Question

Experimental Treatment	Number of bacterial colonies on the plate	What color were the colonies under normal light?	What color were the colonies under UV light?
-pGLO/LB	lawn	beige	No color change
-pGLO/LB/amp	No colonies present	The plate looks the same	No color change
+pGLO/LB/amp	lawn	beige	No color change
+pGLO/LB/amp/ara	lawn	beige	Fluorescence green

1. Which experimental treatment/s would have E. coli cells that are genetically identical to original cells used to set up the experiment? Explain why they are likely to be genetically identical.
2. For bacteria transformation to occur cells must allow foreign DNA to pass across the cell membrane.
   1. What is one advantage to allowing transformation?
   2. What is one disadvantage to allowing transformation?

Answer 1

In the question, there are 4 experimental setups. In the different setups, the growth of the bacteria Ecoli is observed. The four plates were -pGLO/LB plate which was used as a control, -pGLO/LB/amp plate, +pGLO/LB/amp plate, and +pGLO/LB/amp/ara plate.

-pGLO/LB plate- In this plate, we observe three things, the growth of the bacteria, the color of colonies in normal light and the color in UV light. Bacteria are seen to grow in the plate. However, the bacteria did not glow in this setup. One characteristic of pGLO plasmid is to have the green fluorescent protein which causes the glow. But in this case, as the plasmid was absent the bacteria grew but did not glow. Therefore, the lawn of bacteria is observed. The color of these colonies is beige in normal lighting and does not emit any fluorescent light in the presence of UV.

-pGLO/LB/amp plate- This plate is similar to the first was which was used as the control, but this also contains resistance to ampicillin. Due to this reason, the bacteria do not grow as well as does not glow. The bacteria do not grow because of ampicillin acts as an antibiotic for the bacteria. Also, the bacteria do not glow because there is a need for arabinose for starting the operon system. Therefore, no colonies were observed and the rest of the observations were also null.

+pGLO/LB/amp plate-In this case the bacteria do grow, but again it fails to glow because of the absence of arabinose. Therefore, a lawn of bacterial colonies was observed. The color of which is beige in normal lighting but did not emit any fluorescent light in the presence of UV.

+pGLO/LB/amp/ara plate- Here, the bacteria do grow and glow. Here the plate contains arabinose which is a sugar that activates the production of the green fluorescent protein and emits the fluorescent light. Therefore, a lawn of bacterial colonies was observed which looked beige under normal light and emitted fluorescence under UV. However, the light does not emit forever. The enzyme arabinase digests away the arabinose and stops the fluorescence.

a. One advantage of allowing transformation is the increased production of DNA. It is a crucial step in the field of cloning.

b. One disadvantage of allowing transformation is antibacterial resistance.