DNA & RNA(7 Jan) - Free MCQ Practice Test with solutions, JEE

RNA can directly control the synthesis of proteins, hence can easily express the characters. DNA, however, is dependent on RNA for synthesis of proteins. The protein synthesising machinery has evolved around RNA.

In DNA, four bases have been found. They are adenine (A), guanine (G), cytosine (C) and thymine (T). The first three of these bases are found in RNA also but the fourth is uracil (U). RNA contains cytosine and uracil as pyrimidine bases while DNA has cytosine and thymine. Both have the same purine bases i.e. guanine and adenine.

Each type of RNA functions differently, among them mRNA which is also known as messenger RNA carries genetic information from DNA in the form of series of a three-base codon, which specifies the amino acid.

DNA differs from RNA because DNA has deoxyribose sugar while RNA has ribose sugar. DNA has thymine as pyrimidine while, in RNA thymine is replaced by uracil.So, the correct answer is 'In the nature of sugar and pyrimidines'

Both nucleotide and nucleoside have pentose sugar and nitrogenous base. Nucleotide differs from nucleoside with the presence of phosphoric acid as nucleoside do not have phosphoric acid.

Each nucleotide base can hydrogen-bond with a specific partner base in a process known as complementary base pairing: Cytosine forms three hydrogen bonds with guanine, and adenine forms two hydrogen bonds with thymine.

Guanine is a purine derivative. All others are pyrimidines

The correct answer is option C
RNA synthesis, or transcription, is the process of transcribing DNA nucleotide sequence information into RNA sequence information. RNA synthesis is catalyzed by a large enzyme called RNA polymerase.

The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O. group of the amino acid located three or four residues earlier along the protein sequence.

Nucleotides are joined together by phosphodiester linkage between 5′ and 3′ carbon atoms of pentose sugar.