Biological Macromolecules

 Biological macromolecules are large organic molecules that are essential for life and make up the majority of a cell's mass. There are four major classes of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids. Carbon is the foundation element for many molecules in living things because it can form four covalent bonds with other atoms or molecules. Lipids are hydrophobic and perform various functions in a cell, such as energy storage and providing insulation. Proteins are polymers of amino acids and have diverse functions, including acting as enzymes and hormones. Nucleic acids carry the genetic blueprint of a cell and are made up of nucleotides, which combine to form DNA and RNA. DNA has a double-helical structure and is composed of two strands of nucleotides bonded to each other with hydrogen bonds.

I. Biological Macromolecules

• Large molecules necessary for life that are built from smaller organic molecules
• Four major classes: carbohydrates, lipids, proteins, and nucleic acids
• Organic molecules contain carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, and other elements

II. Carbon

• Foundation element for molecules in living things
• Contains four electrons in outer shell, can form four covalent bonds with other atoms or molecules
• Carbon bonding responsible for its important role

III. Lipids

• Diverse group of compounds with a common feature
• Hydrophobic and insoluble in water because they are nonpolar molecules
• Perform many different functions in a cell, including energy storage and providing insulation
• Building blocks of many hormones and important constituent of plasma membrane

IV. Proteins

• Most abundant organic molecule in living systems
• Diverse range of functions due to 20 different chemically distinct amino acids that form long chains
• Can function as enzymes or hormones
• Enzymes are catalysts in biochemical reactions, usually made of proteins

V. Nucleic Acids

• Key macromolecules in the continuity of life
• Carry genetic blueprint of a cell and carry instructions for its functioning
• Two main types: DNA and RNA
• DNA is the genetic material found in all living organisms
• RNA mostly involved in protein synthesis and its regulation
• DNA and RNA made up of monomers known as nucleotides

VI. DNA Structure

• Double-helical structure composed of two strands of nucleotides
• Alternating sugar and phosphate groups form backbone of DNA
• Nitrogenous bases stack in the interior, paired with hydrogen bonds
• Bases pair in such a way that the distance between the backbones of the two strands is the same all along the molecule