Chapter 2: Biochemistry

Introduction

• Begins with the simplest components of living things: atoms and molecules.
• Emphasis on reviewing learning objectives.

Key Concepts

Matter and Energy

• "It happens": Simplified relationship by Albert Einstein, expressed as E=mc².
• Matter: All visible and invisible substances.
• Energy: Interaction and doing between bits of matter.
• Four phases of matter: Solid, liquid, gas, and plasma (not biologically relevant).

Elements and Compounds

• Elements: Substances that cannot be broken down by chemical means.
• Compounds: Made of two or more elements in a fixed ratio (e.g., table salt).
• Chemical symbols: One or two letters, first capitalized.
• Elements listed in the periodic table.

The Periodic Table

• Read from top left to right, then down.
• Organizes elements by atomic numbers and masses.
  • Atomic number: Whole numbers, integers.
  • Atomic mass: Average mass, often close to whole numbers.

Atoms

• Origin: From Greek "atomos" meaning uncuttable.
• Structure: Consists of protons, neutrons (nucleons in the nucleus), and electrons.
  • Protons and neutrons have significant mass.
  • Electrons have negligible mass.
• Mass measured in Dalton or amu (atomic mass unit).

Isotopes

• Atoms with the same number of protons but different neutrons.
• Example: Carbon isotopes (Carbon-12, Carbon-13, Carbon-14).
• Notation: Element's total mass as a superscript (e.g., ¹²C).

Radioactivity

• Some isotopes undergo decay and release energy (radioactivity).
• Application in biology: Useful for tracing chemical reactions and dating fossils.
• Radioactive decay is stable and measured by atomic clocks.
• Elevated radiation levels are harmful (e.g., Fukushima, Chernobyl).

Summary

• Atoms and elements form the foundation of biochemistry.
• Understanding isotopes and radioactivity is crucial in biological and environmental contexts.
• Emphasis on the vastness of atomic structures and their relevance to life and the universe.