circle mechanism. What is the end result after a round of replication?

Accepted Answer

A)  a single-stranded DNA that is immediately packaged in the phage head 
B)  two molecules resulting from a step of circle-to-circle replication 
C)  several circular molecules inserted into each other; the circles are cleaved at the cos sites and eventually relegated 
D)  a concatemer (i.e., multiple genomes joined end to tail, which are cleaved at cos sites by a terminase), producing linear double-stranded DNA prior to packaging 
E)  several Okazaki fragments that are subsequently ligated 
A)  a single-stranded DNA that is immediately packaged in the phage head 
B)  two molecules resulting from a step of circle-to-circle replication 
C)  several circular molecules inserted into each other; the circles are cleaved at the cos sites and eventually relegated 
D)  a concatemer (i.e., multiple genomes joined end to tail, which are cleaved at cos sites by a terminase), producing linear double-stranded DNA prior to packaging 
E)  several Okazaki fragments that are subsequently ligated

Question 17

What types of infections are caused by herpes viruses? Describe the two possible types of replication processes that occur with the herpes viruses.

Accepted Answer

Two of the most common infections in the

Question 18

Herpes simplex virus 1 capsids receive a primary envelope from ________, whereas secondary enveloping uses ________.

Accepted Answer

A)  Golgi; the plasma membrane 
B)  the outer nuclear membrane; endoplasmic reticulum 
C)  vacuoles; lysosomes 
D)  lysosomes; the plasma membrane 
E)  endoplasmic reticulum; Golgi 
A)  Golgi; the plasma membrane 
B)  the outer nuclear membrane; endoplasmic reticulum 
C)  vacuoles; lysosomes 
D)  lysosomes; the plasma membrane 
E)  endoplasmic reticulum; Golgi

Question 19

The segmented genome of influenza virus makes virus assembly problematic. Is there evidence that the assembly mechanism packages the eight unique segments correctly?

Accepted Answer

Combined cryo-electron microscopy images

Question 20

The lysis/lysogeny switch has been used in synthetic biology applications that take advantage of the properties of the interaction between Cro and CI. Give two examples of such an application.

Accepted Answer

A minimal version of the CI/Cro switch h

Exam 11: Viral Molecular Biology

The HIV genome can be characterized by all of the following EXCEPT

The causative agent of chickenpox is

What regulatory elements of herpes genes do NOT resemble those of eukaryotic genes?

What is the cause for cloudy centers appearing in lambda plaques on an Escherichia coli confluent plate?

Which host protein cleaves CI and triggers up to 100% lysis after lysogenic Escherichia coli cells are exposed to ultraviolet light?

Endogenous retroviruses (ERVs) express viral components, including reverse transcriptase, as part of the host cell normal functions. What role do ERVs play in mouse B-cell immune response to carbohydrate antigens?

RNA synthesis of influenza virus is primed by 7-methylguanine fragments of host mRNA, obtained by

Viruses that specifically infect and lyse tumor cells are called

What is the mechanism by which the viriotherapeutic agent T-VEC specifically kills hard-to-treat tumors?

The capsid of the bacteriophage lambda is composed of two types of protein subunits, namely, D and E, arranged in a(n)________ shape.

Which are the main open reading frames (ORFs) present in all retroviruses, including HIV?

The figure below shows a partial map of the lambda DNA genome (23-48 kb). The early left and right operons as well as the late operon are indicated. Which gene or gene set is mislabeled?

Which of the following is FALSE regarding the establishment of lysogeny?

What is the Escherichia coli protein used by bacteriophage lambda as a receptor? Why has this protein not been lost in the process of evolution?

Why do highly virulent strains of the influenza virus appear periodically? Give one example.

The lambda genome is replicated by a rolling circle mechanism. What is the end result after a round of replication?

What types of infections are caused by herpes viruses? Describe the two possible types of replication processes that occur with the herpes viruses.

Herpes simplex virus 1 capsids receive a primary envelope from ________, whereas secondary enveloping uses ________.

The segmented genome of influenza virus makes virus assembly problematic. Is there evidence that the assembly mechanism packages the eight unique segments correctly?

The lysis/lysogeny switch has been used in synthetic biology applications that take advantage of the properties of the interaction between Cro and CI. Give two examples of such an application.

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

Filters

Herpes simplex virus 1 capsids receive a primary envelope from , whereas secondary enveloping uses .