5d. Remembering that hexose metabolism is a highly conserved process among all branches of life, how many genes do you expect to find in this operon? Explain your logic.

1. Suppose there was a mutation in the inducer of the lac operon, such that the inducer was unable to function. How would the lac operon be affected? Please explain your reasoning in 1-3 sentences.

1. Please tell me: What's a mutation in moleculer terms? 2. When a mutation deletes a base in genomic DNA, how does it affect the expression product production and reading frame?  3. How does induction control enzyme synthesis using lactose operon?

1. Compare and contrast repressible and inducible operons. 2. Are genes for enzymes involved in anabolic processes usually repressible or inducible , why?

3. Bacteria are normally haploid organisms (1 copy of the genome), however it is possible to introduce a plasmid into the bacteria to create a pseudo-diploid situation. Here we have introduced a plasmid that carries the lac operon. Based on the following genotypes, predict the state of the beta-glactosidase enzyme (lac Z) in each of the following situations. I- = a mutation in the repressor protein that cannot bind to the operator Is = a mutation in the repressor protein that cannot be removed from the operator Oc = a mutation in the operator that cannot bind the repressor Z` = a mutation in beta-galactosidase that makes the enzyme non-functional Chromosome Lactose Present I, Z, O I, Z, O I. Z-.O I-,Z,O IS,Z-,Oc, Plasmid I, Z, O I, Z, O I, Z, Oc I,Z,O I,Z,O Yes No No Yes Yes Functional enzyme (yes/no) Phenotype (inducible constitutive, repressed constitutive regressed

28.  Which statement does NOT explain why the lac operon would not be effectively regulated by an attenuation mechanism like the trp operon? 1.Lactose is a substrate for the lac operon protein products.   2.Products of lac operon enzymes are not used in protein synthesis.   3.Transcription and translation do not happen simultaneously for the lac operon.   4.Attenuation is a suitable regulatory mechanism for anabolic amino acid pathways.   5.All of these statements explain why regulation by attenuation would not be effective for the lac operon.

1a.Describe the information flow in the central dogma.  1b. How does a gene specify the production of a protein? Explain in words and illustrate in a figure.