Genetic Disorders Flashcards

0
Q

Single Nucleotide Polymorphism is a DNA abnormality where variations are located at single isolated nucleotide positions. This is often biallelic. What does biallelic mean?

A

One of only two choices exist at a given site within population

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1
Q

Mechanism of microRNA in inhibiting gene expression

A

(A)mRNA cleavage

(B)preventing ribosomes fron reading it

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2
Q

Identify:
Photographic representation given as total number of chromosomes (arranged in decreasing length), followed by sex chromosome conplement, and then abnormalities in ascending numerical order

A

Karyotype

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3
Q

True or false. Small interfering RNA and microRNA have the same mechanism

A

True

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4
Q

True or false. All mutations manifest phenotypically

A

False

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6
Q

Identify

Heritable changes in gene expression that are not caused by alterations in DNA sequence

A

Epigenetics

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6
Q

Computer-based techniques that manage data on and analyze gene & protein expression

A

Bioinformatics

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7
Q

Measurement of all proteins expressed in a cell/tissue

A

Proteomics

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8
Q
Which is false?
A. All genetic diseases are congenital.
B. All congenital diseases are genetic.
C. Both are false
D. Both are true
A

C.

Some congenital diseases are not genetic, while some genetic diseases are not congenital.

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9
Q

Mutation where a single base is deleted

A

Point mutation

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10
Q

Mutation where 1-2 bases are inserted/removed

A

Frameshift mutations

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11
Q

Mutations that alter the meaning of sequence of encoded protein

A

Missense mutation

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12
Q

Mutation where amino acid codon is changed to a stop codon

A

Nonsense mutation

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13
Q

Differentiate conservative missense mutation from its non-conservative counterpart

A

Non-conservative : marked change in protein fxn

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14
Q

Mutations within noncoding sequence may lead to __

A

Marked reduction/total lack of transcription

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15
Q

Mutation that is characterized by amplification of a sequence of three nucleotides

A

Trinucleotide repeat mutation

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16
Q

True or false. The degree of amplification @ trinucleotide repeat mutation increases during gametogenesis

A

True

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17
Q

Mutations in single genes are also known as Mendelian disorders. Why?

A

They are consistent with the Laws of Segregration & Independent Assortment

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18
Q

False about autosomal dominant disorders
A. Patients always have infected parents
B. The person may inherit it but remain phenotypically normal
C. Variable expressivity is present in people with these diseases

A

A

Mutations involving egg or sperm may cause this

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19
Q

False about autosomal dominant disorders
A. Two defective genese have to be present
B. Expressed in heterozygotes
C. Unaffected people still can transmit disease to offspring
D. On average, Equal proportion of normal and affected offpspring

A

A

One is enough.

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20
Q

In autosomal dominant disorders, involved genes usually do not encode __

A

Enzyme proteins

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21
Q

Direct consequences of achondroplasia

A

Abnornality of cartilage formation

Shortened bones

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22
Q

Achondroplasia: mutation in ___

A

Fibroblast growth factor receptor 3

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23
Q

Specific mutation + gene mutated @ Marfan syndrome

A

Missense mutation at gene coding for fibrillin – 1(FBN1) on 15q21.1

24
Q

Marfan syndrome : inherited disorder of __

A

Connective tissue

25
Q

Neurofibromatosis-1 is also known as ___

A

von Recklinghausen’s disease

26
Q

What are neurofibromas?

A

Benign tunors of peripheral nerves of Schwann cell origin

27
Q

NF-1 is also characterized by pigmented lesions of the iris, aka __

A

Lisch nodules

28
Q

NF-1 is characterized by areas of dark pigmentation on skin, also known as __

A

Cafe au lait spots

29
Q

Familial hypercholestrolemia involes mutations in the gene encoding ____

A

LDL receptor

30
Q

Gene encoding LDL receptor is located at __

A

Short arm of chromosome 19

31
Q

False about autosomal recessive disorders
A. Only one allele is enough for disorder to manifest
B. Siblings may show disease
C. May be a product of consanguineous marriages
D. Onset is frequently early on in life

A

A

You need two

32
Q

In autosomal dominant disorders, onset is frequently at adulthood. Yes or no?

A

Yes

33
Q

In sickle cell anemia, the substitution happens at ___

A

6th position of beta globin chain

34
Q

In sickle cell anemia, there is substitution of __ for __

A

Valine for glutamic acid residue

35
Q

In phenylketonuria, this enzyme is lacking. High levels of Phenylalanine are present in the blood, therefore.

A

Phenylalanine hydroxylase

36
Q

False about Y-linked disorders
A. Related to spermatogenesis
B. Infertile male
C. May be also transmitted via the mom

A

C

38
Q

False about X-linked disorders
A. Females may only be homozygous
B. Lack of transmission from father to son
C. Most X-linked traits are recessive

A

A

Females may also be heterozygous

38
Q

Fragile X syndrome may lead to inherited mental retardation. What kind of mutation happens here?

A

Expansion of CGG repeat @ Xq27.3 fragile site. Around 200 to 4000 repeats. Average is 29

39
Q

Differentiate hemophilia A from hemophilia B

A

A - defect @ gene encoding for factor VIII

B - defect @ gene encoding for factor IX

40
Q

Identify

Diseases that are consequences of additive effects of several abnormal genese and envt factors

A

Complex multigenic disorders

41
Q

These immune cells are often used in karyotyping

A

Circulating lymphocytes

42
Q

What is a metacentric chromosome?

A

Chromosome at the center –> 4 chromatids of equal length

43
Q

What is a sub-metacentric chromosome?

A

Centromere is a little away from the center. One is slightly longer than the other.

44
Q

What is a acrocentric chromosome?

A

Centromere closer to one end. Lengths of sides are very unequal.

45
Q

What is a telocentric chromosome?

A

Centromere only at one end. One side only. Not in human cells

46
Q

What is an aneuploid chromosomal abnormality?

A

Karyotype is not exact multiple of haploid number

47
Q

What is monosomy?

A

Absence of one chromosome of homologous pair

48
Q

What is trisomy?

A

Extra copy present in normally paired chromosome

49
Q

Trisomy 21 is also known as __

A

Down Syndrome

50
Q

Most conmon cause of trisomy 21 is meiotic nondisjunction. What is meiotic nondisjunction?

A

Failure of paired chromosome to separate and move to opposite poles of the spindle at anaphase

51
Q

Trisomy 18 is also known as __

A

Edwards Syndrome

52
Q

Trisomy 13 is also known as __

A

Patau syndrome

53
Q

False about Klinefelter Syndrome
A. XXY
B. Dahil XX, female
C. Both are false

A

B

Male pa rin. Infertile lang.

54
Q

Cri du chat syndrome has what kind of mutation?and in what part of what chromosome?

A

Deletion of the end of the p arm @ chromosome 5

55
Q

False about Turner Syndrome
A. XXX
B. May come with primary amenorrhea
C. Female hypogonadism

A

A

X lang hehe

56
Q

What is Huntington disease?

A

Repeats of guanine and cytosine nucleotides that occur in coding regions

57
Q

[CHROMOSOMAL REARRANGEMENTS]

What is a translocation?

A

Part of chromosome transferred to another chromosome