Human Genetics test 1 Flashcards Preview

Human Genetics > Human Genetics test 1 > Flashcards

Flashcards in Human Genetics test 1 Deck (128)
Loading flashcards...
1

when will you see a chromatid?

in the DNA duplication phase during the S phase of the cell cycle back in interphase (mitosis or meiosis

2

def of centromere?

single connecting piece of protein that holds the two chromatids together

3

what is the chromosome compliment in humans?

diploidy (23 pairs 46 chromosomes)

4

def of autosomes?

22 homologous pairs behaved indepently from eachother and are not directly related to the sex of the individual

5

what are the three basic ways to identify chromosomes?

size, centromere location, staining and banding

6

def of metacentric?

centroemre is n the middle

7

def of submetacentric?

little off of the center

8

def of acrocentric?

near the end of the tip

9

def of chromosome satellites?

small masses of the chromosomes that are bulged that contain DNA for ribosomal synthesis

10

what is the paris conference system?

after various chemical staining treatments you can read the chromosomes as a bar code

11

what is the International System of Human Chromosome Nomenclature?

the thing that we use today

12

what is the P arm?

the short arm

13

what is the q arm?

long arm

14

how is a karyotype conventionally abbreviated?

listing the total number of chromosomes, followed by sex chromosomes, followed by any derangement in the chromosomes

15

what does the modern way of karyotyping helpful with?

revealing major and minor deletions, duplications, larger rearrangements and translocations

16

def of euploidy

having a complete set of chromosomes

17

def of haploidy

one complete set

18

def of diploidy?

2 complete sets

19

def of aneuploidy?

where one chromosome is missing or an extra one is present

20

def of monosomy?

a chromosome is missing from a homologous pair

21

how many total chromosomes in monosomy?

45

22

def of trisomy?

a chromosome is added to a homologous pair

23

how is trisomy described?

2N+1

24

how many total chromosomes in trisomy?

47

25

what is the facies of down syndrome?

oblique palpebral fissures, epicanthic folds

26

what are the neurological signs of down syndrome?

hypotonia, mental retardation

27

what percentage of mental retardation is from down syndrome?

1/3rd

28

how can you screen for down syndrome?

amniocentesis, chorionic-villus sampling, ULTRASOUND OF NUCHAL AREA TRANSLUCENCY

29

what is the recurrent risk of women under 40?

about 1 percent

30

how are aneuploidy's get made?

produced from non disjunction durning anaphase (one or two)

31

def of deletion?

partial monosomy wherein a piece of a chromosme is deleted

32

what is prader-willi and angelman syndrome?

disorders involving a spontaneous deletion of 15q11 to 15q13

33

prader-willi is a defect of paternal or maternal homolouge?

paternal

34

Angelman syndrome is a defect of a paternal or maternal homolouge?

maternal

35

def of imprinting?

a phenomenon whereby inherited chromosomes from one parent are modified such that the genes at that location are not properly expressed

36

what is cri du chat syndrome?

a rare disorder involving a spontaneous deletion from 5p14 to 5p15

37

what are the symptoms cri du chat?

cats cry syndrome, cat like cry during infancy

38

def of duplication?

a piece of a chromosome is duplicated

39

what do significant duplications revealed as?

added or altered bands (smaller difficult to detect)

40

what is pallister killian syndrome? (fyi)

duplication on 12

41

Inversion def?

wherein a piece of chromosome is flipped around or inverted

42

where do you see significant inversions?

as reversed bands and the centromere may be in different spot

43

translocation def?

two chromosomes break and exchange places

44

what percent of trisomy 21 are translocation?

5.00%

45

what are the potential offspring of translocation down syndrome

normal, monosomy 21 (nonviable), translocation down sydrome, translocation down sydrome "carrier" (normal)

46

what is chronic myelogenous leukemia?

rare cancer though a common form of leukemia with an exchange b/t chromosome 9 and 12 t(9:22)

47

what is the "philadelphia chromosome?"

t(9:22) which is seen as a stubby chrom 22

48

what is the ratio of live births with a chromosome deformity?

1 in 200

49

what percentage of recognizable pregnancies abort?

15.00%

50

what percentage of miscarriages conceptuses have a normal karyotype?

about 1/2 of 15% of recognizable pregnancies

51

how common are chromosomal defects in any type of pregnancy (miscarrage or not)

01/01/00

52

what percentage of livebirths are chromosomally abnormal?

0.6% (50:8,500)

53

what is the incidence of a chromosomal disease a function of?

function of the conceptus production rate AND the likelihood of in utero survival

54

what does repeated miscarriages suggestive of?

a chromosomal defect in either one or both rents

55

what are the roles of meiosis?

formation of gametes, reduction of chromosome number, random assortment, and crossing over

56

def of random assortment?

jumbling of maternal and paternal chromos

57

def of crossing over?

jumbling of maternal and paternal chromosomal segments

58

what is meiosis 1?

separation of homologous pairs

59

what is meiosis 2?

separation of chromatids

60

what is pre-meiotic interphase?

only chromaTIN visable in nucleus as DNA double

61

what is prophase 1?

chromoSOMES appear and cont. condensing

62

what is metaphase 1?

HOMOLOGOUS PAIRS of chromosomes line-up on an equatorial plane and are attached to a spindle apparatus

63

what is anaphase?

separationof homologous pairs

64

def of disjunction?

separation of homologous pairs

65

what is telophase?

reconstruction of the nuclei and division of the cytoplasm

66

what is prophase 2?

recoiling of chromosomes to managable size

67

what is metaphase 2?

single chromo line up on equatorial plane and attach to a new spindle apparatus

68

what is anaphase 2?

separation of chromaTIDS

69

def of telophase 2?

final reconstruction period: chromosomes uncoil to chromaTIN

70

what is post-meiotic interphase?

two haploid daughter cells created

71

how many cells will you see at the end of meiosis?

4

72

do each of the new cells at the end of meiosis have the same amount of DNA compared to the start?

yes

73

def of gene?

1) a nucleotide coding for a specific protein. 2) the smallest unit of biological function

74

what is the DNA organization?

Nucleotides>codons>domains>genes>gene clusters> Chromosome bands> chromosome arms> chromosomes> karyotype

75

how many genes are in the human genome?

25000

76

how many different base pairs are in the human genome?

3 billion and 99% are non-coding

77

def polymorphisms

significant allelic variation

78

what does it mean for a gene to be conserved?

the critical genes for metabolic function donメt vary too much

79

def mutant allele

some variant, does not have to be bad

80

what are point mutations?

the most common mutation where a single base pair changes. Which may or may not cause changes in the final polypeptide

81

def of genotype

the genetic constitution of an individual organism

82

def of phenotype?

a set of observable characteristics of an individual from the interaction of its genotype with the enviroment

83

def of incomplete dominance?

niether allelic form in a heterozygote is fully expressed, producing intermediate phenotypes beyond the basic combos of multiple heterozygous forms

84

def of mutation?

any change in genetic material

85

what is the class of disease is sickle cell anemia part of?

hemoglobinopathies

86

what causes sickle cell anemia

single base pair substitution in the beta-globulin gene on chromosome 11

87

what are the two broad sources of mutations?

radiation and chemicals

88

what are the things that cause radation mutations?

cosmic rays, solar energy, radioactive decay and x-rays

89

what re the things that cause chemical mutations?

(AKA mutagens) polycyclic aromatic hydrocarbons,, and oxidative agents

90

what is a tautomeric shift?

the nucleotide thiymine can shift into its -enol form where it can then pair with guanine not adenine

91

what did hermann muller do?

in 1927 showed that x-rays are mutagenic

92

what did charlotte auerback do?

in 1941 showed that mustard gays is mutagenic

93

def of loss-of-function mutation?

loss of the genes function;later seen to be recessive

94

def of gain-of-function mutation?

gene gains a function; later seen to be dominant

95

def of dominant negative mutations?

acts as a antagonistically to othe normal state; later seen to be dominant or co-dominant

96

def of lethal mutations

worst possible dna change.. Often in urero

97

def of genetic load?

a somatic cell accumulates about 30 new mutations in a lifetime

98

what is gene expression "about"?

health and disease

99

def of epigenetics?

trying to understand the gene expression which will show what it means to have a genetic disease

100

def structural genes?

code for components in or out of the cell

101

what happens if a structural gene fails?

dominant negative mutations

102

def of metabolic genes?

code ofr metabolic components that control reactions

103

what happens if a metabolic gene fails?

usually recessive mutation

104

what is harrtnup disease?

defective tryptophan transport across membrane (Ta)

105

in hartnup disease is the diseased gene dominant or recessive?

homozygous recessive= hh

106

what is the clinical feature of hartnup disease?

niacin deficiency

107

what is galactosemia?

disorder of defective carbohydrate metabolism inside cell (Ebc) which leads to an accumulation of galactose in gut

108

in galactosemia is the diseased gene dominant or recessive?

homozygous recessive= hh

109

clinical features of galactosemia?

gi problems, cataracts, cirrhosis

110

what is albinism?

a disorder of amino acid metabolism (Eab) which results in a defiency of melanin in regularly pigmented tissues

111

in albanism is the diseased gene dominant or recessive?

homozygous recessive= hh

112

what is PKU?

a disorder of amino acid metabolism (Eab and F and G) which results in an accumlation of phenyalanine in the body because it can not be changed to tyrosine by phenylalanine hydroxylase

113

in PKU is the diseased gene dominant or recessive?

homozygous recessive= hh

114

what are the symptoms of PKU?

severe mental retardation, hypo-pigmentation, and unusual odor

115

what is Lesch-Nyhan syndrome?

disorder of purine metabolism inside of the cell which results in deficiency of adenosine and the accumulation of uric acid

116

what sex will you see lesch-nyhan?

since itメs on the x chromosome and the mutant allele is recessive you only see it in males

117

wgat are the symptoms of lesch nyhan?

mental retardation, HYPERURICEMIA

118

def of gradual onset of metabolism?

metabolite needs time to accumulate to cause problem

119

def of unusual dietary response to metabolism?

to a metabolite that cannot be metabolized

120

what is the Iac operon in prokaryotes?

a promoter sequence sits next to a series of genes that control the production of the enzymatic machinery to digest lactose

121

what is the homeobox (HOX)?

highly conserved, gene grouping that code for transcription factor that regulates the cascade expression

122

where will you see HOX?

chromosomes 2,7,12,17

123

what is the function of HOX?

control patterning of the body axis and the resultant development of body organs

124

def of variable expressivity?

variable presentation of phenotype and remember that enviroment may play a role in the phenotype

125

def of penetrance

expression/non-expression of a dominant gene

126

when a disease has less than 100% penetrance what do you do?

take an expected probability and multiply it by the percent penetrance

127

def of pleiotropy?

where one gene effects mulitple traits (in cats single gene does white fur, blue eyes and blindness)

128

how is monosomy described?

2N-1