Correct Answer: (4) genetic engineering

The illustration shows the process of genetic engineering or recombinant DNA technology. The first step in this technique is called DNA extraction. During this process, the DNA from the desired organism in extracted then treated with restriction enzymes which cuts the DNA into smaller portions with defined ends to so that it can be cloned into bacterial vectors. These vectors are transformed into bacterial cells and thousands of copies are produced. After gene cloning, the gene of interest will be linked to other DNA components that will regulate its expression in the cell. Then the gene will be inserted to the bacterial cell through the use of gene gun or Agrobacterium-mediated transformation.

Incorrect Answer:

(1) chromatography

Chromatography is a laboratory technique used to separate mixtures. The sample of the mixture is dissolved in a mobile phase. The mobile phase is then forced through a steady, immiscible stationary phase. The phases are selected so that the components of the sample have differing solubilities in each phase. The component that is soluble in the stationary phase will be slower in moving through it than the component that is not very soluble in the stationary phase but very soluble in the mobile phase. Since they have different rates of movement due to solubility, the components of the sample will be separated from each other as they move through the stationary phase. There are no DNA, plasmid vector, and bacterial cell involved in this process, thus the illustration does not pertain to chromatography.

(2) gel electrophoresis

Gel electrophoresis refers to the process of separating molecules on their differential mobility in an electric field. The smaller molecules move through the gel faster than the larger molecules. In genetic engineering, it is used to separate DNA fragments. Therefore, the illustration does not explain this process.

(3) direct harvesting