Summary of "BIOLOGIA - Lezione 2 - Le Biomolecole"

This video provides an introductory overview of biomolecules, their structures, classifications, and functions, with a focus on human biology. It explains the concept of biomolecules as large Polymers made from smaller subunits called monomers, then explores the four major classes of biomolecules: Carbohydrates, Lipids, Proteins, and Nucleic Acids. The video also covers key biochemical reactions involved in polymer formation and breakdown.

Main Ideas and Concepts

Definition of Biomolecules:
- Biomolecules are essential molecules for life, usually produced by or constituting living organisms.
- They are typically large macromolecules (Polymers) made of smaller units called monomers.
- Common atoms in biomolecules include carbon, hydrogen, oxygen, nitrogen, and trace microelements.
Polymers and Monomers:
- Polymers = molecules made of many monomers.
- Monomers join via condensation reactions (release water) and separate via hydrolysis reactions (use water).

Classes of Biomolecules

Carbohydrates:
- Composed of carbon, hydrogen, and oxygen (ratio ~C:H2O).
- Functions:
  - Energy source and storage in humans.
  - Structural roles in plants and some animals.
- Types:
  - Monosaccharides: Single sugar units (e.g., glucose, fructose).
  - Oligosaccharides: Few monosaccharides linked (e.g., sucrose = glucose + fructose).
  - Polysaccharides: Many monosaccharides linked.
    - Starch (energy reserve in plants like potatoes).
    - Glycogen (energy reserve in animals, stored in muscles and liver).
    - Cellulose (structural component in plants, forms rigid fibers).
    - Chitin (structural polysaccharide in crustacean and insect exoskeletons).
Lipids:
- Diverse group but all insoluble in water.
- Main types:
  - Triglycerides: Glycerol + 3 fatty acids; energy storage and thermal insulation (e.g., fat under skin, important for polar animals).
  - PhosphoLipids: Glycerol + 2 fatty acids + polar phosphate head; amphipathic (hydrophilic head, hydrophobic tails); form cell membranes.
  - Steroids: Different structure; act mainly as signaling molecules (hormones).
    - Examples: Testosterone and estrogen (sexual hormones).
Proteins:
- Polymers of 20 different Amino acids.
- Amino acids have:
  - Acid group (carboxyl),
  - Amino group (NH2),
  - Variable side chain (R group).
- Amino acids link via peptide bonds.
- Functions:
  - Structural (muscles, tendons, cartilage, hair).
  - Immune defense (antibodies, complement Proteins).
  - Transport (hemoglobin transports oxygen).
  - Signaling (some hormones).
  - Enzymatic (enzymes speed up biochemical reactions).
Nucleic Acids:
- Polymers of nucleotides.
- Nucleotides consist of:
  - Sugar (ribose or deoxyribose),
  - Phosphate group,
  - Nitrogenous base (A, T, G, C in DNA; A, U, G, C in RNA).
- DNA stores genetic information.
- RNA copies and translates DNA instructions to produce Proteins.
- RNA also has other regulatory roles.
- ATP (adenosine triphosphate) is a special nucleotide acting as the cell’s energy carrier.

Important Biochemical Reactions

Condensation Reaction:
- Joins monomers by removing a water molecule.
Hydrolysis Reaction:
- Breaks Polymers into monomers by adding a water molecule.

Summary of Biomolecule Functions in Humans

Biomolecule Monomer Main Functions Carbohydrates Monosaccharides Energy source, energy storage, structural roles Lipids Fatty acids Energy storage, insulation, cell membrane formation, signaling (hormones) Proteins Amino acids Structure, movement, immunity, transport, signaling, enzymatic activity Nucleic Acids Nucleotides Genetic information storage and transmission, protein synthesis, energy transfer (ATP)

Methodology / Instructional Points

Biomolecules are Polymers made by linking monomers via condensation reactions.
Polymers can be broken down by hydrolysis.
Classification of biomolecules into four main groups helps understand their diverse functions.