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Definitions |
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RNA
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ribonucleic acid
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melting
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denaturation of DNA
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Multiple Alleles: AB
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IAIB
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Blastomere -->
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morula (16 cels)
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PACHYNEMA
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crossing over occurs, increasing genetic variability; synaptonemal complex disassembled
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PACHYNEMA
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prophase I
crossing over
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Terminator
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signals the end of transcription
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DNA
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(deoxyribonucleic acid)- a double chain of linked nucleotides; the fundamental substance of which genes are composed
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Lipid hormone examples
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estrogen, progestin, testosterone
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Monosomy
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(2n-1)usually lehtal in animals unless chromosome involved is a: 1)very small autosome 2)sex chromosome [XO, but YO lethal]
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Tx: avoid dairy products
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Classic Galactosemia
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Production of multiple, often seemingly unrelated, phenotypic effects by one gene
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Pleiotropy
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Recombinants
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an offspring whose phenotype differs from that of the parents
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Which type of balanced rearrangement is described as exchange of segments between 2 nonhomologous chromosomes?
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Translocation
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pseudodominance
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homozygous for an autosomal recessive disorder mates with heterozygous equalling 50% chance of disease
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DAZ
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AZFc encodes for ___(deleted in azoospermia
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• PR
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– controls large operon encoding proteins necessary fpr assembly of Phage coat, packaging of DNA, and lysis of bacterial cell.
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What is the key transcriptional regulator for blood cells?
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GATA-1
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Trisomy
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-1 extra chromosome-homologous pair + 1 extra chromosome = 3-three copies of a chromosome
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Genotype
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(1) Genetic constitution of an individual.
(2) Specific alleles present at specific loci.
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Complete linkage describes the inheritance patterns for 2 genes on the same chromosome when the observed frequency for crossover between the loci is zero.
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complete linkage.
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What is anticipation
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severity worsens by generation
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lysis
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the dissolution or destruction of cells by lysins.
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Sickle-Cell Anemia
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A genetic disorder leading to misshaped RBCs. Symptoms = low O2 , joint pain, thrombosis, anemia, fever
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Does Angelman syndrome come from the mother or the father?
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mother
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autosomal dominant pedigree
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characterized by vertical transmission of the disease phenotype, a lack of skipped generations, and roughly equal numbers of affected males and females. Father-to-son transmission may be observed
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119. What is the recommendation for someone whose family member has a dx of colon cancer?
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Subtotal colectomy
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Xp
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Most genes on the inactive chromosome are transcriptionaly silent (10-15% can still be expressed and are usually located on ___
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Repressors
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Bind to DNA and inhibit transcription – Negative control
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propositus
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in a human pedigree, the individual who first came to the attention of the geneticist
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What is a consequence of progenitor or blast cells blood cell not being properly regulated?
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Leukemia
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structure of the animal cell that houses genetic material, DNA
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nucleus
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In absence of any male chromosomes during development, all you get is _____.
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ICMs
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What tweaks the protein into specific shape to bind to DNA and chooses which genes are read?
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homeodomain
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Transition Mutation
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a mutation in which a purine (A/G)– pyrimidine (C/T) base pair replaces a base pair in the same purine – pyrimidine relationship
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Expressivity
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The extent to which allele is expressed at the phenotypic level (affected by genetic background, developmental noise, and/or environment).
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ALLELE
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an alternative form of a specific gene
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Generally a cross involving a homozygous recessive individual. When a single trait is being studies, a test cross is a cross between an individual with the dominant phenotype but of unknown genotype (homozygous or heterozygous) with a homozygous recessive
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test cross
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What inhibits Cyclin D (cell cycle kinases)?
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p16INK4
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dominant allele
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the allele that is fully expressed.
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Mendel used _______ to pollinate his plants
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cross-pollination
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euchromatin
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the part of a chromosome that condenses maximally during metaphase and contains most of the genetically active material.
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Homozygous
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having the same allele at the same locus on both members of a pair of homologous chromosomes. An individual may be homozygous dominant (TT) or homozygous recessive (tt).
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During meiosis...
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the segregation of one pair of homologous chromosomes occurs independently of the segregation of another pair.
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What genetic condition is most common in males and is described as congenital absence of parasympathetic ganglion cells in the colon?
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Hirschprung Dz
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unit inheritance
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parental phenotypes do not blend in offspring
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This has normal and abnormal cell lines within the cells of the body, cannot be transmitted to offspring unless present in germline?
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Somatic mosaicism
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dihydropteridine reductase
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BH4 is recycled by the enzyme
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Gene regulation
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– necessary to ensure (1) expression of genes in an accurate pattern during development (2) differences between distinct cell types. Influences = regulatory transcription factors, compaction level of chromatin during transcription, DNA methylation (inhibits), Durign RNA processing: Alternative splicing, RNA editing. During Translation: Small RNAs (miRNA) silence translation of mRNA. Phosporylation of TFs, Protein binding to 5’ end Posttranslational: feedback inhibition, covalent modifications
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What is RNA editing?
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2 forms of apo-Bliver: apo-B100intesting: apo-B48 b/c has UAA (a stop codon) instead of CAAposttranscriptional editingso you get a shorter version in the gut.
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teratoma
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a tumor composed of a chaotic array of different tissue types
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selected marker
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a genetic mutation that allows growth in selective medium
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Independent assortment
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The alleles of genes on different chromosomes segregate (or assort) independently of each other
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Homolog
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A gene related to a second gene (common ancestral DNA sequence).
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Mosaicism
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A mutation affects only some cells in the body with a variable phenotype
osteogenesis imperfecta Type II (lethal autosomal dominate trait)
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Gene Therapy
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direct transfer of genes to treat disease
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Each nucleotide belongs to how many codons?
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Just one
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What diseases show mitochondrial inheritance
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mitochondrial myopathies, leber's hereditary optic neuropathy (acute loss of central vision)
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complementation test
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- recessive mutations
- to cross two homozygous mutant lines to produce a heterozygote; if the heterozygote is wild type, then the two mutations must have been in different genes --- they complemented each other
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law of segregation
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the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.
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Law of Independent Assortment
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pairs of alleles are inherited independently
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Punnett Squares
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When the genotypes of the parents are known, a punnett square allows you to determine the ratios of __________ genotypes or offspring (not actual ratios).
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Cause of breast cancer
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BRCA1 and BRCA2 mutations. these protein products repair radiation incuded breaks, a post replication repair process
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Clinical manifestations of 22q11 deletion?
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Mild craniofacial abnormalities, slow development, palatal problems, mental retardation, heart defects
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IDL (VLDL remnants)
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picks up cholesterol from HDL to become LDL. Picked up by liver; apoprotein E; uptake by liver
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Give 2 common mutations
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1) deamination of C (methylated)2) depurination (AP sites) hot spots
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epiblast gives rise to ____.
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all tissues of the body
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isochromosomes
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Mirror image chromosomes. 2 p arm or 2 q arms joined at the centromere
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X-linked recessive inheritance:
Pedigree characteristics?
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Females: 2 X chromosomes
Males: 1 X chromosome (need only one 'recessive' mutation to produce the recessive phenotype.
(1) Incidence is MUCH higher in males than females
(2) Trait is expressed in hemizygous males or homozygous females
(3) Heterozygous females are USUALLY unaffected (may express trait due to skewed X-inactivation)
(4) All daughters of affected males are carriers
(5) Sons of a carrier female have a 50% risk of being affected
(6) Typical pedigree shows only males affected with 'skipped' generations
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2 X oocytes fertilized by 1 y sperm
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Klinefelter Syndrome
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Define characteristics of Alkaptonuria
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rare autosomal recessive; urine turns black with exposure to air
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second filial generation (F2)
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the immediate progeny of mating between members of the F1 generation
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incomplete dominance
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the appearance in a heterozygote of a trait that is intermediate between either of the trait's homozygous phenotypes.
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Which diagnostic test for down syndrome has the lowest risk? The highest risk?
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Lowest risk = AmniocentesisHighest risk = Percutaneous Umbilical Blood Sampling (PUBS)
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What is somatic cell hybridization, and how is it used to figure out which chromosome a gene is on?
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Somatic cell hybridization or radiation hybrids are a rodent cell line that carries a small pierce of the genome of another organism, like that of a human. Irradiating human cells with X rays to cause the DNA to break randomly producing these pieces. The higher the dosage of X-rays the smaller the pieces of DNA. The irradiation kills the human cells but the fragments can be rescued by fusing them with the rodent cells. Each piece of human DNA is usually a few mega base pairs long. The human DNA in the RH is analyzed for the genetic markers it carries. The basic idea behind RH mapping is: the closer two markers are together, the better chance they have of being on the same DNA piece and therefore ending up in the same RH. Both gene and DNA markers can be used in RH mapping.
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What is incomplete dominance?
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when an intermediate for a trait exists between homozygous and heterozygous phenotypes
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housekeeping genes
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a gene that is experessed at the same level in virtually all cells and whose product participates in basic metabolic processes
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What are some examples of secreted ligand genes?
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Fibroblast Growth Factor (FGF)
Hedgehog Family, e.g. sonic headgehog (shh)
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Explain the splicing mechanism
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a) binding of snRNPs to consensus sites, via base pairing
b) assembly of spliceosomes brings players into appropriate position
c)endonucleolytic attack (formation of lariat loop structure)
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Novel property mutation
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A mutation that confers a new porperty on the proein
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Other screening for BRCA1/2 carriers:
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colonoscopy @ 50 (every 3-5 years), pancreatic screening, women: annual pap starting @ 18, men: annual PSA and DRE @ 40-45
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What is xyy?
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It has no name. Male may be taller and/or have minor behavioral disorders?
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Describe Rett Syndrome
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Brought on by a mutation that leads to overexpression of certain genes. The MeCP2 gene is dysfunctional and not able to recognize its target of methylated cytosene and then unable to bind HDAC, which would suppress the gene.
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In transcription, what do genes do?
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a gene provides information for the sysnthesis of mRNA
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What are the two major mechanisms by which cell identity is established (determination)?
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1. Asymmetric Division: Inheritance of cytoplasmic determinant, thus sister cells are born different 2. Symmetric division: sister cells become different due to influences acting on them
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Why are genes split (5 reasons)?
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1. make multiple proteins from one gene (ex. immunoglobin)
2. evolutionary combinatories (evolution takes exons that work and recombine them to make new things)
3. proteome is greater than genome
4. makes tissues more specific (ex. heart)
5. back up proteins
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Name 2 forces that hold the double helix together.
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1) H bonds2) pi-electron interactions between the bases (base stacking)
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Role of IF2 in prokaryotic translation initiation and final steps
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IF2 binds first aminoacyl-tRNA to the 30S subunit at the P-site, then first codon is AUG and IF3 dissociates, then 50S subunits joins complex--done with initiation, IF1 and IF2 dossociate
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Provide an example of an X-linked disorder
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Hemophilia A - Factor VIII for blood clotting found on long arm of X chromosome. This protein is absent in affected persons and disrupts blood clotting cascade
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What tissues does the mesoderm give rise to?
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it splits into 2 linings and forms the muscles, bone, and cardiovascular system
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