CHAPTER 4 Flashcards
Genes and Genetic Diseases
1
Q
_____ can be applied in a variety of context
- _____
- _____
- _____
A
genetic testing
amniocentesis
chorionic villus sampling
preimplantation genetic diagnosis
2
Q
Amniocentesis
- carried at _____ gestation, involves the withdraw of _____ from _____
- this test can detect _____ like _____ and _____ can be detected as an elevation in _____ in the amniotic fluid
- anmiocentesis- indicates a _____ when an _____ in _____ is evident
A
16 weeks amniotic fluid the uterus neural tube defects spina bifida anencephaly alpha fetoprotein level neural tube defect increase protein
3
Q
_____ (CVS)
- carried out at _____ gestation CVS is performed by extracting a small amount of _____ directly from the _____
- the most clinically useful technique for prenatal diagnosis of _____ at _____ gestation
A
chorionic villus sampling 10-12 weeks villus tissue chorion chromosomal abnormalities 3 months (12 weeks)
4
Q
chromosomal aberrations
- _____
- is usually the cause of aneuploidy
- is the failure of _____ or _____ to separate normally during _____ or _____
- the most common cause of down syndrome is _____
A
nondisjunction homologous chromosomes sister chromatids mitosis meiosis maternal nondisjunction
5
Q
down syndrome
- is the best-known example of _____
- _____
- occurs in _____ live births
- manifestations: mental challenges, _____, _____ folds, protruding _____, _____ low set _____, and poor _____.
- risk _____ with _____
- has an increased risk of _____, _____, and _____
- IQ of _____
A
aneuploidy trisomy 21 1 in 800 low nasal bridges epicanthal tongue flat ears muscle tone increases maternal age congenital heart disease respiratory infections leukemia 25-70
6
Q
sex chromosome aneuploidy
- _____
- females have only one _____
- denoted as karyotype _____
- characteristics include:
- absence of _____ (_____)
- _____
- webbing of _____
- widely spaced _____
- high number of _____
- _____ that is usually inherited from the _____
- occurs in _____ female births
- teenagers receive _____
- absence of _____ with only a _____ exhibits features that include a _____, widely spaced _____, and webbed _____
A
turner syndrome X chromosome 45,X ovaries sterile short stature neck nipples aborted fetuses X chromosome mother 1 in 2500 estrogen homologous X chromosome single X chromosome short stature nipples neck
7
Q
sex chromosome aneuploidy
- _____
- males with at least _____ and _____ chromosomes
- characteristics include:
- _____ appearance
- _____
- small _____
- sparse _____
- _____ male births
- some individuals can be XXXY and XXXXXY; will have _____ appearance; abnormalities will _____ with each _____; can also have an extra _____
- disorder _____ with the mothers age
- klinefelter syndrome karyotype: _____
- chromosomal variation that causes klinefelter syndrome _____ of _____ in the _____
A
klinefelter syndrome one Y two X male femalelike breasts (gynecomastia) testes body hair 1 in 1000 male increase X Y increases 47,XXY nondisjunction X chromosome mother
8
Q
fragile sites
- _____: site on the _____ of the _____; has an _____ number of repeated _____
- is the second most commonly recognized genetic cause of _____
A
fragile site syndrome long arm X chromosome elevated DNA sequences mental retardation
9
Q
chromosomal abnormalities are the leading cause of:
A
mental retardation and fetal miscarriages
10
Q
- _____: the composition of genes at a given locus or the individuals makeup
- _____: is the outward appearance of an individual; results from genotype in the environment
- example: infant with phenylkentonuria (PKU) has the _____
- if left untreated, the infant will have _____, which is the _____
- if treated, the infant will still have the _____ but can have a normal _____
A
genotype phenotype PKU genotype cognitive impairments PKU phenotype PKU genotype phenotype
11
Q
four major types of genetic diseases:
- _____
- _____
- _____
- _____
A
autosomal dominant
autosomal recessive
x linked dominant
x linked recessive
12
Q
autosomal dominant inheritance
- diseases are _____
- occurs in fewer than _____ individuals
- the union of a _____ with a _____ usually produces the affected offspring
- an affected parent can pass either a _____ or a _____ to his or her children; each event has a probability of _____; on average, half will be _____ and will express the disease and half will be _____
A
1 of 500 normal parent affected heterozygous parent disease gene normal gene 0.5 heterozygous normal
13
Q
autosomal recessive inheritance
- is _____, but many individuals are carriers
- abnormal allele is recessive, and the person must be _____ to express the disease
- trait usually appears in _____, not in the _____
- example: _____
- gene forms _____ with defective _____, which leads to _____ imbalance that results in _____; the _____ and _____ are affected; the person does not survive past _____ years of age
- characteristics:
- condition is expressed _____ in males and females
- is observed in _____ but not in _____
- approximately _____ of offspring will be affected
- _____ may be present: marriage between related individuals
A
rare homozygous children parents cystic fibrosis sodium channels transport salt abnormally thick, dehydrated mucous lungs pancreas 40 equally siblings parents one quarter consanguinity
14
Q
_____
- known as inbreeding
- is the mating of two _____ individuals
- offspring are termed _____
- proportion of shared genes depends on the _____ of the biological relationship
- dramatically _____ the reoccurrence risk of _____
- offspring of marriages of first cousins who are affected by genetic diseases is approximately _____ that of the general population
A
consanguinity related inbred closeness increases recessive double
15
Q
X linked inheritance
- is a disorder that involves _____ and _____
- Y linked disorders are _____ because the Y chromosome contains relatively _____ genes
- females: have _____ X chromosomes; can be _____ for the _____, _____ for _____, or heterozygous
males: have _____ X chromosome; are always _____; if inherits an _____, then he will express the disease because no _____ is present to counteract the _____; males are affected more often with X recessive conditions
A
X Y chromosomes uncommon few two homozygous disease homozygous normal one hemizygous X recessive gene normal allele diseased allele
