Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Path > Genetics > Flashcards

Genetics Flashcards

1
Q

Each gene contains the genetic information required to produce a _____. Each of these is made specifically to perform a necessary body function

A

protein

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

Mutation of a gene locus affecting only one chromosome? Both chromosomes?

A

heterozygous for the disorder

homozygous for the disorder

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

Permanent change in DNA

A

mutation

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

Mutation affecting germ cells can….

A

be transmitted to progeny aka is inherited

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

Mutations affecting somatic cells can…

A

form tumors or developmental malformations

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

3 types of mutations

A

point mutation (missense mutation)
frameshift mutation
Trinucleotide repeat mutations

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

Describe Point mutations and give example

A

single nucleotide base substitued

i.e sickle cell anemia

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

Describe frameshift mutation

A

when one or two base pairs are inserted or deleted causing an alteration in the reading frame of the DNA strand

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

Describe trinucleotide repeat mutation and give an example

A

Amplification of sequence of 3 nucleotides

i,e- Fragile X syndrome - a normal human has 5-54 repeats of CGG, while a person with Fragile X syndrome has 230-4000

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

3 examples of alterations in protein-coding genes other than mutations

A
  1. Polymorphisms - single nucleotide polymorphism and copy number variations
  2. Epigenetic changes
  3. Alterations in non-coding RNAs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe single nucleotide polymorphism and give examples of what this could be a marker of:

A

variation in just one nucleotide at a single site on the DNA molecule.

May be markers for diabetes or hypertension

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

What is the difference between single nucleotide polymorphism and point mutation

A

the frequency.

Missense/point mutations dont occur often
Single nucleotide polymorphism occurs VERY ofter

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

How many single nucleotide polymorphisms have been identified and where do most occur

A

Over 6,000,000 have been identified, but most are within exons, introns, or intergenic regions

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

Describe copy number variations and what does this account for….

A

When you have different numbers of large continuous stretches of DNA, from 1,000 to millions of base pairs.

This may account for phenotypic variation

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

What is an epigenetic change?

A

when a modulation of gene expression occurs without an altered DNA sequence

ie. a methylation of promoter regions makes them inaccessible to RNA polymerase causing reduction in protein synthesis

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

Describe alterations in non-coding RNAs

A

micro-RNAs inhibit translation of their target messenger RNAs into their corresponding proteins

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

T or F; Autosomal dominant disorders create outward physical changes and many exhibit a delayed age of onset even though the mutant gene has been there since birth

A

true

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

2 examples of autosomal dominant disorders

A

Huntington disease
Neurofibromatosis (from lecture) - seen nearly 100% of the time but the extent is variable - some people have tumors everywhere on their body

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

Define reduced or incomplete penetrance

A

person has a mutant gene but does not express it phenotypically

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

define variable expressitivity and what autosomal dominant disorder is an example of this

A

trait is seen phenotypically in the individuals having the mutant gene but is expressed differently among individuals

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

Define: de novo mutation

A

affected individuals may not have affected parents because their disease arose from a new mutation

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

What represents the largest group of mendelian disorders?

A

autosomal recessive

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

In autosomal recessive disorders, if the mutant gene is rare, there is a strong probability that the affected child (proband) is the product of a _________________

A

consanguineous relationship (coming from the same descendants)

24
Q

In autosomal recessive disorders, the age of onset is more frequent at what period in life?

and

describe the expression of the defect

A

early in life

and

defect tends to be more uniform and complete penetrance is common

25
Q

What is the one Y-linked disorder?

A

hairy ears

26
Q

Almost all x-linked disorders are: recessive or dominant?

A

recessive

27
Q

Who is affected by x-linked disorders?

A

females who are homozygous for the disorder (unless they have an unusual x-linked dominant disorder) and all males because they only have one x-chromosome

28
Q

what would be the reason a heterozygous woman may demonstrate full expression even though the x-linked disorder is recessive?

A

unfavorable lyonization (inactivation of an abnormally high percentage of normal X chromosomes leading to clinically evident heterozygote disease)

29
Q

Describe lyonization

A
  • occurs only in females
  • 16 days after conception, all but one X chromosome is randomly inactivacted in all of the cells of the zygote
  • either the maternal or paternal X may be inactivated in each cell and that X remains inactivated for life
30
Q

Example of X-linked dominant

A

Oral-Facial-Digital syndrome (OFD) type I

31
Q

Diseases caused by mutations in STUCTURAL PROTEINS

A

Marfan syndrome

Ehlers-Danlos Syndromes

32
Q

How does Marfan Syndrome:

- occur
- give general characteristics of people who tend to get             this
 - prevalence
 - symptoms people with syndrome get
A

Autosomal dominant disorder of CT due to mutation of “FBN1 gene” –> you get abnormal “fibrillin” (which is a glycoprotein necessary for normal elastic fiber production

1 in 5000

Tall, thin body with abnormally long legs, arms, and fingers (Wolters….)
Dislocation of the eyes
Aortic aneurysm and dissection leading to heart failure and aortic rupture

33
Q

How does Ehlers-Danlos syndrome come about?

Symptoms of people who get it?

A

collagen synthesis problem

  • hyperextensible skin and hypermobile joints (can extend fingers all the way back)
  • Skin fragility and delayed wound healing
  • rupture of colon, large arteries
  • hernias
34
Q

Diseases caused by mutations in RECEPTOR POINTS

A 
Familial Hypercholesterolemia
Cystic Fibrosis (lecture)
35
Q

Frequency of hypercholesterolemia?

Where is the mutation?

What can this cause?

A

One of the most common inherited disorders:
1 in 500

Mutation in the gene for the LDL receptor resulting in impaired metabolism and increased LDL cholesterol in plasma

This causes:
xanthomas of the skin
premature atherosclerosis - plaque build-up in arteries

36
Q

In hypercholesterolemia, how much more cholesterol do homozygotes and heterozygotes have compared to the normal levels?

A

homozygous - 5X
-often die of MI before age of 20

heterozygous - 2-3X

37
Q

In hypercholesterolemia, understanding the role of LDL receptors have led to the design of what medication?

And what does this medication control?

A

the statin family of drugs

-they control cholesterol levels

38
Q

Diseases caused by mutations in ENZYME PROTEINS

A

Phenylketonuria

and

Lysosomal Storage Diseases
   Tay-Sachs disease
   Niemann-Pick disease
   Gaucher disease 
   Mucopolysaccharidoses
39
Q

Phenylketonuria:

  • Type of disorder: dominant or recessive?
  • prevalence and whose affected?
  • lack of what enzyme? and what does this lead to?
  • when does onset occur?
  • how can this be treated if detected early on?
A
  • autosomal recessive disorder
  • 1 in 10,000 white infants
  • lack of phenylalanine hydroxylase, leading to hyperphenylalaininemia and PKU
  • normal at birth, but within 6 months elevated phenylalanine levels impair brain development and mental retardation is evident
  • Screening at birth is mandatory in USA and restricting dietary phenylalanine intake will prevent mental retardation
40
Q

Lysosomal Storage Diseases

  • Type of disorder: dominant or recessive?
  • Whose affected?
  • How does this occur?
  • Symptoms of a person withthis?
A
  • Autosomal recessive transmission
  • infants and young children
  • accumulation of insoluble large molecules in macrophanges with hepatosplenomegaly
  • frequent CNS involvement, mental retardation, and/or early death
41
Q

what is it called if two or more genes, plus environmental/nongenetic influences, are responsible for a disorder?

give an example

A

multifactorial inheritance

ie- genes make one susceptible for diabetes and obesity is the environmental factor contributing as well

42
Q

What is the composite picture of the human chromosome strands that are stained, photographed, and arranged in pairs?

A

karyotype

43
Q

In as many as 50% of 1st trimester spontaneous abortions, the fetus has a ________

A

chromosomal abnormality

44
Q

Euploid is

A

a normal chromosomal count (2 x 23 = 46)

45
Q

Polyploidy is

A

an increased chromosomal count that is a multiple of that normally seen (3 x 23 or 4 x 23)

results in spontaneous abortion

46
Q

Aneuploidy and examples of it

A

any number that is not an exact multiple of the normal chromosome count

examples include:
an extra chromosome (trisomy = 2 X 23 + 1 = 47)
an absence of a chromosome (monosomy 2 X 23 -1 = 45)

47
Q

Translocation is…

A

the transfer of a part of one chromosome to another nonhomologous chromosome

48
Q

Trisomy 21 aka Down Syndrome:

  • Is it common within chromosomal disorders?
  • What is associated with this occuring?
  • Symptoms of child with this syndrome?
A

-Most common of the chromosomal disorders
-associated with increased maternal age
45 years old - 1:25

-mental retardation, epicanthic folds (skinfold of upper eyelid covering inner angle of eye), flat facial profile, increased susceptibility to infection (severe periodontal disease in childhood), large tongue, cardiac malformations

49
Q

-How does Trisomy 21 occur?

A

-this occurs due to meiotic non-disjunction of chromosome 21 during formation of the ovum

50
Q

Klinefelter Syndrome:

  • What is the mutation
  • Characteristics/symptoms
  • Dental fact
A

defined as male hypogonadism that develops when there are two X chromosomes and one or more Y chromosomes

  • increased length of lower limbs, reduced body hair, gynecomastia - most common reason for hypogonadism (swelling of breasts in males)
  • increased frequency of taurodontism (body of tooth and pulp chamber is enlarged vertically at the expense of the roots)
51
Q

Turner Syndrome

 - What is the mutation
 - Symptoms of people with this
A

due to partial or complete absence of the X chromosomes

-short stature, webbed neck, low post hairline, high-arched palate. primary amenorrhea (absence of menstruation)

52
Q

Diagnosis of Genetic diseases

A
  1. fluorescence in situ hybridization
  2. comparative genomic hybridization
  3. molecular diagnosis of genetic disorders
53
Q

How is fluorescence in situ hybridization achieved?

A

used fliorescent dye-labeled probes that recognize sequences specific to chromosomal regions

54
Q

How is comparative genomic hybridization achieved?

A

uses different colored dyes attached to large segments of the test DNA and normal DNA, followed by hybridization

55
Q

How is molecular diagnosis of genetic disorders achieved?

A
  1. PCR analysis - amplify the DNA in question
  2. compare the order of nucleotides of this DNA to a normal DNA sequence
  3. use restriction enzymes and run the segments on gel electrophoresis, compare to normal DNA
56
Q

Prenatal Indications for genetic analysis

A
  • mother’s age > 34 years
  • parent who is a carrier of a chromosomal translocation
  • history of a previous child with chromosomal abnormality
  • parent who is a carrier of an x-linked disorder
57
Q

Postnatal indication for genetic analysis

A
  • multiple congenital abnormalities
  • unexplained mental retardation and/or delayed development
  • suspected aneuploidy (ie - down syndrome)
  • suspected sex chromosomal abnormality
  • infertility
  • multiple spontaneous abortions

Path (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions