Genetics basics, Congenital abn, genetic abn

Question 1

mutaton=

Answer 1

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

Question 2

allelle=

Answer 2

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.

Question 3

genotype vs phenotype

Answer 3

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

Question 4

homozygous vs heterozygous

Answer 4

homozygous=having 2 identical allelles for a given gene

heteroygous is different

Question 5

a congenital abnormality is____

d/t

Answer 5

any defects present at birth

d/t dev errors durin gestation (wouldnt happen unless theres a disruption)

Question 6

when is vulnerability to congenital abnormality?

what is it

Answer 6

during organogenesis 15-60 days approx

-a time when vital organs are vulnerable to maternal or external interruption

Question 7

what is a critical period

Answer 7

each organ of the embryo is forming at a specific time

Question 8

which organs experience maximal sensitivity to teratogens when?

Answer 8

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

Question 9

teratogen=

Answer 9

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

Question 10

egs of teratogens

what are positive factors vs negative factors

Answer 10

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

Question 11

how many chromosomes do people have

Answer 11

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

Question 12

a chromosome is

Answer 12

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

Question 13

autosomal conditions affect-

x linked conditions affect-

Answer 13

affct males and females

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

Question 14

dominant=

Answer 14

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

Question 15

autosomal recessive=

Answer 15

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

Question 16

4 types of genetic abnormalities

Answer 16

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

Question 17

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

Answer 17

1

50% chance of inheriting

Question 18

3 types of monogenic problems:

Answer 18

autosomal reessive
autosomal dominant
x-linked recessive

Question 19

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

Answer 19

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

Question 20

how many mitochondrial genes are there

Answer 20

37

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

Question 21

mitochondrial gene function

Answer 21

code resp chain Es. (nec for ATP)

u

Question 22

how are mitochondrial genes inherited

Answer 22

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

Question 23

what do mitochondrial gene disorders affect most and why

Answer 23

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

Question 24

complex trait=

Answer 24

may be a genetic predisposition

• polygenic
• genes and environmental cmponenets

Question 25

2 types f chromosomal problems

Answer 25

numerical abnormality or stuctural defects

Question 26

chromosomal numerical abnormaltiy
aneuploidy=
monosmy
trisomy=

Answer 26

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

Question 27

how are chromosomal numerical abnormailites named

Answer 27

by the chromosome number eg trisomy 21=down syndrome

Question 28

types of chromosomal structural defects

Answer 28

inversion
translocation
deletion

Question 29

chromosomal str defect: deletion

Answer 29

loss of geneti material and shortening of the chromosome

Question 30

chr str defct: inversion

Answer 30

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

Question 31

chr str defect: translocation

Answer 31

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

Question 32

Klinefelters syndrome vs Turners syndrome which affects males?

Answer 32

klinefelters

Question 33

klinefelters and turners sydromes are exampes of what

Answer 33

genetic abnormalities

Question 34

Klinefelters syndrome=

mnfts=

Answer 34

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

Question 35

Turners syndrome=

organs affected

Answer 35

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