The distinctive 'X' pattern meant DNA had what structure?

The distinctive 'X' pattern meant DNA had what structure?

• A. Linear
• B. Helix
• C. Beta sheet
• D. Coiled coil

Answer: (B)

The distinctive X-shaped pattern in X-ray diffraction signals a helical arrangement. DNA is a double helix—two strands wound around a common axis with a regular rise per base pair. This uniform, cylindrical symmetry causes the scattered X-rays to interfere in a way that produces a characteristic X shape. If DNA were simply linear, the pattern would look different; beta sheets are a protein structure that doesn’t produce this X-form, and coiled-coil motifs are another protein feature. So the X pattern specifically reflects DNA’s helical structure.

The distinctive X-shaped pattern in X-ray diffraction signals a helical arrangement. DNA is a double helix—two strands wound around a common axis with a regular rise per base pair. This uniform, cylindrical symmetry causes the scattered X-rays to interfere in a way that produces a characteristic X shape. If DNA were simply linear, the pattern would look different; beta sheets are a protein structure that doesn’t produce this X-form, and coiled-coil motifs are another protein feature. So the X pattern specifically reflects DNA’s helical structure.