What is not true for genetic code? 1)it is unambiguous 2)A codon in mRNA is read in a non-contigious fashion. 3)it is nearly universal 4)it is degenerate?

Question

Answer

Option 2...It's also mentioned in Ncert...'A mRNA reads in a contiguous fashion & there are no punctuations'......Hence; option 2 is correct...Do refer molecular basis of inheritance chapter in Ncert..

Answer

Option 2)

A codon in mRNA is read in a non contiguous fashion

This option is correct

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The codon is read in mRNA in a contagious fashion. There is no punctuations. So, option B is correct.

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Introduction:
The genetic code is the set of rules by which information encoded in the nucleotide sequence of DNA or RNA is translated into proteins. It is a fundamental aspect of molecular biology and plays a crucial role in protein synthesis. However, there are certain statements about the genetic code that are not true. Let's examine each statement in detail.

1) The genetic code is unambiguous:
The genetic code is generally unambiguous, meaning that each codon (a sequence of three nucleotides) encodes for a specific amino acid. For example, the codon AUG always codes for the amino acid methionine. However, there are a few exceptions to this rule. Some codons can have dual meanings and code for different amino acids in different contexts. This phenomenon is known as codon ambiguity. One example is the codon UGA, which typically serves as a stop codon, but in certain organisms or specific mRNA sequences, it can code for the amino acid selenocysteine. Therefore, it is not entirely accurate to say that the genetic code is unambiguous.

2) A codon in mRNA is read in a non-contiguous fashion:
This statement is not true. A codon in mRNA is read in a contiguous fashion, meaning that the nucleotides within the codon are read sequentially. Each codon specifies a particular amino acid, and the order of the codons determines the sequence of amino acids in a protein. For example, the codon sequence AUG codes for the amino acid methionine, and the codon sequence UUU codes for the amino acid phenylalanine. The reading of codons in a contiguous manner is essential for accurate protein synthesis.

3) The genetic code is nearly universal:
This statement is true. The genetic code is nearly universal, meaning that the same codons code for the same amino acids across most organisms. This universality allows for the exchange of genetic information and the production of functional proteins in different organisms. However, there are a few exceptions to this universality. Some organisms, such as certain bacteria, archaea, and mitochondria, have variations in their genetic codes. For example, in mitochondria, the codon UGA codes for the amino acid tryptophan instead of being a stop codon. Despite these exceptions, the genetic code remains largely universal.

4) The genetic code is degenerate:
This statement is true. The genetic code is degenerate, meaning that multiple codons can code for the same amino acid. For example, the amino acid leucine is encoded by six different codons: UUA, UUG, CUU, CUC, CUA, and CUG. This redundancy in the genetic code provides a level of robustness and protects against the harmful effects of mutations. Even if a single nucleotide is changed in a codon, the resulting codon may still code for the same amino acid due to this degeneracy.

Conclusion:
In conclusion, the genetic code is not entirely unambiguous, as some codons can have dual meanings. However, it is read in a contiguous fashion, is nearly universal with a few exceptions, and is degenerate, allowing for redundancy and robustness in protein synthesis. Understanding the intricacies of the genetic code is crucial for comprehending the molecular basis of life and the processes of DNA

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