Translation is the process of conversion of macromolecule information into amino acids. This genetic information is encrypted within the sort of code called ordering or codon. The ordering may be a set of data encoded within the sequence of nucleic acids that does the coding for proteins to be synthesized. Any change in genetic codes might cause mutation.
Mutation in Terms of Genetic Codes
Genes are the functional units of heredity of organisms. It is mainly responsible for the structure and functional changes and for the variation in organisms which could be good or bad. Even a moment change within the DNA sequence could alter the amino acids to be produced and proteins to be synthesized.
The ordering may be a dictionary that corresponds with the sequence of nucleotides and sequence of the Amino Acids.
Mutation
The phenomenon of change occurring within the DNA sequence is termed because of the mutation. This is mainly caused either by the interior factors or through external factors including smoking, UV rays, etc. Apart from these factors, there are other causes for the DNA variation in an organism, and it's the recombination. Mutation leads to the alteration in the expression of the genotype and phenotype. Eventually, this might affect cells or maybe damage the organism.
DNA sequences build the genes of organisms which successively encode for particular proteins. Any fluctuation during this sequence, for instance , mishaps during DNA transcription, might cause a change within the genetic codes, which alter the protein synthesis.
There are differing types of mutation and are mainly supported by the range of alternation. It could begin with one nucleotide to a segment of DNA. A variation which is caused by the change within the building block and nucleotide of DNA is termed as some extent mutation. An example of point mutation is Sickle cell anaemia.
The red blood cell anaemia may be a disease condition caused thanks to the change during a single nucleotide of the gene. In this condition, the codon for the amino alkanoic acid glutamate is replaced by that for valine. When the reading frame of the ordering is altered by the insertion or deletion of 1 or two bases, it's called frame-shift mutation.
MAN AND THE RED SEA
MAN CAN DTH ERE DSE A
MAN CAA NDT HER EDS EA
MAN CAT AND THE RED SEA
In the above statement, the insertion of every letter altered the reading frame of the statement. Deletion of every letter could also cause the frameshift mutation.
FAQs on Genetic Code Mutation
1. What is a genetic mutation in the context of the genetic code?
A genetic mutation is a permanent alteration in the DNA sequence that makes up a gene. This change can alter the genetic code, which is the set of rules used by cells to translate information encoded within genetic material into proteins. A change in a DNA codon can lead to a different amino acid being incorporated during protein synthesis, potentially affecting the protein's structure and function.
2. What are the main types of gene mutations according to the CBSE syllabus?
Gene mutations are primarily classified into two main categories as per the Class 12 syllabus:
- Point Mutations: These are changes in a single base pair of DNA. A classic example is the substitution of one nucleotide for another. Sickle-cell anaemia is a result of a point mutation.
- Frameshift Mutations: These occur when one or more base pairs are inserted into or deleted from the DNA. Such mutations shift the "reading frame" of the genetic code, altering every amino acid that is coded for after the mutation.
3. Can you provide a real-world example of a point mutation in humans?
A classic example of a point mutation is Sickle-cell anaemia. This genetic disorder is caused by a single nucleotide substitution in the gene that codes for the beta-globin chain of haemoglobin. The DNA codon GAG, which codes for glutamic acid, is mutated to GUG, which codes for valine. This single amino acid change is enough to cause haemoglobin molecules to form rigid, sickle-shaped red blood cells under low-oxygen conditions.
4. How does a frameshift mutation fundamentally differ from a point mutation in its impact?
The fundamental difference lies in the scope of the error. A point mutation affects only a single codon, potentially changing one amino acid, which may or may not significantly alter the protein. In contrast, a frameshift mutation (insertion or deletion) alters the entire reading frame from the point of the mutation onwards. This means that not just one, but a whole sequence of subsequent amino acids will be incorrect, usually resulting in a completely non-functional protein.
5. Why are not all mutations harmful? Explain with the concept of silent mutations.
Not all mutations are harmful because of a property of the genetic code called degeneracy, where multiple codons can specify the same amino acid. A silent mutation is a type of point mutation where the change in the DNA nucleotide results in a new codon that still codes for the exact same amino acid. Since the amino acid sequence of the protein remains unchanged, the mutation has no effect on the protein's function and is therefore neither harmful nor beneficial.
6. How can a single nucleotide change, as seen in sickle-cell anaemia, lead to such a significant disease?
This illustrates the critical link between a gene's sequence and a protein's function. The mutation in sickle-cell anaemia replaces a hydrophilic amino acid (glutamic acid) with a hydrophobic one (valine). This change in chemical properties causes the haemoglobin molecules to polymerise, or stick together, in low-oxygen conditions. This polymerisation distorts the red blood cell's shape from a flexible disc to a rigid sickle. These sickled cells can block small blood vessels, leading to pain, organ damage, and other severe symptoms of the disease.
7. What are mutagens, and what are some common examples relevant to Biology?
A mutagen is any physical or chemical agent that permanently alters the genetic material (DNA) of an organism, thus increasing the frequency of mutations above the natural background level. Common examples include:
- Physical Mutagens: High-energy radiation such as UV rays (from the sun), X-rays, and gamma rays.
- Chemical Mutagens: Various chemicals that can interact with DNA, such as certain components of tobacco smoke, base analogues, and alkylating agents.
