Nucleic Acids

Nucleic Acids

Definition and Types

  • Nucleic acids are large biomolecules crucial for all forms of life.
  • They are composed of building blocks known as nucleotides.
  • Two main types exist: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

Structure and Composition of Nucleotides

  • Each nucleotide is made up of three components: a sugar, a phosphate group and a nitrogenous base.
  • Sugars can either be ribose (in RNA) or deoxyribose (in DNA).
  • Nitrogenous bases fall under two categories: purines (adenine, guanine) and pyrimidines (cytosine, thymine for DNA, uracil for RNA).
  • The nucleotides are linked together to form a polynucleotide chain via phosphodiester bonds.

Structure of DNA

  • DNA is usually a double helix, consisting of two polynucleotide chains twisted around each other.
  • Complementary base pairs (adenine with thymine and cytosine with guanine) are bonded together with hydrogen bonds, forming the rungs of the helical ladder.

Functions of DNA

  • Primary function is to store and transfer genetic information.
  • DNA controls the synthesis of proteins, hence directly influencing the traits of an organism.
  • Genetic information from DNA is transferred to RNA in a process known as transcription.

Structure of RNA

  • RNA is often a single-stranded molecule and can fold into complex three dimensional structures.
  • Instead of thymine, RNA incorporates the pyrimidine base uracil.

Functions of RNA

  • RNA acts as a messenger carrying instructions from DNA for controlling the synthesis of proteins, hence its name messenger RNA (mRNA).
  • Other types of RNA, transfer RNA (tRNA) and ribosomal RNA (rRNA), play vital roles in protein synthesis.
  • Some RNA molecules can act as catalysts for biochemical reactions much like enzymes. These are known as ribozymes.

Genetic Engineering and Nucleic Acids

  • The manipulation of nucleic acids is fundamental to genetic engineering.
  • Techniques, such as gene cloning, polymerase chain reaction (PCR) and genome sequencing, are based on the understanding and manipulation of nucleic acids.

By understanding the structure and functions of nucleic acids, we consequently grasp the basics of the genetic code that forms every life form we know. This comprehension branches out into avenues beyond our imagination, enabling breakthroughs in fields like genetic engineering and biotechnology.