Ch. 1 Flashcards

1
Q

What is a phenotype?

A

expression of a genotype

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2
Q

What are autosomes?

A

pairs of chromosomes that are not sex-determining

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3
Q

What is a mitochondrial chromosome? What genes does it encode for?

A

small circular chromosomes in mitochondria; encodes for all tRNA, rRNA, and proteins involved in oxidative metabolism

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4
Q

How are mitochondrial chromosomes passed down?

A

from cytoplasm of fertilized ovum = maternal in origin

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5
Q

What is somatic mutation?

A

mutation that occurs AFTER conception

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6
Q

What is chromosomal aberration?

A

change in physical structure of chromosome

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7
Q

What is aneuploidy?

A

extra or less than 46 chromosomes

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8
Q

What are the 3 types of aneuploidy?

A

monosomy, trisomy, and polysomy

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9
Q

What is monosomy?

A

one chromosome of a pair is present = missing other pair = incomplete (ie: X0)

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10
Q

What is trisomy?

A

a chromosome pair has 1 extra chromosome = 3 chromosomes

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11
Q

What is polyploidy?

A

there is 4+ copies of a chromosome

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12
Q

What is translocation?

A

rearrangement of chromosome arms

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13
Q

What is inversion?

A

chromosomal region reoriented 180 degrees

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14
Q

What is a degenerate?

A

amino acid corresponds to more than 1 codon

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15
Q

What is a truncated protein?

A

protein isn’t full length or proper form = cannot fully function properly

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16
Q

What are 6 health problems associated with Down’s Syndrome?

A

heart defects | GI issues | vision | hearing | infections | intellectual

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17
Q

What is mosaicism?

A

person has two or more genetically different sets of cells in their body

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18
Q

Why is Trisomy 21 considered mosaic?

A

affected individuals have both trisomic (42,XX/Y and XXX) and euploid (44,XX/Y)cell lines.

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19
Q

What is the life expectancy of Down Syndrome?

A

55 yrs

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20
Q

What is the screening done for a newly pregnant woman for Down Syndrome?

A

blood test either 1st trimester w/ cell free DNA or 2nd trimester

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21
Q

What is Klinefelter syndrome?

A

when an XX ovum is fertilized with a Y sperm = XXY = sterile male

22
Q

What is Turner Syndrome?

A

monosomy disorder with a sex-empty ovum (0) gets fertilized with a sperm (X) = X0 = female appearance and sterile

23
Q

What is penetrance?

A

how much of the genotype is phenotypically showing

24
Q

What is variable expressivity?

A

same genes but differ in characteristics or symptoms displayed with varying intensity or presentation (ie: same painter’s palette, different pictures)

25
Q

What is consanguinity?

A

both partners descended from a common ancestor

26
Q

What is the definition Mendelian?

A

phenotypes due to alterations at a single gene

27
Q

What is Mendelian disorders?

A

monogenic human diseases

28
Q

What is inborn errors of metabolism?

A

autosomal recessive phenotypes associated with deficient activity of an enzyme

29
Q

What is Mendelian genetics?

A

genes passed from generation to generation ; dominance vs recessive alleles; heterozygous vs homozygous

30
Q

What is a missense mutation?

A

changes to a different protein by changing a single nucleotide

31
Q

What is a nonsense mutation?

A

codes for a premature stop codon

32
Q

What is a silent mutation?

A

changes the codon but no effect on protein product

33
Q

What is a frameshift mutation?

A

deletion or insertion of an amino acid = shifts the sequence = codons read differently

34
Q

What type of mutation is observed in Edward’s syndrome?

A

trisomy 18 and is a germinal mutation

35
Q

What is mitochondrial inheritance?

A

comes from maternal mitochondria

36
Q

What kind of diseases do mitochondrial inheritance commonly entail?

A

affecting oxidative metabolism

37
Q

What is cytogenetics?

A

studying chromosomes via light microscopy

38
Q

Explain fluorescence in situ hybridization

A

obtain gene –> make a probe (tag) for a specific target sequence –> tag finds target sequence –> match = glow

39
Q

What is fluorescence in situ hybridization used for?

A

localization of genes on specific chromosomes

40
Q

What is the limitations of karyotyping?

A

identifies sex NOT gender ; atypical/mutated genes are not visualuzed

41
Q

What is karyotyping?

A

staining chromosomes –> rearranged from longest to shortest

42
Q

What is karyotyping used for?

A

observing chromosome structure and quantity

43
Q

What is DNA analysis?

A

understanding gene expression via study of DNA sequences on chromosomes

44
Q

What test is used for DNA analysis?

A

Polymerase Chain Reaction

45
Q

What is PCR?

A

amplifies gene of interest

46
Q

What is PCR used for?

A

observing a gene of interest via amplification

47
Q

Simple steps of PCR

A

denature = open up DNA –> primers bind = Taq polymerase copies template || NEED control DNA to compare and determine if sample has disease of interest

48
Q

What is biochemical analysis?

A

determine presence/absence of certain protein ; looks for enzymatic defects

49
Q

Phenylketonuria (PKU)

A

disorder = inability to convert phenylalanine into tyrosine

50
Q

What causes PKU?

A

absence/defect of enzyme phenylalanine hydroxylase (PAH)

51
Q

What effect does PKU have on an affected individual?

A

severe intellectual disability unless treated in infancy and childhood by a low-phenylalanine diet

52
Q

What are the 3 stages of embrology?

A

pre-embryonic; embryonic, and fetal