Biological Macromolecules BIO1111
Introduction to Biological Macromolecules
Living matter is predominantly organic molecules, excluding water.
About 98% of living matter comprises organic molecules, categorized mainly into four types, known as biological macromolecules: carbohydrates, proteins, lipids, and nucleic acids.
Importance of understanding these macromolecules as they play crucial roles in the structure and function of organisms.
Types of Biological Macromolecules
Carbohydrates
Common examples include bread, potatoes, chips, and sugars found in fruits and candies.
Composed of monosaccharides, which combine to form polysaccharides (complex carbohydrates).
Monosaccharides include simple sugars like glucose, fructose, and sucrose.
Proteins
Common sources include meat, nuts, and legumes, rich in dietary proteins.
Proteins are essential for every observable process in living organisms; DNA codes for proteins.
Composed of amino acids (monomers); there are 20 different amino acids.
Examples include insulin, hemoglobin, and antibodies, which are formed into polypeptides.
Lipids
Unique molecules that do not interact well with water; classified as non-polar, hydrophobic.
Include oils, butter, wax, steroids, and phospholipids specific to cell membranes.
Not classified as polymers, as they do not have repeating monomer units.
Nucleic Acids
Include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Comprised of nucleotides (monomers); DNA contains four types of nucleotides, and RNA contains different but overlapping types.
Nucleotides have a structure that includes a five-carbon sugar, phosphate group, and nitrogenous base.
When nucleotides are combined, they form polynucleotides (nucleic acids).
Polymer Structure of Macromolecules
Three out of four macromolecules (carbohydrates, proteins, nucleic acids) are polymers, built from monomers.
Lipids do not consist of monomers and thus are considered a separate category of macromolecules.
Chemical Reactions Involved in Macromolecule Formation
Dehydration Reactions
Synthesis reactions that build larger molecules from smaller ones and produce water as a byproduct.
Example: Combining two glucose monosaccharides to form maltose (disaccharide) by losing water.
Indicators of dehydration reactions include the presence of smaller reactants and the production of a larger product along with water.
Hydrolysis Reactions
Breakdown reactions that use water to split larger molecules into smaller components.
Water is a reactant, and products are typically smaller than the reactant.
The term "hydrolysis" literally refers to water breaking down bonds.
Example: A large carbohydrate molecule being broken down into its monosaccharide components using water.
Review of Key Concepts
Biological macromolecules include carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates, proteins, and nucleic acids are polymers made from specific monomers: monosaccharides, amino acids, and nucleotides respectively.
Dehydration reactions build larger molecules and release water, while hydrolysis reactions break down molecules and use water.
Upcoming Content
Next video will focus more on carbohydrates and lipids.
Final video will cover proteins and nucleic acids, including their structures and properties.