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35 Cards in this Set
- Front
- Back
What is in each DNA?
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DNA is packaged into 23 pairs of chromosomes in each cell except in the germ cells (X&Y or X&X) which have 23 SINGLE chromosomes.
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Where does each pair of chromosome come from?
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Once chromosomes for each pair comes from the individuals' mother and the other comes from the father.
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What are the four bases of DNA?
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A
T G C C & G always pair up together A & T always pair up together |
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What chromosomal defect is a characteristic of Down Syndrome?
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There are three chromosomes on chromosome 21
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What are the maternal age risks when getting pregnant?
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Maternal Age 25 > Risk of Down's = 1 in 2500
Maternal Age 30 > Risk of Down's = 1 in 952 Maternal Age 35 > Risk of Down's = 1 in 378 Maternal Age 40 > Risk of Down's = 1 in 106 |
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What is Robertsonian translocation?
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Another way to get Down Syndrome in which the extra chromosome on 21 moves to the tip of chromosome 14.
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What is Klinefelter Syndrome?
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Its when a male karyotype with more than one X (XXY).
Approx. 1 in every 500 males. S/S: reduced fertility, learning disabilities, hypogonadism; decreased muscle mass & strength; feminine distribution of adipose tissue; decreased physical endurance; osteoporosis |
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What is a centromere?
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?
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What is mitosis?
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?
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What is meiosis?
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?
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What is 47 XYY?
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Its when there's an extra Y chromosome (eg: XYY)
About 1 in 1,000 ppl. Usually no unusual physical features or medical problems and have normal sexual development & fertility. S/S: taller than average, risk of learning disabilities & delayed speech & language skills; some behavioral problems but these characteristics vary widely. |
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What is Turner Syndrome?
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Caused by a large collection of lymphatic fluid in back of neck that can not drain.
Most babies with Turner Syndrome are miscarried but if they survive then as a baby puffy feet and hands & neck is distended from fluids. As girls progress into womenhood, they are usually shorter & are infertile. |
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What is reciprocal translocation?
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look at picture in slides
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What is Cri du chat Syndrome?
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Main characteristic as a baby is their cat like cry.
These children have severe retardation. |
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What is DNA?
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Each cell has 46 human chromosomes = that is 23 pairs in each cell.
3 billion DNA subunits (the bases: A, T, C, G) Approx. 30,000 genes code for proteins that perform nost life functions each DNA molecule is half "old" & half "new" |
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What is the start codon & what is the end codon?
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ATG = start codon (indicates the beginning of a DNA strand)
TAA, TAG, TGA = stop codon (indicates the end of a DNA strand) |
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What is translation?
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?
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What is transcription?
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?
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What is Gene mutation?
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a mutation is an alteration in the code of a gene that may be or may not prevent the production of that gene's normal protein.
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What are types of mutations?
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1) Normal - eg: the sun was hot
2) Missense or subsitution - eg: the sun wBn hot 3) Frameshift - eg: INSERTION ~ the suA nwa sho t eg: DELETION ~ ths unw ash ot |
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What are somatic mutations?
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Somatic mutations are passed on to successive generation of the cell (ie: all the daughter cells from then on has the mutation but they are not passed on to future offspring of the individual)
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How do genes & cancer interelate?
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Cancer results from a series of mutations that take place in genes that control the reproduction of the cell. Cells with such mutation reproduce themselves at a much more rapid rate.
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What are the 3 classes of cancer genes?
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1) Oncogenes - that positively regulate growth
2) Tumor suppresser genes - that negatively regulate growth 3) DNA Repair Genes - |
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What are germline mutations?
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If a mutation occurs in a germ cell of an individual then it will cause mutations to any cells after fertilization to all somatic cells and approx. 1/2 of the germ cells of the new individual.
Therefore the cell mutations will be passed on to successive gerneations of that individual. |
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What is an allele?
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An allele is a variant form of a gene at a particular locus location on a chromosome).
Different alleles produce variation in inherited characteristics such as hair color or blood type. |
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What is the mendelian pattern or inheritance?
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Autosomal dominant
Autosomal recessive X-linked recessive X-linked dominant |
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What is the CARDINAL features of hereditary cancer?
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Hereditary cancer is cancer in two or more close relatives.
Bilateral cancer in paired organs. Early age onset. Specific constellation of cancers that compose a known syndrome. Medelian pattern of inheritance. |
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What is Huntington Disease?
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Excessive number of CAG repeats in HD gene.
Its a disorder of mood, mentation, & movement. Onset in middle adult years. HD gene has virtually 100% penetrance. No cure or effective treatment. Onset in 40s; die within 10-15yrs. of diagnosis. |
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What is autosomal recessive inheritance?
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Afftected individuals have mutations in both alleles of the gene pair.
Carriers of the mutations have a mutation in one of the alleles. |
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What is Tay Sachs?
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Build-up of GM2 ganglioside in neuronal lysosomes results in hypotonia, the loss of developmental milestones, seizures, blindness, deafness and death by 4 or 5.
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What is sickle cell disease?
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A to T point mutation in Beta globin gene.
Heterozygote frequency of 1/12 among African-Americans. Homozygotes have increased frequency of infectious disease, chronic anemia, painful sickle crises. |
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What is the newborn screening?
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All newborns are screened.
Used to diagnose autosomal recessive disorders for which early treatment can make a difference. Happens prior to discharge, repeat testing if before 24hrs, within first week. Its used to help prevent illness, mental retardation and death. |
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what is Phenylketonuria (PKU)?
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Very rare - 1 in 13,000 to 1 in 19,000.
Its an absence or deficiency of phenylalinine hydroxlase due to mutation in PAH gene. Phenylketones in urine. Genetic and clinical variability > 4000 mutation and most of those affected are compound heterozygotes. |
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What is an example of x-linkied recessive disorders?
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Muscular Dystrophy - loss of muscle control.
One normal gene & one mutated gene. |
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What is the fragile X mental retardation?
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X-linked dominant
2nd most common form of retardation due to genetics. Characteristics: hyperextensible joints & large or prominent ears. |