a parental strand of double stranded DNA unzips- (enzyme) DNA polymerase inserts the complementary nucleotides (a-t g-c) along the missing half of each parental strand's ladder- until 2 copies of double stranded DNA are created which are exactly identical to the origianal parental DNA.
the original strand & newly synthesized daughter strand then unwind, each new double stranded DNA molecule contains one origianl(conserved) & one new strand.
(mrna to protein) decoding the language of nucleic acids and converting that info into the language fo proteins.
a designated section of DNA(a gene) uncoils. one strand on the DNA acts as the template to create mRNA. this mRNA then leaves the nucleus and travels to the ribosomes, carrying the instruction blueprint, from the gene (DNA)
(aug, ggc,etc) found on RNA, contains the language of mRNA. (3 groups fo nucleotides.)
the 3 nucleotides by which a tRNA recognizes the mRNA codon.
code for A.A.'s
DO NOT!!! they signal the end of the protein molecule's synthesis.
both recognizes the specific codons and transports the required A.A.'s.
DNA- transcription- mRNA- translations(at ribosomes)- protein.
occur naturally/spontaneously,or artificially induced. an inheritable change in the gene, often a change in nucleotide bases or base sequences.
a mutation induced by environmental factors. (ex: UV light)
Base Substitution ( missense, nonsense, frameshift)
base substitution: a single base at one point in the DNA sequences is replaced with a different base. missense:if the base substitution results in an A.A. substitution in the synthesized protein. nonsense mutation: a base substitution resulting in a nonsense codon. frameshift mutation: one or a few nucleotide pairs are deleted or inserted in the DNA.
the transfer of genetic material during cell-to-cell contact, a type "mating" pili utilized for the transfer.
this involves the transfer of genetic material from a bacterial virus (bacteriophage) into a bacterium. (the genetic material may originally come from other bacteria or the virus itself.
the defense mechanisms of humans/animals in their attempt to resist or overcome infection by microorganisms.
lines of defense
1/2-nonspecific (innate) 3rd-specific (adaptive)
1st line of defense:
mechanical & chemical barriers, normal flora which fight microorganisms in general rather than a specific microorganisms.
skin, mucous membranes, respiratory cilia, tears, hairs, vaginal secretions, urine, vomiting, epiglottis, & defacation.
sebum, perspiration, lysozyme, & gastric juice
Normal Flora inhibits microorganisms by:
prevents patogens from colonizing/production of phagocytes, can produce products or waste products that are harmful to pathogens, can alter pH/O2 conditions to kill pathogens, and prevents pathogens from obtaining nutrients.
2nd line of defense:
interferon, complement, inflammation, fever, phagocytosis, and formed elements of blood
Granulocytes 3 types:
neutrophils (60-70%) eosinophils (2-4%) basophils (.5-1%) dendritic cells.
(60-70%) have the ability to leave the blood, enter an infected tissue & destroy microbes, foreign particles (phagocytosis: 1st to show up)
2-4% produces toxic proteins against certain parasites, such as helminths.
.5-1% releases histamines that are important in inflammation & allergic responses.
(in skin/epidermis)destroys microbes by phagocytosis & to initiate adaptive immunity responses(interact w/3rd defense.)
monocytes, natural killer cells
3-8%, becomes macrophages which remove miccroorganisms by phagocytosis and dispose worn out RBC's.
Natural Killer Cells
(a type of lymphocyte) found in blood/spleen/lymph nodes, bone marrow. has ability to hill infected cells in the body. has perforin-which punches a hole in the pathogen cell wall that causes it to lyse.
the ingestion of a miccroorganism or other substanes by a cell.
Process of Phagocytosis
chemotaxis & adherance of microbe to phagocyte--ingestion of microbe by phagocyte--formation of a phagosome--fusion of the phagosome w/a lysosome to form a phagolysosome--digestion of ingested microbe by enzymes--formation of residual body containing ingestible material--discharge of waste material.
(aka-mononuclear phagocytic system) various macrophages of the body.
Tissue damaged by the infection causes histamine to be released from tissue mast cells and basophils. histamine causes area blood vessels to dilate and initially "leak" out neutrophils, which then try to phagocytize invading microorganisms. Fluids often leak out w/neutrophils, causing swelling, pain, as pressure builds on local nerve endings.
swelling, pain, redness, possible area temp. elevation (cardinal signs)
3 fxn.'s of inflammation
1.destroy injurious agent (& remove its by-products from the body.)2.if destruction isn't possible, then it limits the effects on body by confining/walling off injurious agent/by-product. 3. to repair/replace tissue damaged by the injurious agent/or its by-products.
the collected phagocytes begin to squeeze between the endothelial cells of the blood vessel to reach the damaged area.
an abnormally high body temp.
Process of a fever
foreign invader--cytokines produce interleukin I & alpha--travel to bloodstream--hypothalamus--which elevates the body temp.--chills--begins to eliminate pathogens--body temp. goes down--sweat--"crisis" breaking pt. of fever--infection is under control.
Beneficial effects of fevers.
1. a defense against disease, helps body temp. to repair/heal after the fever(which brought on certain chemicals for healing) 2. increases T-cell production 3. production of transferrin (proteins that help bind up free iron, which many bacteria feed on.)
a defensive system consisting of over 30 proteins produced by the liver & circulating in blood and tissues w/i the body.
so named because it "complements" the cells of the immune sytem in destroying microbes.
opsonization/ cytolysis/ MAC/Inflammation
enhancement of phagocytosis by coating the pathogen w/C3b which attracts WBC's
cytolysis/MAC-membrane attack complex
C9's activated which makes a ring around the microorganism, it punches down through the wall of the mircroorganism
stimulated by complement. increase of blood vessel permeability and chemotactic attraction of phagocytes.
3 types of complement activation
CLASSICAL-initiated by antibody/antigen reaction ALTERNATIVE-initiated by contact between certain comp. proteins LECTIN-fxn's as an opsonin that enhances phagocytosis & activates comp.
a protein produced by some lymphocytes and tissue cells under viral attack. it acts as a messenger and spreads to surounding cells, stimulating these cells to produce antiviral proteins which interfere with viral mulipliation, preventing the spread and sytheses of the virus.- interferrons are host-cell specific, but not viral specific. (alpha, beta, gamma)
iron building protein, transports and stores iron. found in blood, tissue fluids, deprives most pathogens from available iron.
Antimicrobial peptides (AMP's)
inhibit cell wall synthesis, forms pores in plasma membranes, resulting in lysis, & destroys DNA/RNA. produced by nearly all plants & animals, bacterial resistance to amp hasn't been seen yet.
3rd line of defense!!!
the specific/adaptive immune sytem involves the activities of WBC's called lymphocytes that often become involved in the fight against invading microorganisms. the body has the ability to recognize self versus non-self or dangerous vs. non-dangerous.
2 main types fo immune responses
cell mediated/ humoral.
characterized by B cells that form antibodies.
immunoglobulin, a protein produced by B-cells in response to an antigen & is capable of combining specifically to that antigen.
immunogen, a chemical substance that causes the body to produce specific antibodies
a low molecular weight substance that can't cause the formation of Ab unless combined w/a carrier molecule. haptens react w/their Ab's independently of the carier molecule.
antigenic determinant, specific regions on antibodies where they interact w/Ag's
programmed cell death!!!
Factors that stimulate an immune response
threshold level of Ag, route of entry of the Ag, type of Ag. (must be protein/polys.)
80% blood, lymph, intestines, enhances phocytosis neutralizes toxins/viruses, protects fetus/newborn.
physical, chemical, & fxnal.
5-10% in blood, lymph, B-cell surface, especially effective agianst microorganisms & agglunitating Ag's, 1st Ab's produced in response to initital infection.
10-15% secretions, blood/lymph,localized protection on mucosal surfaces.
.2% B-cell surface, blood, lymph, serum fxn. not known, presence on B-cells fxns. in initiation of immune response
.002% bound to most mast/basophil cells throughout body,blood, allergic reactions, possibly lysis of parasitic worms.
involved in resistance to infection & fighting acute and toxigenic infections.
MHC ( major-histo-compatibility-complex)
the genes that code for histocompatibility Ag's,(ag.'s that's a part of you/self ag)
Antigen-presenting cell (APC)
b-cells, dendritic cells, macrophages, they carry ag's to lyphoid tissues where T cells that recognize the ag are located.
results of Ag/Ab binding
1. agglutination 2.opsinization 3. neutralization 4. activation of comp. 5. Ab- dependent cell mediated cytotoxicity.
programmed in the thymus!!!
(helper t cell) activates cells involved in cellular immunity.
(helper t cell) associated w/allergic reactions & parasitic infections.
2 Classes of T cells
1. cytotoxic t cell (Tc) 2. Regulatory t cell (Tr)
Types of Ag presenting cells
Dendritic cell, Activated macrophage
the relative amount of Ab's in blood serum.
the response of the body to the first contact a/an Ag, caracterized by appearance of IgM-IgG
(quicker) has memory cells, subsequent contact w/the same Ag results in a very high Ab titer, Ab's are IgG
helper cells of the immune system communicate w/each other by means of the chemical cytokines.
cytokines that serve as communicators between leukocytes
causes leukocytes to migrate to an infection
Naturally aquired immunity
active-immunity from infection passive-immunity passed from mom to baby
Artificially aquired immunity
active-immunity aquired from vaccine passive-immunity aquired from Ab injection.