Bio Chem - Genetics

Front 1

How many chromosomes are there? How many are X? How many are Y?

Back 1

23 pairs of 46 individual chromosomes. Females have two Xs, males have one X and one Y. 22 of the 23 are autosomal (nonsex)

Front 2

Name the trisomies and other chromosomal abnormalities mentioned in class. Trisomy of which is down syndrome?

Back 2

Trisomy 21 is down.
Trisomy 13 Edwards syndrome
Trisomy 18 Patau's
XXY Klinefelter's
XYY syndome
Triple-X (XXX)

Front 3

Name 4 autosomal recessive disorders

Back 3

Tay-Sachs
Sickle Cell
Hereditary hemochromatosis
Cystic Fibrosis

Front 4

Name 2 autosomal dominant disorders

Back 4

Huntingtons disease, familial hypercholesterolemia

Front 5

How is duchenne muscular dystrophy inherited?

Back 5

X-linked

Front 6

Name 4 mitochondially inherited disease

Back 6

NARP, Leigh Syndome, MERRF, Leber's hereditary optic nueropathy

Front 7

in which forms of inheritence do heterozygous individuals have symptoms?

Back 7

only heterozygotes of an autosomal recessive disease DO NOT show symptoms

Front 8

How does inheritance of a mitochondial gene differ from inheritance of an autosomal gene? How about X-linker?

Back 8

mitochondrial gene has one allele from the female/mother only and all offspring will show some degree of the disease, whereas an autosomal gene has one allele from the mother and one allele from the father. An X-linked gene comes from the mother on the X chromosome only, but can affect both males and females, although mostly males show the disease, whereas autosomal genes come from chromosomes other than the sex chromosome

Front 9

what kinds of enzymes are often involved in disease of mitochondrial genese

Back 9

any enzymes related to energu production - oxidative phosphorylation

Front 10

what is meant by a genetic disease that is never inherited

Back 10

a defect that if inherited would prevent survival of the fetus or prevent reproduction of the fetus

Front 11

what disease is a genetic disease in which the mutations that cause it can occur AFTER birth

Back 11

Rhett syndrome

Front 12

dsecribe the genetic defect that results in Huntington disease (what is there more of in terms of nucleotides and of amino acids)

Back 12

a triplet repeat of CAG amino acids that encode for polyglutamine tract. Normally have 11-34 glutamines, however, an afflicted individual has 37-121 glutamines.

Front 13

what problem generally causes death in cystic fibrosis patients?

Back 13

chronic lung infections due to P. aeruginosa

Front 14

what protein is defective in cystic fibrosis? in what organs is the defect most problematic?

Back 14

a Cl transporter is defective, specifically the cystic fibrosis transmembrane conductance regulator (CFTR). The defect is most problematic in the lung, as the pancreas is manageable.

Front 15

What is the most common inherited disease in the USA? Is it sometimes fatal without treatment? What is the most lethal inherited disease in the USA?

Back 15

Most common inherited disease is hereditary hemochromatosis. Disease can be fatal without treatment. Most lethal inherited disease is cystic fibrosis.

Front 16

what enzyme is defective in Tay Sachs disease? What builds up as a result (and where)? What are the symptoms? Is the enzyme defective in Tay Sachs the only enzyme involved in trimming sugars off of glycosphingolipids that when defective leads to disease? What is the class of diseases known as?

Back 16

Defective enzyme is hexosaminidase A. Causes glycosphingolipids to build up in the brain. Symptoms include mental retardation, blindness, paralysis, muscle atrophy and cherry red spot on retina. It is not the only enzyme involved in trimming sugars off that when defective leads to disease. Class of diseases known as sphingolipid storage disorders.

Front 17

Name 3 inherited diseases that are thought to protect against an infectious disease.

Back 17

Cystic Fibrosis - typhoid fever
Sickle Cell Anemia - malaria
Tay Sachs - tuberculosis (not well established)

Front 18

why does an X-linked disease such as Duchenne muscular dystrophy seldom cause symptoms in females? When do they cause symptoms in females?

Back 18

there is inactivation of an X in females, and males with the defect rarely reproduce. in order for the female to show symptoms both Xs have to be defective or she must inactivate the normal X.

Front 19

A new inherited disease has been discovered in which it only occurs when the defect is inherited from the father. The disease gene is :

Back 19

imprinted

Front 20

three examples of diseases that can be caused by a single gene defect (monogenic) or by the combined effect of many genes (polygenic).

Back 20

Monogenic or polygenic: Hypertension, Cardiovascular disease. Type 2 diabetes.

Polygenic: Nueral tube defects (anencephaly or spinal bifida), alcoholism, asthma, idiopathic gout, schizophrenia, obesity. Type 1 diabetes.

Front 21

what genes are associated with type 1 diabetes

Back 21

HLA-DR3, HLA-DR4

Front 22

what genes are associated with type 2 diabetes

Back 22

MODY genes associated with monogenic type 2 diabetes

PPAR and Calpain-10 genes with polygenic type 2 diabetes.
not all individuals will have disease.

PPARgamma may protect against it.

Front 23

screening for genetic diseases by using DNA sequencing?

advantages or disadvantages

Back 23

ADV: catch false positive by another method, easier and less expensive than biochemical assay, can use family history to know which to screen for

DISADV: false positives due to location of mutation, limited coverage of test

Front 24

what % frequency are the two most often occuring mutations known in the CFTR gene? Are there any high frequency mutations in FH?

Back 24

70% of CF patients have 3-nucleotide deletion at the 508th amino acid. Greater than 2% have single nucleotide change that produces a much shorter polypeptide chain.
No high frequency mutations are seen in FH

Front 25

What is a "snip"? What is their frequency in human DNA?

Back 25

snip is a single nucleotide polymorphism. Occurs about every 300 base pairs.

Front 26

Penetrance

Back 26

penetrance has to do with extent to which a given trait is expressed. It can range from 0-100%. if 0% or extremely low, the trait may not be expressed at all.

Front 27

"phenotype differs from the genotype"

Back 27

genotype is genetic makeup of the individual for a particular trait and the phenotype is the outward appearance.