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

Define reagents-nelson somogyi method for glucose estimation, Define Reagen...

Define Reagents - Nelson Somogyi Method for Glucose Estimation? 1. Alkaline copper reagent Alkaline A- Buy commercial from SDS chemicals etc Alkaline B- Weigh 6.25 g anhy

How different are taenia solium and taenia saginata, Q. Concerning their re...

Q. Concerning their respective intermediate hosts how different are Taenia solium and Taenia saginata? The midway hosts of the Taenia solium are pigs and the intermediate hosts

State about the halstead tactual performance test, The Halstead Tactual Per...

The Halstead Tactual Performance Test This procedure used a version of the Seguin-Goddard Form board, but it is done blindfold. The subject's task is to place all the 10 blocks

Why the physician suspect, Kevin and his wife have been trying to have a ba...

Kevin and his wife have been trying to have a baby for the past three years. On seeking the help of a fertility specialist, Kevin learned that he has a hereditary form of male ster

Explain the procedure for testing quality of water, Explain the Procedure f...

Explain the Procedure for Testing Quality of Water Using Presumptive Test? Now carry out the exercise following the steps indicated herewith. 1. Make 3 series of lactose bro

Definition of osseointegration, Q. Definition of Osseointegration From the ...

Q. Definition of Osseointegration From the view of the patient? An implant fixture is osseointegrated if it provides a stable and apparently immobile support of a prosthesis un

What is counsellor, Q. What is Counsellor? Counsellor is someone who gi...

Q. What is Counsellor? Counsellor is someone who gives advice about the problem. A counselor's role is to help patients help themselves. In our context  a counsellor is  a comm

Omega-3 essential fatty acids, Q. Omega-3 Essential Fatty Acids? Omega-...

Q. Omega-3 Essential Fatty Acids? Omega-3 essential fatty acids found in flax and cold-water fish help fight inflammation. For a condition such as diverticulitis, it may be wis

Saturated fatty acids, Saturated Fatty Acids - These are solid at ro...

Saturated Fatty Acids - These are solid at room temperature. These are metabolically less active so have a tendency to deposit in the body (synthesized in body) These

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