Chemistry of Life: Study Notes

Chapter 2 - Chemistry of Life: Study Notes

Basic Terms

  • Matter:

    • Definition: Anything that has mass and takes up space.

  • Element:

    • Definition: A pure substance made of one type of atom.

  • Atom:

    • Definition: The smallest unit of an element.

Four Most Abundant Elements in the Body

  • Oxygen
  • Carbon
  • Hydrogen
  • Nitrogen

Structure of an Atom

  • Protons:

    • Charge: Positive
    • Location: Nucleus

  • Neutrons:

    • Charge: Neutral
    • Location: Nucleus

  • Electrons:

    • Charge: Negative
    • Location: Electron cloud

Atomic Number

  • Definition: The number of protons in an atom; this number identifies the element.

Atomic Weight

  • Definition: The sum of the number of protons and neutrons in an atom.

Isotopes

  • Definition: Atoms of the same element that have different numbers of neutrons.

Unstable/Reactive Atoms

  • Characteristics:
    • Have incomplete outer electron shells.
    • Become stable by gaining, losing, or sharing electrons.

Chemical Bonds

  • Ionic Bonds:

    • Mechanism: Electrons are transferred from one atom to another, forming ions.

  • Covalent Bonds:

    • Mechanism: Electrons are shared between atoms, forming molecules.

Ions

  • Cation:

    • Definition: A positive ion that has lost one or more electrons.

  • Anion:

    • Definition: A negative ion that has gained one or more electrons.

  • Electrolyte:

    • Definition: A substance that, when dissolved in water, conducts electricity.

Organic vs Inorganic Compounds

  • Organic Compounds:

    • Definition: Compounds that contain both carbon and hydrogen.

  • Inorganic Compounds:

    • Definition: Compounds that do not contain both carbon and hydrogen.

Properties of Water

  • Universal Solvent:

    • Definition: Water is capable of dissolving many substances.

  • High Heat Capacity:

    • Definition: Water can absorb a lot of heat before its temperature changes significantly.

  • Cohesion:

    • Definition: Water molecules stick to each other due to hydrogen bonding.

  • Adhesion:

    • Definition: Water molecules stick to other substances.

pH Scale

  • Definition: A scale from 0 to 14 used to measure acidity and alkalinity.
    • Values below 7 represent acids.
    • Values above 7 represent bases.
    • A value of 7 indicates neutrality.

Dehydration vs Hydrolysis

  • Dehydration:

    • Definition: A chemical reaction that builds larger molecules by removing water.

  • Hydrolysis:

    • Definition: A chemical reaction that breaks down molecules by adding water.

Organic Compounds

  • Carbohydrates:

    • Examples: Glucose, glycogen.

  • Lipids:

    • Examples: Phospholipids, steroids.

  • Proteins:

    • Building Blocks: Amino acids, enzymes.

  • Nucleic Acids:

    • Types: DNA and RNA.
    • Structure: Composed of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base.

Metabolism

  • Definition: The sum of all chemical reactions that occur within the body.

Enzymes

  • Function: Biological catalysts that speed up chemical reactions without being consumed in the process.

ATP

  • Definition: Adenosine triphosphate, the main energy carrier in cells, providing energy for many cellular processes.