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.