Nucleic Acids

  • Nucleic acids are a critical component of all life forms on Earth, as they carry the genetic information necessary for the control of cell functions and the development and maintenance of organisms.

  • The two main types of nucleic acid are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

  • DNA is stored in the nucleus of cells and forms the shape of a double helix. Each ‘rung’ of this spiral ladder shape consists of two nucleotides connected by hydrogen bonds.

  • DNA contains the inherited material or genes, which are segments on the DNA that code for specific proteins, giving individuals their unique features.

  • RNA is single-stranded, and it acts as a messenger for DNA, transferring the gene’s instructions to the site of protein synthesis (the ribosomes in the cell).

  • Although RNA is typically single-stranded, it can form into complex 3D structures.

  • Nucleotides themselves are made up of three components: a phosphate group, a sugar molecule (deoxyribose in DNA and ribose in RNA), and a nitrogenous base (adenine, guanine, cytosine, thymine in DNA, and adenine, guanine, cytosine, and uracil in RNA).

  • In DNA, Adenine (A) always pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G) - this is known as base pairing rule.

  • In RNA, the base pairing changes slightly where Adenine (A) pairs with Uracil (U), and Guanine (G) pairs with Cytosine (C).

  • The order of nitrogenous bases on a DNA or RNA molecule determines the message or the code which is used during protein synthesis.

  • During cell division, the DNA must replicate itself so that the two new cells will each have a complete set of DNA molecules.

  • Errors in DNA replication, known as mutations, can cause diseases, including cancers. At the same time, they also provide the basis for biological evolution.

  • Biotechnology and medical science heavily rely on the understanding and manipulation of nucleic acids. They are important in areas such as genetic engineering, forensic science (DNA profiling), and the development of new medicines and treatments, such as gene therapy.

  • In order to analyse DNA, biologists often use techniques such as PCR (Polymerase Chain Reaction) and Gel Electrophoresis.

  • The human genome project, which aimed to determine the nucleotide sequence of the entire human DNA genome, has revolutionised our understanding of how DNA influences human health and disease.

Remember, understanding the structure and function of nucleic acids is crucial to the understanding of life and life processes at a molecular level. So, take some time to familiarise yourself with the details. Good luck with your revision!