Comprehensive Study Notes on General Chemistry, Biochemistry, and Cell Biology

Energy is the ability to do work. It exists in two main forms:

  • Potential Energy: Stored energy that can do work, but isn't currently.

  • Kinetic Energy: Energy in action, seen through movement.

  • Chemical Energy: Found in the bonds of chemicals. When chemical reactions happen, this stored energy is released and turned into kinetic energy. In living things, energy from food (like glucose) is converted into ATP, which cells use for work.

  • Electrical Energy: Created by moving charged particles (ions like sodium and potassium) in the body. This energy is used by the nervous system to send signals.

  • Mechanical Energy: Involves moving matter. An example is muscles contracting to move bones.

  • Radiant Energy: Travels in waves and includes light. Light helps our eyes see.

Composition of Matter, Elements, and Atomic Structure

Four key elements make up about 96% of the human body:

  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
  • Nitrogen (N)
Atomic Structure
  • Atomic Number: Number of protons in an atom, which identifies the element.
  • Mass Number: Total of protons and neutrons in the nucleus.
Physiological Role of Iron

Iron (Fe) is crucial for making hemoglobin, which helps red blood cells carry oxygen. Without enough iron, a person can develop anemia, leading to fatigue and low energy.

Chemical Reactivity
  • Oxygen vs. Argon: Both are gases, but behave differently. Argon has a full outer electron shell, making it unreactive, while oxygen needs two more electrons, so it readily forms bonds.
Chemical Bonds
  • Polar Covalent Bonds: Electrons are shared unequally, creating partial charges on atoms.
  • Nonpolar Covalent Bonds: Electrons are shared equally with no partial charges.
  • Hydrogen Bonds: Weak attractions between a hydrogen atom with a partial positive charge and an electronegative atom (like oxygen).
Molecules and Compounds

A molecule is two or more atoms bonded together. A compound is a substance made of different elements, like sodium chloride (NaCl).

Chemical Reactions
  • Synthesis: Small molecules combine to make larger ones.
  • Decomposition: Large molecules break down into smaller ones.
  • Exchange: Both synthesis and decomposition occur.
Water Properties

Water has a polar structure enabling it to dissolve many substances and stabilize temperature. It is vital for life.

  • Electrolytes conduct electricity in water, where salts break up into ions.
  • pH reflects the acidity of a solution, impacted by acids and bases.
Organic Macromolecules
  • Carbohydrates: Made of simple sugars. An example is glucose, a primary energy source.
  • Lipids: Types include triglycerides (energy storage) and phospholipids (cell membranes).
  • Proteins: Made of amino acids, they perform many functions in the body.
  • Nucleic Acids: DNA and RNA, crucial for storing genetic information.
Cell Theory
  • Key Points:
  1. All living organisms are made of cells.
  2. The cell is the basic unit of life.
  3. Cells come from existing cells.
Cellular Structure

All cells have a plasma membrane, cytoplasm, and a nucleus. Cellular membranes are made of a flexible phospholipid bilayer with proteins and cholesterol, allowing for diverse functions.