Biological Macromolecules and Lipids

Four Classes of Biological Molecules:
- Carbohydrates (polymers of sugars)
- Proteins (polymers of amino acids)
- Nucleic acids (polymers of nucleotides)
- Lipids: Not polymers, hydrophobic molecules

Macromolecules as Polymers:
- Built from smaller units called monomers.
- Polymerization: Process of linking monomers to form polymers.

Dehydration Reaction:
- Bonds monomers by removing water, forming new bonds.
Hydrolysis:
- Breaks polymers into monomers by adding water.

Monosaccharides: Basic sugar units with molecular formula multiples of $C<em>nH</em>{2n}O_n$ .
- Example: Glucose ( $C<em>6H</em>{12}O_6$ ).
Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen, cellulose).
- Storage or structural roles.

Types of Lipids:
- Fats: Composed of glycerol and fatty acids.
- Phospholipids: Form cell membranes, are amphipathic (hydrophilic head and hydrophobic tails).
- Steroids: Contain a carbon skeleton with four fused rings (e.g., cholesterol).

Functions of Proteins:
- Catalyze reactions (enzymes), transport substances, support structures, regulate functions, and more.
Composition: Built from 20 amino acids connected by peptide bonds.
- Unique structure determined by amino acid sequence (primary structure).
- Structures include secondary (coils and folds), tertiary (3D shape), and quaternary (multiple polypeptides).
- Example of disease: Sickle-cell anemia resulting from amino acid substitution affecting structure/function.

Types:
- DNA: Double-helix structure, carries genetic information.
- RNA: Single-stranded, involved in protein synthesis.
Components: Nucleotides (nitrogenous base, sugar, phosphate group).
Function: DNA to RNA to protein flow of genetic information.

Macromolecules (polymers made of monomers) play essential roles in cellular activities. Different types of macromolecules contribute to structure, function, and energy in biological systems.