Molecular Biology: Viruses + Vaccines

i recommend turning on override answers in case you get the correct meaning but not wording :)

is a virus living or non-living?

non-living

what did Martinus Beijerinck do?

he coined the term “virus”

what did Wendell Stanley do?

he proved viruses were particulate

what did James Watson do?

he published a paper describing viral structure (also used electron microscope to confirm)

what unit are viruses measured in?

nanometers

each nanometer corresponds to what number of a meter?

one billionth of a meter

all viruses possess what features?

capsid and nucleic acid

what are the optional virus features?

lipid envelope and protein spikes

what is a capsid?

a crystalline protein coat

what makes up a capsid?

capsomeres

what is nucleic acid?

the virus’s core of either DNA or RNA

what is the lipid envelope?

a protective layer that encloses some viruses

what are protein spikes?

they are similar to a key as they help the virus to bind to a host cell’s receptors

what do we call a virus without an envelope?

naked

what is the name of this basic virus shape?

complex/mixed

what is the name of this basic virus shape?

spherical

what is the name of this basic virus shape?

polyhedral

what is the name of this basic virus shape?

helical

how are viruses classified?

by families

what are the four sections of classifying viruses into virus families?

genome, morphology, physical properties, and biological properties

what factors are there in classifying by genome?

DNA or RNA, number of chromosomes, double (ds) vs single (ss) stranded

what factors are there in classifying by morphology?

size, shape, symmetry, envelope

what factors are there in classifying by physical properties?

mass, pH stability, thermal stability

what factors are there in classifying by biological properties?

host range, pathogenicity

all virus family names end in what?

-viridae

why do viruses exist?

to replicate

where do viruses replicate?

inside of a host cell

what are the two cycles of virus replication?

lytic and lysogenic

true/false: viruses are usually not host specific.

false

the common cold, influenza, and rabies are all examples of which cycle?

the lytic cycle

herpes and chickenpox are examples of which cycle?

lysogenic

what is the first step in the lytic cycle?

attachment

what happens during attachment (lytic)?

the virus lands on the host cell and attaches to its receptors

what is the second step in the lytic cycle?

entry/penetration

what happens during entry/penetration (lytic)?

viral DNA or RNA enters the host cell, and the host’s DNA is destroyed

what is the third step of the lytic cycle?

replication/biosynthesis

what happens during replication/biosynthesis (lytic)?

viral DNA is replicated, transcription, translation

what is transcription?

when viral mRNA is made

what is viral mRNA?

the code to make more viral parts

what is translation?

when the mRNA travels to ribosomes, where viral proteins are made

what is the fourth step in the lytic cycle?

assembly/maturation

what happens during assembly/maturation (lytic)?

new viruses self-assemble in the cytoplasm

what is the fifth (last) step in the lytic cycle?

release/lysis

what happens during the release/lysis (lytic)?

the viral DNA shares a code to make an enzyme that causes the host’s cell membrane to lyse/burst. viruses are released, the host dies, and the cycle repeats

what is the first step in the lysogenic cycle?

attachment

what happens during attachment (lysogenic)?

the virus lands on the host cell and attaches to its receptors

what is the second step of the lysogenic cycle?

entry/penetration

what happens during entry/penetration (lysogenic)?

viral DNA or RNA enters the host cell and fuses with the host’s DNA

what is a provirus?

when the viral nucleic acid fuses with the host cell’s DNA

what happens between the second and third steps of the lysogenic cycle?

the latent period

what is the latent period?

a resting period where the infected cell performs mitosis (cell division) and makes copies of the provirus

what ends the latent period?

triggers

what are examples of triggers?

stress, sunburn, menstruation, pregnancy, aging

what is the third step of the lysogenic cycle?

replication/biosynthesis

what happens during replication/biosynthesis (lysogenic)?

viral DNA is replicated, transcription, translation

what is the fourth step in the lysogenic cycle?

assembly/maturation

what happens during assembly/maturation (lysogenic)?

new viruses self-assemble in the cytoplasm

what is the fifth (last) step in the lysogenic cycle?

release/lysis

what happens during the release/lysis (lysogenic)?

the viral DNA shares a code to make an enzyme that causes the host’s cell membrane to lyse/burst. viruses are released, the host dies, and the cycle repeats

what cycle does this represent?

lytic

what cycle does this represent?

lysogenic

what cycle + step is this? (format: cycle name, step name (#))

lytic and lysogenic, attachment (1)

what cycle + step is this? (format: cycle name, step name (#))

lytic, entry/penetration (2)

what cycle + step is this? (format: cycle name, step name (#))

lytic, replication/biosynthesis (3)

what cycle + step is this? (format: cycle name, step name (#))

lytic, assembly/maturation (4)

what cycle + step is this? (format: cycle name, step name (#))

lytic, release/lysis (5)

what cycle + step is this? (format: cycle name, step name (#))

lysogenic entry/penetration (2)

what cycle + step is this? (format: cycle name, step name (#))

lysogenic, replication/biosynthesis (3)

what cycle + step is this? (format: cycle name, step name (#))

lysogenic, assembly/maturation (4)

what cycle + step is this? (format: cycle name, step name (#))

lysogenic, release/lysis (5)

what does budding mean?

when the virus pushes out of the host’s membrane without using enzymes

what nucleic acid does influenza have?

RNA

true/false: influenza is enveloped.

true

true/false: influenza has surface proteins/protein spikes.

true

how many types of influenza are there?

four

what type of influenza does not infect humans?

influenza D

what type of influenza is the most virulent/dangerous?

influenza A

how many types of protein spikes does influenza A have?

two

what does the protein spike “H” stand for?

hemagglutinin

what does the protein spike “N” stand for?

neuraminidase

how many types of hemagglutinin (H) are there?

18

how many types of neuraminidase (N) are there?

11

what does hemagglutinin (H) do?

helps the virus attach to the host cell

what does neuraminidase (N) do?

helps the virus to be released when replicated

how is influenza A classified?

by subtypes

how are the subtypes created?

based on the combination of H and N proteins

true/false: influenza A is host specific.

false

how is influenza B classified?

by lineages

what are the two lineages of influenza B?

Yamagata and Victoria

what part of influenza makes us need an annual flu vaccine?

the RNA

why does having RNA instead of DNA make a difference for the influenza vaccine?

RNA is extremely error prone, and it has high mutation rates

what is antigenic drift?

the natural mutation over time of known strands of influenza

what is antigenic shift?

when two different strands of a virus combine to form a new subtype

why is antigenic shift more dangerous than drift?

it is unpredictable

what is a vaccine?

a means of producing immunity against pathogens by the introduction of live, killed, or altered antigens that stimulate the body to produce antibodies against more dangerous forms

what is an antigen?

a foreign object

what does efficacy mean?

the ability to produce a desired or intended result

what does vaccine efficacy mean?

the percent reduction in disease when comparing vaccinated and unvaccinated groups

what is herd immunity?

when enough people become immune to a disease, it makes its spread less likely

what is immunity?

the ability of an organism to resist a particular infection or toxin by the action of specific antibodies