Biomolecules Overview

Overview

This lecture provides an introduction to the four main biological macromolecules—carbohydrates, proteins, lipids, and nucleic acids—focusing on their structure, monomers, and roles in living organisms. It also covers lab safety and procedures for upcoming experiments involving these molecules.

Macromolecules Overview

• Macromolecules (biomolecules) are large organic molecules essential to life.
• The four major types are carbohydrates, proteins, lipids, and nucleic acids.
• Macromolecules are polymers, made by linking smaller units called monomers.

Carbohydrates

• Carbohydrates are commonly known as sugars and are made of carbon, hydrogen, and oxygen.
• Simple sugars (monosaccharides) include glucose and fructose; two joined monosaccharides form a disaccharide (e.g., sucrose, lactose).
• Complex carbohydrates (polysaccharides) are long chains of sugars, like starch (plants), glycogen (animals), and cellulose (plants).
• The suffix "-ose" typically indicates a sugar.

Proteins

• Proteins are polymers made from 20 different amino acid monomers.
• Amino acids have a central carbon bonded to an amine group (NH2), carboxylic acid group (COOH), hydrogen, and an R group (varies).
• Amino acids link by peptide bonds to form polypeptides; proteins consist of one or more folded polypeptides.

Lipids

• Lipids include fats and oils, mainly known as triglycerides.
• Triglycerides are made from one glycerol molecule and three fatty acids.
• Lipids are non-polar (hydrophobic), so they do not dissolve in water.
• Fats (usually from animals) are solid at room temperature and have saturated fatty acids (no double bonds).
• Oils (usually from plants) are liquid at room temperature and have unsaturated fatty acids (contain double bonds, causing kinks).

Nucleic Acids

• Nucleic acids are DNA and RNA, polymers made from nucleotide monomers.
• Each nucleotide consists of a sugar, phosphate group, and a nitrogenous base (adenine, thymine/uracil, guanine, cytosine).
• DNA uses deoxyribose sugar; RNA uses ribose sugar.

Lab Safety & Procedures

• Clean test tubes with soap and a test tube brush, then rinse and place upside down to dry.
• Use wet paper towels to clean the workstation.
• Avoid cross-contaminating samples by using separate pipets for each molecule tested.
• Use lab safety gear, handle hot plates carefully, and be cautious with stains and broken glass.
• Refer to page 5 of the manual for indicators and stains used in tests.

Key Terms & Definitions

• Macromolecule — Large molecule made by joining many smaller units (monomers).
• Monomer — Small basic unit that forms polymers.
• Polymer — Large molecule made of repeating monomers.
• Monosaccharide — Simple sugar molecule.
• Disaccharide — Two monosaccharides joined together.
• Polysaccharide — Many monosaccharides linked in a chain.
• Amino Acid — Building block of proteins.
• Peptide Bond — Linkage between amino acids in proteins.
• Triglyceride — Lipid made of glycerol and three fatty acids.
• Nucleotide — Building block of nucleic acids (DNA/RNA).

Action Items / Next Steps

• Read lab instructions and procedures before class.
• Study page 5 of the manual for stains and indicators.
• Practice identifying macromolecules and their monomers for the lab.