Which type of microscope is most appropriate for generating a three-dimensional image of a bacterium?

• A. Dark-field microscope
• B. Scanning electron microscope (SEM)
• C. Transmission electron microscope (TEM)
• D. Compound light microscope

Answer: (B)

Verified step by step guidance

1. Understand the goal: We want to generate a three-dimensional (3D) image of a bacterium, which means the microscope should provide surface details and depth information.
2. Review the options: A dark-field microscope enhances contrast but mainly provides 2D images; a transmission electron microscope (TEM) produces highly detailed 2D images of internal structures; a compound light microscope is limited in resolution and typically provides 2D images.
3. Focus on the scanning electron microscope (SEM): SEM scans the surface of the specimen with electrons and collects signals that create detailed 3D images of the surface topography.
4. Compare SEM with TEM: While TEM passes electrons through thin sections to reveal internal structures in 2D, SEM detects electrons reflected or emitted from the surface, enabling 3D visualization.
5. Conclude that the SEM is the most appropriate microscope for generating a 3D image of a bacterium because it provides detailed surface morphology and depth information.