Exam 1: Genetics Flashcards Preview

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Flashcards in Exam 1: Genetics Deck (26):
1

Another name for base pair substitution:

Single nucleotide polymorphism

2

Most catastrophic form of genetic mutation:

Frameshift mutation

3

Three types of single gene disorders:

Dominant
Recessive
X-linked

4

X-linked recessive disorders predominantly affect which gender? Why?

Men, because with only one X gene, any inheritance will be expressed; for women, takes two

5

X-linked dominant disorders are:

Rare and few in number

6

Define aneuploidy. Which type is better?

Monosomy or trisomy of a chromosome

Trisomies are less devastating than monosomies

7

Which is the only monosomy which people typically survive?

Turner syndrome (female with only one X)

8

Give the aneuploidy for each disease:
Down syndrome
Edward syndrome
Patau syndrome
Turner syndrome
Klinefelter syndrome

Down: trisomy 21
Edward: trisomy 18
Patau: trisomy 13
Turner: 45:X
Klinefelter: 47:XXY

9

XXX females and XYY males:

Typically pretty normal

10

Define polyploidy:

69 instead of 48 chromosomes

11

Define penetrance:

The chance that phenotype follows genotype

12

Define haplotype:

Alleles on a single chromosome

13

What is nondisjunction?

When chromosomes don't separate during meiosis

14

Which cells are more likely to experience nondisjunction? Why?

Oocytes; proteins are older at time of replication and less reliable

15

At what maternal age does the incidence of Down syndrome begin to rise?

35ish

16

Relationship between X and Y chromosome:

Part of Y is homologous with X; this part is needed for fertility

17

S/s of Turner syndrome:

Menopause before menarche
Webbed neck
"Less female" features
Short stature

18

S/s of Klinefelter syndrome:

Nonfunctional spermatagonia
Infertile
Mostly normal development
Small testes, long limbs

19

Is extra genetic material better or worse tolerated than missing genetic material?

Better tolerated

20

Types of errors with crossover:

Deletion when a chromosome segment is lost
Unequal crossing over leads to duplication on one side and deletion on the other

21

What is chromosome translocation?

Crossover between non-homologous chromosomes

22

Result of chromosome translocation:

Unbalanced gametes result in zygotes that are partially trisomic and partially monosomic

High rate of spontaneous abortion and cancer in survivers

23

Name six dominant single gene disorders:

Familial hypercholesteremia
Huntington disease
Achondroplasia
Marfan's syndrome
Retinoblastoma
La-Fraumeni

24

Name five recessive single gene disorders:

Sickle cell anemia
Cystic fibrosis
Lysosomal storage diseases (Tay-Sachs, Gaucher, Niemann-Pick)
Phenylketonuria
Glycogen storage diseases

25

Name two X-linked recessive diseases:

Duchenne muscular dystrophy
Hemophilia A, B

26

Hemophilia A and B - which factor is missing?

A: VIII
B: IX