Question

Nucleotide arrangement in DNA can be seen by

• A. X-ray crystallography
• B. electron microscope
• C. ultracentrifuge
• D. light microscope.

Answer 1

The Correct Option is A

To determine how nucleotides are arranged in DNA, scientists use a technique known as X-ray crystallography. This method was instrumental in the discovery of the double helix structure of DNA, as carried out by James Watson, Francis Crick, and Rosalind Franklin in the 1950s.

Explanation of X-ray Crystallography:

• X-ray crystallography is a powerful technique that allows researchers to visualize the atomic and molecular structure of a crystal.
• In this process, X-rays are directed at a crystal, and the pattern of the diffraction is measured and analyzed to infer the arrangement of atoms or molecules within the crystal.
• Since DNA can be crystallized, this technique is effectively used to visualize its molecular structure, enabling understanding of how nucleotides (the basic units of DNA) are arranged.

Evaluating Other Options:

• Electron Microscope: While electron microscopy provides highly detailed images, it is not typically used for resolving atomic arrangements in biological molecules such as DNA.
• Ultracentrifuge: This device is used for separating particles based on density and is not suitable for observing molecular arrangements.
• Light Microscope: Light microscopes lack the resolution required to view individual nucleotides or detailed molecular structure of DNA.

Therefore, the correct option is X-ray crystallography, as it is the only technique capable of determining the nucleotide arrangement in DNA with atomic precision.