Fundamental Biomolecules in General Biology

Biomolecules: The Building Blocks of Life

Overview of Biomolecules

Biomolecules are essential organic compounds that form the structural and functional basis of all living organisms. The four major classes of biomolecules are carbohydrates, proteins, nucleic acids, and lipids. Each class plays a unique role in cellular processes and organismal physiology.

• Carbohydrates: Organic molecules composed of carbon, hydrogen, and oxygen, typically with the formula $C_n(H_2O)_n$. They serve as energy sources and structural components.

• Proteins: Polymers of amino acids that perform a wide range of functions, including catalysis (enzymes), structural support, and transport.

• Nucleic Acids: DNA and RNA, which store and transmit genetic information.

• Lipids: Hydrophobic molecules such as fats, oils, and phospholipids, important for energy storage and membrane structure.

Carbohydrates

Structure and Function

Carbohydrates are classified based on their complexity:

• Monosaccharides: Simple sugars (e.g., glucose, fructose) that serve as basic energy units.

• Disaccharides: Composed of two monosaccharides (e.g., sucrose, lactose).

• Polysaccharides: Long chains of monosaccharides (e.g., starch, cellulose, glycogen) used for energy storage and structural support.

Example: Glucose is a monosaccharide that is central to cellular respiration.

Proteins

Structure and Function

Proteins are made up of amino acids linked by peptide bonds. Their structure determines their function:

• Primary Structure: Sequence of amino acids.

• Secondary Structure: Local folding (e.g., alpha helices, beta sheets).

• Tertiary Structure: Overall 3D shape of a single polypeptide.

• Quaternary Structure: Assembly of multiple polypeptides.

Example: Hemoglobin is a protein that transports oxygen in the blood.

Nucleic Acids

DNA and RNA

Nucleic acids are polymers of nucleotides. They store and transmit genetic information:

• DNA (Deoxyribonucleic Acid): Double-stranded molecule that stores genetic instructions.

• RNA (Ribonucleic Acid): Single-stranded molecule involved in protein synthesis and gene regulation.

Example: DNA contains genes that code for proteins.

Lipids

Types and Functions

Lipids are diverse hydrophobic molecules:

• Fats and Oils: Energy storage molecules composed of glycerol and fatty acids.

• Phospholipids: Major components of cell membranes.

• Steroids: Include hormones like cholesterol.

Example: Phospholipids form the bilayer of cell membranes.

Comparison of Biomolecule Classes

Major Properties

The following table summarizes the main features of each biomolecule class:

Biomolecule	Monomer	Main Function	Example
Carbohydrates	Monosaccharide	Energy, structure	Glucose, cellulose
Proteins	Amino acid	Catalysis, structure, transport	Enzymes, hemoglobin
Nucleic Acids	Nucleotide	Genetic information	DNA, RNA
Lipids	Fatty acid, glycerol	Energy storage, membranes	Triglycerides, phospholipids

Additional info:

• Some content was inferred due to fragmented and unclear original notes. The main topic is the four classes of biomolecules, which are foundational in General Biology.

• Key terms and examples were expanded for clarity and completeness.