What phenomenon is used to view the structure of small biological samples in laboratories?

• A. X-ray diffraction.
• B. Ultraviolet fluorescence.
• C. Microphotography.
• D. Thermal imaging.

Answer: (B)

The phenomenon used to view the structure of small biological samples in laboratories is ultraviolet fluorescence. This technique involves illuminating a biological sample with ultraviolet light, which excites certain molecules within the sample, causing them to emit light at a longer wavelength. This emitted light can then be detected and used to visualize various components of the sample, such as proteins, nucleic acids, and other cellular structures.

Ultraviolet fluorescence is particularly useful in biological research because it enhances the contrast of specific components, allowing researchers to observe structures with greater clarity and detail that would not be possible with visible light alone. This method is widely employed in techniques such as fluorescence microscopy, where specific fluorescent markers are used to label particular structures within cells, enabling the study of their morphology and function.

In contrast, X-ray diffraction is typically used to study crystalline structures and is not primarily applicable to biological samples. Microphotography refers to capturing images through a microscope, but it may not specifically utilize ultraviolet light or the fluorescent properties of samples. Thermal imaging focuses on detecting heat emitted from objects and is not relevant for visualizing biological structures at the microscopic level. Thus, ultraviolet fluorescence stands out as the correct phenomenon for observing the intricate details of small biological samples.