Chem

1. Organic Compounds and
Macromolecules
Comprehensive Study Material

2. Organic Compounds
• Contain carbon, hydrogen, and often oxygen, nitrogen, phosphorus, sulfur.
• Called 'organic' because originally linked to living organisms.
• Carbon’s 4 valence electrons allow stable, versatile bonding.
• Difference: Organic = C-H bonds; Inorganic = usually no C-H bonds.

3. Macromolecules
• Macromolecules = 'large molecules' built from monomers.
• Monomers join via dehydration synthesis → polymers.
• Polymers broken by hydrolysis.
• 4 major types: Carbohydrates, Lipids, Proteins, Nucleic Acids.

4. Carbohydrates
• Made of C, H, O in 1:2:1 ratio.
• Monomer: monosaccharide (glucose, fructose, galactose).
• Disaccharides: sucrose, lactose, maltose.
• Polysaccharides: starch, glycogen, cellulose, chitin.
• Functions: energy (ATP), storage, structure, cell signaling.

5. Lipids
• Hydrophobic molecules made of C, H, (little O).
• Not true polymers, but built from glycerol + fatty acids.
• Triglycerides, phospholipids, steroids, waxes.
• Saturated = solid fats; Unsaturated = oils.
• Functions: long-term energy, membranes, insulation, hormones.

6. Proteins
• Composed of amino acids (20 types).
• Levels of structure: Primary, Secondary, Tertiary, Quaternary.
• Functions: structure (collagen, keratin), enzymes, transport, hormones,
antibodies.
• Peptide bonds join amino acids.

7. Nucleic Acids
• Monomer: nucleotide (sugar + phosphate + base).
• DNA: deoxyribonucleic acid — deoxyribose sugar, double helix, A-T, G-C
pairing.
• RNA: ribonucleic acid — ribose sugar, U replaces T, single-stranded.
• DNA stores genetic info; RNA carries out protein synthesis.

8. DNA Storage and Organization
• DNA in eukaryotes stored in nucleus.
• Wrapped around histone proteins → nucleosomes → chromatin.
• Condenses into chromosomes during cell division.
• Mitochondria & chloroplasts have circular DNA.

9. Nitrogenous Bases
• Purines: Adenine (A), Guanine (G).
• Pyrimidines: Cytosine (C), Thymine (T), Uracil (U).
• DNA base pairs: A-T, G-C.
• RNA base pairs: A-U, G-C.

10. Summary
• Organic compounds = foundation of life.
• Carbohydrates: quick energy + structure.
• Lipids: long-term energy + membranes.
• Proteins: versatile functions in structure, enzymes, defense.
• Nucleic acids: genetic information storage and transfer.