Nucleic Acids (part of Biological Molecules)

• Watson and Crick won the Nobel Prize for the discovery of DNA in 1953.
• Base pairs form the ‘rungs’ of the DNA ‘ladder’ through complementary base pairing between bases on two antiparallel DNA strands in a double helix, and their specific order determines protein production during protein synthesis.
• Two hydrogen bonds hold together the complementary DNA bases adenine and thymine, and three hydrogen bonds hold together the bases cytosine and guanine.
• The hydrogen bonding between base pairs of DNA are responsible for joining together the two DNA strands to produce a functional double helix structure.
• Hydrogen bonds are collectively extremely strong, and billions of base pairs in one cell’s length of DNA ensure that there are sufficient hydrogen bonds present to stabilise the DNA molecule (prevent it from unwinding, breaking, etc.).
• The importance of hydrogen bonding:

  • the DNA molecule is held together strongly as a compact, functional molecule which can successfully carry genetic information if it is in the double helix structure created by hydrogen bonding between complementary base pairs
  • without the presence of hydrogen bonds, DNA would have to exist as a different shape, possibly unable to fit the entirety of a necessary genome (all of the genetic material) into one cell’s nucleus – this would condemn the cell to an extremely limited supply of functional proteins and most likely cell death.
• Deoxyribonucleic Acid (DNA) is a molecule that carries all of the genetic information of a living organism.
• DNA structure consists of a phosphate backbone with a nitrogenous base pair attached (Adenine, Thymine, Guanine, Cytosine).
• Base pairs make up part of nucleotides, which DNA is built from (the other parts being a deoxyribose sugar and a phosphate group).