Exam 1- Genes And Genetic Disease Flashcards

1
Q

Codon

A

Sequence of 3 nitrogenous bases that specifies a particular amino acid. Triplets of based.

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

Sequence of 3 nitrogenous bases that specifies a particular amino acid. Triplets of based.

A

Codon

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

Noncoding segment spliced out of mRNA

A

Intron

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

Segment of mRNA that codes for proteins

A

Exon

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

Alteration of DNA capable of being passed to offspring.

Missense _________
Nonsense _________
Frameshift _________

A

Mutation

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

Substance that alters genetic material (DNA)

A

Mutagen

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

Segment of DNA that is the basic unit of inheritance

A

Gene

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

Strand of condensed chromatin visible right before cell division. A somatic cell has 23 pairs of_______________. 1 sex_______________ and 22 nonsectarian_____________(autosomes)

A

Chromosome

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

Chromosome that is not a sex chromosome. 1 pair of sex chromosomes and 22 pairs of___________.

A

Autosome

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

Different version of a paired gene at a given locus.

If 2____________ are found together, the___________ that is observable is the dominant, and the one whose effects are hidden is recessive.

Dominant_____________: capital letter
Recessive: lowercase letter
Can be codominant

Ex: Hgb A vs Hgb S

A

Allele

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

A DNA mutation that involves an addition or deletion of a number of base pairs that is not a multiple of three, and thus alters all of the codons downstream from the site of insertion or deletion.

A

Frameshift mutation

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

Interchanging of genetic material between nonhomologous chromosome. One chromosome breaks and becomes part of another chromosome.

Type of chromosomal aberration/ alteration.

Ex: Philadelphia chromosomal____________. Increased chances of CML and ALL.

A

Translocation

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

Loci on a pair of chromosomes have identical genes (type O)

A

Homozygous

DD, dd affected or unaffected homozygous

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

A pair of chromosomes have different genes (Person/Type A and B genes mix and are different), that, when mixed are called this.

Dd affected or unaffected____________.

A

Heterozygous

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

One of the chromosomes in somatic cell has only one copy instead of 2 normal.

A

Monosomy

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

One of the chromosomes in somatic cell has 3 copies instead of the normal 2.

A

Trisomy

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

The genetic material

A

Genotype

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

Expression of genes

A

Phenotype

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

Diploid cell makes a copy of itself

A

Mitosis

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

The process by which haploid cells are formed from diploid

A

Meiosis

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

1) RNA polymerase binds to DNA promoter region
2) transcription
3) mRNA is spliced to remove noncoding sections
4) mRNA leaves the nucleus
5) translation

A

Steps of protein synthesis

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

Ex: Turner syndrome, Down syndrome, fragile X syndrome, klinfelter syndrome

A

Chromosomal disorder

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

A somatic cell that has 46 chromosomes in its nucleus

A

Diploid cell

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

Determined by one gene mutation. Autosomal dominant, autosomal recessive, or X-linked recessive.

Strongly determined by genes.

Ex: CF, hemophilia A, sickle cell

A

Single gene disorder

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

Disorder linked to X Chromosome

Y chromosome only carries a few genes, so most sex-linked traits are X-linked.

More often seen in males than female, because they only have 1 X chromosome.

Dominant (rare) or recessive.

A

X-linked disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cells have 3 copies of each chromosome

A

Triploidy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Inactivated X chromosome that is seen in normal female cells.

A

Barr body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Has 23 chromosomes, one member of each pair. Will meet up with another _________ to make a diploid. Aka gamete.

A

Haploid cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

More sets of chromosomes. In multiples of 23. Incompatible with life. More than 2 copies of each chromosome.
Triploidy- 3 sets of 23 chromosomes
Tetraploidy- 4 sets (92 chromosomes)

A

Polyploidy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Error during meiosis or mitosis. Homologous chromosomes fail to separate normally. Results in aneuploidy.

A

Nondisjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

_____________ have Rr so can still pass it on but don’t have the expressed trait.

Phenotypically normal. Carries disease causing alleles.
Have to have 2 recessive genes to have expressed trait (rr).

A

Carrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

XY- male
XX- female

1 pair of sex chromosomes and 22 of autosomes.

A

Sex chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Abnormal number of single chromosomes. Loss of chromosome (monosomy) material more serious than duplicate.

23 pairs usually. On one pair you’re missing one chromosome and only have 1 (monosomy). On another pair you have 2 from one parent, for a total of 3 instead of 2 (trisomy). Autosomal aneuploidy usually lethal, but Can survive with trisomy13, 18, and 21.

Sex chromosomal aneuploidy is not lethal (except for monosomy (X): Y chromosome has little genetic info and extra X chromosome is usually inactive (fragile X). Having 1 X is lethal.

A

Aneuploidy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

3 copies of the 21st chromosome.
Nondisjunction in egg.
Linked with maternal age.
Intellectual disability, poor muscle tone, increases congenital heart defects, increased risk for Alzheimer’s after age 40.

A

Down Syndrome (Trisomy 21)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Broken chromosomes or loss in DNA in 1 chromosome can have serious effect.

Cri du chat Syndrome- deletion of long arm of chromosome 5. Microcephalic, low birth weight.

A

Chromosomal deletion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Multiple copies of DNA portion. Less serious than deletion. But when they have offspring, chromosomes don’t align and offspring can have issues.

A

Chromosomal duplication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Single-gene disorders

Diseases are rare. Very rare for two affected people with the dominant trait to produce offspring. Dd if they have one capital D, they are effected. Only need to inherit a D from 1 affected parent to get the disease.
Genotype of affected person: DD or Dd
Genotype of unaffected person: dd

Males and female equally likely.
One of the patents has to have the disease.
Heterozygous individuals pass it on to 50% of their offspring. Does not skip generations because there are no carriers.

75% chance to pass on (recurrence rate) if both parents Dd (affected):
25% DD homozygous affected
50% Dd heterozygous affected
25% dd homozygous unaffected

Phenotype: observable effect

Ex: achondroplasia, Huntingtons

A

Autosomal dominant disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Single gene disorder

Disease: A person must have 2 recessive alleles. Must receive a a recessive gene from each parent. (dd) to get the disease. non sex-linked (same in M and F).

Rare, but number of carriers can be high.
Usually in children not parents.

If both parents heterozygous carriers (Dd) 25% of passing it on (recurrence rate). 50% that offspring will be phenotypically normal and 25% genetically normal.

Example: CF

Chances increase with consanguineous mating between relatives.

A

Autosomal Recessive trait (d)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Sections of chromosome. Each_______ is responsible for different characteristics of a person. If same on both ________ in a chromosome pair, it’s homozygous. If different, heterozygous.

A

Locus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Variation in a phenotype linked to a particular genotype. Severity may vary. A parent with a mild expression of a disease (they may not even know that they have it) can transmit the gene to a child, who can the exhibit severe expression of the disease.

Ex: neurofibtomytosis

A

Expressivity

41
Q

Female with 3 X chromosomes.
Sterility, menstrual irregularity, to mental retardation.
Worse with each additional X.
Trisomy on the X chromosome.

A

Trisomy X

42
Q

Chromosomal disorder.

At least 2 Xs and 1 Y.

Male appearance, develop breasts, small testes, sparse body hair, long limbs.

A

Klinefelter Syndrome

43
Q

Areas on chromosomes that develop distinctive breaks or gaps when cells are cultured. No apparent relationship to disease.

A

Chromosome fragile sites

44
Q

Chromosomal disorder

Site on long arm of the X chromosome.

Usually in men because only one X.

Associated with mental retardation, second in occurrence to Down Syndrome.

A

Fragile X Syndrome

45
Q

Liability distribution. For multifactorial traits, as the number of multifactorial traits increases, the liability for that disease increases as well. As the factors reach the threshold, the person will definitely be effected.

Though liability may be the same between men and women, the threshold may be different.

A

Threshold model

46
Q

Complete set of chromosomes in an individual

A

Karyotype

47
Q

_______________ of a trait is the percentage of the individuals with a specific genotype who also express the expected phenotype. Incomplete means that the person with the disease-causing allele may not exhibit the disease phenotype ally all, even though it might be transmitted to the next generation.

A

Penetrance

48
Q

Affected fathers (XhY) will transmit the affected genes to all his daughters but not his sons (he gives his sons the Y gene).

Affected mothers (XhXh) will pass to all her sons and all her daughters will be carriers.

Carrier mothers (XhXH) will pass the condition to 50% of their sons (no 2nd X to counteract disease gene) and 50% of her daughters will be carriers.

A

X-linked recessive disorders

49
Q

Rare

Affected father will pass the condition on to daughters but not sons

Affected mother will pass on to 50% of children (50% of getting c chromosome from mom), both male and female

A

X-linked dominant disorders

50
Q

2 of the same identical traits. In females, we have XX sex traits, a homologous pair. Males have a nonhomolygous pair.

A

Homologous

51
Q

Intron

A

Noncoding segment spliced out of mRNA

52
Q

Exon

A

Segment of mRNA that codes for proteins

53
Q

Mutation

A

Alteration of DNA capable of being passed to offspring.

Missense mutation
Nonsense mutation
Frameshift mutation

54
Q

Mutagen

A

Substance that alters genetic material (DNA)

55
Q

Gene

A

Segment of DNA that is the basic unit of inheritance

56
Q

Chromosome

A

Strand of condensed chromatin visible right before cell division. A somatic cell has 23 pairs of chromosomes. 1 sex chromosomes and 22 nonsectarian chromosomes (autosomes)

57
Q

Autosome

A

Chromosome that is not a sex chromosome. 1 pair of sex chromosomes and 22 pairs of autosomes.

58
Q

Allele

A

Different version of a paired gene at a given locus.

If 2 alleles are found together, the allele that is observable is the dominant, and the one whose effects are hidden is recessive.

Dominant allele: capital letter
Recessive: lowercase letter
Can be codominant

Ex: Hgb A vs Hgb S

59
Q

Frameshift mutation

A

A DNA mutation that involves an addition or deletion of a number of base pairs that is not a multiple of three, and thus alters all of the codons downstream from the site of insertion or deletion.

60
Q

Translocation

A

Interchanging of genetic material between nonhomologous chromosome. One chromosome breaks and becomes part of another chromosome.

Type of chromosomal aberration/ alteration.

Ex: Philadelphia chromosomal translocation. Increased chances of CML and ALL.

61
Q

Homozygous

A

Loci on a pair of chromosomes have identical genes (type O)

DD, dd affected or unaffected homozygous

62
Q

Heterozygous

A

Loci of a pair of chromosomes have different genes (Type Dd)

Dd affected or unaffected heterozygous.

63
Q

Monosomy

A

One of the chromosomes in somatic cell has only one copy instead of 2 normal.

64
Q

Trisomy

A

One of the chromosomes in somatic cell has 3 copies instead of the normal 2.

65
Q

Genotype

A

The genetic material

66
Q

Phenotype

A

Expression of genes

67
Q

Mitosis

A

Diploid cell makes a copy of itself

68
Q

Meiosis

A

The process by which haploid cells are formed from diploid

69
Q

Steps of protein synthesis

A

1) RNA polymerase binds to DNA promoter region
2) transcription
3) mRNA is spliced to remove noncoding sections
4) mRNA leaves the nucleus
5) translation

70
Q

Chromosomal disorders

A

Ex: Turner syndrome, Down syndrome, fragile X syndrome, klinfelter syndrome

71
Q

Diploid cell

A

A somatic cell that has 46 chromosomes in its nucleus

72
Q

Single gene disorder

A

Determined by one gene mutation. Autosomal dominant, autosomal recessive, or X-linked recessive.

Strongly determined by genes.

Ex: CF, hemophilia A, sickle cell

73
Q

X-linked disorders

A

Disorder linked to X Chromosome

Y chromosome only carries a few genes, so most sex-linked traits are X-linked.

More often seen in males than female, because they only have 1 X chromosome.

Dominant (rare) or recessive.

74
Q

Triploidy

A

Cells have 3 copies of each chromosome

75
Q

Barr body

A

Inactivated X chromosome that is seen in normal female cells.

76
Q

Haploid cell

A

Has 23 chromosomes, one member of each pair. Will meet up with another haploid to make a diploid. Aka gamete.

77
Q

Polyploidy

A

More sets of chromosomes. In multiples of 23. Incompatible with life. More than 2 copies of each chromosome.
Triploidy- 3 sets of 23 chromosomes
Tetraploidy- 4 sets (92 chromosomes)

78
Q

Nondisjunction

A

Error during meiosis or mitosis. Homologous chromosomes fail to separate normally. Results in aneuploidy.

79
Q

Carrier

A

Carriers have Rr so can still pass it on but don’t have the expressed trait.

Phenotypically normal. Carries disease causing alleles.
Have to have 2 recessive genes to have expressed trait (rr).

80
Q

Sex chromosomes

A

XY- male
XX- female

1 pair of sex chromosomes and 22 of autosomes.

81
Q

Aneuploidy

A

Abnormal number of single chromosomes. Loss of chromosome (monosomy) material more serious than duplicate.

23 pairs usually. On one pair you’re missing one chromosome and only have 1 (monosomy). On another pair you have 2 from one parent, for a total of 3 instead of 2 (trisomy). Autosomal aneuploidy usually lethal, but Can survive with trisomy13, 18, and 21.

Sex chromosomal aneuploidy is not lethal (except for monosomy (X): Y chromosome has little genetic info and extra X chromosome is usually inactive (fragile X). Having 1 X is lethal.

82
Q

Down Syndrome (Trisomy 21)

A

3 copies of the 21st chromosome.
Nondisjunction in egg.
Linked with maternal age.
Intellectual disability, poor muscle tone, increases congenital heart defects, increased risk for Alzheimer’s after age 40.

83
Q

Chromosomal deletion

A

Broken chromosomes or loss in DNA in 1 chromosome can have serious effect.

Cri du chat Syndrome- deletion of long arm of chromosome 5. Microcephalic, low birth weight.

84
Q

Chromosomal duplication

A

Multiple copies of DNA portion. Less serious than deletion. But when they have offspring, chromosomes don’t align and offspring can have issues.

85
Q

Autosomal dominant disorders

A

Single-gene disorders

Diseases are rare. Very rare for two affected people with the dominant trait to produce offspring. Dd if they have one capital D, they are affected. Only need to inherit a D from 1 affected parent to get the disease.
Genotype of affected person: DD or Dd
Genotype of unaffected person: dd

Males and female equally likely.
One of the parents has to have the disease.
Heterozygous individuals pass it on to 50% of their offspring. Does not skip generations because there are no carriers.

75% chance to pass on (recurrence rate) if both parents Dd (affected):
25% DD homozygous affected
50% Dd heterozygous affected
25% dd homozygous unaffected

Phenotype: observable effect

Ex: achondroplasia, Huntingtons

86
Q

Autosomal Recessive trait (dd)

A

Single gene disorder

Disease: A person must have 2 recessive alleles. Must receive a recessive gene from each parent. (dd) to get the disease. non sex-linked (same in M and F).

Rare, but number of carriers can be high.
Usually in children not parents.

If both parents heterozygous carriers (Dd) 25% of passing it on (recurrence rate). 50% that offspring will be phenotypically normal and 25% genetically normal.

Example: CF

Chances increase with consanguineous mating between relatives.

87
Q

Locus

A

Sections of chromosome. Each locus is responsible for different characteristics of a person. If same on both locus in a chromosome pair, it’s homozygous. If different, heterozygous.

88
Q

Expressivity

A

Variation in a phenotype linked to a particular genotype. Severity may vary. A parent with a mild expression of a disease (they may not even know that they have it) can transmit the gene to a child, who can the exhibit severe expression of the disease.

Ex: neurofibtomytosis

89
Q

Trisomy X

A

Female with 3 X chromosomes.
Sterility, menstrual irregularity, to mental retardation.
Worse with each additional X.
Trisomy on the X chromosome.

90
Q

Klinefelter Syndrome

A

Chromosomal disorder.

At least 2 Xs and 1 Y.

Male appearance, develop breasts, small testes, sparse body hair, long limbs.

91
Q

Chromosome fragile sites

A

Areas on chromosomes that develop distinctive breaks or gaps when cells are cultured. No apparent relationship to disease.

92
Q

Fragile X Syndrome

A

Chromosomal disorder

Site on long arm of the X chromosome.

Usually in men because only one X.

Associated with mental retardation, second in occurrence to Down Syndrome.

93
Q

Threshold model

A

Liability distribution. For multifactorial traits, as the number of multifactorial traits increases, the liability for that disease increases as well. As the factors reach the threshold, the person will definitely be effected.

Though liability may be the same between men and women, the threshold may be different.

94
Q

Karyotype

A

Complete set of chromosomes in an individual

95
Q

Penetrance

A

Penetrance of a trait is the percentage of the individuals with a specific genotype who also express the expected phenotype. Incomplete means that the person with the disease-causing allele may not exhibit the disease phenotype allele at all, even though it might be transmitted to the next generation.

96
Q

X-linked recessive disorders

A

Affected fathers (XhY) will transmit the affected genes to all his daughters but not his sons (he gives his sons the Y gene).

Affected mothers (XhXh) will pass to all her sons and all her daughters will be carriers.

Carrier mothers (XhXH) will pass the condition to 50% of their sons (no 2nd X to counteract disease gene) and 50% of her daughters will be carriers.

97
Q

X-linked dominant disorders

A

Rare

Affected father will pass the condition on to daughters but not sons

Affected mother will pass on to 50% of children (50% of getting c chromosome from mom), both male and female

98
Q

Homologous

A

2 of the same identical traits. In females, we have XX sex traits, a homologous pair. Males have a nonhomolygous pair.