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Viral structure
1. Genome 2. Protein coat 3. (some have additional membrane)
protein coat
urination barrier
removes bacteria from urethra
Virus caused by Orthomyxoviridae, structure of spikes mutates rapidly
Cro gene
produces Cro protein
Cell mediated immune response
macrophages cruise through bloodstream, sccop up and phagocytose any odd particles, particles are digests and parts are presented on surface of macrophage in its MHC class II protein
T cell receptors
Each t cell is covered with thousdands of identical receptors,each is capable of binding a single antigen
Nonspecific immunity
general barriers to infection, things related to general ability to repel infection
soap barrier
chemical, kills many bacteria
Isopycnic density gradient centrifugation
separate by isopycnic point (buoyant density)
Intercellular adhesion molecule-I, rhinovirus receptor
Virus Classification
1. Nucleic Acid Type 2. Nucleic Acid Strandedness 3.Sense of ss RNA 4. Structural Features 5. Host range
type of picornavirus, common cold,
transducing particle example
Prohead of lambda phage
Generalized transduction
transfer of bacterial genes by phages
B-cell and T-cell similarities
Both have 2 types of proteins that each have constant/variable regions
age barrier
babies and elderly most susceptible
lysozyme secretion barrier
chemical, dissolves peptidoglycan
Reasons for phage to end lysogeny
1. Drop in levels of Lambda repressor (UV light, chemicals) 2. Lambda repressor becomes less, xis, int, cro genes transcribed
MHC (Major histocompatibility Complex) class I molecule
bits of complex are placed on cell surface, recognized by t cell, and looked at to see what antigen was presented. If mature t cell ban bind to it, t cell reacts to set off an immune response
DNA packaging
into prohead- takes host and viral DNA
Cro protein
Inhibits production of transcription of lambda repressor
good nutition barrier
eat healthy
Nucleic acid and capsid
ssRNA- example
influenza virus, ebola virus
Non-enveloped virus
Enveloped virus
Necleocapsid, envelope
Spike on orthomyxovirus that cuts sialic acid
Multiplicity of Infection (MOI)
Average amoun of virues added per cell
Epstein-Barr virus
mononucleosis, Burkitt's lymphoma, nasopharyngeal carcinoma
biological barriers
living cells that actively kill passing bacteria
Spanish flu
flu epidemic in 1918, must have new vaccine each year
CD28 receptors
binds to macrophages
helps neutrophils to bind to and engulf bacteria
type of retrovirus, +ssRNA
Phage Beta
Encodes for diptheria toxin during lysogenic conversion
of immature t cells die, leaving ONLY those t cells that gind to antigens not found in the body
Purification Methods
1. Differential Centrifugation 2. Density gradient centrifugation 3. Isopycnic density gradient centrifugation 4. rate zonal gradient centrifugation
once capillaries are stimulated, stimulates nerve cells to send a pain signal to brain
DNA-dependent DNA polymerase
used by normal cellular DNA replication
Beta chain splices these regions
V,D, J
Family of viruses, +ssRNA
DNA concatemer
long continuous DNA molecule that contains many copies of same DNA sequence
Example of generalized transduction for E. coli
Phage 1
Specialized transduction
Only specific portion of bacterial genome is transferred
mucosa barrier
on internal surfaces exposed to bacteria- the intestines, lungs, reproductive tracts
Cell with no cell wall, used to study uptake of viruses
Lytic life cycle
Lyse host cells, release progeny virions
HPV- cervical cancer
methods of nonspecific immunity
healthy, nutrition, age-babies and elderly most susceptible, fever-higher body temp kills some bacteria and slows some viral replication, genetic factors
types of capsomer
pentamer, hexamer
temperate phages 2 options
1. lytic cycle 2. lysogenic cycle
protein that can interact with lambda repressor if damaged, causing to cleave itself in induction
disulfide bond
how alpha and beta chains are linked together
binding site for HIV receptor on helper t-cells
shortened term for bacteriophage
chemical barriers
prevent infection from entering body
Virus: Rhinovirus
Receptor: ICAMs
Of Tc cells CD8 binds to MHC Class I and tcell receptor binds to antigen while tc cells are activated by IL2, cells will secrete proteins that induce: (3)
1. slow viral replication (interferon) 2. Die more accurately, commit suicide (tumor necrosis Factor) 3. Lyse (perforin)
late mRNA
structural proteins required for assembly, lysis, and release
Influenza virus
phiX174 Virus
+ ssDNA virus
Translation takes place
Antigenic glycoprotein on influenza virus that binds virus to cell
Virus Titer
Virus Concentration
Reaction to a protein foun on the surface of flial cells, which insulate the electrical connections of our nerves
Multiple Sclerosis
icosahedral asymmetric unit
containing 3-protein subunits
Salmonella during lysogenic conversion
lipopolysaccharide structure is modified
CD4 receptros
bind to MHC class II molecules
Infected bacterial host
Bone marrow
where helper cells are born, but mature elsewhere
Th1 cells
contain CD28 and CD4 receptros, send out an alarm signal, interleukin 2 (IL 2)
Structural studyies (3)
1. electron microscopy 2. electron tomography 3. x-ray crystallography
hydroxymethyl-cytosine (HMC)
modifies cytosine
Relationship that benefits both creatures
dsRNA example
Reovirus, rotavirus, blue tongue virus
include bullet-shaped Rabies vrius, enveloped,
ring-shaped unit made of 5 or 6 proteins
Programmed cell death
replicative form
+/- DNA
alarm signal when tissue/cells are damaged
early mRNA
creates proteins/enzymes involved in phage DNA synthesis
Spike on orthomyxovirus that binds to receptor sialic cid
autoimmune disease
a t cell that reacts with known antigen manages to survive in body
Virus: HIV
Receptor:CD4 on t-helper cells, macrophages, receptor sites CXCR-4 or CCR5
Phage T4 life cycle
Attachment, Penetration, Insertion, Transcription early mRNA, Replication phage DNA, Transcription late mRNA, Assembly, Lysis
peplomer-glycoprotein spike on capsid or envelope. only bind to receptors with host specificity/infectivity
Bacterial LPS
binds to complement protein C3b
+ssRNA virus
white blood cells that pass by in the bloodstream, roll along surface of selectin-expressing cells, and crawl between capillary cells to infected tissue and phagocytose everything they find
Clonal selection
If t cell receptor can bind to presented antigen, then tcell is activated and divides rapidly
"cos" sites
cohesive ends, DNA of phage Lambda contains 12 base ss cos sites
Benefits one creature at expense of other
t cells that have CD8 receptors that bind specifially to MHC class I molecules so that cells can examine antigens presented by any cell
Tc (cytotoxic t cells)
lysogenic bacteria is immune, lambda phage blocks any new lambda phage
method eukaryotic viruses use to escape host cell by using host plasma membrane
Rate zonal gradient centrifugation
Counteract increasing force so particles move in proportion with time in field
Lambda repressor
blocks transcription of Cro gene, other genes needed for lytic cycle
sialic acid
binding site for haemagglutinin, cut by neuraminidase
breaks sealed phage Lambda in complementary base-pairing
Receptor-mediated endocytosis
cytoplasm folds inwards, budding vesicles
Alpha and Beta chains
proteins embedded in plasma membrane of t cell
human cytomegalovirus
Birth defects, blindness
washing barrier
removes microbes
Proteins involved in Cell lysis and phage release
T4 Lysozyme, Holin
ability to hide in host cell without reproducing
causes slow viral replication
skin barrier
a dry surface
engulfing solid particles by cell membrane to form internal phagosome (vacuole)
Gag, Pol, Env
poliovirus receptor
Giant virus that attacks amoeba
Virus: Hepatitis A
Receptor: Alpha 2-macroglobulin
condition caused by poliovirus
Satellite Tobacco masaic virus
icosahedral virus
Human T-cell lymphotropic viruses
(retrovirus) leukemia
ebola virus, causes hemorrhagic fever, membrane envelope with helical symmetry
restriction endonucleases
restriction enzyme, cuts dsDNA restriction sites
Hemagglutination assay
Viruses with hemagglutinin on surface
Virus: Influenza A
Receptor:Sialic acid glycoprotein
once endosome lyses, microtubules omove particles towards nuclear pore
Hepatitis C virus
4 types of cells in specific immune system
1. Helper T cells 2. cytotoxic T cells 3. B cells 4. Macrophages
Virus: Rotavirus
Receptor: a2b1, a4b1
protein for making capsid proteins
Tumor necrosis Factor
Causes virus to die, commit suicide
Ways Eukaryotic virus may enter a cell
1. Enveloped- fusing with plasma membrane 2. Enveloped- endocytosis 3. non-enveloped- endocytosis
type of pucornavirus, polio
Types of capsid symmetry
Helical, Icosahedral
Eukaryotic virus
Virus that binds to receptors on surface (proteins, glycoproteins
Special properties of viruses
1. Acellular 2. DNA or RNA, not both 3. Can't reproduce independently
Inactivated virus vaccine
Using heat/chemical treated virus, dangerous to produce, must be 100% inactivated, multiple vaccinations
dsDNA virus process
1. use DNA genome as template for mRNA synthesis 2. mRNA translated to produce viral proteins 3. use host RNA polymerase
transducing phage example
lambda phage
B-cell receptors
antibodies, immunoglobulins
binded to by lambda repressor or cro protein
T4 phage receptor
E. coli lipopolysaccharide
Parasite of medical important, responsible for many deaths
fever barrier
high body temp kills some bacteria and slows some viral replication, some bacterial components such as lipopolysaccharide induce fever
Norwalk virus
Plaque forming unit (PFU)
measure of particles capable of forming plaque in a limited volume
stomach acid, liver bile, intestinal enzymes
chemical, kill bacteria
Example of generalized transduction for Salmonella
Phage P22
caused by the poxvirus
Burst size
Number of viruses produced per infected cell
Virulent phage
Pathogenic phage, uses lytic life cycle
Integration of viral genome with host genome in a relationship
Physical barriers
any block that precents access to the inside of the body
clonal deletion
T cells tracel to thymus gland, where they are presented with all antigens present in human body. If immature t cell can bind to antigen, it undergoes apoptosis
dead skin barrier
sloughs off regularly
DNA-dependent RNA polymerase
used by transcription
Virus: Epstein-Barr
Receptor: C3d on human B lymphocytes
MHC class II proteins
present on surface of macrophages and Bcells only
Lipid bilayer, spikes
Herpes simplex virus 1 (HSV-1)
oral herpes, cold sores
T-cell receptors are made of two types of proteins
Alpha (light) chain and Beta (heavy) chain
Fuses with enveloped viruses/endocytosed viruses
cell/tissue damage
burst dead cells cause neighboring cells to produce an alarm signal-bradykinin
form of phage that remains in host integrated into chromosome
Recombinant vector
Genetically modified such as adenovirus that carry additional gene encoding antigens from virulent viruses. Presented to immune system to induce immunity.
secreated by mast cells, binds to capillary cells and causes them to change shape slightly to permit lique from blood stream to enter tissue
variable region in t cell
different amino acid sequence in every t cell
Measles virus
largest family of human/animal viruses. linear dsDNA
Lysogenic cycle
Remains in host without destroying it
binds to mast cells near capillaries, causes them to degranulate to release amounts of histamine
Type of herpesvirus, non-enveloped linear dsDNA- uses endocytosis
Virus: Herpes Type 1
Receptor:Heparan sulfate
Corynebacterium diphtheriae
produces diptheria toxin in lysogenic conversion
constant region in t cell
same amino acid sequence
Rolling circle
Mechanism using +ssDNA to create ds+/- DNA
att site
where lambda genome is integrated into host genome
tRNA (while creaing DNA)
used as primer for reverse transcriptase
Infectious virus as it exists outside of host cell
Acellular infectious agent
ds DNA example
herpesvirus, bacteriophages
Bacteriophage viruses replicate and spread, generating cell destruction
protein for making envelope spikes
binding site for T4 phage
length of urethra
slows bladder infection
Temperate phage
has two options for reproduction, lytic or lysogenic life cycle
Order, Family, Subfamily, genus and species
-virales, -viridae, -virinae, virus
Herpes simplex virus 2 (HSV-2)
genital herpes
ss RNA+, simplest significant virus
infected tissue
body's general response to localized infection
Influenza virus
enzyme E
blocks synthesis of host cell peptidoglycan, causes to lyse and release
-stranded RNA virus
Eukaryotic compartments
Cell wall, nucleus, nuclear pore, endoplasmic reticulum, golgi apparatus, endosome
ssDNA example
Smallest subunit in viral capsid
Differential/density gradient centrifugation
Purify by size, viruses are smaller than cells, larger than proteins
HIV protease,
viral protease that cleaves polypeptides Env, Gag, Pol into individual proteins
indigenous microbes
biology barrier, in the intestine and reproductive tracts, and on skin, kill other bacteria by secreting bacteriocins, eating available food, and taking up places to which parasites could attach
Icosahedral virus example
Immune response
If mature t cell can bind to antigen, t cell sets off alarm
ssRNA+ example
Poliovirus, rhinovirus
genetic factor barrier
unknown aspects of persons genetic background make them more or less susceptible to particular diseases
consecutive pieces, referring to the variable regions in t cells
electron microshopy/tomography
Can see shape of virus particles, not much detail
DNA vaccine
Take genes from viruses and inject them into host to produce viral proteins that cannot produce the virus, safe, multiple vaccinations
Virus that infects bacteria
Replication and transciption take place
cI gene
produces Lambda repressor
acid secreted in female reproductive tract barrier
kills bacteria, neutralization of this acid can cause infections
Virus Life Cycle
1.Attachment 2.Viral Entry 3.Synthesis 4.Assembly 5. Release
Plasmodium falciparum/Plasmodium vivax
Viruses account for Malaria deaths
T4 head
DNA packed
rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis
autoimmune diseases
Virus: Viccinia
Receptor: epidermal growth factor
Interleukin 2 (IL 2)
alarm signal, one needed to activate cytotoxic T cells
Plaque assay
Indirect measure of concentration of viruses
Virus Cultivation methods
1. Animal host cell. 2. Embryonated chicken egg 3. Tissue/cell culture
mosquito that carries Malaria virus in saliva
Virus: Measles
Receptor: CD46
reverse transcriptase
creates DNA from RNA-also carries ribonuclease Hwhich degrades RNA
clathrin-coated vesicle
what adenoviruses use to internalize into host
sloughing off of mucous barrier
from mucosal surfaces
X-ray crystallography
Challenging method of producing atomic structures of virus
Engulfment by receptor-mediated sites to form coated vesicles
5-subunit capsomer
Living together
Virus: Adenovirus
Receptor: Coxsackie (CAR)
transcribed to make mRNA and to provide more +ssRNA for packaging
T4 long tail fiber
binds to receptor
aid in phagocytosing
C3b receptors on neutrophil surface
Viral assays
1. Electron microscope 2. Hemagglutination assay 3. plaque assay
family of enveloped, helical, -ssRNA
6-unit capsomer
non-enveloped, icosahedral, dsRNA genome, use endocytosis
attract neutrophils
ribonuclease H
degrades RNA
Causes virus to lyse
Alpha chain splices these regions
V, J together
immobile phagocytes
biological, of the reticuloendothelial system phagocytose bacteria
Kaposi's sarcoma-associated herpescirus
Kaposi's sarcoma
example of specialized transduction
lambda phage
Phage T4
classic virulent phage, infects E. coli
Benefits one creature, neither helps nor harms other
T4 Lysozyme
Attacks peptidoglycan of E. coli cell wall
+ssRNA with DNA steps
retrovirus (HIV)
health barrier
stay healthy
Creates holes in E. coli plasma so lysozyme can get from cytoplasm to cell wall
RNA-dependent RNA polymerase
viruses use to encode
Cytopathic effect
Causes red blod cells to clot, leads to creation of plaque
cI Promoter (Prm)
enhances own synthesis of lambda repressor
Attenuated virus vaccine
Virus modified genetically to make a cirus that replicates poorly in us, only one vaccination
cell shape change
histamine binds to capillary cells
Most efficient way to make closed shell using little proteins, largest size for encapsidation 12 vertices, 20 faces, 30 edges, 60 units
Specific surface structures on host to which viruses attach
+ RNA viruses
Genome utilized like mRNA, produce single proteins needed for replication
foreign antigens
antigens not normally found in the human body
largest known animal virus- dsDNA- complex icosahedral structure
conditions in cell cause prophage to initiate synthesis of new phage particles, how a phage gets out of lysogeny
Phage Lambda
Icosahedral temperate phage dsDNA
non-enveloped, icosahedral, linear dsDNA
Vericella-zoster virus
Chicken pox, shingles
Methods of reproduction for bacteriophages
Lytic, lysogenic
- RNA viruses
Must have genome copied by RNA polymerase to make + RNA
Cariola cirus
Causes smallpox
coxsackie adenovirus receptor (CAR)
receptor site for adenovirus
Proteins or pieces of proteins that can be bound by receptor proteins on teh surfaces of the T and B cells
Lipid Bilayer
Sensitive to desiccation, heat, detergents
reverse transcriptase plus integrase
lysogenic conversion
changes in phenotype induced by lysogeny
Reverse transcription
makes ds DNA from ssDNA
oil on skin barrier
chemical barrier

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