Question

Would the DNA helix be more or less stable in the absence of MG2+? Explain your response.

Answer 1

Mg+2 ion stabilizes DNA helix

Answer 2

Answer:

The DNA helix would be less stable in the absence of Mg²⁺ (magnesium ions).

Explanation:

1. Role of Mg²⁺ in DNA Stability:

• Mg²⁺ neutralizes the negatively charged phosphate groups in the DNA backbone, reducing electrostatic repulsion between strands.

• It stabilizes the DNA double helix by shielding phosphate charges and promoting proper folding (e.g., in tertiary structures).

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2. Consequence of Mg²⁺ Removal:

• Increased repulsion between phosphate groups weakens hydrogen bonding between base pairs.

• Higher likelihood of DNA denaturation (strand separation) under physiological conditions.

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Key Point:

Mg²⁺ is essential for maintaining DNA structural integrity; its absence reduces stability.