Virus replication

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How do viruses replicate within a host cell?

By binary fission, like bacteria
By hijacking and utilizing the host cell’s machinery (correct)
By self-assembling outside the host cell
By mitotic division within host cells

Which of the following best describes the virus replication process in a host cell?

It resembles an assembly line, where different viral components are produced in stages (correct)
It occurs through direct division of the virus
It involves the self-replication of viral nucleic acids outside the host cell
It occurs by the fusion of multiple viral particles into a larger unit

What is the absorption and entry phase?

Virus attaches and enters the cell (free virus declines)

What is the eclipse period in the virus growth curve?

The time between viral entry and the first appearance of intracellular new virus particles (A) Signup and view all the answers

What defines the latent period in the virus growth curve?

The time between viral uncoating and the first appearance of extracellular new virus particles (B) Signup and view all the answers

Briefly list the steps in the virus growth curve.

Absorption and entry, eclipse period, latent period and viral release (AKA burst size) Signup and view all the answers

What does “burst size” mean?

The number of virions released Signup and view all the answers

A permissive cell is a cell that:

Allows virus replication (C) Signup and view all the answers

A non-permissive cell is a cell that:

A virus can’t replicate in Signup and view all the answers

What does Multiplicity of Infection (MOI) refer to?

The number of virions added per cell during infection (B) Signup and view all the answers

Briefly list the steps of virus replication

Attachment, penetration, uncoating, synthesis of viral components, assembly and maturation, release in large numbers Signup and view all the answers

How do viruses attach to host cells?

By recognizing and binding to specific receptors on the host cell surface (B) Signup and view all the answers

What is the function of a co-receptor in viral attachment?

It is an additional cell surface molecule required for viral entry when binding to the primary receptor alone is insufficient (C) Signup and view all the answers

How do naked viruses typically penetrate host cells?

Pore-mediated penetration and endocytosis (A) Signup and view all the answers

Which of the following is a correct mechanism by which enveloped viruses penetrate host cells?

Surface membrane fusion (pH-independent) or receptor-mediated endocytosis (pH-dependent) (A) Signup and view all the answers

How does antibody-mediated attachment facilitate viral entry into host cells, as seen in Feline Infectious Peritonitis Virus (FIPV)?

The virus binds to host cell receptors, and antibodies enhance attachment, leading to increased viral uptake by immune cells. (B) Signup and view all the answers

What happens during the uncoating stage of viral replication?

The viral genome is released inside the host cell, leading to loss of infectivity (B) Signup and view all the answers

Which of the following is NOT a step in the processing of viral RNA during replication?

Breaking down of the host cell nucleus (D) Signup and view all the answers

Where can viral assembly and maturation take place?

In the nucleus, cytoplasm, or plasma membrane, depending on the virus (D) Signup and view all the answers

How do enveloped viruses typically exit the host cell?

Budding or exocytosis (C) Signup and view all the answers

Which of the following describes intracellular spread of viruses?

Viruses remain inside the host cell, spreading rapidly while evading the immune system (B) Signup and view all the answers

Which of the following best describes extracellular spread of viruses?

Viruses are released into the extracellular environment, travel to new cells, and initiate another replication cycle. (B) Signup and view all the answers

Which of the following viruses spreads by integrating its genome into the host DNA and passing it to the next generation of host cells?

Retroviruses (e.g., HIV) (B) Signup and view all the answers

Viral Replication

The process by which a virus replicates inside a host cell, using the host's machinery to produce more viruses.

Absorption & Entry

The stage where the virus attaches to and enters the host cell, marking the start of the replication cycle.

Eclipse Period

The period between the virus entering the cell and the first appearance of new viral particles within the cell. The virus is essentially 'hidden' during this stage.

Latent Period

The time between the virus 'shedding' its outer coat and the appearance of new viruses outside the cell.