A Level Biology Practice Exam

Which tool is required to view the ultrastructure of a cell?

1. An optical microscope

2. A light microscope

3. An electron microscope

4. A magnifying glass

The correct answer is: An electron microscope

The electron microscope is essential for viewing the ultrastructure of a cell due to its ability to achieve much higher resolutions than light-based methods. Unlike an optical or light microscope, which is limited by the wavelength of visible light (about 400-700 nanometers), an electron microscope uses electron beams to visualize samples. This technology allows it to resolve details at the nanometer scale, enabling the observation of intricate cellular components like organelles, membranes, and macromolecular complexes that are not discernible under optical microscopes. The electron microscope can provide detailed images of the fine structure of cells, revealing aspects like ribosomes, endoplasmic reticulum, and Golgi apparatus in much greater detail than other microscopic techniques. As a result, researchers can study the organization and function of these structures within the cell, which is crucial for understanding cellular processes and disease mechanisms.