BIOL123 Lecture 1-4

What does virus mean?

poison

How old are viruses?

3.5 billion years

What is the oldest virus in the world?

Hep B

3 main components of viral structure:

nucleic acid genome, capsid, envelope

What is the nucleic acid genome?

genetic material: DNA/RNA

some carry enzymes to help in replication

What is the capsid?

all viruses have

protein shell that encloses genome

made of individual protein subunits called capsomeres

for protection and attaching to host cells

Some viruses have an () that originates from the host cell’s membrane
It helps () and () into host and protect from () and ()

Some viruses have an (envelope) that originates from the host cell’s membrane
It helps (attach) and (enter) into host and protect from (immune) and (environmental)

Some viruses have other (), such as () to help in attachment and entry into host

Some viruses have other (specialized features), such as (spikes or tail fibers) to help in attachment and entry into host

Structure and components of virus are optimized for ()

efficient replication and transmission

What is the first written record of a virus infection?

hieroglyph of paralytic poliomyelitis

What did Edward Jenner do?

vaccinated a child who had never had smallpox with cowpox from milkmaid

How did smallpox travel to Americas?

from ancient Egypt to China to Europe to America by Hernando Cortez

Who is the Father of Virology?

Martinus Beijerinck

Who discovered bacteriophages?

Felix d’Herelle

Who crystallized tobacco mosaic virus and shows that it remains infectious?

Wendell Stanley

Who was the first to breed yellow fever virus in chick embryos and produce a vaccine?

Max Theiler

Who demonstrated that bacteriophages mutate?

Salvador Luria and Alfred Hershey

Who demonstrated that DNA was the genetic material of bacteriophage?

Alfred Hershey and Martha Chase

Who discovered Hep B and made the first vaccine for it?

Baruch Blumberg

Who discovered reverse transcriptase in retroviruses?

Howard Temin and David Baltimore

Who discovered HIV?

Luc Montaigner and Robert Gallo

Except plant viruses, all viruses contain ()

receptor binding proteins

Viral DNA needs ()

transcriptase

Viral genome may be infectious if it is ()

RNA +

RNA - needs () to make ()

RNA polymerase

RNA +

T/F: Some viruses integrate their capsid into the host cells chromosome

False; Some viruses integrate their genome into the host cells chromosome

Animals can have () icosahedral symmetry

enveloped

Both plants and animals can have () icosahedral symmetry

non enveloped

RNA viruses encode () proteins

less than dozen

Viruses are host specific because of their ()

envelope

() are viruses that infects bacteria by injecting genetic material through pins

bacteriophage

End goal of all viruses is to make () to make protein

mRNA

Baltimore class I () contains adenovirus, herpes, poxviruses

dsDNA

Baltimore class II () contains parvoviruses

ssDNA

Baltimore class III () contains reoviruses

dsRNA

Baltimore class IV () contains picornaviruses and togaviruses

+ssRNA

Baltimore class V () contains orthomyxoviruses and rhabdoviruses

-ssRNA

Baltimore class VI () contains retroviruses

ssRNA-RT; DNA intermediate in life cycle

Baltimore class VII () contains hepadnaviruses

dsDNA-RT

ICTV classifies viruses into 5 groups:

order (virales)

family (viridae)

subfamily (virinae)

genus (virus)

species

What are the 4 main criteria for ICTV classification?

morphology

size

type of host

genome

T/F: All dsRNA viruses are enveloped

False; None of the dsRNA viruses are enveloped

The minus strand viruses are enveloped with () nucleocapsids

helical

Most of the plus strand viruses have () nucleocapsids

icosahedral

() is the only dsDNA virus that replicates in cytoplasm

pox

T/F: The Frederick Griffith “transforming principle” showed that living S cells transformed to R cells in the presence of heat inactivated R cells

False; living R cells transformed to S cells in the presence of heat inactivated S cells

() experiment showed that DNA is the transforming principle

Avery, MacLeod, McCarty

() experiment showed that DNA is the genetic material for bacteriophage

Hershey and Chase

() experiment proved the existence of genomic RNA through switching genetic material and seeing the capsomeres transform according to the new RNA

H Fraenkel-Conrat

() invented PCR

Kary Mullis

() introduced single point mutation

Michael Smith

() discovered reverse transcriptase

David Baltimore, Renato Dulbecco, Howard Martin Temin

() discovered prions

Stanley B Prusiner

() discovered HPV and its role in cervical cancer

Harald zur Hausen

() received the Nobel Prize for HIV

Francoise Barre Sinoussi, Luc Montagnier

() discovered Hep C

Charlie M Rice

() discovered CRISPR technology

Emmanuelle Charpentier, Jennifer Doudna

() discovered nucleoside base modifications that aided in mRNA vaccines against COVID-19

Katalin Kariko, Drew Weissman

() developed polio vaccine

Dorothy Horstmann

All RNA viruses replicate in () except () and () that have replicative stages in nuclei

All RNA viruses replicate in (cytoplasm) except (orthomyxoviruses) and (retroviruses) that have replicative stages in nuclei

Most dsDNA viruses replicate in the () except for () which replicates in the ()

Most dsDNA viruses replicate in the (host cell nucleus) except for (poxviruses) which replicates in the (cytoplasm)

What is the primary application of PCR technology?

to amplify DNA sequences

What is the primary site of replication for cytomegalovirus?

only in nucleus

What is the primary function of the viral protein in the adsorption phase of viral infection?

to inject viral genome into host

During which phase do enveloped viruses typically acquire their membrane?

release

Which viruses are known to use strategy of degrading host mRNA?

HSV1 and poxvirus