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Human Heredity- Test #3 Part 2
Chapters 15, 17
43
Science
Undergraduate 1
04/28/2009

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Term
Genomics
Definition
the study of the organization, function and evolution of genomes
Term
Sequencing Method #1
Definition
-developed in 1970s
-uses four separate chemical reactions using radioactive isotopes, one for each base. The fragments generated by these reactions are separated by sixe n four adjacent lanes in a gel, read from the bottom up
-useful for sequencing small amount, but is labor-intensive
-needed new tech to sequence entire genome.
Term
Sequencing Method #2
Definition
-refined, only one chem reaction needed
-each base, new dye
-used DNA sequencers to scan the bases, high speed
Term
Bioinformatics
Definition
the use of computers and software to acquire, store, analyze, and visualize the information from genomics.
-includes:
-Comparative genomics which compares the genomes of different species to look for clues to the evolutionary history of genes or a species
-structural genomics derives 3-D structures for proteins
-pharmacogenomics analyzes genes and proteins to identify targets for therapeutic drugs
Term
Clone-by-clone method
Definition
a method of genomic sequencing that begins with genetic and physical maps and sequences clones after they have been placed in order
-cut in pieces by restriction enzymes,and a genomic library is made
-overlapping fragments help to organize the clones into genetic and physical maps
-then each clone is sequenced and software assembles the sequence into a genomic sequence
-used by gov sponsored group headed by Francis Collins
- 1990-1998
-finished months after Venter
Term
Shotgun sequence
Definition
a method of genomic sequencing that selects clones at random from a genomic library and after sequencing them, assembles the genome sequence by using software analysis
-no genetic or physical maps are created
-restriction enzymes are cut at different sites, several libraries containing overlapping fragments are created. Clones are selected at random from each library and sequenced. software detects overlaps in libraries and organizes the info into a genomic library.
-used in 1999 by privately funded Celera Corp, led by J Craig Venter.
-finished sequencing faster
Term
Heterochromatic regions
Definition
highly dense region, difficult to sequence, will be a couple more years
Term
Annotation
Definition
the analysis of genomic sequence data to identify the protein-coding genes, the non-protein-coding genes, their tegulatory sequences and their functions
Term
Open Reading Frame (ORF)
Definition
the codons in a gene that encode the amino acids of the gene product
Term
What have we learned from Human Genome Project?
Definition
-only 5% of genome encodes for genetic info
-genes not distributed equally along chromosomes, gene-rich clusters vs gene poor regions
-not all genes have been identified
-more types of proteins than genes
-human genome is similar to animal genomes- 90% similarities with mouse
-mutations in a single gene can yield difference genetic disorders, depending on how gene is affected
Term
Proteomics
Definition
the study of all the proteins present in a cell at a specific time
Term
Pathogens
Definition
disease causing agents; virus, bacteria, fungi and parasites
Term
Three levels of defense to infection
Definition
1. the skin
2.non-specific responses such as inflammation; designed to block entry of disease causing agents and block the spread of infection in body
3. specific responses like an immune reaction; has two possibilities, antibody mediated immunity and cell-mediated immunity, responsible for monitoring blood and organ transplants
Term
Complement System
Definition
a chemical defense system that kills microorganisms directly, supplements the inflammatory response and works with the immune system
Term
Histamine
Definition
a chemical signal produced by mast cells that triggers dilation of blood vessels
-triggered during a non-specific response of inflammatory reaction. cells infected by microorganisms release chemical signals, which often include histamine
-it increases blood flow to the area, heat, which is unfavorable conditions for infection growth. This attracts the white blood cells which aid in healing.
if the infection persists, it will swell, scab and specific white blood cells, like microphages are recruited to destroy invading bacteria
Term
Inflammatory response
Definition
The body's reaction to invading microorganisms, a non specific active defense mechanism that the body employs to resist infection.
-mutations in genes that encode proteins in this reaction result in inflammatory disease
Term
The Immune Response
Definition
has two components: the anti-body mediated immunity and cell-mediated immunity
-more specific, has a memory component, allows a faster response to pathogen upon second exposure.
Term
Lymphocytes
Definition
white blood cells that originate in bone marrow and mediate the immune response
Term
B Cells
Definition
a type of lymphocyte that is formed from stem cells and matures in the bone marrow and mediates antibody-directed immunity
-as it matures, is programmed to produce large amounts of antibodies (proteins)
-each individual B cell only makes one type of antibody, paired with a unique TCRs, there are billions of possible combinations
Term
T Cells
Definition
a type of lymphocyte that matures in the thymus and mediates cellular immunity
-T cell receptors are produced by T cells in thymus
-mature T cells circulate in the blood and concentrate in the lymph nodes and the spleen
Term
stem cells
Definition
cells in bone marrow that produce lymphocytes by mitotic division
Term
Antibody
Definition
a class of proteins produced by B cells that bind to foreign molecules, antigens, and inactivate them
-are y shaped protein molecules that bind to specific antigens in a lock-and-key manner to form an antigen-antibody complex
-are secreted by effector cells or on surface of B cells
-goal is to recognize and bind an antigen and inactivate it
Term
Antigens
Definition
Molecules carried or produced by microorganisms that initiate antibody production
Term
T Cell Receptors (TCRs)
Definition
Unique proteins on the surface of T cells that bind to specific proteins on the surface of cells infected with viruses, bacteria or intracellular parasites.
Term
Anti-body mediated immunity
Definition
Immune reaction that protects primarily against invading viruses, and bacteria using antibodies produced by plasma cells
-Several stages: antigen detection, activation of helper T cells and antibody production by B cells.
-A B cell, with antibodies displayed, wanders, searching for nonself molecules. When it finds an antigen, the antigen binds to the surface antibody, is internalized and partially destroyed. Fragments of antigen move to outer surface of B cell and the B cell becomes an antigen presenting cell.
-This cell encounters a helper T cell. TCRs make contact with antigen fragment on membrane and activate the T cell. The T cell then activates the B cells that make the antibody to fight the antigen encountered.
-The activated B cells form effector cells and memory B cells
Term
Cell-mediated immunity
Definition
Immune reaction mediated by T cells directed against body cells that have been infected by viruses or bacteria
Term
Helper T cells
Definition
a lymphocyte that stimulates the production of antibodies by B cells when an antigen is present and stimulates division of B cells and cytotoxic T cells.
-Connects the cell mediated and antibody mediated immunity systems
-can kill cells in the body if they become cancerous
Term
Effector cells
Definition
Daughter cells of B cells, which synthesize and secrete 2000-20000 antibody molecules per second into the bloodstream
Term
Memory B cells
Definition
a long-lived B cell produced after exposure to an antigen that plays an important role in secondary immunity
-life span of months or years
Term
Immunoglobin
Definition
the five classes of proteins to which antibodies belong
Term
IgM
Definition
found on surface of B cells and in plasma, first immunoglobin produced by B cells, largest
Term
IgA
Definition
found in body fluids, tears, breast milk, digestive fluid, spit
Term
IgD
Definition
found in circulation
Term
IgE
Definition
allergies and parasitic response
Term
IgG
Definition
can cross placenta, most abundant
Term
Suppressor T cells
Definition
slow down or stop the immune response of B cells and other T cells
Term
Cytotoxic T cells
Definition
destroy body cells infected by viruses or bacteria. They can also viruses, cancer cells, bacteria and cells of transplanted organs directly.
Term
vaccine
Definition
stimulates the production of memory cells against a disease causing agent. it is a weakened, disease causing antigen, given orally or by injection, that provokes a primary immune response and the production of memory cells. a second dose is called a booster shot. Made from Killed or Weakened strains (attenuated) that stimulate the immune system but do not produce life threatening symptoms
Term
xenotransplant
Definition
organ transplant between species
Term
allergens
Definition
antigens that provoke an inappropriate immune response, a weak antigen
-develop after a first exposure
-cause B cells to make IgE instead of IgG
-attach to mast cells and cause release of histamine
Term
anaphylaxis
Definition
a severe allergic response in which histamine is released in the circulatory system
-prompt response with antihistamines, epi pen or steroids needed to prevent death
Term
x linked agammaglobulinemia
Definition
a rare sex linked recessive trait characterized by the total absence of immunoglobulins and B cells
-no bursa-like
Term
SCID
Definition
a genetic disorder where there is no immune response, both the cell mediated (T Cells) and anti-body mediated (B cells) responses are missing
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