Reference no: EM133431171

Question 1 Sometimes when a mutation occurs, it results in the loss of activity in a specific enzyme. Can we then conclude that there was no protein produced by the mutated gene? Explain your answer.

Question 2 A trio of APUS genetics students created a mutant strain of E. coli that, unlike the normal strain, cannot synthesize methionine (i.e. it is auxotrophic for MET). MET therefore must be present in its growth medium. This is kind of a big deal, since MET corresponds to the start codon in DNA transcription. Each of the 3 students built plasmid DNA libraries from the wild-type parental (normal) strain. They each used different restriction enzymes to clone the fragments, and then transformed the mutant (auxotrophic) strain with their own library. Their chosen restriction enzyme and their results are as follows: Student 1: used EcoR1 ; lots of prototrophic colonies in very little medium Student 2: used HINDIII ; no colonies Student 3: Xhol ; no colonies Their experimental control suggests that the actual transformation process worked fine, so how can these results be explained? (HINT: Think about how restriction enzymes work, their degree of precision, etc.)

Question 3 the use of a plasmid carrying an a+ gene to rescue an a- strain. The product of the a+ strain is Enzyme A. Could you rescue a- using growth medium containing Enzyme A? What about growth medium containing the product of Enzyme A?

Question 4 Does all DNA have a function? Is all of the DNA in your genome, for example, part of a gene? Explain (be specific).

Question 5: When RNA molecules are transcribed, do they always end up being mRNA transcripts? Explain (be specific).