Question

29. Step 3 is required to -a. hybridize the primers to the template DNA b. denature the template DNA C. synthesize the new DNA strand d. denature the polymerase Figure 1 below is a Kirby Bauer assay using Micrococcus luteus as the test bacterium (the yellow bacterium covering the plate) $1 is choramphenicol, #2 is tetracycline, #3 is erythromycin, and 814 is penicillin. You can say with certainty that a. M. luteus is resistant to chloramphenicol b. M. luteus is most sensitive to tetracycline c. M. luteus is resistant to penicillin d. M. luteus is equally sensitive to erythromycin and tetracycline Figure 2 below displays the antibiotic resistance of Micrococcus luteus, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter aerogenes. 31. Which bacterium is most sensitive to all of the antibiotics tested? a. Micrococcus luteus b. Staphylococcus aureus Klebsiella pneumonia d. Pseudomonas aeruginosa e. Enterobacter aerogenes 32. Which bacterium is most resistant to all of the antibiotics tested? a Micrococcus luteus b. Staphylococcus aureus c. Klebsiella pneumonia d. Pseudomonas aeruginosa e. Enterobacter aerogenes Cloure 3 below is a co-culture assay using different soil bacteria indicated by the numbers and Micrococcus luteus as the test bacterium (the yellow bacterium covering the platel. 33. The soil bacterium producing the most antibiotic is b. C. 2 3 34. The soil bacterium producing the least antibioticis .

Answer 1

29. The right answer is option c - synthesise the new DNA strand.

Explanation :

• In PCR, step 3 involves the elongation or the extension of the new DNA strand by the addition of the complementary nucleotides. This is completely in line with the third option and hence c is the right option.
• Option a is wrong as hybridisation of the primers to the template DNA is done in the second step and not the third step.
• Option b is also wrong as the denaturation of the template DNA is done in the first step and not the third step.
• Option d is also wrong as the denaturation of the polymerase does not happen in step 3.