Spring Sprint Review Notes - Unit 1: Chemistry of Life

Properties of Water

• Water as a Polar Molecule:

  • Exhibits polarity due to unequal sharing of electrons, leading to a slight charge on different ends.

  • Enables formation of hydrogen bonds with other polar molecules.

• Hydrogen Bonds:

  • Occur between molecules with hydrogen bonded to oxygen or nitrogen.

  • Critical in maintaining structure and properties of molecules.

• Characteristics of Polar Molecules:

  • Hydrophilic: Attracted to polar substances.

  • Hydrophobic/Nonpolar: Repel polar substances.

• Effects of Hydrogen Bonding in Water:

  • Adhesion: Attraction between different substances (e.g., water and plant cell walls).

  • Cohesion: Attraction between like molecules (e.g., water molecules).

  • Capillary Action: Movement of water through narrow spaces against gravity.

  • High Heat Capacity: Water can absorb significant heat without temperature change, stabilizing environments.

  • High Surface Tension: Creates a 'skin' on water's surface allowing small objects to rest on it.

• Importance of Hydrogen Bonds Beyond Water:

  • Key to the structure of DNA/RNA (base pairing).

  • Essential for protein folding (conformation).

The SPONCH Elements

• SPONCH:

  • Acronym for the six elements that form 99% of living organisms: Sulfur, Phosphorus, Oxygen, Nitrogen, Carbon, Hydrogen.

  • Used to construct the four major macromolecules: carbohydrates, proteins, lipids, and nucleic acids.

• Macromolecules and Their Elemental Composition:

  • Carbohydrates:

  • Composed of carbon (C), hydrogen (H), oxygen (O).

  • Primarily serve as energy sources.

  • Proteins/Polypeptides:

  • Composed of carbon (C), hydrogen (H), oxygen (O), nitrogen (N).

  • Function as functional molecules in cells.

  • Lipids:

  • Composed of carbon (C), hydrogen (H), oxygen (O) (and sometimes phosphorus (P)).

  • Functions include energy storage, protection, and membrane structure.

  • Nucleic Acids:

  • Composed of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P).

  • Serve as information-carrying molecules.

Construction and Deconstruction of Macromolecules

• Chemical Reactions Involved:

  • Dehydration Synthesis:

  • Process of joining two or more monomers to form polymers, with the removal of water.

  • Hydrolysis:

  • Process of breaking down polymers into monomers through the addition of water, breaking covalent bonds.

• Key Monomers for Each Polymer Type:

  • Monosaccharides form carbohydrates.

  • Amino Acids form polypeptides/proteins.

  • Nucleotides form nucleic acids.

Protein Structure and Function

• Shape Determines Function:

  • The principle that a protein's function is largely determined by its structure.

  • Protein Conformation Levels:

  • Primary Structure: Sequence of amino acids in a polypeptide chain.

  • Secondary Structure: Local folding patterns (alpha-helices and beta-sheets) resulting from R-group interactions.

  • Tertiary Structure: Full 3D folding based on R-group interactions within the protein.

  • Quaternary Structure: Assembly of multiple polypeptide chains into a protein complex (not all proteins exhibit this level of structure).