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

The skin, what is vaso-constriction

what is vaso-constriction

Implantation, Implantation : It is the process in which the blastocyst (de...

Implantation : It is the process in which the blastocyst (developing zygote) is attached to the glandular uterine wall and then embedded in the wall of uterus. 1) In human bein

Day-neutral plants, Day-Neutral Plants  Besides SDP and LDP, those pla...

Day-Neutral Plants  Besides SDP and LDP, those plants that flower irrespective of the length of light are called day-neutral plants. For these there is no specific requirement

Describe the recovery process of an extracellular product, Question 1: ...

Question 1: Describe the recovery process of an extracellular product through downstream processing. Different criteria's for the choice of recovery process Brief on

Explain about insulin concentrations, Insulin Concentrations The doctor...

Insulin Concentrations The doctor always prescribes insulin dosage in units. Thus all types of insulin (crystalline, NPH, Lente, and so forth) is available in 10-ml vials that

Breeder select for in a cereal crop, What characteristics might a breeder s...

What characteristics might a breeder select for in (i) a cereal crop, (ii) a farm animal? (i) In a cereal variety, a breeder might select for high yield; disease-, frost- or dr

Explain process of rice milling, Rice milling Rice milling involves the...

Rice milling Rice milling involves the following processing steps: rough rice (paddy rice) → hull removal  →  brown rice  → polishing to remove the bran coats (fruits and seed

Adrenal medulla, ADRENA L MEDULLA The adrenal medulla develops from th...

ADRENA L MEDULLA The adrenal medulla develops from the neuroectoderm of the embryo. Medulla consists of chromaffin cells or phaeochromocytes. These cells are connected wi

Biological conduits, Biological Conduits : Freeze dried arterial, bov...

Biological Conduits : Freeze dried arterial, bovine MA, human umbilical vein, cryo preserved umbilical vein or artery and omniflow sheep collagen tube grafts also have poor

Determine the uses of electrical recording - brain function, Determine the ...

Determine the uses of Electrical Recording - Brain function We can also learn about brain function by recording its electrical activity. In electroencephalography (EEG) and the

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