Virus Entry Mechanisms

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What is the common mechanism for virus entry that does not require specific virus proteins beyond those involved in receptor binding?

Fusion

Receptor binding

Uncoating

Endocytosis (correct)

What is the process by which the virus sheds its outer coat to release its genetic material into the host cell?

Uncoating (correct)

Receptor binding

Fusion

Endocytosis

What is required for fusion to occur between the virus envelope and the cell membrane?

Specific fusion proteins in the virus envelope (correct)

Spike protein priming

ACE2 receptor binding

Host cell proteases

What occurs simultaneously in some viruses, such as bacteriophages?

Entry and uncoating Signup and view all the answers

What is the result of the uncoating step in the viral life cycle?

The viral genome is released into the host cell Signup and view all the answers

What is involved in the interactions between the virus and the host cell during virus entry?

Proteins in the virus capsid and specific membrane receptors on the host cell Signup and view all the answers

What determines the tropism of a virus?

The presence or absence of specific receptors on the host cell surface Signup and view all the answers

What is the role of viral attachment proteins?

To bind to cellular receptor molecules Signup and view all the answers

What is the usual requirement for cell entry into the host cell?

The cell being metabolically active Signup and view all the answers

What is the primary function of host cell proteases such as TMPRSS2 and cathepsin in the priming of the spike protein?

To cleave the spike protein at specific sites, facilitating its fusion with the host cell membrane Signup and view all the answers

What is the process by which the virus is engulfed into the cell within a vesicle called an endosome?

Endocytosis Signup and view all the answers

What is the result of the attachment phase of viral replication?

The virus gains entry into the host cell Signup and view all the answers

What is the rare mechanism of virus entry into host cells where the entire virus particle is transported across the cell membrane?

Translocation Signup and view all the answers

What is the name of the protease that cleaves the spike protein at a specific site located at the junction of the S1 and S2 subunits?

Furin Signup and view all the answers

What is the result of the cleavage of the spike protein by host cell proteases?

The activation of the spike protein, facilitating its fusion with the host cell membrane Signup and view all the answers

What is the type of RNA contained in the viral particle of SARS-CoV-2?

Single-stranded RNA Signup and view all the answers

What is the primary function of the furin cleavage site in the spike protein of SARS-CoV-2?

To enhance viral infectivity by allowing furin-mediated cleavage of the spike protein Signup and view all the answers

Where does the cleavage of the spike protein by TMPRSS2 and cathepsins occur?

At the cell surface or within endosomes Signup and view all the answers