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Genetics Test 4


Test 1   Test 1a*
Test 2   Test 3
Quiz 1   Quiz 2
Quiz 3   Test 4

*including answer


Part A:  Mechanics (12%, 4 each)


1 .         What molecules are used in building DNA during replication?



2 .         What molecules are used in building RNA during transcription?



3 .         What molecules are used in building proteins during translation?




Part B:  Calculations and Stuff  (16%; 8 each)



1 .         How many codons (minimum) are required to code for a protein 300 amino acids in length?


2 .         Show how introns and exons and the cut-and-paste technique of post-transcriptional modification of mRNA can allow many different proteins to be created from only one gene.



Part C: Control (72% of the test, 18 each)


1 .         Explain the mechanism of the control of the (-galactosidase operon, the CAT operon OR the trp operon)  In answering the question, describe what turns the structural gene on, or off.



2 .         What is the difference between a gene being ON and a gene being "not on"?




3 .         How serious, on a scale from 1 to 10, would a mutation in the initiator codon of the gene for DNA replicase be?  Explain your logic.



4 .         A cell is supposed to be build the molecule tyrosine. (The synthesis is a one step reaction, mediated by tyrosine synthetase.)  For some reason, the cell can't.  Describe six reasons which would explain what's happening.  You may refer back to some of the answers you have used so far.  If so, then shorten your answer for just those explanations.