Problem 62 - A Complete Resource Book in Chemistry for JEE Main

Question

In biological systems, the RNA molecules direct the synthesis of specific proteins which are characteristics of each kind of organism. This process is known as (a) transcription (b) mutation (c) replication (d) translation

Step-by-Step Solution

Answer

The process is known as translation.

Step 1: Understanding the Exercise

The exercise is testing your knowledge about a specific process in molecular biology where RNA molecules play a critical role in producing proteins.

Step 2: Identifying the Key Process

The question asks for the name of the process where RNA directs the synthesis of proteins, which are characteristic of organisms. This process is part of gene expression.

Step 3: Reviewing Each Option

- Transcription: The process of creating RNA from DNA. - Mutation: A change in the DNA sequence. - Replication: The process of copying DNA before cell division. - Translation: The process where RNA is decoded to synthesize proteins.

Step 4: Selecting the Correct Option

RNA directs the synthesis of proteins in the process of 'translation'. This occurs after transcription, where mRNA is translated into a protein sequence by ribosomes.

Key Concepts

RNA

RNA, short for Ribonucleic Acid, is vital in the biology of all living organisms. Unlike DNA, RNA is usually single-stranded and plays a pivotal role in the coding, decoding, regulation, and expression of genes. In the grand scheme of cellular functions, RNA acts as a messenger carrying instructions from DNA for controlling the synthesis of proteins.

RNA comes in several forms, each serving a unique purpose:

• mRNA (messenger RNA): Carries genetic information from DNA in the nucleus to the ribosomes, where proteins are synthesized.
• tRNA (transfer RNA): Brings the correct amino acids in line with the mRNA sequence at the ribosomes, facilitating the assembly of amino acids into protein chains.
• rRNA (ribosomal RNA): Combines with proteins to form ribosomes, the site of protein synthesis.

Understanding RNA's role is crucial as it bridges the genetic instructions within DNA with the production of proteins that perform various cellular functions.

Translation

Translation is a second critical phase in the synthesis of proteins, following transcription. It is the process where the information carried by mRNA is used to construct proteins by linking amino acids in a specific sequence. This remarkable process takes place at the ribosome, which can be thought of as the 'factory' where proteins are built.

Here's a simple overview of what happens during translation:

• The mRNA binds to the ribosome, establishing the site for translation.
• As the ribosome moves along the mRNA, tRNA molecules carry specific amino acids to the ribosome.
• Each tRNA molecule has an anticodon that matches a codon (a set of three nucleotides) on the mRNA.
• Once matched, the ribosome facilitates the bonding of amino acids brought by tRNA molecules into a growing peptide chain, resulting in a polypeptide, which will eventually become a functional protein.

Translation efficiently decodes the instructions encoded in mRNA to direct the synthesis of proteins, making it a cornerstone process of molecular biology and essential for life.

Gene Expression

Gene expression encompasses the entire process through which genetic information stored in a gene is used to create a functional gene product, usually a protein. It is a fundamental process that dictates not only how cells function but also how they respond to their environment. Gene expression involves two primary stages: transcription and translation.

During transcription, the DNA sequence of a gene is transcribed to produce RNA. This RNA is then processed and transported to the ribosomes during translation, where it dictates the synthesis of proteins.
The importance of gene expression:

• Regulation: Cells can regulate gene expression to respond to different environmental signals and cellular states. This adaptability is essential for the survival and proper function of cells.
• Diversity: Differences in gene expression contribute to the diversity of cell types and functions within a multicellular organism.
• Technological Implications: Understanding gene expression allows for advancements in biotechnology, medicine, and therapeutics, like creating gene therapies to treat various genetic diseases.

Gene expression is a finely tuned, regulated process that is fundamental to growth, development, and adaptation of organisms.