microbio final

Non-cellular entities which consist mainly of protein and nucleic acid (DNA or RNA) and which can replicate only after entry into specific living cells

The spectrum of host cells that each type of virus can infect. it is determined by specific host attachment sites and cellular factors

a complete viral particle

virus that infects a bacterial cell

• Obligatory intracellular parasites
• Contain DNA or RNA
• No ribosomes
• No ATP-generating mechanism
• Contain a protein coat
• No metabolism and, few or no enzymes of their own.
• No intrinsic motility.
• Cannot grow on artificial lab media.
• Do not respond to physical stimuli in their environment
• Some viruses are enclosed by an envelope
• Some viruses have spikes
• Most viruses infect only specific types of cells in one host

• Polyhedral (many sided) Viruses
• Helical Viruses 
• Enveloped Viruses
• Complex Viruses 
• Bacterial viruses

Many animal, plant, and bacterial viruses are icosahedron (with 20 faces and 12 corners).

Resemble long rods that may be rigid or flexible.

Have a roughly spherical but somewhat variable shape even though their nucleocapsid can either be icosahedral or helical

Many bacterial viruses have capsid symmetry that is neither purely icosahedral nor helical. They may possess tails and other structures or have complex, multilayered walls surrounding the nucleic acid

• Virion is an infectious viral particle
• Nucleic acid
• DNA or RNA Never both
• Circular or linear DNA
• Or single or double stranded RNA
• Capsid
• Capsomeres
• Envelope
• Spikes

• Papillomavirus 
• Adenovirus

• Influenza virus 
• Paramyxoviruses -Mumps

(nucleocapsid) is composed of protein subunits called Capsomeres

consists of combination of lipids, proteins, and CHO, an outer membranous layer surrounding the nucleoapsid

virus without envelope

protein subunits that make capsids

A receptor on the surface of certain enveloped viruses that facilitates specific attachment to the host cellAre CHO and protein complex Can be used as means of identification.Cause clumping of RBC called Hemagglutination

a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium (e.g. agar). The bacteriophage viruses replicate and spread, thus generating regions of cell destructions

A gene that when activated can transform normal cells into cancerous cells

• high-energy radiation
• mutagenic chemicals 
• some viruses

Normal cellular genes that regulate cell proliferation and differentiation that can become oncogenes.

Viruses must be grown in living cellsBacteriophages form plaques on a lawn of bacteriaAnimal viruses may be grown in living animals or in embryonated eggs or in cell cultures (continuous cell lines)

• lytic cycle
• lysogenic cycle

lysis and death of host cell

• Host cell does not die 
• Viral DNA incorporates into host cell DNA 
• Virus remains latent

• Attachment
• Penetration
• Biosynthesis -production of phage or viral DNA and proteins
• Maturation - DNA and capsids are assempled
• Release - plasma membrane breaks open releasing virions

• Eclipse period
• Burst size 
• Burst time

• Adenovirus
• Papillomavirus
• Paramyxoviruses
• Influenza virus
• Bacteriophages
• herpesvirus

tiny pieces of protein (infecious protein)

Inherited and transmissible by ingestion, transplant, and surgical instruments

• Spongiform encephalopathies: sheep scrapie
• Creutzfeldt-Jakob disease
• Gerstmann-Sträussler-Scheinker syndrome
• Fatal familial insomnia
• Mad cow disease
• - there is no treatment

lack of resistance to disease

ability to ward off disease

nonspecific or any pathogen

specific pathogen & long lasting

epidermis, keratin, mucous membranes, ciliary escalator

fungistatic sebum-oily skin, low pH, lysozyme, gastric juice, vaginal secretions

compete with pathogens

one microbe benefits and the other is unharmed

phagocytosis

Histamine, triggers inflammation

kill parasites

single nuclei

branching

targeted, cancerous tissue

cell mediated immunity, supress or amplify

antibodies

clotting

source of T cell creation

ingestion

complement, kinins

prostaglandins

inflammatory response allows phagocytic wbc's to leave vessels and attack pathogens

serum proteins, antigen antibody reaction, C3b opsonization

makes the antigen more susceptible to phagocytosis

bursting of cells

phagocytes

capsules, surface lipid carbs, enzymatic digestion

IFN-a and IGN-B, antiviral proteins

phagocytize bacteria

lacrimal, saliva, urine, vaginal secretions

tears

washes microbes off

consist of tightly packed cells with keratin

a protective main component in hair

traps microbes

microbes trapped in mucus are transported away from the lungs

in perspiration and urine

acquired naturally or artificially specific and have memory

an organism or toxin enters the body and produces an immune response

results from immunization by a vaccine

protects against one pathogenonly exception when two are closely related

much stronger immune response upon reexposurelong term immunity

• Antibody mediated responses 
• Cell Mediated Response

• AKA: Humoral Response
• Ab specifically bind to and inactivate foreign particles

trigger T lymphocytesrecognize and destroy abnormal/infected host cells

foreign particle that enters the bodycan be broken into epitopes

• Protein produced in response to Ag
• like lock and key
• 2 light chains and 2 heavy chains
• 2 antigen bonding sites

• IgG
• IgM
• IgA
• IgD
• IgE

• most common
• found in blood and can enter tissues
• can cross the placenta: confers passive immunity to fetus
• binds antigens very strongly

• pentamer
• stay in blood
• aggregate antigens
• 1st produced

• dimer
• found in body secretions
• protects gastrointestinal tract of newborns

• found on mast cells and basophils
• triggers release of histamine

Immunoglobulin E

• Agglutination
• Neutralization Complement
• Activation
• Opsonization
• Ab Dependent Cytotoxicity

Ag stuck togetherreduces number of infectious units to be dealt with

Ab binds to Ag and inactivates itprevents it from adsorbing to host cells

Ab binds bacteria and starts complement pathway(MAC Attack)

flags down phagocytes to destroy cell

flags down immune system cells to destroy antigens too big for phagocytosis

• B- Lymphocytes 
• T-Lymphocytes

• Ab producing cells
• involved in humoral response

• Helper T-cells
• Cytotoxic T-cells-destroy abnormal body cells
• cell mediated response

macrophages, B cells, dendritic cells

antigens presented to MHC to decide if they are dangerous or not

• B cells circulate until they find antigenspresent to MHC
• MHC says its dangerous 
• Th cells activate B cells- which undergo clonal expansion

• B cell differentiates into plasma cells(Ab cells) and memory cells
• memory cell are long living and if they encounter the antigen again will initiate a quick response

• B cells produce low levels of Ab
• 7-14 days
• IgM first, then IgG and IgA
• memory built

• 2nd encounter
• high levels of Ab1-2 days
• memory cells replenished

destroy abnormal human cells

engulfs foreign antigens and present to a different MHC

• long lasting immunity
• natural- body encounters Ag 
• Artificial- Ag as a vaccine

• temporary immunity
• Natural- mother to infant
• Artificial- Ab injected(for life threatening situations snakebite)