Electron Microscope / Types - TEM & SEM / Difference between Light and Electron microscope / Tamil

Summary

This video delves into the world of electron microscopy, highlighting its superior magnification and resolution capabilities due to the use of electron beams with shorter wavelengths than visible light. It explains how electron microscopes can visualize cellular structures and viruses, with a practical resolution a thousand times better than light microscopes. The script covers various techniques like negative staining, immuno-electron microscopy, and cryo-electron microscopy, which have revolutionized the study of microorganisms. It also touches on the limitations, such as the need for vacuum and thin specimens, and the inability to observe live specimens.

Takeaways

• 🔬 The electron microscope achieves greater magnification and resolution than light microscopes due to its use of a high voltage electron beam with a much shorter wavelength than visible light.
• 🌌 Electron microscopes can resolve details as small as one to two nanometers, allowing the observation of viruses and the internal structures of cells.
• 📈 The practical resolution of electron microscopes is roughly a thousand times better than that of light microscopes, with the ability to distinguish points closer than 0.5 nanometers.
• 🔍 The useful magnification of electron microscopes can exceed 100,000x, providing detailed views of cellular structures.
• 🏗️ In 1939, modifications by Vladimir Cosma Soarin enabled electron microscopes to be used for studying viruses and protein molecules.
• 🛠️ Developments in electron microscopy include the introduction of negative staining, which enhances the visibility of microorganisms by scattering electrons and producing an image on a fluorescent screen.
• 🔬 Scanning electron microscopy (SEM) provides three-dimensional images and high-resolution imaging by detecting secondary electrons emitted from the surface of the specimen.
• 🧬 Immunoelectron microscopy is a technique that uses specific antiviral antibodies to visualize and determine the location of specific antigenic determinants in a specimen.
• 🧊 Cryo-electron microscopy allows the visualization of live organisms by rapidly freezing specimens in liquid nitrogen, which is useful for studying cellular ultrastructure and detecting non-cultivable viruses.
• 🔋 The transmission electron microscope (TEM), developed in the 1930s, offers resolutions up to approximately 0.2 nanometers, compared to 200 nanometers for the best light microscopes.
• 🚫 Live specimens cannot be observed directly through an electron microscope due to the need for vacuum conditions and the specimen preparation requirements.

Q & A

What is the primary reason for the electron microscope's greater magnification and resolution compared to the light microscope?

The electron microscope achieves greater magnification and resolution because it uses a high voltage beam of electrons, which have a much shorter wavelength than visible light.

What is the typical resolution of an electron microscope?

The practical resolution of an electron microscope is roughly a thousand times better than that of a light microscope, with the ability to distinguish points closer than 0.5 nanometers.

Who made modifications to the electron microscope in 1939 that enabled it to be used for studying viruses and protein molecules?

Vladimir Cosma Soarin made modifications to the electron microscope in 1939, which greatly improved its capabilities for studying viruses and protein molecules.

What is the significance of the development of the pan-electron microscopy technique?

The development of the pan-electron microscopy technique is significant because it allows for the visualization of very fine micro-organization by depositing a thin layer of platinum or other metals on the microorganism to be examined.

How does scanning electron microscopy differ from traditional electron microscopy?

Scanning electron microscopy provides a three-dimensional image of the object along with high-resolution images, whereas traditional electron microscopy produces two-dimensional images.

What is immuno-electron microscopy and how does it enhance virus detection?

Immuno-electron microscopy is a technique that enhances sensitivity and specificity by reacting the specimen with specific antiviral antibodies, resulting in clumping of viral particles for easier detection.

What is cryo-electron microscopy and how is it useful for studying cellular structures?

Cryo-electron microscopy is a method that involves rapid cooling of specimens by deep freezing in liquid gas, which is useful for studying cellular ultra-structures without damaging the live cells.

How does the resolution of a transmission electron microscope compare to that of a light microscope?

A transmission electron microscope offers resolutions to approximately 0.2 nanometers, as opposed to 200 nanometers for the best light microscope.

What is the role of the electron beam in the imaging process of an electron microscope?

The electron beam in an electron microscope plays a crucial role in imaging by penetrating the ultra-thin specimen and scattering electrons, which then form an image that is focused on the fluorescent screen.

Why is it necessary for the specimen to be very thin when using an electron microscope?

The specimen must be very thin or ultra-thin because the penetration power of the electron beam is low, requiring minimal obstruction for effective imaging.

What is the importance of the vacuum environment in an electron microscope?

The vacuum environment in an electron microscope is crucial as it prevents interference from air molecules, which could scatter the electron beam and degrade the image quality.