Genetics quiz Flashcards

Terms Definitions
Morula-->
blastocyst
phenotype
physical characteristics
A
adenine, or adenosine
gene
a unit of heredity
DNA
deoxyribonucleic acid; ATGC
double stranded
deoxyribose sugar (found in nucleus and mitochondria)
thymine
Always pairs with adenine.
autosomes
nonsex chromosomes, the sex chromosomes are X and Y females have XX and males have XY
nondisjunction
the reason behind 'exceptional' red-eyed male progeny in Morgan's experiments with the white locus
Mesoderm
end of week 2
middle
muscle, connective tissue reproductive organs
Amelia
Lacking one or more limbs
Quantitative Genetics
Inheritance of continuous traits
dopamine
a catecholamine neurotransmitter in the central nervous system, retina, and sympathetic ganglia, acting within the brain to help regulate movement and emotion: its depletion may cause Parkinson's disease.
heterozgous
an individual with two different alleles for a particular trait. Hh
Risk of schizophrenia if first cousin?
6%
Result of environmental factors acting on a predisposing genetic background
LOAD
minisatellites
variable number tandem repeats 10-100 bp, 10^2, 10^3 copies; some VNTRs involved in disease with 30-40 different alleles are highly informative
• N protein
antiterminator. Binds to RNA polymerase and prevents transcriptional termination
correction
the production (possibly by excision and repair) of a properly paired nucleotide pair from a sequence of hybrid DNA that contains an illegitimate pair
Describe MCAD deficiency?
Multiple organ failureCerebral edemaLiver/kidney damageVomit and lethargy after fastingAdd glucose to IVLead to death by 2
Probabilty
The likelihood that a particular event will occur.
microRNA
new class of non-coding endogenous, small RNAs. important regulatory molecules. found in the introns of coding genes and introns and exons of non-coding transcripts
involved in differentiation, development and apoptosis
may be tumor suppressors and oncogenes
phenotypic frequency
relative proportion of individuals with each phenotype
Homozygous
Organisms that have two identical alleles
pyrimidine
a heterocyclic compound, C4H4N2, that is the basis of several important biochemical substances.
chromatids
the two identical parts of a chromosome present during mitosis
genetic recombination
new combination of genetic information in a gamete as a result of crossing over during prophase I of meiosis
What type of inheritance controls fragile-X?
X-linked recessive
Satellite repeats
are clustered together in certain chromosome locations, where they occur in tandem
What type of pattern in dwarfism?
Genetically heterogenous
maternal
CGG expansion in fragile X is usually
RNA splicing
the excision of introns from transcribed product. Can be done by group-1 inttron splicing, group 2 intron splicing, or by a spliceosome, Groud 1 and 2 self-splice, and does not req. aid of enzymes. RNA is its orn Ribozyme.
phosphodiester bonds
form the sugar-phosphate backbone of DNA
auxotroph
a strain of microorganisms that will proliferate only when the medium is supplemented with some specific substance not required by wild-type organisms
the prominent ratio in the F2 generation
3:1
These control expression of genes responsible for making anatomical structures
Hox genes
Describe the daughter cells of the trophoblast
syncytium
What is genetics?
The scientific study of heredity.\r\n
Penetrance
The proportion of individuals of a specific genotype who exhibit a specific phenotype (it is all-or-none). The mutation is penetrant if ANY sign or symptom of the trait is present.

(1) Often age-specific
(2) May be modified by other genetic factors or the environment
(3) Can be different in males & females
(4) Trait may appear to 'skip' a generation
Mendelian Traits: Autosomal Recessive Inheritance
Homozygotes express the trait
Horizontal pattern of transmission within a sibship.
Transmitted by both sexes
Offspring of carrier parents are at 25% risk
Functional genes are often involved
Ex. Sickle cell disease
Consanguinity is more common
When chromosome segments are sequenced to determine the order of nucleotides,
what type of map is produced?
Restriction map
RNA synthesis requires
DNA template
raw materials (RNA nucleotides)
transcription apparatus
What is imprinting
Phenotypic difference depending on whether gene is maternal or paternal in origin (prader-willi, angelman's)
synthetic lethals
two viable single mutants are intercrossed --> results in lethal double mutant

- 9:3:3 ratio (1 is the double mutant)
microtubules
a hollow cylindrical structure in the cytoplasm of most cells, involved in intracellular shape and transport.
multiple alleles
the existence of more than two alleles
Signal peptide region
Each polypeptide destined for the endomembrane system or for export has a specific signal peptide region at or near the leading end
How many triplets of a genetic code are there?
64
Premutation Range
a normal, but unstable number of repeats. 
when number of repeats falls int his range then they may or may not transmit to the next generation.  Normal individuals may carry the premutation and are unaffected, but their child may inherit the full mutation and be affected. 
Spontaneous mutations arise naturally during the course of DNA replication. Induced mutations are caused by outside agents collectively referred to as mutagens.
Spontaneous vs. induced mutations
These are "extra" pieces of DNA that do NOT appear in the mRNA and do NOT become part of the protein
Introns
cystic fibrosis
Most common fatal genetic disorder in white populationsAutosomal recessive inheritanceIncidence 1 in 2500Carrier frequency  1 in 25Gene implicated is CFTR  codes for a regulated chloride channel located in apical membrane of epithelial cells
Interference
Situation in which a crossover in one region of a chromosome affects the likelihood of a crossover in an adjacent region.
How many chromosomes are there in a human cell?
46
recombinant
an individual or cell with a genotype produced by recombination
diploid
a cell that contains both sets of homologous chromosomes (one set from each parent)
preformationism
we were pre-formed in the gamete as humans
DNA repair mechanisms
(1) Base excision repair (Single nucleotide damaged by hydrolysis, methylation or oxidation)
(2) Nucleotide excision repair (2-30 bases e.g. pyrimidine dimers)
(3) MisMatch repair (repairs mispaired bases)
(4) Non-homologous end joining (double strand breaks)
(5) Recombinational repair (homologous recombination during meiosis of double strand breaks)
polydactyly
An abnormality in which a person is born with more than the normal number of fingers or toes.
base substitutions resulting in a new stop codon
nonsense mutations
Expanding trinucleotide repeats
an increasing number of three-base units are inserted into a chromosomal region
one change at a position is changed back to the original
characters
Sickle cell anemia
human: chromosome 15 (Beta globin gene)

point mutation (A -> T) -- changes glutamate to a valine

- this mutation causes sicle cell anemia in homozygous form

(extreme pain, infections, chronic hemolytic anemia)
chimera
an organism composed of two or more genetically distinct tissues, as an organism that is partly male and partly female, or an artificially produced individual having tissues of several species.
DNA Replication
The process by which the DNA double helix unwinds and makes an exact copy of itself.
incomplete dominance
refers to the phenomenon in which a heterozygote shows an intermediate phenotypeex. TTxtt
Major components in the nucleus
Nucleoli, nuclear matrix, nuclear membrane, nucleoli, chromatin
Mosaic
a chimer; a tissure containing two or more genetically distinct cell types or an individual organism composed of such tissue
DMPK; 19
what is the Mutated gene in myotonic dystrophy?the Gene is located on Chromosome?
Week 10 of development
fully developed
fetus demands too much energy mom "kicks baby out"
What is the result of a hitch-hiking TDF?
XX males
What is a haploid?
Containing a single set of chromasomes; referring to an \"n\" cell.
Angelman Syndrome
deletion of prox arm of chromosome 15 from the mother. severe developmental delay, lack of speech, ataxia and behavioral uniqueness; frequent smiling, laughing, easily excitable, hypermotoric behavior
also if child inherits 2 copies of chromosome 15 from father and none from the mother
Drosophila melanogaster
The fruit fly, a favorite organism for genetic analysis.
Fewer than 1/1000 DNA lesions become a mutation, the majority of lesions___________
get repaired
ribosomal rna
a type of RNA, distinguished by its length and abundance, functioning in protein synthesis as a component of ribosomes.
X-linked recessive - characteristics
Incidence much higher in males and females
All daughters of affected males will be carriers
No male-to-male transmission
Sons of carrier females have 50% chance of being affected and 50% of being unaffected
Daughters of carrier females - 50% chance of being a carrier
1 X 10-6 ± 10^3
what is the average rate approximately mutations per locus per generation
What is a master gene?
these gene are key regulator transcription factors whose expression drive entire tissue and organ programs in development
Overview of genetic code (9)
9)genetic code is universal SINGLE CODING DICTIONARY used by most a)prokaryotic b)eukaryotic
RULE OF ADDITION
the probability of an event that can ovvur in two or more independent ways is the sum of the seperate probabilities of the different ways
Mismatch repair works how
If dna is not corrected by proofreading, replication errors can be corrected by mismatch repair ENZYMES
they detect unpaired loops and replace incorrect nucleotides
X or Y chromosomes; one pair in a normal somatic cell
Sex chromosomes
nucleic acid probe
what do you use to screen a genomic library
a)Polyploidy in animals and plants
rare in animals, common in plants (and important for agriculture)diploid-2ntriploid-3n(sterile)tetraploid-4npentaploid-5n(sterile)hexaploid-6n
Another name for the noncoding strand?
template strand, mRNA has to complement and be antiparallel
What clotting factor disorders are associated with hemophilia?
Hemophilia A and B are X-linked disorders of coagulation caused by mutations of F8 and F9 genes, F8 – deficiency/dysfunction of clotting factor VIII, F9 – deficiency/dysfunction of clotting factor IX
this was Hippocrates understanding of genetics-
little tiny adults were in every sperm
42) What was a key factor in the success of Mendel's experiments?
He started with self-pollinating purebread plants
What are 3 current problems with using HSCs as a cell replacement therapy?
1) not practical because it limited to a rare donor-derived cells… 2) donor cells may fuse to host cells so that transdifferentiation is only apparent… 3) trans-differentiation may require injury to the host cell to get stem cell activity
What holds DNA pol 3 to template so it can work as processing enzyme?
Beta clamp (or pcna)
What two types of tissues does the trophoblasts differentiate into?
Syncytium - multiple nuclei, lots of cytoplasm (no telophase occurs)
Chorion Membrane - cellular portion of fetal placenta
*18. Which of the following is false concerning dosage compensation in mammalian females?
The mechanism is similar to that in Dropsophila where expression of the X-linked genes in males is hyperactivated.
trait
a specific characteristic
LEPTONEMA
chromosomes condense
homologous chromosomes pair
LEPTONEMA
prophase I
Mutation
permanent alteration in DNA
lactose operon model
6 steps
ribosomes
cellular structures that assemble proteins according to instructions of the DNA
Disruption
Actual destruction of previously normal tissue
Introns
– non-coding, intervening sequences. Can be visualized by denaturing dsDNA and mixed with complementary mRNA. The 2 hybridize. If present, forms r-loops where introns are. Bound by specific sequences recognized by the spliceosome. Gives benefit of alternative splicing.
x-chromosome
A chromosome that becomes heterochromatic in human females.
Pleitropy
Multiple, often seemingly unrelated physical effects caused by a single genotype
the small evolutionary changes, typically occurring over short time spans; generally involving a small number of traits & minor genetic changes
migration
centromere
point of attachment of sister chromatids
 
 
Trisomy
A trisomy requires an extra chromosome; so a trisomic of species II for chromosome M would be 2N+1 (MMMNNOO).
Having three copies of a chromosome.
DNA microarray
multiplex technology used in molecularbiology and in medicine
1000 spots of oligonucleotides
male
Risk of mental retardation in grandchildren of normal transmitting ___ (i.e. who have premutation)
What's a processed pseudogene?
intermediate repetitive DNANONFUNCTIONAL COPIES OF A NORMAL GENEcontain mutations, are reverse transcribedusually still have the polyA signal (not normally encoded)
this geneticist studied inheritance using the garden pea
Gregor Mendel
alleles
Different forms of the same gene.(example: the gene for height in pea plants has two forms, T and t)
Exons
Rejoining segments that join together after the introns are excised in RNA processing
protease
A protein that digests other proteins.
Promoter Elements
regulatory element adjacent to transcription start site, vary by species
TATA box (usually closest to start site around 30 bp)
CAAT element (80 bp)
GC element (furthest upstream-helps to bind to RNA polymerase)
the failure 0f h0m0l0g0us chr0m0s0mes t0 pr0perly seperate
n0ndisjuncti0n
autosome
a chromosome not directly involved in determining sex.
Alleles
one of the alternatice DNA sequences of a gene.
Imprinting
Imprinted genes are reset in gametes to reflect new parent of origin
 
meiosis II
four haploid cells with chromosomes consisting of one chromatid; same phases and resembles mitosis
variable expressivity
differences in phenotype severity of brothers or sisters carrying the same anonychia allele
EDS VI
Mutations in lysyl hydroxylase cause this disease
Transformation
Conversion of a cell from one phenotype to another by the uptake of DNA from the environment.
Birth defects
often cause by something in environment
type of genetic analysis involving human genome, and alleles
Genotype analysis
sex chromosome
a chromosome whose presence or absence is correlated with the sex of the bearer; a chromosome that plays a role in sex determination
frequency of cotransduction
the proportion of transductants carrying a selected genetic marker that also carry a nonselected genetic marker
Genetic Mosaic
it contains tissues with distinct genotypes
antisense drugs
commplementary strands of portions of mRNA. drug binds to mRNA to inhibit transcription of protein

fomivirsen
euploid
cell has normal amount of chromosomes (23 or multiple of 23)
reverse genetics
Procedure in which mutations are deliberately produced in cloned genes and introduced back into cell or the germ line of an organism.
deletion
(1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene.
double heterozygote
two haplotypes on sister chromosomes, each with unique alleles, if in linkage equilibrium p(recombinant)=p(nonrecombinant)
All the chromosomes, except the sex chromosomes
Autosomal
crossing over
process where pieces of homologous chromosomes are exchanged
Linkage Map
Genetic map based on the frequencies of recombination between markers crossing over of homologous chromosomes
SYNAPSIS
the side by side pairing of homologous maternal and paternal chromosomes at the start of meiosis
What is the MC cause of dementia?
Alzheimer's dz
Genetic code
the combinations of mRNA codons that specify individual amino acids
Roughly 4x more common than recessive traits?
Dominant trait
Nonrandom mating
happens! Violated freq. in human pops. Wrt phenotypes: Assortative matin, Positive assortative mating, negative assortative mating. Wrt genotypes – inbreeding and outbreeding
mosaic
a chimera; a tissue containing two or more genetically distinct cell types, or an individual composed of such tissues
cruciform configuration
a region of DNA with palindromic sequences in both strands, so that each strand pairs with itself to form a helix extending sideways from the main helix
would you be able to see a translocation on a karyotype?
-no
What is a teratogen that pregnant women should avoid?
retinoic acid
Replication fork
In a replicating DNA molecule, the region in which the parental strands are separated and new strands are being synthesized
How would you describe a normal female karyotype?
A normal male?
-46XX
-46XY
Process of Lysosomal Action
-large molecule enters cell
-lysosome fuses with vesicle containing this large molecule
-molecule is broken down within this fused vesicle
-if lysosomes burst open, would attack cells
polypeptide chain
A polymer of amino acids linked together by peptide bonds.
10. Gene at one locus suppresses masks the effects of a gene at a different locus:
Epistasis
a plasmid that can integrate
Why are triploids sterile?
The dominant gene does not completely maske the effects of the recessive gene in the heterozygote.
Incomplete dominance
recessive
an allele in a heterozygote that does not affect the phenotype
Translation Termination
occurs when one of the three stop codons reaches the A site
What are the two most common unbalanced structural rearrangements of chromosomes?
Deletions & duplications
X-linked dominant traits
• All daughters of an affected male and a normal female are affected
1 million
the human genome has about how many EcoRi sites
messenger RNA (mRNA)
an RNA molecule transcribed from the DNA of a gene, and from which a protein is translated by the action of ribosomes
t/f all cells receive an = amnt of genetic material and cytoplasm in spermatogenesis
T
What happens when the notochord is removed?
no further development
missense mutation
new codon may code for a different amino acid
uracil
One of the four bases in RNA. Always pairs with adenine.
cyclin
Any of a number of proteins that help regulate the cell cycle and whose abundance rises and falls rhythmically, during the cell cycle.
genotypic ratio
ratio of the the genotypes that appear in the offspring
what do you perform a testcross with?
homozygous recessive individual
Nonsense mutations
change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein
What screening is done at 10-13 weeks gestation?
Chronic villus sampling
Clues of autosomal recessive (AR):
1) occurs in siblings, parents unaffected2) males = females3) parents of affected kid are carriers4) parents may be consanguinous5) recurrence risk for each sib in 25% (independent risk)
Bad signals cause mutations and can cause______?
SIM, segment identity mistakes
lysogenic cycle
does not lyse the cell. it becomes integrated into the bacterial genome in a harmless form. (provirus). lying dormant for one or more generations. It may stay indefinitely. it also can spontaneously or as a result of environmental factors enter a lytic cycle.
Possible amino acid replacements
What do DNA amino acid sequence comparisons tell us?
point mutation & it's types
an alteration in a single base pair
missense mutaion: a single base pair substitution resulting in a change in the amino acid coded for  by the codon. 
nonsense mtuation: results in a premature stop codon causing either an abnormally shaped protein with altered function or a protien that is very unstable.
autonomous replication sequence (ARS)
a segment of a DNA molecule necessary for the initiation of its replication; generally a site recognized and bound by the proteins of the replication system
what are some exs of diseases w/ autosomal dominant inheritance?
polycystic kidney disease
huntington disease
neurofibromatosis
marfan syndrome
familial hypercholesterolemia
myotonic dystrophy
achondroplasia
Note: some definitions are good at _______ and other definitions ________
stimulating theoretical biology; help to design experiments
null and missense glycine substitution
what are the two braod classes of mutations in OI
What does the trophoblast give rise to?
fetal placenta and syncytium which implants into endometrium
What are the three major patterns of inheritance?
Chromosomal, single gene and complex (multifactorial) inheritance
In what organism is Hox gene mutations seen very easily?
Why?
Drosophila, which have one chromosome with several Hox genes that go in order from head to tail development
What does CT mean in quantitative PCR?
CT is the point at which the fluorescent signal, ie, PCR product, is first detected.  (PCR cycle number vs. signal intensity on a graph).
When is the onset of Polycystic kidney disease?
Onset in childhood, but over 80% of pts have renal cysts by age 20
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