Medical Biochemistry I-Exam 1 – Flashcards

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question
What stabilizes higher order structures in proteins?
answer
  1. electrostatic attraction of charged residues (salt bridges/repulsive effects)
  2. internal H-bonding (specific distance and angle requirements)
  3. short range Van der Waals interactions and London dispersion forces of neutral charged residues
  4. entropy driven hydrophobicity (Gibbs free E change)
question
Amino Acids that are likely to carry charges on side chains at neutral pH
answer

aspartic acid, glutamic acid, tyrosine, cysteine have negative charges

 

lysine, arginine, and histidine have positive charges

question
Zinc fingers, kringle domains, and leucine zippers are
answer

Zinc fingers

 

loop of 23 AA resulting from Zn ion being complexed to 4 AA, usually cysteines and histidines

 

Kringle domains

 

conserves seq that fold into large loops that are stabilized by 3 disulfide linkages. Impt in protein-protein interactions with blood coag factors.

 

Leucine Zippers

 

arrangments of leucines along one side of an alpha-helix btwn 2 proteins, so that protein can form dimers leaving basic AA regions to bind DNA

question

Ways Proteins Can Be Denatured

 

answer
  1. detergents = straightens out protein (Na dodecyl sulfate makes peptide rodlike
  2. chaotropic agents - remove water to unsolubilize protein
  3. high temps (50-60 degrees C or higher)
  4. drastic pH changes
  5. organic solvents
question
Hydrophobic Effect
answer
when hydrophobic regions of protein in tertiary structure are moved inward and hydrophilic regions outward
question
In which human organ is myoglobin (Mb) most impt?
answer
heart b/c rapid O2 supply needed
question
Explain causes and importance of right shift in Hb/O2 binding curve
answer

right shift caused by:

 

decreased pH (increased [H+])

 

increased [CO2]

 

increased [2,3-BPG]

 

increased temperature

 

all factors lead to increased O2 unloading which means that a higher percentage of O2 is delivered to tissues

question
In Hb, how does binding of first oxygen molecule affect binding of next ones?
answer

Deoxy Hb is usually in taut (T) form where heme groups restricted and hard for O2 to bind

 

When O2 binds to 1st heme group, the Fe of that heme will shift and pull attached his along.

 

Movement breaks salt bridges pushing Hb into relaxed (R) state and allow more O2 binding sites to become available

 

 

question
What is Bohr effect?
answer

A right shift when pH decreases (increase in H+ conc.)

 

O2 release from Hb will increase when pH is lowered or [CO2] is high

 

Hb has decreased O2 affinity

 

Raising pH or decreasing [CO2]-shift curve to left

question
Physiological importance of cooperativity in Hb function
answer
Hb has 4 subunits where binding of O2 at one heme group increases the affinity for O2 of the other heme groups in the same molecule
question
Compare behavior of Mb and Hb with respect to O2, CO2, and H+
answer

Mb has a greater affinity at lower [O2] than Hb

 

Hb can transport more molecules of O2 b/c of cooperative effect of multiple binding sites

 

Hb can't readily bind 1st O2, but once it does has higher affinity for O2 at other sites

;

Hb-sigmoidal curve

;

Mb-hyperbolic

;

Hb responds more readily to small changes in partial pressures of O2

;

Mb saturated quicker than Hb at low partial pressure of O2 (doesn't have much flexibility)

question
How does protein (globin) portion of Mb or Hb affect reactivity of heme?
answer

weaken strength of heme-O2 interaction. Heme binds O2 so strongly it can convert it to a superoxide anion, which can be an unwanted oxidizing agent

 

prevents interaction of oxy-heme groups with other oxy-heme groups

question
How and where does 2,3-BPG interact with Hb?
answer

2,3-BPG binds to deoxy Hb-makes it more stable and resistant to oxygenation after O2 delivery

 

negative charge allows BPG to bind to a site between two alpha chains

 

causes right shift in O2-dissociation curve (increase O2 release)

question
Where does 2,3-BPG come from?
answer
product of glycolytic pathway
question
How does fetal Hb (HbF) differ from HbA?
answer

Fetal Hb has two gamma chains instead of beta chains.

 

2,3-BPG can't bind to fetal Hb and it has greater affinity fo O2 and takes O2 from maternal Hb

;

HbF is left shifted on O2-dissociation curve compared to maternal Hb

;

;

question
What does Hill Eqn describe?
answer
importance of cooperativity
question
How does NO interact w/ Hb and what is physiological significance of that interaction?
answer

Hb binds NO at heme Fe and cys residues in globin chain.

;

NO relaxant for vascular smooth muscle

;

Hb can pick up NO, stiffen vascular tissues, and increase BP

;

NO is strong vasodilator so Hb can be used to mediate vascular tone

question
What is difference btwn HbS and HbA?
answer
HbA has normal beta chain while HbS has sickle cell hemoglobin. 6th AA for normal beta globin would be a glutamic residue but in HbS that Glu is replaced with a Val. Val is uncharged and allows hydrophobic pockets. The chains bind together and crystallize
question
Physiochemical/Pathological Basis for All Clinical Manifestations of Sickle Cell Disease
answer

crystallization and stiffening of Hbs causes them to adhere to the endothelium and often obstruct small vessels (capillaries) or cause hemolysis

;

hemolysis can cause anemia and hyperbilirubinemia, causing pallor and jaundice

;

Complete vasocclusion can cause ishemia or infarction resulting in organ damage

;

Stroke, infection and excrutiating pain can result

question
How is Sickle Cell Disease Inherited?
answer
recessive disorder. Only homozygous HbS cause the disease to become expressed.
question
What is an enzyme?
answer

a protein catalyst for specific biochem rxns.

;

It will not undergo chem rxn itself and can be reused for other rxns

question

What does enzyme effect and not effect in rxn?

;

;

answer

Enzymes reduce activation energy.

;

Keq and delta G are not affected by enzymes.

question
Name and describe 2 models used to describe enzyme specificity and/or catalytic activity
answer

lock and key model

;

describes an enzyme active sites (lock) being specific for binding substrate (key)

describe specificity

;

induced fit model

;

active site will conform to fit substrate

describes specificity and catalytic activity

question
What is prosthetic group?
answer

non-protein organic molecule that is tightly bound to enzyme active site

;

ex-heme, biotin, or flavin

;

holoenzyme-prosthetic group attached

;

apoenzyme-prosthetic group NOT attached

question
Name 6 Classes of Enzymes
answer

oxidoreductases-catalyze RED/OX reactions

Ex-H+ donor to substrate


transferases-transfer group from one molecule to another

Ex-phosphorylases


hydrolases-hydrolytic cleavage of bond

Ex-peptide bond cleavage


lyases-cleave bonds w/o water to leave double bond or addition of other groups to double bond

Ex-decarboxylase


isomerases-change geometry of molecule

Ex-cis-trans isomerase


ligases-join 2 molecules together though hydrolysis of high energy bond

Ex-carboxylase

question
What is Michaelis-Menton Eqn and what do terms mean?
answer

V = Vmax[S]/(Km+[S])

;

V - velocity of rxn

Vmax - max rxn velocity

[S] - substrate concentration

Km - constant value for a specific substrate

;

question
In a Michaelis-Menton plot, where is Vmax and how do you find Km?
answer

Vmax - when [S] is very high

;

Km - [S] when V = 1/2(Vmax)

question
A Lineweaver-Burk plot is also called a ---------
answer
Double-reciprocal plot
question
What is plotted on Lineweaker-Burk plot and what are the x- and y-intercepts of the plot?
answer

The LB graph plots the inverse of the Michaelis-Menten plot, which is 1/V on the y-axis and 1/[S] on the x-axis

 

x-intercept - 1/Km

 

y-intercept - 1/Vmax

question
What are advantages of the Eadie-Hofstee plot?
answer
The E-H plot gives more evenly spaced data points than the  L-B plot.
question
What characteristics distinguish a competitive inhibitor from the other types of inhibitors?
answer

bind directly to the active site and can be overcome by increased [substrate].

 

Other inhibitors bind to other sites on enzyme

question
On the Lineweaver-Burk plots are the vertical or horizontal intercepts the same or different for competitively inhibited rxns?
answer

same y-intercept

 

different x-intercepts

question
On the Lineweaver-Burk plots are the vertical or horizontal intercepts the same or different for non-competitively inhibited rxns?
answer

different y-intercepts

 

same x-intercepts

question
On the Lineweaver-Burk plots are the vertical or horizontal intercepts the same or different for uncompetitively inhibited rxns?
answer

different y-intercepts

 

different x-intercepts

question
What does inhibitor react with for competitive inhibition?
answer
active site of the enzyme
question
What does inhibitor react with for non-competitive inhibition?
answer
react with enzyme to reduce its effectiveness to bind w/ substrate
question
What does inhibitor react with for uncompetitive inhibition?
answer

bind with ES complex.

 

irreversible inhibitors.

question
Sigmoid V versus [S] plot and curved Lineweaver-Burk plots indicate
answer
allostery and positive cooperativity of the enzyme (n = 2)
question
What factors determine the amount of enzyme activity in serum?
answer

amount of tissue producing enzyme

 

rate of enzyme released

 

rate of enzyme inactivation/elimination from plasma

question
Define: Standard International Unit (SIU)
answer
1 standard international unit of enzyme activity converts 1 μM of substrate/minute
question
2 most commonly measured serum aminotransferases and describe rxns they catalyze
answer

Aspartate aminotransferase (AST) - catalyzes exhange of amino group between alpha amino acids (aspartate) and alpha keto acids

 

Alanine aminotransferase (ALT) - catalyzes exchange of amino group between alpha amino acids (alanine) and alpha keto acids

question
In which pathological states are the two most commonly measured serum aminotransferases elevated?
answer

AST - liver damage and myocardial cells,hemolysed blood

 

ALT - liver damage

question
Reaction catalyzed by γ-glutamyltranspeptidase and how it is used diagnostically?
answer

Glutathione + amino acids → γ-glutamyl-amino acid + cys-gly

 

γ-glutamyltranspeptidase found in kidney, intestine, liver, and fetal tissue

 

GGT levels are elevated and very sensitive in liver damage

 

question
2 commonly measured phosphatases and how are they used diagnostically?
answer

Alkaline phosphatase (ALP)

 

Hydrolyzes phosphate groups from organic monophosphate at pH~9

Found in liver, bone, intestine, and placental tissue

Elevation of ALP means damage to liver and bone tissue

Elevated in gowing children, bone fractures, and pregnant women

 

Acid Phosphatase

 

hydrolyzes phosphate groups from organic monophosphates at pH~5

 

found in prostate, platelets, and erythrocytes

Elevation found in metastatic prostate cancer and hemolysed blood samples

 

 

question
Diagnostic utility of LDH
answer
Used to detect MI and hemolysis
question
"flipped" LDH
answer

Most common form is LDH2 (HHHM)

 

After MI or hemolysis, LDH1 (HHHH) predominates causing a "flipped" LDH b/c LDH1>LDH2

question
What reaction does LDH catalyze?
answer

Lactate + NAD → pyruvate + NADH + H

 

interconversion of pyruvate and lactate

question

Another name for alpha hydroxybutyrate dehydrogenase (HBD)?

 

 

answer
LDH1
question
What does elevated serum HBD mean?
answer
damage to myocardial cells due to recent MI
question
Reaction catalyzed by CK (CPK)
answer
creatine phosphate + ADP → Creatine + ATP
question
Diagnostic meaning of elevated serum CK
answer

has 2 subunits, M and B

 

MB-MI or brief ischemia

 

MM-vigorous exercise, injection, convulsions

 

BB-neural tissue damage

question
Diagnostic significance of elevated serum amylase
answer

pancreatitis

 

morphine

question
Reaction catalyzed by serum amylase
answer

starch + H2O → maltose, maltotriose & limit dextrins

 

digest starch

question
Elevated serum lipase means
answer

pancreatic pathology

 

morphine

question
Reaction catalyzed by serum lipase
answer

trigylceride + H2O → fatty acids + glycerol

 

fat digestion

question
What are troponins and how are they used in diagnosis?
answer

proteins that function in the contractile apparatus of the muscle

 

Cardiac troponin I is increased in plasma 3-6 hours after MI

question
Serum Enzyme Levels in crush injury
answer

mildly elevated alkaline phosphatase (healing bone)

 

elevated creatine kinase MM (skeletal muscle)

question
Serum Enzyme Levels in vigorous exercise
answer
elevated creatine kinase MM (skeletal muscle)
question
Serum Enzyme levels in morphine injection
answer
elevation of serum amylase and lipase
question
Serum Enzyme Levels in pregnancy
answer

mildly elevated alkaline phosphatase (bone growth)

 

elevated GGT

question
Four Categories of Cell Adhesion Molecules
answer

integrins

 

immunoglobulin superfamily

 

cadherins

 

selectins

question
Which of the CAM categories would be actively involved in transmitting signals from the inside to the outisde of the cells and vice versa?
answer
integrins
question
What CAM category is involved in adherens junction between cell?
answer
cadherins
question
Abbreviations for 3 types of adhesion molecules of Ig suberfamily and tell their origins
answer

NCAM - neural cell adhesion molecule

 

PECAM - platelet-endothelial cell adhesion molecule

 

VCAM - vascular cell adhesion molecule

 

Named for their similarity in structure to the Igs

question
4 Diseases in which CAMS are involved
answer

Rheumatoid arthritis - overexpression of VCAMs

 

Psoriasis - form of an integrin

 

Pemphigus vulgaris - autoantibodies interacting with desmoglein

 

von Willebrand disease - expression of P-selectin

question
Describe alpha-helix
answer
tightly coiled, stabilized by H bonding btwn imido groups and oxygen of carbony groups, many helices (3.6 AA/turn)
question
Beta sheet
answer

regions of same chain or neighboring chains bond to each other w/ H bonds, the H bonds are perependicular to the long axis of the chain

 

most stable conformation - antiparallel sheets (one side N→C other side C→N

question
Beta turns
answer

H bonding of AA 3 sequences apart in same chain

 

results in U turn bend of chain

question
What AA usually phosphoylated in proteins?
answer

ser

 

thr

 

tyr

question
Commonly occurring modification of AA found in some proteins
answer

acetylation of N terminus

 

carboxylation - add COOH

 

hydroylation - add OH

 

glycosylation - add glucose

 

phosphorylation - add phosphate group

 

disulfide linkages

question
Primary Structure
answer
AA sequence
question
Secondary Structure
answer

alpha helix

 

beta-pleated sheets

 

beta-turns

 

random coiling

 

results from free roation of bonds besides peptide bonds

question
Tertiary Structure
answer

secondary structures fold on each other

 

hydrophobic - inside

hydrophilic - outside

question
Quarternary Structure
answer
multiple polypeptide chains interact by noncovalent bonds to form single structure
question
General Solubility Prop. of Proteins
answer

fibrous and insoluble

 

globular and soluble

 

firbrous and soluble

question
Functions of Proteins
answer

structural roles

 

enzymes

 

role in contractile structures

 

transport (Hb)

 

hormones

 

receptors

 

Abs

question
What are proteins and peptides made of?
answer

peptides - moderate chain length polymers of amino acids joined by peptide bonds

 

proteins - polymeric compounds composed of AA joined by peptide bonds

question
What is unique about peptide bond?
answer
it is rigid b/c tautomerism
question
In ABO blood group, where is difference in oligosaccharide located and how sugars different?
answer

due to presence or absence of N-acetyl-galactosamine or galactose linked to penultimate galactose by C1-C3 linkage

 

1 sugar difference

question
Glycosaminoglycans and 2 Ex
answer

unbranched polysacc w/ repeating disacc - one is AA, other is uronic acid

 

Ex - hyaluronic acid and heparin

question
3 Impt Disacc and which alpha or beta linked?
answer

maltose - alpha linked

 

sucrose - alpha linked

 

lactose - beta linked

question
3 Most Impt polysacc and what are linkages? Why is linkage impt?
answer

starch - alpha linked (spiral)

 

glycogen - 2 types - alpha C1-C4 (linear)

                                 alpha C1-C6 (branched)

 

cellulose - beta linked (linear)

 

alpha and beta linkage affects the shape of the compound and humans can't digest cellulose b/c beta linkages

question
What is glycoside?
answer

anomeric -OH group of sugar reacts w/ another -OH compound

 

 

question
aglycone
answer
compound that attaches to anomeric C of sugar
question
Name and describe 2 commonly found mod. of sugars
answer

amino sugar - -OH group replaced by amino group

Ex - glucosamine, galactosamine

 

deoxy sugar - 1 OH group replaced by H

Ex - 2-deoxyribose

question
2 conformation of 6-membered rings
answer
boat and chair
question
What is mutarotation and where does it take place?
answer

configuration changes in molecule by ring opening and closing

 

occurs at anomeric C

question
Pyran and furan are named after which sugar structures and how many Cs are in each?
answer

pyranose - 6 C ring

 

furanose - 5 C ring

question
Most Impt Monosacc and Polysacc made up of this monosacc
answer

glucose - most impt monosacc

 

Polysacc made up of glucose - starch

                                             cellulose

                                             glycogen

question
What are aldoses?
answer
monosaccharides w/ aldehyde group
question
What are ketoses?
answer
monosaccharides w/ ketone group
question
What are carbohydrates?
answer
polyhydroxy aldehydes or ketones or compounts that can by hydrolyzed to these
question
Two Ex of Differences Between Identical Twins that Illustrate that Environment plays a role in development and health
answer

fingerprints are different of two twins - different positions in womb

 

type I diabetes - if one gets, less than 1/2 the time other twin gets

question

What percentage of live births suffer from a disease causing monogenic defect?

 

answer
1/100 or 1% of libe births suffer from a monogenic defect
question
What percentage of live births suffer from a disease-causing chromosomal abnormality?
answer
1/1000 or 0.1% of live births suffer from a disease-causing chromosomal abnormality
question
How many of the chromosomes are X chromosomes?
answer

normal female - 2 X chromosomes

 

normal male - 1 X chromosome

question
How many chromosomes are Y chromosomes?
answer

normal female - 0 Y chromosomes

 

normal male - 1 Y chromosome

question
How many of the chromosomes are considered autosomes?
answer
44 (22 from father, 22 from mother)
question
What is an autosome?
answer
a chromosome that is not a sex chromosome
question
4 trisomies for which live birth are possible
answer

trisomy 13

 

trisomy 18

 

trisomy 21

 

trisomy X

 

XYY

question
Which of the 4 trisomies produces mild to undetectable symptoms?
answer

trisomy XYY

 

trisomy XXX

question
Which trisomy is otherwise known as Down's syndrome?
answer
trisomy 21
question
What is XYY syndrome?
answer

tall

 

other mild symptoms

question
What is Klinefelter's Syndrome?
answer

male

 

testicular failure

 

can't conceive

question
What is Turner's Syndrome?
answer

X-

 

sexually immature

 

short

 

web neck

 

phenotypically female

question
How does x-linked disease inheritance differ from inheritance of an autosomal disease?
answer

lack of male to male transmission

 

gender-dependent

 

x-linked gene comes from mother on X chromosome only, but can affect both males and females, through mostly males show disease

 

autosomal come from chromosomes other than sex chromosome

question
How does inheritance of a mitochondrial disease differ from the inheritance of an autosomal disease?
answer

An autosomal disease passes on one allele from the mother and one allele from the father

 

A mitochrondrial disease has only one allele from the female/mother only and all offspring will show some degree of the disease

question

Which will probably have greatest number of offspring who suffer from an inherited disease (may be more than one):

 

A. parents both heterozygous for autosomal recessive disease

 

B. parents both heterozygous for an autosomal dominant disease

 

C. a father who suffers from an X-linked recessive disease and a mother who is homozygous wild type (has only well type of disease gene)

 

D. a mother who is heterozygous for an x-linked recessive disease and a father who is wild type hemizygous (has the well form of that disease gene)

 

E. a father who suffers from a mitochondrial disease and a mother who does not at all have it

 

 

answer
B. parents both heterozygous for a dominant disease will have greatest # of offspring
question

Of these, which will probably have the least number of offspring who suffer from an inherited disease (may be more than one):

 

A. parents both heterozygous for autosomal recessive disease

 

B. parents both heterozygous for an autosomal dominant disease

 

C. a father who suffers from an X-linked recessive disease and a mother who is homozygous wild type (has only well type of disease gene)

 

D. a mother who is heterozygous for an x-linked recessive disease and a father who is wild type hemizygous (has the well form of that disease gene)

 

E. a father who suffers from a mitochondrial disease and a mother who does not have it

 

 

answer

E. a male who suffers from mitochondrial disease and a female who does not

 

C. a father who suffers from an x-linked recessive disease and a mother who is homozygous wild type (has only well type of disease gene)

question
Explain how penetrance might mean that individuals with disease symptoms might not be observed in a pedigree
answer
Just because genotypically the person has the disease doesn't mean they express it phenotypically
question

Genotype?

 

Phenotype?

answer

genotype-genetic makeup

 

phenotype-physical manifestation

question
How does penetrance affect onset of hereditary hemochromatosis?
answer

used to be thought rare

 

now known as the most common hereditary disease in the USA

question
What environmental factors affect the onset of hereditary hemochromatosis?
answer

gender - females under 50 not have disease (menstrual cycle expels excess iron)

 

blood donations

 

diet - not enough Fe normally and you make most of Fe intake

 

alcohol consumption

 

environment

question
Why does an X-linked disease such as Duchenne muscular dystrophy seldom cause symptoms in females?
answer

X-inactivation and that males with the defect do not reproduce.

 

Females need both x's to be defective in order the x-recessive diseases to show

 

females have two x's

question
A newly inherited disease has been discovered in which the disease ocuurs only when the defect is inherited from the father. The disease gene has what pattern of genetic inheritance?
answer
imprinted
question
Which is meant by "a genetic disease is never inherited"?
answer
A defect that if inherited would prevent the survival of the fetus and/or prevent reproduction of the fetus
question
What disease is a genetic disease in which the mutations that cause it often occur after birth?
answer
cancer
question
Tay Sachs inheritance type
answer
autosomal recessive
question
cystic fibrosis inheritance type
answer
autosomal recessive
question
sickle cell anemia inheritance type
answer
autosomal recessive
question
Huntington disease inheritance type
answer
autosomal dominant
question
hereditary hemochromatosis type of inheritance
answer
autosomal recessive
question
Duchenne muscular dystropy inheritannce type
answer
x-linked (recessive)
question
familial hypercholesterolemia inheritance type
answer
autosomal dominant
question
Leber's hereditary optic neutopathy type of inheritance
answer
mitochondrial
question
genetic defect in Huntington disease
answer

a triplet repeat of CAG (glutamines) amino acids that encode for polyglutamine tract.

 

Normally - ≤ 34

 

Have Disease - ≥ 37

question
most common inherited disease in the USA
answer
hereditary hemochromatosis
question
Is hereditary hemochromatosis fatal w/o txt?
answer
yes
question
most common lethal inherited disease
answer
cystic fibrosis
question
What protein in defective in cystic fibrosis?
answer
CFTR (Cl- transporter)
question
Is what organ is the defect of cystic fibrosis most problematic?
answer
lungs
question
What problem generally causes death in cystic fibrosis?
answer

lung infections caused by P. aeroginosa

 

accumulates in lungs and destroys lining

question
What does the protein involved in cystic fibrosis do to promote the eventually fatal action that happens?
answer

CFTR used to clear out bacteria from lungs

 

dysfunctional in CF and can't remove bacteria anymore

 

lungs get destoyed by inhaled bacteria (P. aeroginosa)

question
2 inherited diseases that protect against infectious disease and what they protect against
answer

cystic fibrosis - protect from typhoid fever

 

sickle cell anemia - protects from malaria

question
Enzyme defective in Tay Sachs disease
answer
hexosaminidase A
question
What builds up and where does it build up in Tay Sachs?
answer
glycosphinogolipids build up in the brain
question
What are the symptoms of Tay Sachs?
answer

mental retardation

 

blindness

 

paralysis

 

muscle atrophy

 

cherry red spot on retina

question
Is hexosaminidase A the only enzyme that is involved in trimming sugars off glycosphinolipids that is defective in disease?
answer
no
question
What is class of diseases that involve defective enzymes involved in trimming sugars off of glycosphingolipids?
answer
sphinogolipid storage disorders
question
3 monogenic or polygenic diseases
answer

hypertension

 

cardiovascular disease

 

type 2 diabetes

question
Only polygenic diseases
answer

anencephaly

 

spina bifida

 

cleft lip/palate

 

alchoholism

 

asthma

 

bipolar disorder

 

inherited epilepsy

 

idiopathic gout

 

obesity

 

schizophrenizia

 

type I diabetes

question
3 inherited monogenic diseases that cause hypertension
answer

glucocorticoid-remediable aldosteronism

 

apparent mineralocorticoid excess

 

Liddle syndrome

question
polygenic syndrome that is generally considered cause of most hypertension
answer
essential hypertension
question
3 genes that have been associated with type 1 diabetes
answer
3 HLA genes
question
Name genes that have been associated with a monogenic disease that may be though of as type 2 diabetes
answer
MODY 1-7
question
3 genes that have been associated with polygenic type 2 diabetes
answer

PPAR-gamma

 

glucokinase

 

calpain 10

question
Are all individuals with a defect in one of the genes associated with polygenic type 2 diabetes going to develop the disease?
answer
no
question
Which of these genes associated with type 2 diabetes has been found in 85% of the world population?
answer
PPAR-gamma
question

Which of the following infectious diseases is NOT thought to be protected against by an inherited genetic mutation or deletion (may be more than one):

 

A. HIV

B. typhoid fever

C. anthrax

D. malaria

E. leprosy

answer

anthrax

 

leprosy

question
What is a "snip" and with what frequency are SNPs encountered in human DNA?
answer

single nucleotide polymorphisms

 

1:300 bps

question

A patient has the form of the gene that cause Huntington's (20 repeats). The patient asks about a "gray area" in testing and whether the result in certain.

 

What do you say?

answer
some people have an intermediate number of repeats (mid-30s) but for someone with 20 repeats the test is certain.
question

You are treating a case of erythroblastosis fetalis, a disease of the fetus in pregnancy. This is most often caused by isoimmune reaction to the D antigen, which is one of the antigens responsible for the Rh blood group. Abs developed by the Rh- mother "attack" an Rh+ fetus's RBCs leading to hemolysis. You want to quickly counsel the expecting couple about the likelihood the offspring will have another Rh+ fetus. The antigen is inherited in autosomal domianant fashion so you know the mother is

homozygous for the genes that make her Rh-. The father knows he is Rh+ so you able to advise them that on avg?

 

AND

 

You ask the father if he has previously fathered an Rh- child and he says YES you are able to advise that on avg?

 

AND

 

if the father says that has  has fathered an Rh- child and he instead says NO you are able to advise that on avg?

answer

the info given you can't determine the likelihood of the disease for their future offspring

 

the info given you can't determine the likelihood of the disease for their future offspring

 

50% of their offspring will suffer from the disease

 

question

autosomal recessive homozygote

 

male and female

 

which get disease?

answer
female and male
question

autosomal recessive heterozygote

 

male and female

 

which get disease?

answer
neither
question

autosomal dominant homozygote

 

male and female

 

which get disease?

answer
both
question

autosomal dominant heterozygote

 

male and female

 

which get disease?

answer
both
question
x-linked recessive hemizygous
answer

male

 

question

x-linked recessive heterozygote

 

male and female

 

which get disease?

answer
neither
question

x-linked recessive homozygote

 

male and female

 

which get disease?

answer
female
question

Mitochondrial, only father has disease

 

male and female

 

which get disease?

answer
neither
question

Mitochondrial, only mother has disease

 

male and female

 

which get disease?

answer
Both
question
What are some ways DNA is obtained from children and adults?
answer

blood

 

saliva

 

cheek swabs

question
3 forms of prenatal diagnosis of inherited disease that utilized together cover most of period between 10 weeks of gestation through birth and rate of fetal loss associated w/ each?
answer

chorionic villus sampling (CVS) - 0.5-1.0% loss

 

ultrasound - 0% loss

 

cordocentesis- 1-2% loss

question
What does preimplantation diagnosis of in vitro eggs allow?
answer
embryo selection
question

How many inherited diseases does FL screen for?

 

What do these diseases have in common that makes them a good idea to screen for?

 

What instrument made possible the recent expansion in the number of diseases screened in FL and does it analyze sequences or metabolites?

answer

35 diseases screened in FL

 

cause early damage and effective txt exists

 

tandem mass spectrometry-analyzes metabolites

question
Advantages of screening for genetic diseases by DNA sequencing
answer

may catch a patient gives a false - by another method

 

easier, less expensive to do in quantity than biochem assays

 

heritage and fam history of person gives info about what diseases and mutations to look for

 

it is predictive (before symptom onset)

question
Disadvantages of screening by DNA sequencing
answer

false negatives due to gene mutation being in unexpected location in gene

 

limited coverage of test - only test for specific disease, might miss others

 

may have added expenses due to patented genes

question

% frequency of two most often occuring mutations in CTFR genes

 

Any high frequency mutations in familial hypercholesterimia genes?

answer

70% and 2.5%

 

no, high freq mutations in FH genes

question
Gene defect that resulted in fava beans causing health problems in Greece and primaquine causing health problems in WW2
answer
hemolytic anemia
question

Knowledge of person's VKORC1 and CYP2C9 seq can help you decide what about a patient?

 

What other seq can be screened?

answer

drug dosage and type

 

P450 screened also

 

 

question
Pharmacogenomics
answer
use sequence info to make decisions about a drug
question
A 27 y/o patient's father has been diagnosed with Huntington disease. It would be important to:
answer
tell the patient there is a test involving DNA seq to show if he will suffer from Huntington disease later in life
question
Is Cushing syndrome characterized as a cancer b/c it involves overgrowth of cells (a tumor) in the adrenal gland that produces cortisol?
answer
No, it is not metastatic
question
What can be involved in genesis of cancer and which always involved?
answer

bacteria

 

viruses

 

inherited predispositions

 

gene defects - always involved

 

enviro causes

 

question
cell cycle genes
answer
Rb and p53
question
growth signal transduction genes
answer
ras, HER2, PDGF, EGF
question
DNA repair genes
answer

hMLH1

 

hMSH2

question
BRCA-1
answer
anti-oncogene
question
Why can hEGFR be considered a protooncogene and how might become an oncogene?
answer

protooncogene b/c it is a growth-stimulating gene

 

can become oncogene if its activity starts to result in uncontrolled growth

 

 

question

Gene A loses activity w/ certain mutation.

 

Is the normal gene a tumor suppressor, oncogne, anti-oncogne, or proto-oncogene?

answer
tumor suppressor and anti-oncogene for both normal and mutant genes
question
characteristics of matrix metalloproteinases and involved in what cancerous process
answer

protein/enzymes that require a metal (Zn or Ca) ion to break down proteins in ECM of cell

 

involved in metastasis

question
Tumorigenic cells for cancer therapy
answer

only some cells in tumor can generate new tumor

 

if can treat or cut out those cells, then localize tumor and control metastasis

question
Unique Characteristic of PARs
answer
proteolytically remove N-terminus of receptor itself and new N-terminus is the ligand that activates receptor
question
Kd
answer

[ligand] for 1/2 max occupancy of receptors

 

measure affinity of ligand for receptor

question
EC50
answer

[ligand] for 1/2 max response

 

effectiveness in eliciting cellular response

question
largest superfamily of receptors
answer
GPCRs
question
What family of receptors facilitates addiction to tobacco?
answer
ionotropic nicotinic Ach-R
question
Differences and Similarities in Intracellular Receptors
answer

some reside in cytoplasm until encounter ligands-glucocorticoid and aldosterone-Rs

 

most reside full time in nucleus

 

receptor ligand complex acts on nucleus by binds to DNA and affecting expression (turn on/off expression)

question
concentration of albumin in serum
answer
4 g/dL
question
4 functions of plasma albumin
answer

fatty acid transport

 

bilirubin transport

 

transport of steroid hormones

 

transport of sulta drugs, penicillin, aspirin

question
Plasma protein degraded randomly at a rate of 100%/day. What is biological half life?
answer
0.693 days
question

most abundant alpha-1 globulin?

 

Function?

 

Clinical result of its absence?

answer

alpha-1 antiprotease

 

protease inhibitor on compounds such as elastase and collagenase

 

prevents proteolysis in lungs

 

lung loses ability to recoil after inspiration leading to emphysema and respiratory failure

question
organ albumin is synthesized in
answer
liver
question
major class of proteins NOT synthesized in liver
answer
immunoglobulins
question
most abundant of plasma proteins
answer
albumin
question
how are fatty acids transported in plasma
answer
bound to albumin
question
major fetal plasma protein
answer
alpha-1 fetoglobulin
question
plasma protein that binds and transports iron
answer
transferrin
question
plasma protein that binds and transports cortisol
answer

cortisol-binding globulin (alpha-1 globulin)

 

 

question
plasma protein that binds and transports vitamin A derivitives
answer
retinol-binding protein (alpha-1 globulin)
question
plasma protein that binds and transports testosterone
answer

sex hormone binding globulin (SHBG)

 

beta-globulin

question
plasma protein that binds and transports bilirubin
answer
albumin
question
What ahppens to free hemoglobin in plasma?
answer
degraded by reticulothelial cells
question
What would happen to hemoglobin in plasma if haptoglobin were absent?
answer

iron would be lost due to Hb breakdown.

 

Hb is lost through the kidney and excreted in urine.

question
blue protein and what is its function
answer

ceruloplasmin

 

blue b/c of copper

 

oxidize Fe 2+ Fe 3+ in plasma

 

low levels found in Wilson's disease

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