Problem 208 - Objective Biology for NEET

Question

Assertion: Ribosomes were discovered after discovery of electron microscope. Reason: Ribosomes can be observed by electron-microscope.

Step-by-Step Solution

Answer

The assertion and reason are both correct. Electron microscopes, which were developed in the early 20th century, were necessary to see ribosomes due to their small size (~20 nm in diameter). Thus, ribosomes were indeed discovered after the discovery of electron microscope.

Step 1: Assess the Assertion

First, it's important to examine the claim given in the exercise. The assertion is 'Ribosomes were discovered after the discovery of electron microscope'. To confirm if the assertion is true or false, conduct research to find out the timeline of these scientific discoveries.

Step 2: Assess the Reason

The reason given is 'Ribosomes can be observed by electron-microscope.' While it's true that ribosomes can be observed with an electron microscope, this doesn't necessarily confirm or refute the timeline proposed in the assertion. Research this point to find out when electron microscopes began to be used to observe cellular structures.

Step 3: Compare and Conclude

Using the historical data gathered in step one and two, assess if the assertion and the reason hold true. The 'After' in the assertion implies that the electron microscope was pivotal for the discovery of ribosomes, check if this was the case.

Key Concepts

Electron Microscope

Electron microscopes are powerful tools that enable scientists to see incredibly small details of cellular structures. Unlike traditional light microscopes, which use optical lenses to magnify images, electron microscopes use beams of electrons.
This allows them to observe much smaller and more detailed images.
There are two main types of electron microscopes:

• Transmission Electron Microscopes (TEM): These are used to view the internal structures of cells and can reach magnifications of more than 1,000,000x.
• Scanning Electron Microscopes (SEM): These create 3D images of the surfaces of samples, providing detailed images of textures.

The development of electron microscopes has opened up new avenues in the study of cellular biology and has been instrumental in many scientific discoveries.

Scientific Discoveries Timeline

Understanding the timeline of scientific discoveries helps us see the progression of knowledge over time. Discoveries often build on previous knowledge, making each breakthrough pivotal. The electron microscope was first developed in the 1930s by scientists Max Knoll and Ernst Ruska. This tool revolutionized cellular biology by allowing us to see things that were previously invisible, like ribosomes.
Ribosomes themselves were discovered later, in the 1950s. The ability to see and understand these structures came as a direct consequence of the advanced imaging techniques made possible by electron microscopes. This timeline shows that indeed, the discovery of the electron microscope preceded and facilitated the identification and study of ribosomes.

Cellular Structures Observation

Observing cellular structures is essential for understanding how cells function and maintain life. With the development of the electron microscope, scientists gained the ability to view and study complex structures like ribosomes in great detail.
Ribosomes, which are crucial for protein synthesis, were too small to be observed with a traditional light microscope.
The electron microscope allowed for:

• Detailed observation of the ribosomes' size and shape.
• Understanding of their function and role in producing proteins.
• Study of their interaction with other cellular components.

The observation of these sub-cellular structures has been key in advancing our knowledge of molecular biology and cellular processes.