Biology: Nucleic Acids and Carbohydrates

Nucleic Acids

• Definition: Nucleic acids are biomolecules that contain the genetic instructions used in the development and function of all living organisms.
• Types:
  • DNA (Deoxyribonucleic acid): found in the nucleus of eukaryotic cells and in the cytoplasm of prokaryotic cells. It is a double-stranded helix made up of nucleotides.
  • RNA (Ribonucleic acid): found in the cytoplasm of cells. It is a single-stranded molecule made up of nucleotides.
• Structure:
  • Nucleotides are composed of:
    • Sugar molecule (deoxyribose in DNA, ribose in RNA)
    • Phosphate group
    • Nitrogenous base (A, C, G, T, or U)
  • The sugar and phosphate molecules make up the backbone of the nucleic acid, while the nitrogenous bases project inward from the backbone and pair with each other in a complementary manner.
• Functions:
  • Storage of genetic information
  • Transmission of genetic information from one generation to the next
  • Synthesis of proteins and other biomolecules

Carbohydrates

• Definition: Carbohydrates are biomolecules that serve as energy sources for cells and provide structural support for organisms.
• Types:
  • Monosaccharides: simple sugars, such as glucose, fructose, and galactose.
  • Disaccharides: composed of two monosaccharides, such as sucrose and lactose.
  • Polysaccharides: composed of three or more monosaccharides, such as starch, glycogen, and cellulose.
• Structure:
  • Monosaccharides have a general formula of C6H12O6.
  • Carbohydrates can be classified as either aldoses or ketoses, based on the presence of an aldehyde or ketone group.
• Functions:
  • Energy source for cells
  • Structural support for cells and organisms (e.g., cellulose in plant cell walls)
  • Component of nucleic acids and other biomolecules