Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
75 Cards in this Set
- Front
- Back
|
Name the 5 point mutations
|
Transition
Transversion Missense Nonsense Frame Shift |
|
|
Name the five Chromosomal Aberrations
|
Deletion
Insertion Duplication Translocation Inversion |
|
|
Name the two aneuploidies
|
Monosomy
Trisomy |
|
|
Polyploidies
|
Triploidy
|
|
|
What is a silent mutation
|
One that does not induce a phenotypic effect.
Examples Third base of a wobbly codon INtron that is spliced out of a message Spacer region of a chromosome that is outside of any expressed gene similiar amino acid with the same effect on protein function Region of a protein that is not critical for function |
|
|
What is a transition?
|
Pyr-Pyr
Pur-Pur |
|
|
What is a transversion?
|
Pyr-Pur
or Pur-Pyr |
|
|
What is translocation?
|
When a misplaced DNA fragment is moved to a differnt location in the genome. Can be on the same or different chromosome.
|
|
|
Chromosome 3 Duplication-Deletion syndrom?
|
Inversion of the center of chromosome three
No defects in teh first gen. 1/2 the second die General delay of development, recurrent urinary,respiratory, and eye infections due to numerous head and facail abnormalties |
|
|
What is Cri du chat syndrome
|
Deletion of part of the q arm of chromosome 5
Infant or early childhood fatality Plaintitive catloike meowing, microcephaly, broad face, saddle nose, widely spaced eyes with epicanthic folds, mental retardation |
|
|
Ploidy?
|
The number of parental chromosomes.
|
|
|
Hydatidform moles.
|
Develops in some triploidies
Develop from eggs that lose thier maternal nucleus, and are fertilized by two sperm, resulting in all paternal and no maternal genes. Both dypes of mole develop with trophoblastic tissue but little or no fetal tussue. No vasculature develops the placenta cant drain. The villi become swollen resembling bunches of grapes. |
|
|
Choriocarcinoma?
|
If the hydatidiform mole is not aborted this malignancy can form
Even with modern medicine it carries a 20% fatality rate |
|
|
Aneuploidy?
|
Having th ewrong number of chromosomes in a parental set.
|
|
|
Nondisjunction
|
Failure of chromatids to separate during meitotic anaphase. THIS PRODUCES ANEUPLOIDIES
OLDER WOMAN ARE AN INCREASED RATE OF NONDISJUNCTIONS. DUE TO SUSPENSION OF THIER OOCYTES IN A PROLONGED MEITOTIC PROPHASE 1 |
|
|
Prenatal Screen for Down Syndrome
|
Lower levels of alpha fetoprotein
unconjugated estriol hCG, and serum dimeric inhibin A (the quad screen) |
|
|
Prenatal screen for open defects?
|
Elevated levels of alpha feto protein
acetylcholinesterase |
|
|
Down Syndrom
|
Trisomy 21
1/700 Short stature, epicanthal eyelid folds, broad skulls, large tongues, loose joints, stubby hjands with simian crease, singe crease of the fifth digit, mental retardation |
|
|
Edward syndrome
|
Trisomy 18
1/6500 One patient has survived to adulthood Clenched fists with 235 overlapping 4 rocker bottom foot, prominent occiput, micrognathia, short sternum, narrow hips, faunlike ears, profoundly retarded |
|
|
Patau Syndrom
|
Trisomy 13
1/20,000 HIGHEST post partum mortality holoprosencephaly, cleft palate, prominent proboscis, polydactyly, rocker bottom foot, seizures |
|
|
Turner Syndrome?
|
Monosomy of X chromosome
(XO) 1/3000 Most abort spontaneously Females, no ovaries, limited secondary sexual characteristics, short stature, low-set ears, webbed neck, broad shield like chest, widely spaced nipples, NO MENTAL RETARDATION |
|
|
Klinefelter syndrome?
|
An extra X chromosome(XXY)
1/1000 Males with some female secondary characteristics, underdeveloped male characteristics, little body hair, no mental retardation The more Xs the more likely retardation will occur |
|
|
Extra sex chromosomes
|
XYY, XXX
XYY=slightly reduced IQ little to no physical abnormalities, minor learning disabilities. increased incidence in prision populations due to ADD |
|
|
List the Endogenous Mutagenic process(8)
|
DNA Ligase ERrors
Unequal crossing over Nondisjunction DNA polymerase infidelity The cycochrome p-450 system Depurination Deamination Tautomeric shifts |
|
|
DNA ligase errors
|
Automatical forms phosphodiester bonds between any free 3'OH and 5' phospahte. If strands are cleaved they may be rejoined incorrectly. There is no repair mechanisms
|
|
|
Unequal crossing over
|
Displaced exchange of strands suring crossing over so the sequence is deleted from one homolog and added to another.
|
|
|
DNA polymerase infidelity
|
Inherent error rate=1 mismatch per 10^9 to 10^10 replicated base pairs
|
|
|
Cytochromep-450 sytem
|
Natural liver function to remove toxins. Occasionally makes innocuous products mutagenic
|
|
|
Depurination
|
Release of purate (A or G) by cleavage of the bond with the 1' site of ribose. If not repaired then any of the 4 bases can be incorporated into the new strand
|
|
|
Deamination
|
Removal of an amino group from a base by oxidation to a keto group. With A or C this will result in a transtion mutation during the next round of DNA replication. Deamination of G is no tmutatgenic while T does not have an amino group ot remove.
|
|
|
Tautomeric shifts
|
Transient changes in the electron configuration of a base, causing it to resemble anothe rbase. All four undergo these shifts. If occur during DNA replicaiton they can induce transition mutations.
|
|
|
What is the problem with UV light
|
electrons in the atoms of DNA absorb the energy of UV rays making them chemically reactive.
Causes thymine dimers These interfere with processes of DNA replication causing point mutations and chromosomal aberrations |
|
|
Ionizing radiation?
|
Alpha, beta, and X. |
Collide with molecule and result in excise electrons, producing highly reactive, ionic atoms. Usually produces point mutations |
|
|
Gamma rays
|
Breaks DNA strands and causes chromosomal aberrations.
|
|
|
Alkylating agents?
|
Nitrogen musterd.
These add one or two carbons to DNA this interferes with DNA replication causeing point mutations and chromosomal aberrations |
|
|
Strand cleavers
|
Peroxides, sulfur compounds
These severe phophodiester bonds directly, inducing chromosomal aberrations |
|
|
Base analogs
|
These mimic nucleotides inducing bp substitutions undergoes tautomeric shift between keto and enol configs.
Keto=T Enol=G |
|
|
Intercalating agents
|
Acridine orange, proflavin
These wedge themselves between bases of DNA this creates tension in the strands resulting in chromosomal aberrations during replication |
|
|
Insertion elements
|
(viruses and transposons)
Theyse are DNAs with the ability to intergrae into a chromosome and to b e excised from a chromosome. Can casue insertional mutatgenesis Deletions or Insertions |
|
|
DNA polymeraase proofreading?
|
Allows it to double check for base pair mismatches during replication and to excise the incorrect base.
Inherent errors error rates occur and mistakes do occur. |
|
|
Ligation of strand breaks?
|
The enzyme DNA ligaese will automatically join any frfee 3')H of one strand to a free 5' phosphate of another. Cant determine original orientation so strands may be tanslocated or inverted
|
|
|
Direct base repair
|
Some cellular process can repair specific bases which have been covalently damaged
|
|
|
Excisiion repair
|
Endonucleases nick strand
Exonucleases remove strand DNA polymerase B fills in gap DNA ligase seals the nick |
|
|
Xeroderma pigmentosum
|
Defective UV specific endonucleases resulting in extensive skin tumors after exposure to sunlight
|
|
|
1
|
1
|
|
|
2
|
2
|
|
|
3
|
3
|
|
|
4
|
4
|
|
|
5
|
5
|
|
|
6
|
6
|
|
|
What is a nonsense mutation?
|
BP substition resulting in a stop codon a truncated polypeptide
|
|
|
Missense mutation?
|
A single BP subsitition altering one amino acid
|
|
|
Is the first generation of reciprocal translocations affect?
|
Negator
|
|
|
What do the progeny of inversions look like?
|
The first g is usally wild type however some of the progeny will be mutated.
|
|
|
What is cri-du-chat?
|
Deletion of p arm of chromosome 5
|
|
|
Anuploidy?
|
To have one or chromosomes added or removed. To have the wrong number of chromosomes in a parental set.
|
|
|
What produces aneuploidies?
|
The failure of chromatitds to separate during meitotic anaphase.
Older women have an increased rate of nondisjunctions. |
|
|
What are the sex chromosome aneuploidies?
|
Turner and klinefelter
|
|
|
What produces polyploidy?
|
Polyspermy
|
|
|
What is c p450 do?
|
Natural function of the liver to remove toxins. Oxidized hydrophobic compouns and makes them water soluble cna make products mutagenic
|
|
|
Can T be deaminated?
|
Nopers. I lacks an amino group so there is nothing to be removed
|
|
|
Tautomeric shifts?
|
Ransient changs in the elctron configuration of a base causingit to resemble another base. If occur during DNA rep can induce Transition mutationg
|
|
|
What type of radiation causes point mutations>
|
Alpha beta and X catagorized as point mutations
|
|
|
Gamma rays cause what
|
Chromosomal aberrations
|
|
|
Excision repair steps?
|
1)Endonuclease nucks phosphdiester bond at 5' end
2) Exonucleases ten remove a region of the strand with damaged bases 3) DNA polymerase B fills in the gap and DNA ligase seals the nick |
|
|
what is teratogenesids?
|
Non-genetic developmental defect
|
|
|
What is deformation?
|
Malformations produced over a prolinged period of time due to persistent molding forces.
|
|
|
What is disruption?
|
Malformations produced after the initial formation of a normal dtructure due to abruptly occurring foreces
|
|
|
What is the most sensitve time period for teratogenic malformations?
|
3-8 weeks.
|
|
|
What is catagory x?
|
teratogenic humans. DO NOT GIVE TO PREGGERS
|
|
|
Cat D?
|
TG in humans but benefits may exceed risk.
|
|
|
What is thalidomide?
|
Sedative given to preggers in w. germany
Causes phocomelia which is absence of long bones |
|
|
Fetal alcohol syndrome?
|
Most pronounced malformation is holoprosencephaly
|
|
|
What is the importance of administration of folic acid during pregnancy?
|
During the 3rd and 4th week it can reduce chance of developing neural tupe defect.
|
|
|
blank
|
blank
|
