Question 1

Which of the following best describes the main purpose of using the pGLO plasmid in bacterial transformation experiments?

Accepted Answer

To introduce a gene that allows bacteria to glow under UV light and survive in the presence of ampicillin

Question 2

What is the role of the beta-lactamase gene on the pGLO plasmid?

Accepted Answer

It provides resistance to ampicillin by breaking down the antibiotic

Question 3

During the transformation procedure, why is CaCl$$_2$$ used?

Accepted Answer

To shield the negative charges on DNA and the bacterial membrane, facilitating DNA uptake

Question 4

Which of the following steps is essential for the expression of the GFP gene in transformed E. coli?

Accepted Answer

Addition of arabinose to the growth medium

Question 5

If you plate transformed E. coli on LB/amp/ara plates, what phenotype would you expect to observe?

Accepted Answer

Growth with green fluorescence under UV light

Question 6

What is the function of the origin of replication (ori) on the pGLO plasmid?

Accepted Answer

It enables the plasmid to replicate independently within the bacterial cell

Question 7

Why is heat shock used during the transformation process?

Accepted Answer

To increase the permeability of the bacterial membrane, allowing plasmid DNA to enter

Question 8

Which equation best represents the central dogma of molecular biology as applied in the pGLO experiment?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 9

A student forgets to add arabinose to the LB/amp plate after transformation. What is the most likely result?

Accepted Answer

Transformed bacteria will grow but will not fluoresce under UV light

Question 10

Which of the following best explains why only transformed bacteria grow on LB/amp plates?

Accepted Answer

Transformed bacteria express beta-lactamase, which breaks down ampicillin

Question 11

Which regulatory protein acts as an ON/OFF switch for the GFP gene in the pGLO system?

Accepted Answer

AraC

Question 12

In the context of genetic engineering, what is a plasmid?

Accepted Answer

A circular, extrachromosomal DNA molecule that can replicate independently

Question 13

Which of the following is NOT a typical reason for genetically modifying organisms (GMOs)?

Accepted Answer

To reduce the nutritional value of food

Question 14

What would happen if you plated –pGLO E. coli on LB/amp plates?

Accepted Answer

No colonies would grow

Question 15

Which step in the transformation protocol allows for the expression of the beta-lactamase gene before plating?

Accepted Answer

Incubation at room temperature with LB broth

Question 16

Why is it important to use a sterile loop when picking E. coli colonies for transformation?

Accepted Answer

To prevent contamination with other microorganisms

Question 17

Which of the following best describes the function of arabinose in the pGLO experiment?

Accepted Answer

It induces the expression of the GFP gene by interacting with AraC

Question 18

A researcher wants to produce large quantities of a human protein using bacteria. Which sequence of steps should they follow?

Accepted Answer

Insert the gene into a plasmid, transform bacteria, grow bacteria, purify the protein

Question 19

Which of the following is a multi-step process that explains why only some E. coli colonies glow green on LB/amp/ara plates?

Accepted Answer

Only bacteria that take up the pGLO plasmid survive ampicillin; arabinose in the medium activates AraC, which allows transcription of the GFP gene, resulting in green fluorescence.

Question 20

Which of the following best explains why the recovery step on ice is necessary after heat shock during transformation?

Accepted Answer

It restores the integrity of the bacterial cell membrane

Bacterial Transformation and Genetic Engineering: pGLO Plasmid Study Guide

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