Question 6 of 17beginner💡 UnderstandShort Answer2 marks

Describe the role of chelating agent in the process of DNA extraction.

Correct Answer

In the process of DNA extraction, the medium contains a chelating agent, specifically ethylene diamine tetraacetic acid (EDTA). Its primary role is to chelate or bind divalent cations, particularly Mn2+^{2+} and Mg2+^{2+}, which are present in the cellular environment.

By binding these cations, the chelating agent effectively prevents the action of nucleases. Since nucleases require these metal ions for their enzymatic activity, their removal inhibits the degradation of DNA. Furthermore, chelating these cations prevents the formation of their respective salts with the phosphate groups of nucleic acids, ensuring the integrity of the extracted DNA.

Exercise: EXERCISES | Q: 7 | (Page 38)
For More Understanding

Explanation

The answer is derived directly from the textbook context which states that the chelating agent EDTA is used to bind divalent cations like Mn2+ and Mg2+. This serves two main purposes: preventing nuclease activity (which protects the DNA from degradation) and preventing the formation of salts between the cations and the phosphate groups of nucleic acids.

Solution Steps

  1. Step 1: Identify the chelating agent mentioned in the context (EDTA).

  2. Step 2: Identify the target ions (divalent cations like Mn2+ and Mg2+).

  3. Step 3: Explain the consequence of chelating these ions: inhibition of nucleases and prevention of salt formation with phosphate groups.

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