BIOL 121 (2009) Fall Exam 3+ Key

C consider a mutation in which the gre adjacent to

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Unformatted text preview: dfather is heterozygotes = 2*(.5*.5)= 0.5 Probability right grandmother is heterozygotes = 2*(.5*.5)= 0.5 Probability parents are heterozygotes = 0.5 if grandparent is het * probability that grandparent is het = 0.25 each Answer = 0.25 if both parents are hets * probability mother het (.25) * probability father het (.25) = 1.56% ii. If the couple’s first child has Tay-Sachs, then what is the probability that a second child will not have Tay-Sachs? (5 pts) 75% - both parents are hets. 5 BIOL 121 NAME: Exam 2 11/04/09 12) In mice, transcription of the TH gene is activated by the hormone glucocorticoid. The transcriptional activation requires the glucocorticoid receptor. A glucocorticoid response element (GRE) has been identified adjacent to the TH gene. a) A certain mutation results in constitutive transcription of TH, i.e. TH transcription is no longer dependent on glucocorticoid. Is it likely or unlikely that this mutation is in the GRE? Briefly explain your reasoning. (8 pts) Answer: The glucocorticoid receptor (GR) binds the GRE and activates transcription. However in the absence of glucocorticoid, GR is normally in the cytoplasm. It is therefore unlikely that a mutation at the GRE could lead to transcriptional activation independent of glucocorticoid. b) Suppose an additional base is inserted in the TATA box associated with the TH gene, would you expect this to change the amino acid sequence of the protein encoded by TH? Explain your reasoning. (5 pts) Answer: The TATA box is...
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This note was uploaded on 01/16/2014 for the course BIOL 121 taught by Professor Dustinbrisson during the Fall '11 term at UPenn.

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