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Biochemistry Genetics
KYCOM Block 1
204
Biochemistry
Graduate
09/12/2012

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Term
gene
Definition
basic unit of inheritence
Term
locus
Definition
location of a gene on a chromosome
Term
allele
Definition
alternative form of a gene at a locus
Term
genotype
Definition
genetic constitution of a person
Term
phenotype
Definition
observed expression of a genotype
Term
homozygous
Definition
identical allels on each locus of a chromosome pair
Term
heterozygos
Definition
different allels on each locus of a chromosome pair
Term
dominent
Definition
condition in homozygotes and heteroxygotes where only one copy of the gene is needed for the phenotype
Term
recessive
Definition
condition in homozygotes and heteroxygotes where two copies of the gene are needed for the phenotype
Term
autosome
Definition
non sex chromosome
Term
how many autosomes do we have
Definition
22
Term
sex chrommosome
Definition
X or Y chromosome
Term
diploid
Definition
2 copies of each chromosome
Term
haploid
Definition
1 copy of each chromosome
Term
somatic cell
Definition
body cell
Term
gamate
Definition
sex cell, haploid egg or sperm
Term
single gene disorder
Definition
single gene mutated, transmitted in simple patterns
Term
what are the types of single gene disorders
Definition
autosomal, recessive, X linked
Term
chromosome abnormality
Definition
deviation in number of chromosomes
Term
structural chromosome abnormality
Definition
more, less, or wrong chromosome info
Term
multifactoral traits
Definition
multiple genes and non-genetic (enivormental) influences
Term
what shape and color is an asympatmatic male
Definition
white square
Term
what shape and color is an asymptamatic female
Definition
white circle
Term
what shape and color is an symptamatic male
Definition
black square
Term
what shape and color is an symptamatic female
Definition
black circle
Term
what shape and color is an dead male
Definition
square with line through it
Term
what shape and color is an dead female
Definition
circle with line through it
Term
what shape shows two are mating
Definition
line between circle and square
Term
what shape shows two related people are mating
Definition
2 lines between circle and square
Term
what shape shoes dizygotic twins
Definition
single line that branches from parents that splits to the two twins
Term
what shape shows monozygotic twins
Definition
triangle with points being parents and two kids
Term
how can you tell by a pedigree that a disease is autosomal dominent
Definition
affected person in every generation, always one affected parent, affects either sex, has male to male transmission
Term
what proteins are associated with autosomal dominate disorders
Definition
non-catalytic
Term
what diseases are autosomal dominate
Definition
familial hypercholsterlemia, huntingtons, myotonic dystrophy, neurofibromastosis type 1, osteogenesis imperfecta, marfans syndrome
Term
what is the recurrance risk
Definition
probability of disease being passed to offspring with each reproductive event not affecting the occurance of another in the data
Term
when determining recurrance risk in autosomal dominent disorders what does an upper case letter mean
Definition
dominent allele (nothing to do with mutant or not)
Term
when determining recurrance risk in autosomal dominent disorders what does an lower case letter mean
Definition
recessive allele (nothing to do with mutant or not)
Term
what is the most common autosomal dominant cross, what is the percentage of having affected children
Definition
aa x Aa, 50% affected
Term
in a pedigree, what trends show it is an autosomal recessive disorder
Definition
affected person normally has unaffected parents, either sex affected, both parents are at least carriers, male to male transmission, skipping of generations
Term
what proteins are involved in autosomal recessive disorders
Definition
catalytic
Term
what are some autosomal recessive disorders
Definition
sickle cell anemia, cystic fibrosis, pku, tay-sacs
Term
what familial situation usually causes autosomal recessive disorders
Definition
incestous
Term
what type of genetic cross is commonly involved in autosomal recessive diseaes, what percent of the children are affected
Definition
Aa x Aa giving a 25% chance of disease
Term
when doing a cross for chance of inheritence with an autosomal recessive disorder, what does a lower case letter signify
Definition
mutant allele
Term
what are the two categories of diseases associated with the X gene
Definition
x-linked dominent and x-linked (recessive)
Term
what type of genetic disease is fragile x
Definition
it is considered to be x-dominent sometimes and x-linked others
Term
who is affected by x linked disorders
Definition
only or mostly males
Term
in a pedigree, how can you tell a disorder is x linked
Definition
usually unaffected parents, male inherits diseased allele from mom, no male to male transmission
Term
what are some x-linked diseases
Definition
duchene and becker muscular dystrophy, lesh-nyhan syndrome, glucose-6-phosphate dehydrogenase deficiency, hemophilia A and B, menches
Term
what is the most common genetic cross involved in x-linked diseases, what percent of children will be affected
Definition
XY x Xx, 25%
Term
what does mitochondrial DNA encode for
Definition
13 proteins, 2 rRNA, 22 tRNA
Term
on a pedigree, how can you tell if a disorder is mitochondrial
Definition
affected female affects all children, affected male affects none of the children, males and females affected,
Term
what diseases are due to mitochondrial inheritance
Definition
leber's hereditary optic neuropathy, neuropathys, myopaths, cardiomyopaths
Term
how do you calculate the risk of recurrance in mitochondrial diseases
Definition
you don't it does not follow mendilian genetics
Term
what are the symptoms of leber's hereditary optic neuropathy
Definition
blindness, rapid, irreversable, begins in central field, around age 30, optic atrophy
Term
what is wrong with the proteins in osteogenesis imperfecta
Definition
defect in structural proteins
Term
what diseases have a defecit in regulatory proteins
Definition
familial hypercholsterloemia, myotonic dystrophy
Term
what is a gain of function disorder
Definition
normal protein becomes too toxic
Term
what disease causes a gain in protein function, what does it affect
Definition
huntington disease causes toxic effects to neurons
Term
why type of inheritence is neurofibromatosis type 1
Definition
autosomal dominent
Term
what is mutated in neurofibromatosis type 1
Definition
regulatory protein involved in controlling the cell cycle
Term
what are the symptoms of neurofibromatosis type 1
Definition
cafe-au-lair spots, multiple neurofibromas, axillary freckling, lisch nodules in eye, variable expression
Term
what type of inheritance is marfans syndrome
Definition
autosomal dominent
Term
in marfan syndrome what is mutated, in what major areas is it located
Definition
fibrillin mutation, ECM and connective tissue
Term
what are the symptoms of marfan syndrome
Definition
thin long limbs, long fingers, hypermobile joints, myopia, detached lens, aortic aneurysm
Term
what is pleiotropy
Definition
1 mutation affects multiple organ systems, common
Term
what disease is an example of pleiotropy
Definition
marfan syndrome
Term
what type of inheritance is thalassemia
Definition
autosomal recessive
Term
what gene is affected in alpha-thalessemia, what is the result
Definition
insufficient synthesis of alpha chain of hemaglobin, beta globin acclumulates
Term
what gene is affected in beta-thalessemia
Definition
insufficient synthesis of beta chain of hemaglobin, alpha chain accumulates
Term
where in the world are thalassemia diseases common
Definition
mediterian sea, africa, southeast asia
Term
describe the globin content in a normal hemaglobin
Definition
2 beta globin from 2 normal genes make 2 beta chains, 4 alpha globin from 2 copies of 2 adjacent genes make 2 alpha chains
Term
what chromosome is alpha globin on
Definition
16
Term
what chromosome is beta globin on
Definition
11
Term
so if there are more alpha globin genes and less beta globin why isnt there always more alpha globin
Definition
the body accounts for this and we still get equal production
Term
describe the globin content of a fetal hemaglobin
Definition
2 gamma chains and 2 alpha chains
Term
what makes fetal hemaglobin functionally different from adult
Definition
it has a higher affinity for oxygen so it can pull oxygen from the mother;s hemaglobin
Term
when does fetal hemaglobin go away, what replaces it
Definition
from 6 mo - 2 yrs old it decreases and is replaced by beta globin
Term
when someone has beta thalasemia, they have a decrease in beta Hb and increase in alpha Hb, why can't they use use 4 alpha Hb and be fine
Definition
a Hb with 4 alpha Hb chains is insoluble and percipitates and is removed by the spleen and other blood cleaning organs due to 'damage'
Term
what is hemolytic anemia
Definition
anemia due to thalasemia
Term
what does it mean when said that beta-thalasemia has compounded anemia
Definition
beta globin is decreased giving anemia, and the 4 alpha globin Hb that took its place are removed giving further anermia
Term
describe the genes of a beta thalasemia carrier
Definition
1 normal copy and 1 mutated
Term
describe the genes of a person affected with beta thalassemia
Definition
2 mutated copies of the gene with various intensities B0 or B+ and combinations of these intensities
Term
what is a B0 (beta o) mutation
Definition
total absence of the functional B globin in that copy of the gene
Term
what is a B+ (beta +) mutation
Definition
leads to reduct beta globin but it is still normal
Term
what may be some of the reasons for a beta + mutation
Definition
may be a problem with the promoter, not getting sufficient promotion of transcriptioon but do get some
Term
what are the symptoms of thalassemia minor
Definition
usually asymptamatic of have mild anemia which may be mistaken for Fe deficiency anemia.
Term
how do you diagnose thalassemia minor
Definition
hemaglobin electrophoresis or blood work
Term
describe the genes of someone with beta thalassemia minor
Definition
carrier, one affected gene
Term
what are the symptoms of beta thalassemia major
Definition
severly reduced or no Hb production, severe anemia, hepatosplenomegaly, skeletal deformities especially in face and scull, bone marrow expansion, increased systemic Fe accumulates in liver and heart
Term
why is beta thalassemia not seen in babies
Definition
because they dont use beta globin until 6 mo old, they use gamma
Term
why is there hepatosplenomegaly in b-thalassemia
Definition
because the liver and spleen are trying to make new RBC and are getting rid of so many that they swell
Term
what does someone with b-thalassemia get skeletal and face deformities
Definition
because the bone marrow swells due to trying to make so many RBC
Term
how do you treat thalassemia major
Definition
regulat blood transfusions (every 2-4 weeks) combined with Fe chelation therapy, bone marrow transplants, potential gene therapy
Term
what are the symptoms and treatment of thalassemia intermedia
Definition
vary a lot, defined on clinical symptoms, treat with occasional blood transfusions
Term
what is gamma-globin synthesis continued into adulthood
Definition
turning the gene on could kill of b-thalasemia but people could have a hard time releasing O2, so less athletics, or could kill baby if pregant becase mom is stealing all the o2
Term
in regard to genes, what usually causes alpha-thalassemia
Definition
usually due to missing genes, classified by how many are missing
Term
in alpha-thalassemia, what is the phenotye of aa/aa, what are the symptoms
Definition
normal, none
Term
in alpha-thalassemia, what is the phenotye of -a/aa, what are the symptoms
Definition
silent carrier, none
Term
in alpha-thalassemia, what is the phenotye of --/aa, what are the symptoms
Definition
alpha-thalassemia trait, symptoms like thalassemia minor or are asymptmatic
Term
in alpha-thalassemia, what is the phenotye of -a/-a, what are the symptoms
Definition
alpha-thalassemia trait, symptoms like thalassemia minor or are asymptmatic
Term
in alpha-thalassemia, what is the phenotye of --/-a, what are the symptoms
Definition
hemaglobin H (HbH) disease, symptoms like thalassemia intermedia
Term
in alpha-thalassemia, what is the phenotye of --/--, what are the symptoms
Definition
hydrops fetalis, cannot support life because babies need alpha thalasemia unline beta
Term
what does hydrops fetalis mean
Definition
not specific to alpha-thalassemia, general term for death in utero with adema and swelling
Term
what happens in utero to the globin molecule when someone has alpha-thalassemia
Definition
gamma-globin forms tertameres (Hb Bart)
Term
what happens in utero when someone has alpha thalassemia with 1 copy of alpha globin
Definition
evuntally B-globin tetramere HbH forms
Term
what is the difference between HbH / HbBart and the beta-globin tetramere, what differences does this cause in the symptoms
Definition
they are less toxic which is why someone with any alpha globin at all has less severe symptoms that someone with b-thalassemia
Term
in regards to x-linked genes, what is the word that classifies males, what does this mean
Definition
hemizygos, they only need one copy of the gene to show symptoms wether it is dominent or recessive
Term
what gene is damaged in hemophellia a
Definition
blood clotting factor 8
Term
what gene is damaged in hemophelia b
Definition
blood clotting factor 9
Term
what type of mutations can cause hemophelia
Definition
deletions, nonsense, DNA inversions
Term
what cellular difference leads to difference severities in the symptoms of hemophelia
Definition
different mutations leading to different levels of the clotting factors in the body
Term
how can you tell the differences, in regard to symptoms, between hemophelia a and b
Definition
they have the same symptoms so you need to do a blood test or gene sequencing
Term
is hemophelia common or rare
Definition
common
Term
what type of hemophelia is more common
Definition
a
Term
what are the symptoms of hemophelia
Definition
prolonged bleeding, intercranial hemorraging, easy bruising, hemarthorsis
Term
what is hemophelia often mistaken for
Definition
a vitamin k deficiency
Term
what signs of hemophelia are often noticed at birth
Definition
too much bleeding during circmucision or cutting umbilical cord, intercranial hemmorage that can cause death
Term
what is hemarthorsis
Definition
bleeding into the joints
Term
what is the most frequent cause of death in people with hemophelia, why
Definition
AIDs, because treatment is factor replacement therapy and we used to use concentrated human plasma and during purification viruses are not eliminated
Term
why is AIDs less of a problem for hemophelia patients now
Definition
because we have better screening processes and are moving towards recombinent clotting factors and potential gene therapy
Term
what worries do people with hemophelia still have today when doing factor replacement therapy
Definition
some viruses not eliminated or tested for still, like hepititis
Term
in duchenne and becker muscular dystrophy what gene is affected
Definition
dystrophin gene in both diseases
Term
in duchenne and becker muscular dystrophy, they affected gene causes problems in cells of which areas
Definition
cytoplasm of muscle (all kinds) and some neuro tissue
Term
why does the gene for duchenne and becker muscular dystrophy have a higher mutation rate and get new mutations
Definition
because it is so large
Term
why type of mutation causes duchenne muscular dystrophy
Definition
frameshift insertion/deletion, also leads to a trunkated protein due to the potential of an early stop codon
Term
compare duchenne muscular dystrophy to myotonic muscular dystrophy in severity and frequency
Definition
duchenne muscular dystrophy is more common overall and more sever, myotonic is only the most common adult muscular dystrophy
Term
what are the symptoms of duchenne muscular dystrophy
Definition
apparent at 5 yrs, 10-12 years wheelchair, muscle atrophy, progressive, cognative impairment, death due to decreased respiratory function causing infections and decreased cardiac function around 20 yrs
Term
what type of deletion is becker muscular dystrophy
Definition
non-frameshift insertion/deletion
Term
what is the differences in the gene for becker muscular dystrophy vs duchenne
Definition
the gene makes a partially functional protein causing more mild symptoms
Term
what are the symptoms of becker muscular dystrophy
Definition
same general progression as duchenne but takes longer, onset is about 11 yrs and death 42
Term
what is the treatment for duchanne and becker muscular dystrophy
Definition
only therapy, gene therapy has show potential in animal models but the large gene makes things difficult
Term
what is another name of x-inactivation
Definition
lyonization
Term
why do we need x-inactivation
Definition
because gemales have 2 X and males only 1, so in theory, females would make double of all the proteins which they do not need
Term
what is x-inactivation
Definition
where one chromosome in females is shut off and not available for transcription
Term
what is the inactivated x chromosome called
Definition
barr body
Term
how are the genes of a barr body shut off
Definition
highly methlyated
Term
in what phase are the nuclei of a barr body when they are shut off
Definition
interphase
Term
at what stage does the cell shut off the barr body duriing the development
Definition
the 100 cell stage
Term
how does the cell decide which X chromosome to shut off during x-inactivation
Definition
it is random but after the 100 cells choose, all of their decendents will have the same one shut off
Term
what is ment when said that x-inactivation is incomplete
Definition
the entire barr body isn't shut off, about 10% is able to be transcribed
Term
what does incomplete x-inactivation explain
Definition
why some females show traits of mutant with only one copy mutated and one normal gene and why the symptoms are less severe (because they only have one X it makes it almost like they can get recessive x-linked diseases like males, but because they are females and do have normal genes it is less severe)
Term
why does it matter which x is shut off in each cell during x-inactivation
Definition
some come from mom and some come from dad and the one left on is randomly chosen, this gives potential for good genes to be deactivated and bad ones to stay active (or vice versa). unlucky choosing can produce more bad genes than good ones even though the female would normally be an asymptamatic carrier and they will then express the disease
Term
how can severe hemophelia occur in females
Definition
because unlucky shutting off of the barr body can make a carrier express more of the mutant genes, giving them the full symptoms anyways
Term
what type of mutation is fragile x
Definition
trinucletide repeat expansion in the 5' non coding region
Term
what are the symptoms of fragile x
Definition
long face, large mandible, large everted ears
Term
what is the most common know cause of autism
Definition
fragile x
Term
what is the most common inherited mental retardation
Definition
fragile x
Term
why can't fragile x be considered x-linked dominent
Definition
dominent should have 2x as many females as males affected and there are quite of bit of females affected but not more than males
Term
why can't fragile x be considered x-linked recessive
Definition
because recessive means that almost no females should be affected and quite a few are
Term
when a female gets fragile x, how do her symptoms differ
Definition
they are more variable and less severe
Term
how many fragile x mutations does a female with fragile x have, explain your answer
Definition
1 or 2. they can get symptoms with only one because of the barr body situation where it makes only one x chromosome anyways, or they can have two
Term
what type of x-linked disease is fragile x most likley to be in conclusion, why
Definition
x-linked recessive, because you can't say dominent/recesive when your only expressing one gene as it has seen to be the case in all males and most all females with fragile x
Term
What disorder type is delayed age of onset a symptom of
Definition
Single gene disorders
Term
What disorders have a delayed age of onset
Definition
Huntingtons, myotonic dystrophy
Term
What is locus heterogeneity
Definition
Same phenotype is caused by mutations at different loci
Term
What disease has locus heterogeneity, in regards to inheritance what does this cause
Definition
Elhers danlos syndrome, several inheritance patterns
Term
What types of instance can elhers danlos have
Definition
Autosomal dominant and recessive, x linked
Term
What is the mutation in elhers danlos autosomal dominant
Definition
Collagen gene
Term
What is the mutation in elhers danlos autosomal recessive, what process does this disrupt
Definition
Mutation in Lysol hydroxylase, processing collagen
Term
What is the mutation in elhers danlos x linked recessive, what does this cause
Definition
Mutation in copper binding protein gene on the x chromosome leading to reduced copper in serum (copper is involved in lysyloxidase which causes cross linking in collagen)
Term
how do all diseases start
Definition
with a new mutation
Term
what are the characteristics of a disease that in most cases comes from a new mutation
Definition
high mortality or decreased fertility
Term
what categories of disorders often come from a new mutation (dominent, recessive, autosomal, X)
Definition
autosomal dominent, x-linked recessive
Term
what disease did we talk about is an example of a new mutation, what inhertience model is it
Definition
duschenne muscular dystrophy, x-linked
Term
what is anticipation
Definition
most recent generations have earlier onset and more severity
Term
what mutation is associated with anticipation, how does the aspects of this mutation correlate with the definition of anticipation
Definition
trinucleotide repeats, more repeats means more severity, there are more repeats with each generation
Term
what diseases are and example of anticipation
Definition
myotonic dystrophy, huntington, fragile x
Term
what do we use to evaluate population genetics
Definition
hardy weinberg equlibrium
Term
what are the assuptions that make the hardy weinberg equlibrium possible
Definition
assume 2 alleles (p and q)
the frequency total is 100%: so p + q = 1
Term
how do you determine the frequency of the genotype qq
Definition
q squared
Term
how do you determine the frequency of the genotype pp
Definition
p squared
Term
how do you determine the frequency of the genotype pq
Definition
2pq
Term
what are the factors that affect genetic variation
Definition
mutations, natural selection, heterozygote advantage, genetic drift, gene flow
Term
how much do mutations affect the genetic variation
Definition
it is different in every population, in humans not that much
Term
what is natural selection
Definition
influce on gene frequency by selecting for survival or fertility making disease genes more rare
Term
what is fitness
Definition
natural selection for fertility
Term
which types of genes are exposed to selection more often
Definition
dominent
Term
why are recessive genes exposed to selection less often
Definition
because they are often hidden in the heterozygote
Term
what is the heterozygote advantage
Definition
when a heterozygote mutation is selected for because it prevents other, worse diseases
Term
what are examples of the heterozygote advantage
Definition
sickle cell helps milaria, thallesemia helps malaria, cystic fibrosis may help with typhoid fever, G6PD helps malaria
Term
why in sickle cell is the carrier not affected
Definition
because in the carrier the plasmodium survives poorly giving malaria resistance without too many side effects
Term
what is genetic drift
Definition
in populations with a finite small size rare genes are present because they founders had them and there wasn't much room for genetic variance
Term
what is another name fo genetic drift
Definition
founder effect
Term
what is a disease that is an example of the founder effect
Definition
ellis van cerveld
Term
what type of inheritence is ellis van cerveld
Definition
autosomal recessive
Term
what are the symptoms of ellis van cerveld
Definition
usually in old order amish communities, polydactyly (short limbed dwarfism)
Term
what gene is effected in ellis van cerveld
Definition
EVC gene
Term
what is gene flow
Definition
the exchange of genes amoug populations
Term
what is the cause of methemoglobinemia
Definition
elevated Met Hb in the blood which has oxidized Fe so it cannot pick up oxygen as well
Term
what are the symptoms of methemoglobinemia
Definition
blue skin, blood that upon introduction to air stays brown
Term
what happens to normal deoxygenated blood upon esposure to air
Definition
it immediatly reoxygenates and turns red
Term
what is another name for methemoglobinemia
Definition
chocolatecyanosis
Term
normal people do get met hb, why are they not blue
Definition
because normally the body makes enzymes to reduce it
Term
how can someone aquire methemoglobinemia
Definition
oxidative stress: drugs, antibiotics, thromethoprimcane, anaesthetics, compounds with nitrates
Term
why are infants under 6 mo more prone to methemoglobinemia, what should they stay away from because of this risk
Definition
they do not have adult levels of the enzymes that combat met hb yet, nitrates ingested in food / water can cause it
Term
what is defective in congenital methemoglobinemia
Definition
decreased NADH met hb reductace which normally reduces Fe so it can pick up oxygen, increased HbM and HbH. thee enzyme is active just not efficient
Term
what is another name for NADH met hb reductase
Definition
diaphorase I
Term
what are diseases with congenita methemoglobinemia
Definition
pyrivate kinase deficiency, G6PDH deficiency
Term
how is methemoglobinemia treated
Definition
methlyine blue, electron donor reduces Fe back to normal so it can pick up oxygen. gives blue pee
Term
what is the mutation in hippel lindau syndrome
Definition
nutation in tumor supressor,
Term
many times hippel lundeau is cause by what type of tumor
Definition
pheochromocytomas: tumors in the adrenal gland
Term
what symptoms does a pheochromocytomas cause, why
Definition
explosive temper, due to excessive production of adreniline
Term
what genetic trend is lynch syndrome and example of
Definition
the founder effect
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