Problem 200 - Objective Biology for NEET

Question

Assertion: Ribosomes are found in both prokaryote and eukaryotes. Reason: Ribosomes are protein factories which is required for both types of cells.

Step-by-Step Solution

Answer

Yes, the assertion and reason are correct. Ribosomes are found in both prokaryotic and eukaryotic cells, as they are vital for protein synthesis, a function required by all cells.

Step 1: Understand Cell Structures

The first step is to understand what prokaryotic and eukaryotic cells are. Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they don’t have a nucleus, but, instead, mostly circular DNA. Eukaryotic cells are more complex and contain a nucleus, where the genetic material is stored, and different types of organelles.

Step 2: Identify Commonalities

Once the basic understanding of these two types of cells is established, it's important to identify the features they share. Both eukaryotic and prokaryotic cells have, amongst other things, a cell membrane, cytoplasm, and ribosomes.

Step 3: Validate the Assertion and Reason

Once we know that ribosomes are indeed found in both types of cells, we can validate the assertion. The reason given is also correct - ribosomes are essential for protein synthesis, which is a vital process in all living cells.

Key Concepts

Prokaryotic Cells

Prokaryotic cells are among the simplest forms of life. These cells are primarily found in single-celled organisms like bacteria and archaea. What sets prokaryotic cells apart is their lack of a nucleus and membrane-bound organelles. Instead, their genetic material is located in the nucleoid, a simple region without a membrane.
This makes prokaryotic cells efficient, allowing them to adapt quickly to different environments. Despite their simplicity, they perform all necessary functions to sustain life, including energy production, reproduction, and responding to stimuli.
In terms of structure, prokaryotic cells have:

• a plasma membrane to protect the cell
• cytoplasm where cellular processes occur
• ribosomes for protein synthesis

Ribosomes are critical, as they are responsible for translating genetic information into proteins, a key process for life.

Eukaryotic Cells

Eukaryotic cells are more complex compared to their prokaryotic counterparts. They are found in both single-celled organisms and multicellular organisms like plants and animals. The defining feature of eukaryotic cells is the presence of a nucleus. This nucleus contains most of the cell's DNA, organized into chromosomes.
Eukaryotic cells are packed with various organelles, each performing specialized functions. This includes mitochondria for energy production and the endoplasmic reticulum for protein and lipid synthesis.

• They have a more structured cytoskeleton providing shape and support.
• Ribosomes in eukaryotic cells may be free in the cytoplasm or bound to the endoplasmic reticulum.

These ribosomes play an identical role to those in prokaryotic cells, synthesizing proteins necessary for the cell's work and survival.
All this complexity allows eukaryotic cells to participate in more advanced functions, including differentiation and development.

Protein Synthesis

Protein synthesis is a vital biological process occurring in both prokaryotic and eukaryotic cells. It involves translating genetic information from DNA into proteins, which are essential for various cellular functions. This process occurs in two main stages: transcription and translation.
Transcription occurs when the DNA sequence is copied into messenger RNA (mRNA). This mRNA then travels to the ribosome, the site of translation.
Translation is the process whereby ribosomes read the sequence of mRNA, decodes it, and builds the corresponding protein by linking the appropriate amino acids in sequence.

• In prokaryotic cells, translation begins even before transcription is complete.
• In eukaryotic cells, transcription occurs in the nucleus, and translation occurs in the cytoplasm.

This synthesis is continuous and crucial, ensuring cells produce proteins necessary for their growth, repair, and overall function.