mti_exam_key

mti_exam_key - Biological Sciences 101 Dr. Mark Sanders...

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Biological Sciences 101 Dr. Mark Sanders Summer Session II 2008 Midterm I Exam Key 1a. (2) 5 = 32 phenotypic classes 1b. (1/2) 5 = 1/32 = .031 1c. (1/2) 2 (1/4) 3 = 1/256 = .0039 [Scoring: 2 pts answer, 2 pts work for each] 2a. The probability Marta is a carrier of galactosemia is ¼ (2 pts). Since Marta’s great grandmother was aa , Marta’s grandmother was Aa . There is a ½ chance the recessive allele was passed to Marta’s mother and another ½ chance the allele was passed to Marta. (1 pt). 2b. There is a 2/3 chance Paul is a carrier of galactosemia. Both of Paul’s parents are carriers, and since Paul is healthy and is not aa like his sister, his carrier probability is the 2/3 as determined by conditional probability. 2c. (1/4) (2/3) (1/4) = 1/24 = .042 2d. (23/24) 2 = (0.958) 2 = 0.918 2e. ¼. Having a child with galactosemia confirms that both Marta and Paul are carriers of the recessive allele. Each time they have a child there is a 1 in 4 chance the child will be homozygous recessive. [Scoring on 2b-e: 2 pts work, 1 pt answer or explanation]
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mti_exam_key - Biological Sciences 101 Dr. Mark Sanders...

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