BIO 152 Lecture Notes; Learning Manuel Chemistry

The Chemistry of Life

I. Basic Chemical Concepts

• Chemistry: Branch of science dealing with structure, properties, and interconversions of matter.

• Matter: Anything with mass that occupies space.

• Mass: Amount of matter in a substance.

II. Forms of Matter

• Homogeneous Matter: Same composition and properties throughout.

• Heterogeneous Matter: Variable composition and properties.

• Pure Substance: Homogeneous matter with consistent composition.

A. Types of Pure Substances

1. Element: Cannot be broken down into smaller units; all atoms are nearly identical.

2. Compound: Can be broken down into simpler substances larger than atoms.

III. The Elements of Life

• Only about 20 elements are used in the human body; 6 make up over 99%:

  • Sulfur: Protein production.

  • Phosphorus: Nucleotides and ATP.

  • Oxygen: Found in biological molecules.

  • Nitrogen: Component of proteins and nucleotides.

  • Carbon: Core element of biological molecules.

  • Hydrogen: Used in most biological molecules.

IV. Atomic Structure

1. Atom: Smallest unit maintaining element properties.

2. Subatomic Particles:

   • Proton: +1 charge, 1 amu.

   • Neutron: 0 charge, 1 amu.

   • Electron: -1 charge, negligible mass.

3. Atomic Terminology:

   • Atomic Number: Number of protons.

   • Atomic Mass: Protons + Neutrons.

   • Isotopes: Same atomic number, different mass.

V. Bonding

• Stability and the Octet Rule: Atoms seek to fill their valence shells.

1. Ionic Bonding: Transfer of electrons, creates charged ions.

2. Covalent Bonding: Sharing of electrons; no charged particles.

VI. Electronegativity

• Definition: Ability of an atom to attract electrons; affects bonding and solubility.

  • Polar Covalent Bonding: Unequal sharing of electrons.

  • Nonpolar Covalent Bonding: Equal sharing of electrons.

VII. Types of Chemical Reactions

1. Synthetic Reaction: A + B → AB (anabolic).

2. Decomposition Reaction: AB → A + B (catabolic).

3. Exchange Reaction: AB + CD → AD + CB.

VIII. Acids and Bases

• Acids: Produce H+ when dissolved in water.

• Bases: Absorb H+ in water.

• pH Scale: 0-14 measuring acidity and basicity; physiological pH is 7.4.

IX. Chemical Constituents of Cells

• Organic Compounds: Contain carbon, excluding carbon dioxide.

• Inorganic Compounds: Do not contain carbon, also excluding carbon dioxide.