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The amino acid order of proteins is decided by the order of nucleotides in deoxyribonucleic acid and ribonucleic acid. Proteins are not generated directly from DNA, despite the fact that the linear sequence of nucleotides in DNA provides the information for protein sequences. There are two forms of genetic coding. RNA codons or DNA codons may be used to express the genetic code. RNA codons are those which actually got checked during the polypeptides synthesis and are found in messenger RNA .
Characteristics of genetic code-
Now we will take a look at what we mean by genetic code in detail, characteristics of genetic code, which characteristics describe genetic code of humans and lastly at what are the properties of genetic code.
Genetic code-
The genetic code is a collection of principles by which living cells transform information stored in genetic material (DNA or RNA sequences) into proteins (amino acid sequences).The code shows a relation between codons and amino acids; each triplet of nucleotides in a nucleic acid sequence designates a single amino acid.
The canonical or standard genetic code, or simply the genetic code, is commonly referred to as such because the great majority of genes are encoded with precisely the same code, despite the fact that there are numerous alternative codes; hence, the canonical genetic code is not universal. Protein synthesis in mitochondria in humans, for example, is based on a genetic code that differs from the canonical code.
Characteristics of genetic code-
The genetic code is the same for everyone. The genetic code of all known living species is the same. This shows that all organisms have gone through similar evolutionary journeys.
The genetic code is unmistakable. Each codon specifies just one amino acid (or start or stop). What if codons would code for more than one amino acid?
It is superfluous to have a genetic code. The majority of amino acids are encoded by several codons.
1.Comma-free genetic code: Genetic code is commaless. This indicates that triplet codons on m-RNA are arranged one after the other without a gap.
2.Clear nature: Each codon designates a certain amino acid. Only AUG, which codes for methionine, and GUG, which codes for valine, are exceptions. In the absence of AUG, however, GUG may code for methionine.
3.Degenerate nature: For each of the 20 amino acids, there are 61 codons. However, certain amino acids are coded by several codons. As a result, it is considered deteriorated. Glycine is represented by the letters GGG, GGA, GGC, and GGU.
4.Polarity: On m-RNA, genetic information could only be read in the 5′-3′ orientation. The importance of polarity in the genetic code cannot be overstated. There are also start and stop signals on it. The start or initiation codon is AUG, whereas the stop or termination codes are UAG, UAA, and UGA.
5.Universality: All species, from small bacteria to large organisms, have the same genetic code.
So, these are the characteristics of genetic code.
Which characteristics describe genetic code of humans-
Everyone’s human genome is mostly the same. However, there are differences in the genome. This genetic diversity accounts for around 0.001% of each person’s DNA and leads to physical and mental variations. People who are related have more DNA in common.Epigenetic alterations are responsible for some of the differences between people. Chemical tags that bind to DNA cause these modifications.
The genetic code is the same for everyone. The genetic code of all known living species is the same. This demonstrates that all creatures have followed a similar evolutionary path.The genetic code is unmistakable. Each codon specifies just one amino acid (or start or stop).So, characteristics of genetic code of humans are also same as everyone
What are the properties of genetic code-
Some codes serve as start codons- The AUG codon is the start or initiation codon in most organisms, meaning that the polypeptide chain begins with methionine (eukaryotes) or N- formylmethionine (prokaryotes).
The initiation site of mRNA containing the AUG initiation codon is selectively bound by methionyl or N-formylmethionyl-tRNA. In other circumstances, such as bacterial protein production, GUG also functions as the start codon. GUG normally codes for valine, but only when the regular AUG codon is deleted due to deletion is GUG employed as an initiation codon.
It is a universal code- The same genetic code has been discovered to be valid in all creatures, from bacteria to humans. Marshall, Caskey, and Nirenberg (1967) discovered that E. coli (Bacterium), Xenopus laevis (Amphibian), and guinea pig (mammal) amino acyl-tRNA utilise almost the same coding. The genetic code may have evolved 3 billion years ago with the first bacterium, according to Nirenberg, and it has altered very little throughout the history of living species.
Conclusion-
In this we read how about the genetic code,its characteristics,properties,also read about human genetic code,from this all we can say that genetic code is a collection of principles that specify the linear sequence of a polypeptide from a linear sequence of nucleotides.That is, they dictate how an mRNA’s nucleotide sequence is translated into a polypeptide’s amino acid sequence.
It is the relation between the nucleotide sequence of mRNA and the amino acid sequence of the polypeptide.
