Gene mutatiorns, Biology

Assignment Help:

Gene or point mutations occur when the DNA sequence of a gene is altered and the new nucleotide sequence is passed on to the offspring. This occurs either due to addition or deletion or substitution of one or a few nucleoticles. Nucleotide substitutions can be either transitions or transversions. Transitions are replacements of a purine by another purine (A by G or vice versa) or a pyrimidiile by another pyrimidine (C by T or vice versa). Transversions are replacements of a purine by the pyrimidine or vice versa (G or A by C or T or vice versa). We will briefly explain the different types of gene mutations.

a) Substitutions : substitution of one base by another would result in an altered amino acid in a polypeptide chain. For instance triplet AAT in DNA (UUA in mRNA) would specify leucine. But if the first A is ieplaced by C, it will code for valine. Some of the codons are degenerate and substitutions may not alter the amino acid specified. For instance, in the triplet AAT if the first A is replaced by G the amino acid coded would still be leucine. Gene mutations which do not normally affect the active site of a protein will not alter its biological functions. But nucleotide substitutions that change a triplet coding lor an amino acid into a termination codon would produce adverse effects. Once again in AAT, if the second A is replaced hy T (An), the resulting rnRNA codon IJAA is a termination codon. When a termination codon is present in the middle of an mRNA molecule the subsequent codons are not translated and an incomplete polypeptide will be released from ribosomes.


Related Discussions:- Gene mutatiorns

Explain risk management, Explain Risk Management Risk Management :  ...

Explain Risk Management Risk Management :  The  process  of weighing  policy  alternatives  to accept, minimize or reduce assessed risks and  to select and  implement approp

Who was gregor mendel, Who was Gregor Mendel? The Mendel is considered ...

Who was Gregor Mendel? The Mendel is considered the father of Genetics. He was a monk, botanist and biologist born in Austria in 1822 and who died in 1884. Throughout the years

Define the dietary guidelines, Define the Dietary Guidelines? Dietary G...

Define the Dietary Guidelines? Dietary Guidelines are becoming increasingly powerful tools to help the general public to appreciate the role of diet in prevention of degenerati

Determine teh term - magnesium, Determine teh term - Magnesium  Magnes...

Determine teh term - Magnesium  Magnesium helps in translocation of carbohydrates and regulates the uptake of other nutrients, presumably by helping in the formation of phosph

Explain about vitamin k, Vitamin K (Menadione - Vitamin K3, oil soluble) ...

Vitamin K (Menadione - Vitamin K3, oil soluble) Menadione is a yellow, lustrous, crystalline powder. It is easily soluble in benzene, soluble in fats and fatty oils.  It is spa

Stable atoms have no vacancies in their outer shell, Select all that are tr...

Select all that are true/correct: Stable atoms have no vacancies in their outer shell. Hydrogen is more stable than carbon Helium is more stable than carbon Helium is more stable t

Why is it important for chromosomes to be condensed, Why is it important fo...

Why is it important for chromosomes to be condensed during mitosis and decondensed during interphase? During mitosis the major problem to be solved is the correct separation of

What is the adp phosphorylation, Q. What is the ADP phosphorylation? What r...

Q. What is the ADP phosphorylation? What respectively are oxidative phosphorylation and photophosphorylation? ADP phosphorylation is the addition of one inorganic phosphate in

Introduction to biodiversity, Biological diversity is the new buzzword, the...

Biological diversity is the new buzzword, the magic door to international funding and global travelling. We share the earth with million of other living beings. Just as we humans m

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd