Microbiology Chapter 6: Viral Multiplication
15 Questions
100 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are the 5 basic steps in viral multiplication?

Attachment, entry into host, synthesis, assembly and virion release

How are viruses similar to cellular organisms, and in what fundamental way do they differ?

Viruses and cellular organisms both contain genetic material that can be replicated and passed down. They differ in that viruses require a host to replicate.

What is a nucleocapsid?

Composed of nucleic acid (DNA or RNA); helps make up the simplest of virions.

What is a capsid?

<p>A protein coat that surrounds the nucleocapsid.</p> Signup and view all the answers

What are the types of capsid symmetry?

<p>Helical, icosahedral, and complex.</p> Signup and view all the answers

What are enveloped viruses?

<p>Viruses with virions having an envelope.</p> Signup and view all the answers

What are naked viruses?

<p>Viruses with virions lacking an envelope.</p> Signup and view all the answers

What types of genomes can viruses have?

<p>Viruses can have dsDNA, ssDNA, dsRNA, or ssRNA.</p> Signup and view all the answers

What is a segmented genome?

<p>Some RNA viruses contain genomes that consist of two or more segments of RNA.</p> Signup and view all the answers

What are the types of viral infections and their effects on animal cells?

<p>Rapid multiplication (lytic), viral components present (latent), slow release without cell death (chronic), and activation of host proto-oncogene (cancer).</p> Signup and view all the answers

What is lysogeny?

<p>The process by which a bacterial virus combines its DNA with the host cell's genome.</p> Signup and view all the answers

What is a temperate phage?

<p>These multiply like virulent phages and can lyse the host cell or remain within the host without destroying it.</p> Signup and view all the answers

What is a lysogen?

<p>The infected bacteria of the cell.</p> Signup and view all the answers

What is a prophage?

<p>A form of the virus that remains within its host.</p> Signup and view all the answers

What does immunit refer to?

<p>The term that describes the inability to be reinfected by the same virus.</p> Signup and view all the answers

Study Notes

Viral Multiplication

  • Five basic steps: attachment, entry, synthesis, assembly, and virion release.
  • Attachment involves specific interactions with host cell receptors and microdomains.
  • Entry occurs when the nucleocapsid penetrates the host cytoplasm; includes uncoating and membrane fusion.
  • During synthesis, there is strict regulation of viral gene expression and protein production.
  • Assembly involves multiple subassembly lines that later join to form the complete nucleocapsid structure.
  • Virion release occurs through lysis or budding, facilitated by viral proteins.

Similarities and Differences between Viruses and Cellular Organisms

  • Both viruses and cellular organisms possess genetic material that can replicate and be inherited.
  • Viral genetic material is enclosed within a protein shell, unlike cellular organisms which have a membrane.
  • Viruses encode both DNA and RNA but require a host for replication due to missing essential proteins.
  • This dependency on a host leads to viruses not being classified as living organisms.

Components of Virions

  • Nucleocapsid consists of nucleic acid (DNA or RNA) and forms the simplest viral structure.
  • Capsid is the protective protein coat surrounding the nucleocapsid.

Capsid Symmetry

  • Three types of capsid symmetry: helical, icosahedral, and complex.
  • Helical capsids resemble hollow tubes; icosahedral capsids are formed from ring or knob-shaped protomers.
  • Complex capsids do not fit into helical or icosahedral categories, seen in poxviruses and large bacteriophages.

Types of Viruses

  • Enveloped viruses have an additional lipid bilayer surrounding their virions.
  • Naked viruses lack an envelope entirely.

Genome Diversity

  • Cellular genomes typically contain double-stranded (ds) DNA.
  • Viral genomes can be dsDNA, ssDNA, dsRNA, ssRNA; variations are common across plant and bacterial viruses.
  • Small genomes (~4,000 nucleotides) can code for 3-4 proteins; large genomes, like mimiviruses, can exceed 1.2 million nucleotides.

RNA Viruses

  • Some RNA viruses feature segmented genomes consisting of multiple RNA segments.

Viral Infections

  • Infections vary:
    • Lytic infections result in rapid multiplication and acute diseases.
    • Latent infections persist with the viral genome present.
    • Chronic infections release virions slowly without cell death.
    • Some infections can transform host cells, activating proto-oncogenes leading to cancer.

Mechanisms of Lysogeny

  • Lysogeny is the integration of a bacterial virus's DNA into the host genome, beneficial for the virus.
  • Temperate phages can either lyse the host or remain within without destruction.

Host Interactions

  • Viral receptors evolve from essential host surface proteins, highlighting their importance to host cell functions.
  • Enveloped viruses are rare in plants and bacteria due to cell walls differing from animal cell membranes, complicating envelope formation.

Definitions

  • Lysogen refers to the bacteria infected by a temperate phage.
  • Prophage is the form a virus takes when it resides within its host.
  • Immunity refers to the state that prevents reinfection by the same virus.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your knowledge on the five basic steps in viral multiplication. This quiz covers essential events in the lifecycle of viruses, including attachment, entry, synthesis, assembly, and release. Perfect for students studying microbiology.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser