Topic 3: Genetics

Outline a possible cause of Down syndrome. (4)
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Terms in this set (15)
Explain how males inherit hemophilia and how females become carriers for the condition(8)- hemophilia is a recessive trait - sex linked - gene is on X chromosome - Males inherit X chromosome from their mother - Males have only one copy so recessive trait is not masked - 50% of hemophilia - Carrier is heterozygous for the gene - females inherit X chromosome from father and one from mother - affected males have carrier daughters - hemophilia could inherit from either parentExplain the use of karyoptying in human genetics(8)- karyotype is a number and image of chromosomes in a cell - cells collected from chorionic villus - identify gender -Male is XY and female is XX - used identify non-disjunction and chromosome mutations - down syndrome due to extra chromosome 21 - may lead to decision to abort the fetus - prepare for consequences of abnormaility in offspringOutline the outcomes of the human genome project(4)- complete human DNA sequence - identification of all human genes - discover protein structures - find evidence for ancestorsDiscuss the role of gene and chromosomes in determining individual and shared character features of the member of a species(7)- genes have multiple alleles - alleles can be dominant or recessive - all members of a species have shared genes - all human have 46 chromosomes - some individuals have extra chromosome - X and Y determine the gender of individualExplain how meiosis results in an effectively infinite genetic variety in gametes (8)- 1 chromosome from mother and 1 from father - homologous chromosome pair in prophase I - crossing over formation in prophase I - recombination of linked genes - random orientation in metaphase I - independent assortment of chromosomes - 4 genetical different nuclei