Genetics Flashcards

1
Q

gamete cells are ___loid and somatic cells are ___loid

A

haploid

diploid

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2
Q

totipotent cells…

A

can differentiate to become any human cell

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3
Q

DNA found in the…

A

nucleolus

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4
Q

pyrimidines

A

thymine

cytosine

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5
Q

purines

A

adenine

guanine

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6
Q

3 base pairs

A

codon

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7
Q

autosomes

A

first 22 of 23 pairs in males & females

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8
Q

sex chromosomes

A

remaining 23rd pair of chromosomes - XX (homologous) in females, XY (nonhomologous) in males

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9
Q

mutation

A

any inherited alteration of genetic material

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10
Q

silent mutation

A

has no effect, codon still codes for same amino acid

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11
Q

missence

A

mutation that causes replacement with an incorrect amino acid - changes protein itself

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12
Q

nonsense

A

premature stop - protein is unfinished

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13
Q

frameshift

A

mutation that involves deletion or insertion of a base pair - 2 or 4 in a codon rather than 3

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14
Q

________ mutations have the worst outcomes for the organism

A

frameshift

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15
Q

mutagen

A

any agent known to increase the frequency of mutations

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16
Q

from __ to __ weeks, the fetus is not susceptible to teratogens

A

0-2

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17
Q

period in which fetus is most susceptible to teratogens

A

2-8 weeks, embryonic stage

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18
Q

locus

A

position of a gene along a chromosome

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19
Q

allele

A

different form of a particular gene at a given locus

we have one from each parent

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20
Q

polymorphism

A

locus that has 2+ alleles that occur with appreciable frequency

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21
Q

homozygous

A

loci on a pair of chromosomes have identical genes

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22
Q

heterozygous

A

loci on a pair of chromosomes have different genes

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23
Q

genotype

A

composition of genes at a given locus

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24
Q

phenotype

A

outward appearance of genetics

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25
Q

penetrance

A

percentage of individuals with a certain genotype who also express the expected phenotype

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26
Q

Autosomal dominance causes __% penetrance

A

100%

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27
Q

incomplete penetrance

A

individual who has a gene for a disease but does not express it

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28
Q

expressivity

A

extent of variation in phenotype associated with a certain genotype

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29
Q

examples of diseases with varying expressivity

A

hemophilia A

neurofibramatosis

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30
Q

how we depict a family affected by a genetic disease

A

pedigree

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31
Q

consanguinity & effects

A

incest

increases risk for genetic defects

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32
Q

recurrence risk

A

probability that an individual will develop a genetic disease

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33
Q

3 types of genetic disorders

A

single-gene
chromosomal
multifactorial

34
Q

if you have a gene, you will have disorder

A

autosomal dominant inheritance

35
Q

difference between sexes r/t autosomal dominant

A

no difference

36
Q

generational skipping c autosomal dominant?

A

no

37
Q

most common parent configuration for people c autosomal dominant disorders

A

normal parent + affected heterozygous parent

38
Q

requires both parents to transmit gene

A

autosomal recessive inheritance

39
Q

Heterozygous carriers can pass disease, but do not express it

A

autosomal recessive

40
Q

difference between sexes r/t autosomal recessive

A

no difference

41
Q

generational skipping c autosomal recessive?

A

yes

42
Q

recurrence risk for autosomal recessive

A

25%

43
Q

why are sex linked disorders seen more in men?

A

Y does not contain all of same DNA as X - no “backup allele” if something is wrong on X chromosome

44
Q

Affected father does not transmit disease to _____, but will always transmit it to _____

A

son

daughter

45
Q

sons of female carriers have __% risk of being affected

A

50

46
Q

duchenne muscular dystrophy is an x-linked (dominant/recessive) disorder affecting mainly (males/females)

A

recessive

males

47
Q

any abnormalities to chromosomes

A

chromosomal aberrations

48
Q

euploid

A

has a multiple of 23 chromosomes

49
Q

polyploidy

A

euploid cells with >46 chromosomes

50
Q

triploidy

A

69 pairs

51
Q

tetraploidy

A

92 pairs

52
Q

aneuploidy

A

somatic cell not containing a multiple of 23 pairs of chromosomes

53
Q

trisomy

A

contains 3 copies of 1 chromosome

54
Q

trisomy 21

A

down syndrome

55
Q

monosomy

A

contains only 1 copy of any chromosome

56
Q

lethal aneuploidy

A

monosomy

57
Q

usual cause of aneuploidy

A

nondisjunction

58
Q

nondisjunction

A

failure of homologous chromosomes or sister chromatids to separate during mitosis or meiosis

59
Q

partial trisomy

A

an extra portion of a chromosome is present in each cell

60
Q

down syndrome risk increases c maternal age >35 because

A

rate of nondisjuction increases

61
Q

down syndrome characteristics

A

Mentally challenged, low nasal bridge, epicanthal folds, protruding tongue, low-set ears, poor muscle tone

62
Q

chromosomal mosaic

A

Somebody who has part of a genetic defect on part of the cells in their body

63
Q

Sex chromosome aneuploidy

A

variation of XX or XY

64
Q

XXX

A

trisomy x

65
Q

symptoms of trisomy x

A

sterility, menstrual irregularity, and/or intellectual disability

66
Q

X

A

turner syndrome

67
Q

symptoms of turner syndrome

A

underdeveloped ovaries, sterility, short stature, webbing of neck, edema, underdeveloped breasts, wide nipples

68
Q

XXY, XXXY

A

Klinefelter syndrome

69
Q

symptoms of Klinefelter syndrome

A

male appearance, may develop female-like breasts, small genitals, sterility, sparse body hair, long limbs

70
Q

Deletion of short arm of chromosome 5

A

Cri-du-chat syndrome

71
Q

Cri-du-chat characteristics

A

microcephaly, round face, low-set ears

Severe cognitive delays & developmental deficits

72
Q

fragile site along long arm of X chromosome

A

fragile X syndrome

73
Q

fragile x characteristics

A

Intellectual disability, broad foreahead, elongated face, large ears, crossed eyes, highly arched palette, etc

Higher incidence in males

74
Q

disorders most difficult to predict

A

multifactorial

75
Q

ex. of a multifactorial disorder affecting males more than females

A

pyloric stenosis

76
Q

epigenetics

A

Study of biological mechanisms that switch genes on and off

77
Q

3 epigenetic mechanisms

A

DNA methylation
histone modification
RNA-based mechanisms

78
Q

DNA methylation - what is it, what does it do

A

attachment of methyl group to cytosine

Silences genes
Aberrant methylation can lead to misregulation of oncogenes & tumor-suppressor genes`

79
Q

“spools” of DNA

A

histones

80
Q

histone de/acetylation

A

addition or removal of acetyl group

81
Q

RNA-based mechanisms involve _____ RNA and _____RNA

A

noncoding

micro