Viruses Flashcards
viruses are cellular or acellular
acellular
What do viruses contain
nucleic acids
What are the fancy 3 letter word for viruses
obligate intracellular parasites
why are they called obligate intracellular parsites?
because they require a host cell to replicate
two states of virus’s existence
Extracellular and Intracellular
Extracellular
a virus particle that has no metabolism and can be crystallized
Intracellular
can take over host cell and only replicate themselves
size of viruses
avrage 20 -1000nm
how are viruses messured?
nanometers
how many times microscope zoom for viruses
7000x
what type of microscopes do they use?
electron microscope
4 kinds of virus shapes
Helical, polyhedral and enveloped and bacteriphage
Helical
capsid is arranged in a helical pattern
Polyhedral
most commonly in a icosahedron (20 equilateral triangles)
Enveloped
some surrounded by lipids proteins and carbohydrates
capsid is arranged in a helical pattern
helical
most commonly a icosahedron
Polyhedral
some surrounded by lipids, proteins and carbohydrates
enveloped
virus particle has no metabolism can be crystalized
extracellular
can take over host cell and only replicate themselves
intracellular
shape helical
sprials; microscope; lines
polyhedral viruses
dnd dice; microscope; 6 sided with lines at each corner
enveloped
covid
dots on helical outside
protein subunits
inside helical virus
RNA
dots of polyhedral virus outside
capsomere
inside of polyhedral virus
nucleic acid
shell of a polyhedral virus
capsid
virulent viruses
*Makes you sick right away!
* Undergo a lytic cycle
* Cause death/damage to host cell
* Examples include: Flu, Colds, Mumps
*Makes you sick right away!
* Undergo a lytic cycle
* Cause death/damage to host cell
* Examples include: Flu, Colds, Mumps
virulent viruses
temperate viruses
- Undergo a lysogenic cycle
- Herpes, HIV
- Undergo a lysogenic cycle
- Herpes, HIV
temperate viruses
lytic cycle
viruses immediately replicate and destroy the host cell
viruses immediately replicate and destroy the host cell
lytic cycle
attachment aka
absorption
attachment
to host cell
penetration
where nucleic acid enters cell
absorption
attaches to host cell
absorption
attachment
replication
of viral nucleic acid to form viral proteins
assembly
copies combine to form mature viruses
release aka
lysis
lysis aka
release
release
hot cells lysed to release mature viruses
lysis
host cells lysed to release mature viruses
___ to host cell
attachment
attachment to host cell
absorption
where nucleic acid enters cell
penetration
___ of viral nucleic acid to form viral proteins
replication
copies combine to form mature viruses
assembly
host cell lysed to release mature viruses
release
lysogenic cycle
attachment, penetration and then viral dna atttaches and remains latent
stimuli that causes lytic cycle to begin
radiation, chemicals or stress triggers
what is the odd thing that temperate viruses do
when released take may take a small portion of the hosts dna and may introduce genes to new host (transduction
virus classification
based on disease they cause (poliovirus, influenza virus, HIV)
designated by a greek letter (T4, phi 6, lamda)
based on type of nucleic acid (DNA or RNA)
can be devided based upon single or double stranded nucleic acids
Retrovirus
single strand of RNA serves as a template for DNA synthesis
makes DNA using reverse transcriptase
newly formed DNA combines with host DNA to become provirus(prophage)
interesting about rna viruses
viruses with RNA carry genes from generation to the next
Koch’s Postulates
pathogen, innoculate, compare
immunity
ocures when body produces memory cells
Who and when and what disease ‘first’ (not really) demostrated immunity
Jenner 1796, with cowpox to prevent aginst small pox
viral transmition
air, food, water, touch (blood, shared needles, sexual intercorse)
Chlorea
diarrhea, vomiting, dehydration from fecesses, contaimated from water
Hepatitis
affects liver, jaundice, fatigue, from feces contaminated food and water
sneeze aerosols
cold, flu, TB
dirrect contact
HIV (sex, used needles, tainted blood) and herpes
pasture
(1885) created immunity against rabies
Rabies what nucleic acid?
RNA
what cause death in RAbies
brain swelling
HIV attacs what
helper T-cells, also macorphages, cells in lining of thymus and cerin mucous membrane cells
HIV first infection
flu like illnuss then recovery (fever, aches)
HIV after first infection
spreads killing T-cells decrease, no outward signs of trouble
AIDS amount
once number of helper T-cells fall below 200/ml (normal 700/ml) is onset of AIDS
how many HIV positive mothers pased it to children
25 to 35 percent
% during pregnacy
20
% during childbirth
40%
% during breast-feeding
40
plecenta
ineffective
antivirals
reduce 14-39% down to lower then 5%
antivirals problem
expensive
infection rate childbirth
10-20%
how reduce childbirth rates
c-section
breast feading infection rate
15% after 2 years of breast feeding