This is Chapter 3 – Organic & Biological Chemistry for the Year 12 Chemistry course.

This chapter explores the enormous variety of carbon-based compounds and explains how small differences in molecular structure can produce major changes in physical properties, chemical reactions and biological function. Students will move from relatively simple organic molecules into the chemistry of proteins, carbohydrates and triglycerides, building a clear connection between organic and biological chemistry.

We begin by developing fluency with IUPAC nomenclature and different structural representations, including molecular, condensed and skeletal formulae. Students use functional groups, molecular size and intermolecular forces to predict properties such as boiling point, melting point and solubility.

Alcohols, aldehydes and ketones introduce important relationships between structure and reactivity. Students distinguish between primary, secondary and tertiary alcohols and consider how chemical tests can be used to identify aldehydes and ketones. Carboxylic acids and esters then provide a foundation for studying esterification, hydrolysis and condensation polymerisation, including the purpose of reflux conditions and acid catalysts.

The chapter also examines amines, amides and amino acids. Students explore how protonation affects solubility before investigating peptide bond formation and the different levels of protein structure. This leads naturally into enzyme function and an explanation of how temperature and pH can disrupt a protein’s three-dimensional shape.

Finally, students examine carbohydrates and triglycerides as biologically important molecules. They compare saturated and unsaturated fatty acids, investigate tests for unsaturation and explain how molecular shape affects melting point. Saponification and micelle formation connect these ideas to soaps and cleaning products.

Organic chemistry is essential in medicine, pharmacology, biochemistry, food science, materials development and chemical manufacturing.

Subtopics:

• A: Introduction to Organic Chemistry

• B: Alcohols, Aldehydes, and Ketones
• C: Carboxylic Acids and Asters
• D: Amines, Amides, and Amino Acids
• E: Carbohydrates and Triglycerides

By the end of this topic, students will be able to represent and name organic molecules, predict their properties and reactions, and connect functional groups with biological molecules and everyday chemical applications.