Block 2 Live Review - Genetics Review

A Review of Block 2 Live Review Q & A This review cannot cover everything but should give you a good idea of what to expect and the foundational content you should know for the exam. Answers will only become available AFTER the LIVE session has been held. A few points to cons...

A Review of Block 2 Live Review Q & A This review cannot cover everything but should give you a good idea of what to expect and the foundational content you should know for the exam. Answers will only become available AFTER the LIVE session has been held. A few points to consider… Because human genetics are actually far more complicated than monohybrid and dihybrid crosses estimate, the examples used on the exam will include plants, drosophila, generic organisms, or simplified humans Remember, inheritance questions can be simplified by using Punnett squares. If you get stuck, go back to the basics, and simply change the terms to letters. Don’t overthink the level 1-2 questions. If there is a blank, then the question is leaning closer to a DEFINE objective. If the question is shorter, it is meant to be a quick one that is based on a fact rather than something that should take a long time to work through. There is only so much that can be asked so remember that the goals are based on the skills we practiced and what we spent the most of our time discussing. Basic Genetics How many human chromosome are there and what are they? What does it mean if someone is Mosaic? What does it mean if someone is chimeric? After evaluating a small growth in the shoulder of a healthy 46,XX person, it is determined that the growth has a different karyotype of 47,XY+16. Only the cells within the growth are found to carry this different karyotype. What is the most probable cause of this different karyotype? Making Gametes What is the genotype and what are the possible gametes from an individual who is heterozygous for two unlinked traits A and B? What are the most probable gametes from an individual with the genotype AaBb linked in cis? What gametes would represent recombinant gametes from an individual who is heterozygous for genes linked in trans? Autosomal Heredity What are the expected genotypes and in what frequency for a monohybrid cross of true-breeding parents with two different phenotypes? What cross yields a 1:1:1:1 of 4 phenotypes all in equal frequencies? A cross between a short purple and a tall white yields all tall purple. If several generations of self-breeding before this experiment never caused this mixed phenotype what does this outcome tell you? Autosomal Heredity and Probabilities Aa x aa yields what probability of recessive offspring? AA x aa yields what probability of recessive offspring? Aa x Aa yields what phenotypic outcomes? The dihybrid cross is most commonly Autosomal Heredity and Probabilities The back or test cross for a monohybrid would be? Why is it necessary to do the test cross for evaluating independent assortment? If a gene is linked in trans, what do we expect in the phenotypes of the offspring following the testcross? Sex-linked Heredity Affected female crossed with an unaffected male for a recessive sex-linked trait has what probability of affected male offspring? Unaffected female crossed with an affected male for a dominant X-linked trait would have what percentage of affected males? Unaffected female crossed with an affected male for a recessive X-linked trait would have what probability of producing carrier females? Sex Determination All sex determination can be thought of as ________ because it involves changes in gene expression. Sex determination that involves changes in conditions such as temperature is ____________. Changes in the ratio of males to females expected can be caused by Heterogametic sexes are those with _________ and likely have genes for which they are __________. Meiosis and Recombination Order of meiotic prophase I At which stage would chromosomes exhibit the most force pushing them apart? What would enable two nonhomologous chromosomes align and exchange material? When does crossing-over begin? What is the bivalent and how is it different if there are 3 chromosomes? Meiosis How are meiotic errors different from mitotic ones? Proper segregation in meiosis I involves The two factors that lead to increased diversity in offspring are: Mitosis and Errors in Segregation Most likely cause of a trisomy during meiosis? Mitotic error that generates mosaicism found ONLY in the placenta is known as? What are the two issues with mosaicism in terms of human testing especially prenatally? Aneuploidies Considered only viable whole chromosome monosomy Most likely cause of early pregnancy loss What is worse in terms of autosomes: monosomy or trisomy? Why is there a phenotype associated with 47,XXY? Chromosome Structures Incorporation of what into the nucleosome promotes formation of a centromere AND what is it? What are NORs and where can they be found? In the most condensed form for duplicated chromosomes, _______ is needed to fully condense the chromosome while ______ holds sister chromatids together. TTAGGG repeats in humans are most likely to be found at Chromosome Structures When the sequence of TTAGGG in humans gets critically short, what happens? Lengthening or maintenance of telomeres should only occur in what cell types? Karyotyping Normal Male? Normal Female? Trisomy of chromosome 21? Karyotype of only known viable nonmosaic whole chromosome monosomy? Klinefelter Syndrome? Chromatin Histone deacetylase activity would be expected if transitioning from which type to chromatin? Chromatin remodeling using the Chromatin Remodeling Complex can ____. The addition of methyl groups is correlated with what? Histone 3 is expected to be trimethylated when the corresponding nucleosome is located within a region that is organized as what? Rapid demethylation of mono- or dimethylated histones, would do what? Structural Rearrangements Nonallelic recombination of sister chromatids would cause The larger the structural rearrangement in inversions and translocations _______. Interchromosomal exchanges occur between Structural Rearrangements Allelic exchanges within the inversion loop of a paracentric inversion cause? The centromere is expected within an inversion loop when the inversion is _________. The quadrivalent resolution with the best outcomes is ______ and it yields _______. Homologous centromeres will be found together under which segregation pattern? Imprinting If maternal imprinting of a differentially methylated region does NOT happen, then what would we expect in terms of gene activity? How does oogenesis ensure that only a maternal imprinting pattern is inherited? Prader-Willi and Angelman Maternal imprinting shuts off which genes for chromosome 15? Paternal gene deletion would cause which disease phenotype if the gene loss is of chromosome 15’s differentially methylated region? In addition to gene deletion, _________ can also cause manifestation of the diseases associated with chromosome 15 anomalies. X-inactivation The first step of X-inactivation is what? The second step of X-inactivation is what? What is unique about PAR1 and PAR2 in terms of X- inactivation? Non-mendelian Inheritance Mitochondrial genomes are replicated Human mitochondria are inherited Prescence of paternal mitochondria when maternal inheritance is expected is termed