BIO101 ‒ Topic 4: Biological Molecules (Carbohydrates, Proteins,
Lipids, and Nucleic Acids)
1. Introduction to Biological Molecules
Biological molecules are organic compounds essential for life. They include carbohydrates,
proteins, lipids, and nucleic acids. These molecules form the structural and functional basis
of living cells.
2. Carbohydrates ‒ Structure, Types, and Functions
Carbohydrates are composed of carbon, hydrogen, and oxygen (C:H:O = 1:2:1). They
provide energy and structural support. Types include: • Monosaccharides (e.g., glucose,
fructose) • Disaccharides (e.g., sucrose, maltose) • Polysaccharides (e.g., starch, cellulose,
glycogen) Text Diagram Description: Visualize chains of hexagonal sugar rings connected
together, representing polysaccharide structure.
3. Proteins ‒ Structure, Types, and Functions
Proteins are made of amino acids linked by peptide bonds. They contain carbon, hydrogen,
oxygen, nitrogen, and sometimes sulfur. Functions include: • Structural (e.g., collagen) •
Enzymatic (e.g., amylase) • Transport (e.g., hemoglobin) • Hormonal (e.g., insulin) Text
Diagram Description: Imagine amino acid chains folding into complex 3D shapes, forming
functional enzymes and body structures.
4. Lipids ‒ Structure, Types, and Functions
Lipids are composed of glycerol and fatty acids. They are insoluble in water but soluble in
organic solvents. Functions include energy storage, insulation, and protection. Types
include fats, oils, phospholipids, and steroids. Text Diagram Description: Picture a glycerol
backbone attached to three long fatty acid tails ̶ forming a triglyceride molecule.
5. Nucleic Acids ‒ DNA and RNA
Nucleic acids store and transmit genetic information. DNA (deoxyribonucleic acid) carries
hereditary material, while RNA (ribonucleic acid) assists in protein synthesis. Components:
a phosphate group, a pentose sugar, and a nitrogenous base (A, T, C, G for DNA; A, U, C,
G for RNA). Text Diagram Description: Imagine a twisted ladder (DNA double helix) with
base pairs forming rungs ̶ A pairs with T, and C pairs with G.
6. Importance of Water in Living Organisms
Lipids, and Nucleic Acids)
1. Introduction to Biological Molecules
Biological molecules are organic compounds essential for life. They include carbohydrates,
proteins, lipids, and nucleic acids. These molecules form the structural and functional basis
of living cells.
2. Carbohydrates ‒ Structure, Types, and Functions
Carbohydrates are composed of carbon, hydrogen, and oxygen (C:H:O = 1:2:1). They
provide energy and structural support. Types include: • Monosaccharides (e.g., glucose,
fructose) • Disaccharides (e.g., sucrose, maltose) • Polysaccharides (e.g., starch, cellulose,
glycogen) Text Diagram Description: Visualize chains of hexagonal sugar rings connected
together, representing polysaccharide structure.
3. Proteins ‒ Structure, Types, and Functions
Proteins are made of amino acids linked by peptide bonds. They contain carbon, hydrogen,
oxygen, nitrogen, and sometimes sulfur. Functions include: • Structural (e.g., collagen) •
Enzymatic (e.g., amylase) • Transport (e.g., hemoglobin) • Hormonal (e.g., insulin) Text
Diagram Description: Imagine amino acid chains folding into complex 3D shapes, forming
functional enzymes and body structures.
4. Lipids ‒ Structure, Types, and Functions
Lipids are composed of glycerol and fatty acids. They are insoluble in water but soluble in
organic solvents. Functions include energy storage, insulation, and protection. Types
include fats, oils, phospholipids, and steroids. Text Diagram Description: Picture a glycerol
backbone attached to three long fatty acid tails ̶ forming a triglyceride molecule.
5. Nucleic Acids ‒ DNA and RNA
Nucleic acids store and transmit genetic information. DNA (deoxyribonucleic acid) carries
hereditary material, while RNA (ribonucleic acid) assists in protein synthesis. Components:
a phosphate group, a pentose sugar, and a nitrogenous base (A, T, C, G for DNA; A, U, C,
G for RNA). Text Diagram Description: Imagine a twisted ladder (DNA double helix) with
base pairs forming rungs ̶ A pairs with T, and C pairs with G.
6. Importance of Water in Living Organisms
