BIOL 121 Study Questions Barkel Chapter 15 1 Terms chromosomes chromosomes Hemizygous males have one allele only one X chromosome Monosomic have only one copy of a particular chromosome type and have 2n 1 Trisomic have three copies of a particular chromosome type and have 2n 1 total Polyploid aberrations in the number of chromosome sets 4n 16n common in plants 3 The white eyed trait was thought to be mutant red eyes phenotype What is the normal condition 2 What organism did Morgan use for his research Fruit flies drosophila melanogaster referred to as Wild type red eyes 4 How is sex determined in fruit flies 5 How are linked genes different from unlinked genes Linked genes are on the same chromosome 6 What is a recombinant chromosome gametes 7 How is a linkage map constructed The frequency of crossing over different chromosomes 50 When there is a new combo of parental genes crossing over during prophase 1 and has more types of 8 What is the maximum recombinant frequency the point at which it is the same as being on Female has 2 copies of gene on X chromosome male has 1 copy of gene on X chromosome 9 Why aren t Recombination frequencies additive when making a linkage map The second crossing over event cancels out the first and reduced the observed number of recombinant offspring 10 A female has two X chromosomes are both active in each cell No What is the other one called A barr body inactive form Is the active X the same in each cell No there is always a 50 chance 11 What do the following genetic disorders have in common Red green colorblindness Hemophilia Duchenne muscular dystrophy ALL X LINKED DISORDERS 12 How is aneuploidy different from polyploidy Aneuploidy incorrect number of chromosomes cause by nondisjunction Polyploidy aberations in number of chromosome sets 13 What causes aberrations in chromosome Homo chromosome does not separate during meiosis or sister chromatids do not separate during meiosis Does it make a difference whether or not the error occurs in Meiosis I or II Yes if it occurs in meiosis 1 all gametes messed up If it occurs in meiosis 2 half of the gametes messed up 14 What causes Down syndrome How does the frequency of this disorder vary with the age of the mother An extra chromosome as mother gets older she will more likely have a Down syndrome child 15 What makes a child male If he has a Y chromosome What if a child has XXX Produces healthy females XXY Tends to be taller XO Produces phenotypic but immature females 16 What errors can occur during crossing over Deletion removes a chromosomal segment Duplication repeats a segment in a sister chromatid Inversion fragment reattaches to original chromosome but in reverse order Translocation fragment joins a non homo chromsome