Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochem Quiz 4 > Quiz4_biochem20130928 > Flashcards

Quiz4_biochem20130928 Flashcards

(81 cards)

Start Studying
2
Q

Features of chromosome behavior

A

segregation, independent assortment, recombination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Law of segregation

A

allele pairs separate during gamete formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

principle of independent assortment

A

alleles of different genes assort & are passed independently of one another from parents to offspring during gamete formation; complicated by linkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Linkage

A

tendency of genes located proximal to each other on a chromosome to be inherited together during meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

recombination

A

production of new combinations of alleles encoding a novel set of genetic information (e.g. homologous chromosomal crossing over); any meiotic process generating a haploid product with a genotype differing from that constituted in the meiotic diploid cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

recombinant frequency

A

total number recombinants/total number progeny; note: independent assortment always produces RF of 50%; RF 50% in test cross indicates that the two genes under study assort independently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

LOD score

A

statistical test for linkage analysis to test whether segregation data from family studies indicates linkage btwn 2 loci or if just due to random segretation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LOD score of 3 or more

A

indicates linkage, _ at which LOD is highest is the most likely genetic distance btwn the two loci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

LOD score of -2 or less

A

indicates no linkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Association

A

co-occurrence of a disease and a genetic marker more often than expected by chance in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Linkage vs Association

A

(1) L must be in families/A can be in unrelated individuals; (2) L is btwn loci/A is btwn specific alleles of loci; (3) A may imply causal/physiological relationship btwn disease and allele/L does not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

monogenic genetic disorder

A

mutation in 1 gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

chromosomal genetic disorder

A

increase/decrease in copy # of whole chromosomes or chromosomal regions rich in genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

mitochondrial genetic disorder

A

defects in mtDNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

multifactorial genetic disorder

A

interplay of multiple genes & multiple environmental factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

somatic genetic disorder

A

series of genomic changes in somatic cells over time -> not passed to offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Product rule

A

probability of 2 indpendent events occurring simultaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Sum rule

A

probability of either one of the 2 independent events occurring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Autosomal dominant disorder

A

Normal allele sufficient to compensate for mutant allele; Heterozygotes affected; phenotype appears in every generation (vertical transmission); each child has 50% recurrence risk; males & females equally likely to transmit trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Gain of fx

A

mutant gene product has increased or novel activity over normal gene product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Dominant negative

A

mutant gene product inhibits activity of normal gene product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Haploinsufficiency

A

half of expression from single normal allele is not nenough protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Autosomal recessive disorder

A

both alleles of gene must be defective to cause visible phenotype/disease state; affected individuals homozygous for disease -> both parents must be unaffected heterozygous carriers; if appears in >1 family member typically seen among siblings (horizontal transmission); recurrence risk for each sibling of proband 25%; males & females equally likely to be affected; more common in consanguinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Loss of fx

A

inactivation of gene at molecular level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
X inactivation
achieves dosage compensation btwn males and females for critical X-linked genes -> transcriptional silencing of one of the X chromosomes in females (DNA methylation)-> Barr body
27
genes at distal tip of short arm of X chromosome
do not undergo inactivation (up to 15% of genes) -> candidates for clinical phenotype associated with numerical abnormalities of X chromosome
28
X-linked dominant
few in number; vertical transmission pattern; NO male to male transmission; 2x as common in females
29
X-linked recessive
females: both copies of X must be defective; males hemizygous for X -> inherit only from mother; gene responsible transmitted from affected man to his daughters -> heterozygous carriers: daughters' sons have 50% chance of inheriting disease
30
How can a heterozygous female express an X-linked recessive trait
mosaicism/skewed X-inactivation
31
Y-linked
no known diseases; expected: male to male transmission, only males affected
32
Hardy-Weinberg population frequencies
p^2 + 2pq + q^2 = 1; p+q =1
33
consanguinity
of same kin/mating of related individuals; present more frequently in pedigrees w/ autosomal recessive diseases; increases risk of mating couple both carrying same disease allele
34
factors complicating inheritance patterns
new mutations, germline mosaicism, delayed age of onset, reduced penetrance, variable expressivity, genetic heterogeneity, locus heterogeneity, allelic heterogeneity
35
germline mosaicism
all or part of germ cells have disease mutation, somatic cells normal (parent is non-expressorm risk of affecting multiple offspring)
36
reduced penetrance
individual w/ genotype for disease does not exhibit disease phenotype; can transmit disease to offspring
37
variable expressivity
complete penetrance, but severity differs among affected family members w/ same mutation
38
locus heterogeneity
disease that can be caused by mutations at different loci in different families
39
allelic heterogeneity
different mutations in same gene result in similar phenotypes
40
genetic heterogeneity
single phenotype/disorder may be caused by any one of a multiple number of alleles or non-allele mutations
41
Fragile X syndrome
constriction/gap at end of long arm of X chromosome = fragile site; 5' UTR FMR1 contains tandem repeated trinucleotide sequence (CGG) of variable length; expansion of repeat occurs during meiosis; 6-50 repeats = normal; 50-200 repeats = premutations; >230 repeats = affected
42
Dynamic mutations
repeat expansion results in genetic disease once number of repeats reaches a threshold -> leads to changes in gene function
43
genetic anticipation
increasing severity & earlier onset of disease w/ each passing generation; correlated with increased # of repeats
44
constitutional chromosome abnormalities
inherited, found in all body tissues
45
acquired chromosome abnormalities
not inherited, typically only in 1 tissue
46
FISH
detect & localize presence/absence of specific DNA sequences on chormosomes using sequence specific probes (complementarity)
47
whole chromosome paints
used to spot de novo translocations
48
Alphoid repeats
interphase FISH, chromosome specific centromeric repeat sequences have intense tight signals
49
aneuploidy
abnormal chromosome number
50
Trisomy 21
nondisjunction in meiosis I or II; if 2/3 chromosomes are same -> Meiosis II; if all 3 chromosomes different -> Meiosis I
51
Robertsonian translocation
long arms of 2 acrocentric chromosomes fused at centromeres -> loss of short arms; carrier is normal, risk to offspring
52
Mosaicism
nondisjuntion in mitosis resulting in 2 different cell lines (e.g. normal and trisomy)
53
Polyploidy
any multiple of haploid chromosome number; extra chromosome set is paternally derived
54
Reciprocal translocation
breakage of nonhomologous chromosomes w/ reciprocal exchange of chromosomal material; carrier normal, risk for unbalanced gametes & abnormal offspring
55
Balanced structural mutations
no loss/gain of genetic material, no phenotypic effect; risk for unbalanced gametes; translocation or inversion
56
terminal deletion
1 break, loss of material distal to break point
57
Unbalanced structural mutations
loss/gain of genetic material, severe phenotypic effects; deletions
58
interstitial deletion
2 breaks, loss of material between breaks
59
Prader-Willi syndrome
paternal deletion; maternal unpaired disomy; imprinting center mutation on paternal allele
60
Angelman syndrome
maternal deletion; paternal unpaired disomy, imprinting center mutation on maternal allele
61
Duplication
results from unequal crossing over
62
Turner syndrome
X chromosome monosomy; X0; paternal nondisjunction (45,x); mosaicism 45,x/46,xx or 45,x/46,xy
63
Klinefelter syndrome
X chromosome trisomy; 47, XXY; extra X of maternal origin; mosiacism 46,XY/47,XXY
64
47, XXX
maternal nondisjunction, increased incidence w/ AMA
65
47, XXY
NOT result of maternal nondisjunction, no increased incidence w/ AMA
66
cancer cytogenetics
acquired chromosomal abnormalities in hematologic malignancies; chromosome rearrangements may alter position of genes -> alteration of gene product may cause malignancy
67
functional approach to identify disease genes
based on knowledge of specific protein product of gene, use recombinant DNA technology to isolate genes
68
candidate gene approach to identify disease genes
test DNA coding sequence for protein mutations in affected individuals, no genetic mapping required
69
positional candidate approach to identify disease genes
mapping of disease gene to correct chromosomal subregion via linkage analysis
70
linkage analysis process
use of annotated sequence showing genetic markers -> focus on genetic region of interest -> identify & rank candidate genes -> assay candidate genes
71
units for linkage analysis
1cM = 1% recombination frequency = 10^6 bp DNA
72
marker
polymorphism used to follow a disease gene family -> not related to etiology of disease
73
direct genetic testing
identify specific mutation in affected individuals
74
indirect genetic testing
determine if individual has inherited a chromosome containing disease gene from either parent using genetically linked markers
75
Limitations to sanger/exome sequencing
does not detect most structural changes (large deletions), false negative results (sequence alteration exists in another gene at another locus or in a region not covered by test)
76
Benefits of sanger/exome sequencing
detects changes in coding region of gene, detects documented pathogenic alteration, unknown sequence alteration, documented benign polymorphisms, undocumented sequence predicted to be benign
77
Multiple PCR analysis
simultaneous amplification of everal exons/regions of interest of gene; evaluate products for presence/absence of specific regions amplified, detect deletion of specifc exons of disease
78
Allele specific oligonucleotide analysis
direct gene diagnosis of single nucleotide change for known mutations (automated), 1st ASO oligonucleotide that will hybridize only to mutated sequence, 2nd ASO hybridizes to corresponding normal sequence (control); idnetify genotype of individuals w/ regard to mutation specified by probe
79
microarray analysis
probe expression of 1000s of genes simultaneously to investigate differential expression of genes w/ potential relevance to wide range of disease processes (uses mRNA or cDNA)
80
Array-CGH
comparative genomic hybridization; high res alanylsis of copy number variations (gain/loss) at molecular level; can detect microdeletions and duplications
81
advantages of array-cgh
no dividing cells required, whole genome analysis in 1 experiment, fast, cost-effective, automated, high res analysis - tests multiple loci
82
limitations of array-cgh
sensitivity & quality of analysis depend on probes selected, balanced rearrangements NOT detected (only gain/loss), distinguishing between benign from disease-causing gains/losses requires parental studies

Biochem Quiz 4 (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions