BIO 152 Lecture Notes; Biomolecules Essential for A&P

I. The Biomolecules

A. Important classes of biomolecules

1. Carbohydrates

   • Chiefly used for energy production

2. Lipids (fats)

   • Chiefly used for energy storage

3. Proteins

   • Chiefly used for structure

4. Nucleic acids

   • Chiefly used for information storage

5. High energy molecules

   • Example: ATP (adenosine triphosphate)

B. Characteristics of biological molecules

1. All are polymers made up of monomers

   • Polymer: Large chain-like structure made of repeating units; e.g., protein

   • Monomer: Single unit used to make up polymers; e.g., amino acid

2. All are organic molecules

3. All built on carbon skeletons

   • Different types of carbon skeletons:

     • Straight chain

     • Branched chain

     • Ring structures

4. All contain functional groups

   • Functional group: Group of atoms with a consistent function

   • Common groups include:

     • Carboxyl group (acidic)

     • Amino group (basic)

     • Nonpolar groups

     • Polar groups

C. Carbohydrates

1. Basic formula: Cₙ(H₂O)ₙ

   • Example: Glucose (C₆H₁₂O₆)

2. Functions:

   • Energy source

   • Energy storage

   • Structural role

3. Classification:

   • Monosaccharides

   • Disaccharides

   • Polysaccharides

4. Important examples

   • Pentoses (Ribose, Deoxyribose)

   • Hexoses (Glucose, Fructose, Galactose)

D. Lipids

1. Functions:

   • Energy storage (1g lipid = 9 kcal)

   • Energy source

   • Thermal insulation

   • Protection of vital organs

   • Neural impulse transmission

   • Tissue structure

2. Components:

   • One molecule of glycerol

   • Three fatty acids

   • Classification of fatty acids: saturated, unsaturated (mono- and polyunsaturated)

E. Proteins

1. Functions:

   • Structural, contractile, defense, carrier, regulatory roles

   • Energy source

   • Fluid balance, genetic expression

2. Composition:

   • Amino acids joined by dehydration synthesis

3. Structure:

   • Primary, secondary, tertiary, and quaternary levels

F. Nucleic acids

1. Function:

   • Information molecules (DNA, RNA)

2. Composition:

   • Nucleotides (nitrogen base, pentose sugar, phosphate group)

   • Types: Deoxyribonucleotides (DNA) and ribonucleotides (RNA)

G. Energy molecules

1. Primary example: ATP

   • Function: Used for cellular energy

   • Composition: Adenine, ribose, three phosphates

   • ATP-ADP cycle: Breakdown and synthesis of ATP based on energy needs