3. The following metabolic pathway exists in a strain of bacteria. The bacteria require product D to survive. The three enzymes required to produce D are controlled by three separate genes (genes 1 to 3). A enzyme 1 B enzyme 2° C enzyme 3*D Assume that this pathway is under the control of an operon. a) In the space provided below, draw the operon for this biochemical pathway. [2 A] b)Illustrate a scenario when the levels of D are HIGH (i.e. the bacteria would not require the enzymes to produce D) [2 A] 4. The gel below, was produced by DNA sequencing. What was the original DNA template strand sequence? [4T] ddCTP ddGTP ddTTP ddATP | | |/n5. During an investigation of the promoter region of a gene you apply heat to two sections of DNA that you believe could be a promoter region. One region unwinds at 80 degrees Celsius and the other unwinds around 60 degrees Celsius. Which of the two strands contains the promoter? Explain. [4 T] 6. Use labelled diagrams incorporating the concept of the "Central Dogma of Molecular Genetics" to illustrate how a mutation can lead to disease. [4 C]

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