Topic 2: Basics of Chemistry & Biochemistry

Chemistry Learning Objectives

  • Understand basic atomic structures: atoms, isotopes, ions, and molecules.

  • Calculate atomic and mass numbers, subatomic particles.

  • Differentiate between covalent (polar vs. nonpolar), ionic, and hydrogen bonds.

  • Explain the significance of water for life.

  • Recognize the importance of pH and buffers in living organisms.

Biochemistry Learning Objectives

  • Identify functional groups (amino, carboxyl, hydroxyl, phosphate).

  • Recognize building blocks for carbohydrates, lipids, proteins, nucleic acids.

  • Know key physiological reactions (hydrolysis, dehydration synthesis, etc.).

Basic Concepts of Matter

  • Matter: has mass and occupies space.

  • Elements: cannot be broken down chemically.

  • Atoms: smallest unit of an element retaining its properties.

  • Molecules: formed from bonded atoms.

Common Elements in Human Body

  • Main: Carbon, Hydrogen, Oxygen, Nitrogen

  • Others: Iron, Calcium, etc.

Subatomic Particles

  • Neutrons: neutral charge

  • Protons: positive charge

  • Electrons: negative charge, belong to outer orbit (valence electrons).

Isotopes

  • Same atomic number, different mass (due to neutron variation).

  • Radioisotopes: unstable isotopes used in medical imaging, dating (e.g., Carbon-14).

Chemical Bonds

  • Ionic Bonds: Transfer electrons; occur between charged ions.

  • Covalent Bonds: Share electrons; can be polar (unequal sharing) or nonpolar (equal sharing).

Properties of Water

  • Universal solvent; high heat capacity; less dense when frozen.

  • Polar molecule—with partial charges.

Acids and Bases

  • Acids: release H+ ions (e.g., HCl).

  • Bases: take up H+ or release OH- ions (e.g., ammonia).

pH Scale

  • Ranges from 0 (acidic) to 14 (basic); neutral at 7.

  • Reports concentration of H+ ions.

Buffers

  • Maintain stable pH by absorbing excess H+ or OH- ions.

Organic Molecules

  • Contain Carbon and Hydrogen; includes macromolecules like carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

  • Composed of monosaccharides; function primarily for energy storage.

  • Types: monosaccharides (1 sugar), disaccharides (2 sugars), polysaccharides (many sugars).

  • Ratio typically 1:2:1 for C:H:O.

Proteins

  • Made of amino acids; function in structure, enzymes, transport, hormones.

  • Four levels of organization: primary, secondary, tertiary, quaternary.

Lipids

  • Hydrophobic (do not dissolve in water); include fats, oils, phospholipids.

  • Used for long-term energy storage.

Nucleic Acids

  • DNA contains genetic information; RNA is involved in protein synthesis.

  • Composed of nucleotides (sugar, phosphate, nitrogenous base).