Lecture 3_Organic and Inorganic Molecules

Living Organisms and Molecules

  • Living organisms are composed of organic and inorganic molecules.

Objectives of the Lecture

  • Understanding of:

    • Organic Molecules

    • Carbohydrates

    • Lipids

    • Proteins

    • Nucleic Acids

    • Homeostasis Problems

    • Inorganic Molecules

    • Water, Acids, Bases, Buffers

    • Salts

  • Inorganic Molecules:

    • Typically do not contain carbon

    • Involve ionic bonding and are often soluble in water

  • Organic Molecules:

    • Always contain carbon

    • Usually involve covalent bonding with varying solubility in water.

Organic Compounds

  • Carbon:

    • Unique ability to form four covalent bonds.

    • Can bond with nitrogen, oxygen, and phosphorus.

    • Comprises ~19% of animal weight and ~12% of plant weight.

Macromolecules

  • Building blocks of life, essential for maintaining homeostasis.

  • Polymers constructed from monomers through:

    • Dehydration synthesis (or condensation reaction to form bonds)

    • Hydrolysis (to break down bonds).

Classes of Macromolecules

  1. Carbohydrates

    • Structure: 1:2:1 ratio of carbon, hydrogen, and oxygen

    • Monomer: Monosaccharide (ending in "-ose")

    • Rich in C—H bonds, providing significant energy.

    • Stored as fat when not used.

  2. Monosaccharides:

    • Simple carbohydrates, absorbed without digestion.

    • Composed of 3-6 carbon atoms (examples: glucose, fructose).

  3. Disaccharides:

    • Two monosaccharides linked via dehydration synthesis (e.g. maltose, sucrose).

    • Functions include transporting energy and storage.

  4. Polysaccharides:

    • Long chains of monosaccharides.

    • Function as energy storage (starch in plants, glycogen in animals) and structural support (cellulose in plants).

    • Disruption of homeostasis may lead to sickness.

Problems of Homeostasis: Diabetes

  • Type 1 Diabetes:

    • Reduced insulin production leading to glucose uptake issues.

  • Type 2 Diabetes:

    • Insulin resistance affecting glucose utilization.

Lipids

  • Defined as hydrophobic molecules, including fats.

  • Composed primarily of C, H, and O.

  • Monomers: Fatty acids and glycerol.

  • Linked via ester bonds.

Functions of Lipids

  • Long-term energy storage

  • Insulation, chemical messengers, protection, shock absorption

  • Form biological membranes.

Types of Fats

  • Saturated Fats: Found in animal products, solid at room temperature.

  • Unsaturated Fats: Found in plants and fish, usually liquid at room temperature.

Phospholipids and Steroids

  • Phospholipids: Major component of cell membranes.

  • Steroids: Hormones derived from cholesterol.

Waxes

  • Solid at room temperature, waterproof, protect plants from water loss.

Genetic Disorder: Tay Sachs Disease

  • A progressive genetic disorder affecting nerve cells in the brain and spinal cord.

Nucleic Acids

  • Composed of C, H, O, N, and P; responsible for hereditary information.

  • Monomer: Nucleotide.

    • DNA: Double helix with bases (A, G, C, T).

    • RNA: Single strand with bases (A, C, G, U).

Proteins

  • Composed of C, H, O, N, and S.

  • Monomer: Amino acid linked by peptide bonds.

Functions of Proteins

  • Enzymatic (lactase), defense (antibodies), transport (hemoglobin), structural support (ligaments).

  • Movement (motor proteins).

Protein Structure

  • Primary Structure: Sequence of amino acids.

  • Secondary Structure: Folding into alpha-helices or beta-pleated sheets due to hydrogen bonding.

  • Tertiary Structure: 3D shape from interactions between R groups.

  • Quaternary Structure: Assembly of multiple polypeptides into a functional complex.

Implications of Protein Misfolding: Prion Disease

  • Misfolded proteins lead to diseases like BSE (mad cow disease), causing neurological damage.

Cystic Fibrosis & Other Macromolecules Summary

  • Macromolecules include nucleic acids, lipids, carbohydrates, and proteins, each serving specific biological functions.

    • Elements: C, H, O, N, S for proteins; C, H, O for carbohydrates; C, H, O, N, P for nucleic acids.

Inorganic Compounds

  • Generally lack carbon, example: Water.

Water Characteristics

  • Composed of two hydrogen atoms and one oxygen atom, bonded via hydrogen.

  • Universal solvent with high heat capacity and vaporization; crucial for biological processes.

Importance of Water

  • High cohesion and adhesion, facilitating nutrient and waste transport in plants.

  • Key roles in metabolic processes.

Acids, Bases, and Buffers

  • Acids release H+ ions while bases accept them.

  • Buffers maintain pH homeostasis crucial for biological reactions.

Electrolytes in Body

  • Sodium (Na+), Potassium (K+), Calcium (Ca2+), and others play significant roles in bodily functions such as heartbeat regulation and nerve transmission.