Question

1. You decide to view Pseudomonas aeruginosa under your brightfield microscope. Your lab partner tells you to just place the liquid culture on a slide and view without staining. Which of the following statements is true?
2. Which of the following volumes can be pipetted with a p200 pipette?
   1. 2 µL
   2. 0.15 mL
   3. 1.2x10^-3 L
   4. 0.75 mL
   5. 19.2 µL
3. A bacterial cell contains Nalidixic Acid resistance on its chromosome and an F+ plasmid containing tetracycline resistance. In the process of conjugation, this cell will donate which resistance to the recipient cell? A)Nalidixic acid B)Tetracycline C)Ampicillin D)A and B F)A, B, and C
4. You have discovered a novel organism and are interested in determining whether or not it ferments lactose. You inoculate the organism on an EMB plate and the following incubation you observe no growth. Which of the following is most likely true about this organism based on those findings?
   1. It does not ferment lactose
   2. It is Gram-negative
   3. It ferments lactose
   4. It is Gram-positive
   5. None of the above
5. After starting your PCR reaction in the thermal cycler your lab partner informs you that you forgot to add the deoxynucleoside triphosphates (dNTP’s) to your reaction. They also inform you of the following correct statement:
   1. dNTP’s are not a crucial component; the PCR will be successful
   2. Elongation will not occur
   3. Annealing will still occur
   4. B and C are correct
   5. A and C are correct

Answer 1

Question 1

The correct answer is option b - 0.15 mL

Explanation: Range of p200 pipette is from 20 µL to 200 µL. ).15mL means 150 µL which is within the range. All of the other falls outside the range. So option b is the correct answer.

Question 2

The correct answer is option b -Tetracycline

Explanation: During conjugation F+ cells transfers its F plasmid to the recipient. As the F+ plasmid carry tetracycline resistant gene, the tetracycline resistant gene will be transferred to the recipient cells.

Question 3

The correct answer is option d - It is Gram positive

Explanation: EMB medium contain sucrose, lactose, Methylene blue and Eosin Y. Among them Methylene blue and Eosin Y inhibit the growth of Gram positive bacteria, but it has no effect on Gram negative bacteria. So no growth indicates that the novel organism is a Gram positive Bacteria.

Question 4

The correct answer is option b - Elongation will not occur

Explanation: dNTPs are building block of a PCR reaction. So if dNTP are not there, elongation will not occur as dNTPs are attached with each other by Taq polymerase to form the PCR products. So, if dNTPs are not there no products will be formed.