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Nucleic Acids - DNA and RNA MCQ - Practice Questions with Answers

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET

Quick Facts

  • Nucleic Acids - DNA and RNA is considered one of the most asked concept.

  • 16 Questions around this concept.

Solve by difficulty

Which of the following biomolecules does have a phosphodiester bond ?

A single strand of nucleic acid tagged with a radioactive molecule is called :

Concepts Covered - 1

Nucleic Acids - DNA and RNA

Nucleic Acids - DNA and RNA

DNA:

  • The deoxyribonucleic acid (DNA) is a polymer of deoxynucleotides. 
  • The pentose sugar in deoxynucleotides lack the -O at C-2. This is the reason it is called the deoxyribose sugar.

                         

 

 

  • DNA is a polymer of nucleotides. It means many nucleotides are linked with each other via a covalent bond to form a polymer.
  • The covalent bond that links the two nucleotides is called phosphodiester bond. 

  • Hence, a polynucleotide chain is formed when many nucleotides are united via the phosphodiester bond.
  • A DNA is made up of two polynucleotide chains that are connected with each other via hydrogen bonds.
  • The two polynucleotide chains are helically arranged around each other.
  • In a polynucleotide chain, the backbone is formed of sugar and phosphate while the nitrogenous bases form hydrogen bonds.
  • Adenine forms two hydrogen bonds with thymine.
  • Cytosine forms three hydrogen bonds with guanine.

DNA is the genetic material of the living organisms, except for some viruses. It stores hereditary information.

RNA:

  • The ribonucleic acid (RNA) is also a polymer of nucleotides.
  • The pentose sugar of RNA has -OH group at C-2.
  • It is also a polynucleotide chain wherein the nucleotides are linked with each other via the phosphodiester bond.
  • Unlike DNA, it is single stranded and more reactive.
  • RNA contains uracil as one of the pyrimidines rather than the thymine. 
  • RNA acts as genetic material in some viruses.
  • In majority of the living organisms, following types of RNA molecules are present:
  • mRNA or messenger RNA, carries the message from DNA and forms the polypeptide chain along with the ribosomes.
  • Ribosomal RNA (rRNA) is a major constituent of ribosomes on which the mRNA binds.
  • Transfer RNA (tRNA) is one of the smallest of the three types of RNA, usually 70–90 nucleotides long. It carries the correct amino acid to the site of protein synthesis.

                                                

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Nucleic Acids - DNA and RNA

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