BIOTECH Q3:

I. Introduction to Biomolecules

Definition: Biomolecules are organic molecules essential for life, playing key roles in the structure, function, and processes of living organisms.
Four Major Classes:
- Carbohydrates
- Lipids (Fats)
- Proteins
- Nucleic Acids

II. Carbohydrates

Elements: Primarily carbon, hydrogen, and oxygen (CH₂O)n.
Monomers: Monosaccharides (e.g., glucose, fructose, galactose, maltose, sucrose ).
Polymers: Polysaccharides (e.g., starch, glycogen, cellulose).
Functions:
- Energy Source: Glucose is a primary energy source for cells.
- Energy Storage: Starch (plants) and glycogen (animals) store energy.
- Structural Components: Cellulose (plant cell walls) provides structure.
Key Concepts:
- Monosaccharides: Simple sugars with 3-7 carbon atoms.
- Disaccharides: Two monosaccharides joined by a glycosidic bond (e.g., sucrose, lactose).
- Polysaccharides: Many monosaccharides linked together.

III. Lipids (Fats)

Elements: Primarily carbon, hydrogen, and oxygen; some contain phosphorus.
Monomers: Fatty acids and glycerol.
Types:
- Triglycerides: Fats and oils composed of glycerol and three fatty acids.
- Phospholipids: Major component of cell membranes.
- Steroids: Lipids with a ring structure (e.g., cholesterol, hormones).
Functions:
- Energy Storage: Triglycerides store large amounts of energy.
- Structural Components: Phospholipids form cell membranes.
- Hormones: Steroids like testosterone and estrogen regulate various processes.
- Insulation: Fats provide insulation in animals.
Key Concepts:
- Saturated Fatty Acids: No double bonds; solid at room temperature.
- Unsaturated Fatty Acids: One or more double bonds; liquid at room temperature.
- Hydrophobic: Lipids are insoluble in water.

IV. Proteins

Elements: Carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
Monomers: Amino acids (20 common types).
Polymers: Polypeptides (proteins).
Functions:
- Enzymes: Catalyze biochemical reactions.
- Structural Components: Collagen (connective tissue), keratin (hair, nails).
- Transport: Hemoglobin (oxygen transport).
- Immune Defense: Antibodies.
- Movement: Actin and myosin (muscle contraction).
Key Concepts:
- Amino Acid Structure: Amino group, carboxyl group, R-group (side chain).
- Peptide Bond: Bond between amino acids.
- Protein Structure:
  - Primary: Amino acid sequence.
  - Secondary: Local folding (alpha helix, beta sheet).
  - Tertiary: 3D structure due to R-group interactions.
  - Quaternary: Arrangement of multiple polypeptide chains.
- Denaturation: Loss of protein structure and function.

V. Nucleic Acids

Elements: Carbon, hydrogen, oxygen, nitrogen, and phosphorus.
Monomers: Nucleotides (composed of a sugar, phosphate group, and nitrogenous base).
Types:
- DNA (Deoxyribonucleic Acid): Stores genetic information.
- RNA (Ribonucleic Acid): Involved in protein synthesis.
Functions:
- Genetic Information Storage: DNA stores instructions for cell function.
- Protein Synthesis: RNA molecules (mRNA, tRNA, rRNA) are involved in gene expression.
Key Concepts:
- Nucleotide Structure: Sugar (deoxyribose or ribose), phosphate group, nitrogenous base (adenine, guanine, cytosine, thymine/uracil).
- DNA Structure: Double helix with complementary base pairing (Adenine-Thymine, Guanine-Cytosine).
- RNA Structure: Single-stranded.
- Central Dogma of Molecular Biology (theory stating that genetic information flows only in one direction): DNA → RNA → Protein.

VI. Key Differences and Comparisons

Carbohydrates vs. Lipids:
- Both are energy sources, but lipids store more energy per gram.
- Carbohydrates are more readily available for quick energy.
Proteins vs. Nucleic Acids:
- Proteins are involved in a wide range of functions, including catalysis and structure.
- Nucleic acids store and transmit genetic information.
DNA vs. RNA:
- DNA stores genetic information; RNA is involved in protein synthesis.
- DNA is double-stranded; RNA is single-stranded.

VII. Importance of Biomolecules