Molecular Virology Exam Questions and Answers Latest Update 2025 Already Passed

Molecular Virology Exam Questions and Answers Latest Update 2025 Already Passed what is a virus - Answers can't survive without host, lack genetic info to generate energy, lack protein production capacity common virus components - Answers genome, capsid, matrix, envelope, envelope proteins tropism - Answers if a cell has the right receptor and supports virus replication 8 steps in virus life cycle - Answers attachment/binding entry uncoating genome replication gene expression assembly maturation release what happens during 1. attachment - Answers viruses use cell surface receptors to recognize and bind to target cells what happens during 2. entry - Answers virus enters the cell, endocytosis most common, also fusion what happens during uncoating - Answers after viruses are directed to proper compartment, genome is released 2 methods of genome release - Answers uncoating (pore formation) or lysis how many strategies of genome replication - Answers 7 name the 7 classes of viruses (baltimore classification) - Answers dsDNA ssDNA dsRNA (+)RNA (-)RNA retroviruses RT-DNA (gapped DNA) goal of genome replication - Answers get to (+)mRNA strands which encodes for protiens which classes of viruses have intermediates during genome replication - Answers 2,4,6,7 explain class 2 genome replication - Answers ssDNA first becomes dsDNA, then mRNA explain class 4 genome replication - Answers (+)RNA can either transcribe mRNA directly or create (-)RNA then mRNA explain class 6 genome replication - Answers retroviruses, start with a (+)RNA strand, reverse transcription creates a cDNA strand and then dsDNA, which then goes to mRNA explain class 7 genome replication - Answers gapped DNA, first gaps are repaired, then a RNA strand is produced, reverse transcription creates a dsDNA strand which makes mRNA which direction is DNA replication - Answers 5' to 3' what is RdRp and what does it do - Answers RNA-dependent RNA polymerase required for RNA replication in viruses, classes 3,4 and 5 which classes of viruses already have RdRp - Answers 3 and 5 4 has to produce RdRp first 2 methods of DNA replication - Answers replication forks, strand displacement what happens during gene expression - Answers viral proteins are produced, differs in time and place depending on stage of cycle when does gene expression occur before replication - Answers in RNA(+) viruses what happens during assembly - Answers virion forms, can happen at budding at outer membrane what happens during maturation - Answers virus becomes infectious, can happen before or after release what happens during release - Answers virus exits cell lysis, exocytosis, budding, fusion what is syncytia formation - Answers cell fusion induced by viruses, helps viruses to spread to more cells typical components of viruses - Answers genome genome proteins membrane capsid spike proteins what is a virion - Answers infective viral particle are viruses stable? - Answers no, metastable (structure changes through lifespan) 4 classes of virus morphologies - Answers helical, polyhedral, pleomorphic, complex(can be a combination of any of these) what is TEM and how does it work - Answers transmission electron microscopy, e- beam is transmitted through a sample and gives an outline of the particle it interacts with what is TEM best for - Answers overall morphology, the outline of a particle how does cryo-EM work - Answers e- beam shot through frozen sample, taken from multiple angles and digital reconstruction gives 3D model what is cryo-EM best for - Answers best for larger things, like viruses or large proteins how does x-ray crystallography work - Answers sample is crystalized, x-ray is shot through structure, e- density is captured then atomic model formed what is x-ray crystallography best for - Answers for small things, good for determining specifics (high resolution!) enveloped vs non enveloped viruses - Answers envelope is a host derived membrane that surrounds the viral capsid, non enveloped viruses only have the capsid surrounding the genome what is the viral envelope made from - Answers comes from the host cell's membrane, incorporated during assembly and release