Molecular Biology and Genetics

 Stop codons are nucleotide triplets in m-RNA indicating termination of the process of translation.

 A nitrogenous base linked to sugar in the structure without the phosphate group is called nucleoside.

The nucleoside differs from nucleotide in lacking phosphate molecule.

Uracil is present in place of thymine in the RNA nucleic acid.

It is the nucleoid which is a circular DNA of prokaryotes.

This kind of aberration arises when a purine gets replaced by a pyrimidine or a pyrimidine gets replaced by a purine.

A makes a double bond with T and C forms a triple bond with G.

These two nitrogen bases are the purines of DNA.

This is the correct constant ratio for a species according to Chargaff's rule.

Circular DNA is found in E. coli and mitochondria. Chloroplast also has circular DNA.

DNA stands for Deoxyribonucleic Acid. It is the molecule that carries genetic instructions for the development, functioning, growth, and reproduction of all known organisms.

Satellite DNA are organized as large clusters upto 100 million base pairs in the heterochromatic region of chromosomes near centromeres & telomeres, these are also found abundantly on Y chromosomes.

Many noncoding DNA sequences have important biological functions as indicated by comparative genomics studies that report some regions of noncoding DNA that are highly conserved, sometimes on time-scales representing hundreds of millions of years, implying that these noncoding regions are under strong evolutionary pressure and positive selection. 

Thermal disruption at elevated temperature increases the rate of depurination (loss of purine bases from the DNA backbone) and single-strand breaks. For example, hydrolytic depurination is seen in the thermophilic bacteria, which grows in hot springs at 40-80 °C.

A nuclease is an enzyme capable of cleaving the phosphodiester bonds between the nucleotide subunits of nucleic acids. Older publications may use terms such as polynucleotidase or nucleodepolymerase.