Genetics basics, Congenital abn, genetic abn Flashcards Preview

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Flashcards in Genetics basics, Congenital abn, genetic abn Deck (35):
1

mutaton=

change int he nucleotide sequence of an organisms DNA ultimatey creating genetic diversity

2

allelle=

any of the alternative verions of a gene that produce distinguishable phenotypic events

An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring through sexual reproduction.

3

genotype vs phenotype

genotype is the genetic makeup or set of allelles of an organism
phenotype is the phys and physio. traits of an organism

4

homozygous vs heterozygous

homozygous=having 2 identical allelles for a given gene
heteroygous is different

5

a congenital abnormality is____
d/t

any defects present at birth
d/t dev errors durin gestation (wouldnt happen unless theres a disruption)

6

when is vulnerability to congenital abnormality?
what is it

during organogenesis 15-60 days approx
-a time when vital organs are vulnerable to maternal or external interruption

7

what is a critical period

each organ of the embryo is forming at a specific time

8

which organs experience maximal sensitivity to teratogens when?

wk2-5=CNS
wk3-6ish=heart
wk4-7=extremities
wk 4-7.5ish =eyes
wk7-9=external genitalia

9

teratogen=

a factor external tot he fetus, including the mother, that causes birth defects

10

egs of teratogens
what are positive factors vs negative factors

positive (you must take something)-thalidomide caused limb defects if taken 15-20 days post conception (used for monring sikness)
positive-alcohol--fetal alcohol syndrome
negative (youre missing something)-malnutrition, cigarette smoke, infections

11

how many chromosomes do people have

23 pairs, the last of which is the sex chromosome. the rest are autosomes

12

a chromosome is

A chromosome (chromo- + -some) is a packaged and organized structure containing most of the DNA of a living organism.

13

autosomal conditions affect-
x linked conditions affect-

affct males and females
as the male only gets one x males are more severely affected as these conditions are generally recessive

14

dominant=

a single copy of the disease assoc mutation is enough to cause the mutation

15

autosomal recessive=

child has 50% chance of being a carrier, 25% chance of being affected and 25% chance of being unaffected

16

4 types of genetic abnormalities

1-monogenic
2-mitochondrial gene
3-complex trait or multifactorial (most)
4-chromosomal number and structure

17

with autosomal dominant how many defective genes do you need for the trait to be possibly present in offspring?
% chance of inheriting

1
50% chance of inheriting

18

3 types of monogenic problems:

autosomal reessive
autosomal dominant
x-linked recessive

19

x-linked recessive is an example of hwat kind of genetic abn?
what is it

monogenic
-only appears if you and your prtner have it..or? if a male inherits a recessive x chromosome there cant be another x dominant chromosome as his other chromosome is Y therefore the recessive gene will be expressed
its on sex chromosome

20

how many mitochondrial genes are there

37
(2 are rRNA, 22 transfer or tRNA, 13 structural genes that are encoding subunits of mito. resp. chain enzymes)

21

mitochondrial gene function


code resp chain Es. (nec for ATP)
u

22

how are mitochondrial genes inherited

maternally because most of the mitochondria are in the flagella which drops off when it enters the ovum. the ovum has more mitochondria than the sperm

23

what do mitochondrial gene disorders affect most and why

cause neuromuscular defects because nerves and muscles require a lot of ATP

24

complex trait=

may be a genetic predisposition
-polygenic
-genes and environmental cmponenets

25

2 types f chromosomal problems

numerical abnormality or stuctural defects

26

chromosomal numerical abnormaltiy
aneuploidy=
monosmy
trisomy=

aneuploidy=extra or missing chr
monosomy=missing chr in pair
trisom=extra chr in a pair

27

how are chromosomal numerical abnormailites named

by the chromosome number eg trisomy 21=down syndrome

28

types of chromosomal structural defects

inversion
translocation
deletion

29

chromosomal str defect: deletion

loss of geneti material and shortening of the chromosome

30

chr str defct: inversion

can be pericentric (around centromere
requires two breaks in a single chromosome
paracentric is not around centromere

31

chr str defect: translocation

can be balanced (look in book
Robertsonian in which one is lost
isochromosomal (from fault centromer division) leads to duplication of long arm and dletion of short arm or vice vers

32

Klinefelters syndrome vs Turners syndrome which affects males?

klinefelters

33

klinefelters and turners sydromes are exampes of what

genetic abnormalities

34

Klinefelters syndrome=
mnfts=

male xxy (1 in 500)
gynecomastia
deficient secondary male sex char
tall stature w longer ower than upper body and long extremities
lang impairment
narrow shoulders wide hips
lack of testosterone and inc hypothalamic gonadotropic hormones

35

Turners syndrome=
organs affected

female X0 (1 in 3000) one x and no other chromosome
-doesnt menstruate
o signs of secondary sex char
-webbing of neck
-nonpitting lymphedema of hands and feet
-congeneital heart defects (esp coarctation of the aorta and bicuspid aortic valve)
-abn kidney dev
-small stature