---5. There are four genes in the FAK operon. a. How many mRNAs are encoded by this operon? b. The FAK operon has a weak promoter, where RNA polymerase does not bind well. What type of molecule could directly help RNA polymerase to bind more tightly to this promoter? i. An inducer ii. An activator iii. A promoter iv. A repressor v. A ligand 6. Consider the Lac operon of *E. coli*, which is normally expressed only when lactose is present and glucose absent. You identify a mutant strain of bacteria in which LacZ, LacY, and LacA are expressed in the absence of glucose, whether or not lactose is present. a. Assume that one mutation causes this mis-regulation. Which interaction must be disrupted by this mutation? i. Interaction between RNA polymerase and the lac promoter ii. Interaction between LacI protein and the lac operator (its binding site) iii. Interaction between CRP and cAMP iv. Interaction between CRP-cAMP (aka CAP) at its binding site adjacent to lac operon v. Interaction between LacI protein and lactose vi. Interaction between LacZ protein and lactose b. If the mutation is in a cis-acting factor, where is it located in the bacterial genome? i. It must be close to the origin of replication ii. It must be far from the lac operon iii. It must be close to the lac promoter iv. It could be anywhere c. If the mutation causes this effect is in a protein-coding gene, will adding a wildtype copy of that gene, at a random location in the genome of the mutant bacteria, restore normal regulation? i. Yes, as long as it can be expressed ii. No, not unless it is randomly added exactly in its usual location in the genome ---

Name: ---5. There are four genes in the FAK operon. a. How many mRNAs a
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Description: ---5. There are four genes in the FAK operon. a. How many mRNAs are encoded by this operon? b. The FAK operon has a weak promoter, where RNA polymerase does not bind well. What type of molecule could directly help RNA polymerase to bind more t

Question 5 Answer a) There is only one mRNA that codes for four genes in the FAK operon. Explanation. An operon is a cluster of genes that are transcribed as a single mRNA but code for multiple proteins. b) ii) An activator Explanation. An activator is a protein that helps to increase the transcription rate by interacting with other molecules. Question 6 a) Answer is (ii) Interaction between the LacI protein and the Lac operator (binding site). b) Answer is (iii): It must be close to the lac promoter. cis-acting factors are generally DNA elements. In this case, where all three genes are expressed in the absence of glucose, they might be close to the lac promoter region. c) i) Yes, as long as the protein (repressor ) is expressed