10 Flashcards
Sickle cell disease (SCD)
alson known as sickle cell anemia
first known inherited disorder resulting from protein defect
a potentially fatal autosomal reessive disorder caused by an abnormality in the structure and function of hemoglobin (Hb)
hemoglobin structure
tetramer containing two protein chains encoded by two different globin genes encoded on separate chromosomes
alpha globin and beta globin
Beta S alleles
differ from the Beta A allele in that they produce disfunctional beta globin proteins. two of these results in SCD
less stable then Beta A alleles and when oxygen concentration is low, they collapse.
origin of migration
in each gel electrophoresis tray, when the gel is being made, there is a comb present in the tray that stays in until the gel solidifies. The comb is then removed, leaving several wells behind in the gel on the negative end. Each sample for the gel is put in one of these wells, thus they serve as the origin of migration for eah sample
agarose
one of the most commonly used gels in electrophoresis
a form of cellulose
polyacramide
a synthetic materia made by a polymerization rxn.
one of the most commonly used materials to form electrophoresis gels
what three parameters of molecular structure determine the rate of movement through electrophoresis gel?
Molecular Weight
Molecular Charge
Molecular shape (molecular conformation) -more condensed=faster
electrophoretic mobility
a term describing either the rate of a molecule’s electrophoretic migration or its final position of the protein in the gel
Peptide fingerprint analysis
1) The protein is broken into many fragments by chemical treatment
2) the protein fragments are subjected to electrophoresis to seperate the fragments in one direction on a gel
3) the protein fragments are seperated in a second dimension, perpendicular to the first, by chromatography.
4) at the end of these two seperations, the locations of the protein “spots” serve as a kind of “fingerprint” of the protein
chromatograpphy
uses a solvent to carry fragments with different amino acid composition to different final positions.
single nucleotide polymorphism (SNP)
the most common type of DNA sequence difference between organisms of the same species.
consists of differences of single nucleotide base pairs.
restriction endonucleases (restriction enzymes)
a special class of DNA-digesting enzymes that act only on specific DNA sequences.
restriction sequence
the precise DNA sequence that a restriction endonuclease recognizes and cuts
in 5’ to 3’ direction
restriction fragments length polymorphism (RFLP)
The number of restriction fragments produced by a given restriction enzyme is characteristic for a given sequence of DNA.
RFLP is the inherited variability in the number or the length (in base pairs) of restriction fragments.
sticky ends
some DNA fragments are cut by certain restriction enzymes with ends short, single stranded ends. The ends are called sticky ends
blunt ends
Ends of DNA fragments that are double stranded
ethidium bromide (EtBr)
Stains DNA in electrophoresis gel
blotting
a general name for the transfer of nucleic acids or proteins from an electrophoresis gel to a membrane that can withstand rigorous treatment and analysis
Southern blotting
blotting for DNA
northern blotting
blotting for mRNA
western blotting
blotting for proteins
molecular probes
antibodies or single-stranded nucleic acids that specifically bind to target molecules, thus making possible the identification of a given protein or specific DNA or RNA sequence.
hybridization
the pairing of complementary nucleic acid strands of a molecular probe and a target nucleic acid sequence.
heterozygous advantage
individuals with betaA betaS heterozygous genotypes are given a survival and reproductive edge in populations where malaria is present
Thus that allele provides a heterozygous example
equilibrium frequency
the gain and loss of a certain allele is equal, creating an equilibrium of its frequency in a population. (i.e. betaS in populations dealing with malaria, where homozygous betaA gets screwed by malaria and homozygous betaS gets screwed by sickle cell disease, but heterozygous betaA betaS has a solid resistance to malaria and doesnt get severe anemia)
balanced polymorphism
the term used to describe situations where an equilibrium frequency is reached
because the loss of an allele because of selection of one of its phenotypes is balanced by natural selection in favor of the allele for another phenotype.
