exam 3 part 5

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Questions and Answers

What is the primary role of the viral RNA-dependent RNA polymerase in a sense strand RNA virus?

To facilitate the attachment of the virus to the host cell

To synthesize viral proteins directly from the capsid

To replicate the viral genomic RNA (correct)

To transcribe mRNA from the RNA genome

How does the genome of a sense strand RNA virus behave in relation to mRNA?

It requires a host DNA template for translation

It is a double-stranded RNA and cannot be translated directly

It is complementary to mRNA and needs to be transcribed first

It is identical to mRNA and can be immediately translated (correct)

What occurs during the uncoating phase of the viral life cycle?

The capsid is constructed from the viral proteins

The virus attaches to the host cell's nucleus

Viral RNA and proteins are released into the cytoplasm (correct)

RNA replication is initiated by the host cell's enzymes

Why is a complementary - strand transcribed from the + strand of a sense strand virus?

To serve as a template for new viral genomic RNA Signup and view all the answers

What is the initial step after the entry of a sense strand RNA virus into a host cell?

Uncoating and release of the viral RNA Signup and view all the answers

What enzyme initiates the production of dsRNA in double-stranded RNA viruses?

Viral RNA-dependent RNA polymerase Signup and view all the answers

In which part of the host cell does the release of viral RNA and proteins occur after uncoating?

Cytoplasm Signup and view all the answers

What type of viruses use RNA-dependent RNA polymerase for their replication?

Double-stranded RNA viruses Signup and view all the answers

What role does the capsid play in the lifecycle of a double-stranded RNA virus?

Protects viral RNA Signup and view all the answers

What is the first step in the multiplication process of RNA-containing viruses?

Entry into the host cell Signup and view all the answers

Which type of strand is produced by the viral RNA-dependent RNA polymerase during the replication of a double-stranded RNA virus?

Both positive and negative sense strands Signup and view all the answers

Which of the following describes the genetic material of retroviruses in relation to their replication process?

Retroviruses convert RNA to DNA using reverse transcriptase Signup and view all the answers

What must happen to the antisense strand before viral proteins can be synthesized?

It must be transcribed into a + strand (mRNA). Signup and view all the answers

Which enzyme is responsible for the RNA replication of the viral genome?

Viral RNA-dependent RNA polymerase Signup and view all the answers

In what form is the genetic material of the antisense strand virus primarily structured?

Single-stranded RNA Signup and view all the answers

What happens to the viral RNA once it enters the host cell?

It is uncoated and enters the cytoplasm. Signup and view all the answers

Why is it necessary to transcribe the – strand into a + strand?

The – strand cannot synthesize proteins directly. Signup and view all the answers

What is incorporated into the viral capsid during the virus assembly process?

Additional – strands transcribed from mRNA Signup and view all the answers

During the viral life cycle, what occurs immediately after entry into the host cell?

Uncoating occurs to release viral RNA. Signup and view all the answers

Which statement accurately describes the infectious mechanism of antisense strand viruses?

They require the synthesis of a mRNA strand prior to replication. Signup and view all the answers

Study Notes

Sense Strand RNA Virus

Sense strand viruses contain a positive sense strand RNA genome similar to mRNA.
Genome is replicated in the cytoplasm by a viral RNA-dependent RNA polymerase.
The negative strand is transcribed from a copy of the positive strand and serves as a template for new viral RNA.
The new positive strand RNA is translated into viral proteins in the cytoplasm.

Antisense Strand RNA Virus

Antisense strand viruses contain a negative strand RNA genome.
Viral RNA is transcribed from the negative strand into a positive strand (mRNA) in the cytoplasm of the host.
This positive strand is then translated into viral proteins.
The newly formed positive strand RNA is transcribed into additional negative strands, incorporated into new viral particles.

Double-Stranded RNA Virus

Double-stranded RNA viruses contain a genome with both positive and negative strands.
Both sense and antisense strands serve as templates for mRNA transcription.
Replication takes place in the cytoplasm with viral RNA polymerase.
mRNA is transcribed from the positive strand inside the capsid and released into the cytoplasm for translation.
The negative strand is used as a template to synthesize new viral RNAs.

Retroviruses

Retroviruses contain a genome of RNA.
They use an enzyme called reverse transcriptase to convert their RNA genome into a DNA copy.
This DNA copy is integrated into the host cell's genome.
The integrated viral DNA is then transcribed into new viral RNA molecules, which can be translated into viral proteins.
The viral RNA is incorporated into capsids to form new viral particles.

Animal Virus Life Cycle

Attachment: Viruses attach to the cell membrane with specific receptors.
Penetration: Entry through endocytosis or fusion.
Uncoating: Release of the viral genome from its capsid.
Biosynthesis: Production of nucleic acid and proteins (replication and transcription).
Maturation: Assembly of new viral particles from newly synthesized components.
Release: Escape from the host cell by budding, export, or lysis.

DNA Viruses

DNA viruses contain a genome of DNA.
Their DNA may be replicated in the nucleus or cytoplasm, depending on the virus.
Viral DNA is transcribed into mRNA by host cell RNA polymerase.
The mRNA is translated into viral proteins in the cytoplasm.
New viral particles are assembled from the newly synthesized viral proteins and DNA.

Viral Genomes

Sense strand: + strand, same sequence as mRNA, can be directly translated.
Antisense strand: - strand, complementary to mRNA, cannot be directly translated.
Viral RNA polymerase: This enzyme is responsible for replicating viral RNA.
Translation: The process of converting mRNA into a protein.

Multiplication of DNA Virus

DNA viruses replicate their DNA genome by using host cell enzymes.
New viral proteins are produced using host cell ribosomes.
These proteins join to the newly synthesized DNA to form new viral particles.
These new viruses are then released from the host cell.

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Description

Test your knowledge on RNA viruses, including sense strand, antisense strand, and double-stranded RNA viruses. This quiz covers their genome structure, replication processes, and translation into viral proteins. Perfect for students studying virology or molecular biology.