Lecture 1 Question Bank

A virus is best described as:

Obligate intracellular parasite

A virion referes to:

Infectious extracellular viral particle

Which of the following is NOT encoded by viruses?

Ribosomes

A plaque forming unit (PFU) represents:

One infectious virion

Viral classification is primarily based on":

Genome type and structure

A virus with single-stranded (+) RNA:

Can function directly as mRNA

Which enzyme is required for RNA virus replication?

RNA-dependent RNA polymerase

What does (+) RNA polarity indicate?

It can be directly translated

A (-) RNA virus must first:

Be converted into (+) RNA

Icosahedral symmetry refers to:

20-sided capsid

Enveloped viruses:

Contain a host-derived lipid membrane

Which viruses are most sensitive to detergents?

Enveloped viruses

The correct order of viral replication is:

Entry → mRNA synthesis → Genome replication → Assembly → Release

Which step determines host specificity (tropism)?

Entry

Viral mRNA must be:

Positive strand

Which virus type cannot immediately be translated upon entry?

(-) RNA virus

Viral entry begins with:

Receptor binding

Endosomal acidification is important because:

It triggers viral fusion/uncoating

Which is NOT a step in viral entry?

DNA replication

Dynein moves cargo:

Toward minus end (nucleus)

Kinesin moves cargo:

Toward cell periphery

Which is NOT a part of the cytoskeleton?

Ribosomes

DNA viruses typically replicate in:

Nucleus

Retroviruses use which enzyme?

Reverse transcriptase

The nuclear pore:

Regulates transport into and out of the nucleus

Non-enveloped viruses are typically released by:

Cell lysis

Enveloped viruses acquire membranes from:

Host membranes

Budding allows viruses to:

Exit without immediately killing the cell

Plaques form due to:

Cell death from infection

One plaque corresponds to:

One infectious virion

PFU is usually lower than total particles because:

Not all particles are infectious

PCR detects:

DNA (or RNA via RT-PCR)

ELISA detects:

Proteins or antibodies

Western blot detects:

Specific proteins

Which method is best to visualize infected cells?

Fluorescence microscopy

Why are viruses considered minimal infectious agents?

They encode only essential replication components

Why must viruses rely on host cells?

They lack ribosomes and metabolism

Viral diversity leads to:

Drug resistance and immune evasion

Viral replication is described as “evolution distilled” because:

It is highly optimized for survival and transmission