Question 1

Viroid RNA molecules have a high degree of base pairing throughout the molecule.

Accepted Answer

A) True 
 B)False  True

Question 2

What is surprising about the observation that a cellular RNA polymerase copies the viroid genome?

Accepted Answer

A) RNA polymerases usually require a pre-existing RNA primer. 
B) RNA polymerases usually transcribe from a DNA template. 
C) RNA polymerases don't usually synthesize DNA. 
D) RNA polymerases don't usually initiate synthesis from a protein primer. 
E) RNA polymerases are not found in the cytoplasm of the host cell. 
A) RNA polymerases usually require a pre-existing RNA primer. 
B) RNA polymerases usually transcribe from a DNA template. 
C) RNA polymerases don't usually synthesize DNA. 
D) RNA polymerases don't usually initiate synthesis from a protein primer. 
E) RNA polymerases are not found in the cytoplasm of the host cell. B

Question 3

How do we differentiate between the positive and negative strands of a viroid genome?

Accepted Answer

A) The positive strand produces the viral protein. 
B) The positive strand is transcribed to make the viral mRNA. 
C) The positive strand is packaged into the viroid particle. 
D) The positive strand is the only strand copied by a cellular RNA polymerase. 
E) The positive strand is the most abundant RNA produced. 
A) The positive strand produces the viral protein. 
B) The positive strand is transcribed to make the viral mRNA. 
C) The positive strand is packaged into the viroid particle. 
D) The positive strand is the only strand copied by a cellular RNA polymerase. 
E) The positive strand is the most abundant RNA produced. E

Question 4

The enzymatic function that cleaves the avocado sunblotch viroid genome is called a ribozyme and does not require any proteins to function.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following groups of organisms do viroids cause disease in?

Accepted Answer

A) Plants 
B) Insects 
C) Mammals 
D) Algae 
E) Paramecia 
A) Plants 
B) Insects 
C) Mammals 
D) Algae 
E) Paramecia

Question 6

Which of the following describes the major difference between hepatitis delta virus (HDV)and the plant viroids and satellite RNAs?

Accepted Answer

A) Only the HDV genome contains a ribozyme activity. 
B) Only HDV requires a helper virus. 
C) Only the HDV genome encodes a protein. 
D) Only HDV replicates using a rolling circle mechanism. 
E) Only HDV requires RNA polymerase II during its replication cycle. 
A) Only the HDV genome contains a ribozyme activity. 
B) Only HDV requires a helper virus. 
C) Only the HDV genome encodes a protein. 
D) Only HDV replicates using a rolling circle mechanism. 
E) Only HDV requires RNA polymerase II during its replication cycle.

Question 7

The deamination of an adenine residue in the genome of the hepatitis delta virus causes which of the following to occur?

Accepted Answer

A) A stop codon to be converted to a tryptophan codon. 
B) A stop codon to be converted to a start codon. 
C) A 5' splicing signal to be added. 
D) A 3' splicing signal to be added. 
E) It creates a polyadenylation signal. 
A) A stop codon to be converted to a tryptophan codon. 
B) A stop codon to be converted to a start codon. 
C) A 5' splicing signal to be added. 
D) A 3' splicing signal to be added. 
E) It creates a polyadenylation signal.

Question 8

The ribozyme function found in virioids and hepatitis delta virus can be used to cleave exogenous RNA molecules.Which of the following is a requirement for the ribozyme to be recycled and cleave more than one substrate?

Accepted Answer

A) The entire length of the substrate must not be too long. 
B) The structure of the ribozyme RNA must be very stable. 
C) Only a short region of complementarity between the target and the ribozyme. 
D) The level of magnesium ions must be low enough. 
E) The temperature of the reaction must be high enough. 
A) The entire length of the substrate must not be too long. 
B) The structure of the ribozyme RNA must be very stable. 
C) Only a short region of complementarity between the target and the ribozyme. 
D) The level of magnesium ions must be low enough. 
E) The temperature of the reaction must be high enough.

Question 9

Which of the following is NOT a type of infectious RNA that can cause disease?

Accepted Answer

A) Viroid 
B) Prion 
C) Hepatitis delta virus 
D) Satellite RNA 
E) Viroid-like plant satellite RNA 
A) Viroid 
B) Prion 
C) Hepatitis delta virus 
D) Satellite RNA 
E) Viroid-like plant satellite RNA

Question 10

Hepatitis delta virus is transmitted through the same pathways as hepatitis B virus.

Accepted Answer

A) True 
 B)False

Question 11

When studying the replication of viroids and hepatitis delta virus,which of the following allows scientists to distinguish which of the three cellular RNA polymerases is required?

Accepted Answer

A) The sub-cellular location of each RNA polymerase. 
B) Whether the polymerase requires an RNA primer or not. 
C) Whether the polymerase can synthesize mRNAs or not. 
D) Whether the polymerase will use an RNA molecule as a template. 
E) The sensitivity of the RNA polymerase to the toxin $\alpha$-amanitin. 
A) The sub-cellular location of each RNA polymerase. 
B) Whether the polymerase requires an RNA primer or not. 
C) Whether the polymerase can synthesize mRNAs or not. 
D) Whether the polymerase will use an RNA molecule as a template. 
E) The sensitivity of the RNA polymerase to the toxin $\alpha$-amanitin.

Question 12

How is the 3' end of the hepatitis delta virus mRNA formed?

Accepted Answer

A) It is cleaved by the viral ribozyme activity. 
B) It is cleaved and polyadenylated by cellular enzymes. 
C) It folds into a distinct stem-loop structure. 
D) The polymerase stutters at a poly(U)region in the genome. 
E) The delta antigen is covalently attached to the 3' end. 
A) It is cleaved by the viral ribozyme activity. 
B) It is cleaved and polyadenylated by cellular enzymes. 
C) It folds into a distinct stem-loop structure. 
D) The polymerase stutters at a poly(U)region in the genome. 
E) The delta antigen is covalently attached to the 3' end.

Question 13

Which of the following is a major difference between the group A and the group B viroids?

Accepted Answer

A) Whether they affect the RNAi pathway or not. 
B) Whether they infect animals or plants. 
C) Whether they produce a protein or not. 
D) Whether they have a self-cleaving RNA or not. 
E) Whether they replicate in the endoplasmic reticulum or not. 
A) Whether they affect the RNAi pathway or not. 
B) Whether they infect animals or plants. 
C) Whether they produce a protein or not. 
D) Whether they have a self-cleaving RNA or not. 
E) Whether they replicate in the endoplasmic reticulum or not.

Question 14

Describe how the ribozyme activity found in the plant virioids and hepatitis delta virus can be used as therapeutic agents to treat infections with other viruses.

Accepted Answer

Ribozymes are molecules of RNA that can

Question 15

Which of the following statements about the plant satellite RNAs is FALSE?

Accepted Answer

A) Satellite RNAs encode their own capsid protein. 
B) Satellite RNAs are transmitted to new hosts via a virion. 
C) Satellite RNAs require a helper virus in order to be replicated. 
D) Satellite RNA genomes are composed of small circular RNA molecules that contain a high degree of base pairing. 
E) Satellite RNAs contain a ribozyme function that can cleave longer RNA molecules into single genomes. 
A) Satellite RNAs encode their own capsid protein. 
B) Satellite RNAs are transmitted to new hosts via a virion. 
C) Satellite RNAs require a helper virus in order to be replicated. 
D) Satellite RNA genomes are composed of small circular RNA molecules that contain a high degree of base pairing. 
E) Satellite RNAs contain a ribozyme function that can cleave longer RNA molecules into single genomes.

Question 16

Which of the following is NOT thought to be a mechanism by which viroids cause disease in their plant hosts?

Accepted Answer

A) By basepairing to an important cellular RNA,preventing its function. 
B) By activating the dsRNA induced protein kinase. 
C) By causing the degradation of cellular mRNAs via the RNAi pathway. 
D) By interfering with mRNA splicing because they resemble a cellular snRNA. 
E) By inhibiting the machinery that exports mRNAs out of the nucleus. 
A) By basepairing to an important cellular RNA,preventing its function. 
B) By activating the dsRNA induced protein kinase. 
C) By causing the degradation of cellular mRNAs via the RNAi pathway. 
D) By interfering with mRNA splicing because they resemble a cellular snRNA. 
E) By inhibiting the machinery that exports mRNAs out of the nucleus.

Question 17

When the ribozyme activity in the avocado sunblotch viroid cleaves the RNA genome,which of the following describes the structure of the nucleotide on the 5' side of the cleavage?

Accepted Answer

A) It contains a 5' phosphate group 
B) It contains a 3' phosphate group 
C) It contains a 3'-OH group 
D) It contains a 2',3'-cyclic phosphate 
E) It contains a 3' hydrogen 
A) It contains a 5' phosphate group 
B) It contains a 3' phosphate group 
C) It contains a 3'-OH group 
D) It contains a 2',3'-cyclic phosphate 
E) It contains a 3' hydrogen

Question 18

Viroids encode a single protein which is used to package the RNA for transmission between hosts.

Accepted Answer

A) True 
 B)False

Question 19

The typical structure of the genome of a viroid is described as?

Accepted Answer

A) Circular double-stranded DNA of 3000-4000bp. 
B) Linear double-stranded RNA segment of 500-1000bps. 
C) Circular singled-stranded RNA of 250-400nts. 
D) Linear single-stranded RNA of 500-1000nts. 
E) Circular double-stranded RNA of 400-800bp. 
A) Circular double-stranded DNA of 3000-4000bp. 
B) Linear double-stranded RNA segment of 500-1000bps. 
C) Circular singled-stranded RNA of 250-400nts. 
D) Linear single-stranded RNA of 500-1000nts. 
E) Circular double-stranded RNA of 400-800bp.

Question 20

Coinfection with both hepatitis B and delta virus together makes the resulting liver disease less severe.

Accepted Answer

A) True 
 B)False

Exam 31: Viroids and Hepatitis Delta Virus

Viroid RNA molecules have a high degree of base pairing throughout the molecule.

What is surprising about the observation that a cellular RNA polymerase copies the viroid genome?

How do we differentiate between the positive and negative strands of a viroid genome?

The enzymatic function that cleaves the avocado sunblotch viroid genome is called a ribozyme and does not require any proteins to function.

Which of the following groups of organisms do viroids cause disease in?

Which of the following describes the major difference between hepatitis delta virus (HDV)and the plant viroids and satellite RNAs?

The deamination of an adenine residue in the genome of the hepatitis delta virus causes which of the following to occur?

The ribozyme function found in virioids and hepatitis delta virus can be used to cleave exogenous RNA molecules.Which of the following is a requirement for the ribozyme to be recycled and cleave more than one substrate?

Which of the following is NOT a type of infectious RNA that can cause disease?

Hepatitis delta virus is transmitted through the same pathways as hepatitis B virus.

When studying the replication of viroids and hepatitis delta virus,which of the following allows scientists to distinguish which of the three cellular RNA polymerases is required?

How is the 3' end of the hepatitis delta virus mRNA formed?

Which of the following is a major difference between the group A and the group B viroids?

Describe how the ribozyme activity found in the plant virioids and hepatitis delta virus can be used as therapeutic agents to treat infections with other viruses.

Which of the following statements about the plant satellite RNAs is FALSE?

Which of the following is NOT thought to be a mechanism by which viroids cause disease in their plant hosts?

When the ribozyme activity in the avocado sunblotch viroid cleaves the RNA genome,which of the following describes the structure of the nucleotide on the 5' side of the cleavage?

Viroids encode a single protein which is used to package the RNA for transmission between hosts.

The typical structure of the genome of a viroid is described as?

Coinfection with both hepatitis B and delta virus together makes the resulting liver disease less severe.

Introduction to Virology 2

Virus Structure and Assembly

Virus Classification: the World of Viruses

Virus Entry

Single-Stranded Rna Bacteriophages

Microviruses

Bacteriophage

Bacteriophage Lambda

Viruses of Archaea

Cucumber Mosaic Virus

Picornaviruses

Flaviviruses

Togaviruses

Coronaviruses

Paramyxoviruses and Rhabdoviruses

Filovirouses

Bunyaviruses

Influenza Viruses

Reoviruses

Parvoviruses

Polyomaviruses

Papillomaviruses

Adenoviruses

Herpesviruses

Baculoviruses

Poxviruses

Viruses of Algae and Mimivirus

Retroviruses

Human Immunodeficiency Virus

Hepadnaviruses

Prions

Intrinsic Cellular Defenses Against Virus Infection

Innate and Adaptive Immune Responses to Virus Infection

Antiviral Vaccines

Antiviral Chemotherapy

Eukaryotic Virus Vectors

Filters