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Chapters 3-5

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Terms in this set (27)

  • What is the structure of a water molecule?

    Bent shape with polar covalent bonds.

  • Why is water considered a polar molecule?

    Because oxygen is more electronegative than hydrogen

  • What are hydrogen bonds in water?
    Weak interactions between the partial positive hydrogen of one water molecule and the partial negative oxygen of another.
  • Name three emergent properties of water that support life.
    • Cohesion and adhesion
    • High specific heat
    • Excellent solvent
  • What is cohesion in water?

    The attraction between water molecules due to hydrogen bonding

  • Define adhesion in the context of water.
    The clinging of water molecules to other substances, aiding water movement against gravity in plants.
  • What does high specific heat of water mean?

    Water can absorb or release a large amount of heat with little temperature change

  • Explain the significance of water's solvent properties.
    Water dissolves many substances due to its polarity, facilitating chemical reactions in cells.
  • What is an acid in biological terms?
    A substance that increases hydrogen ion concentration (\(\mathrm{H^+}\)) in a solution.
  • What is a base in biological terms?
    A substance that reduces hydrogen ion concentration by accepting \(\mathrm{H^+}\) or releasing hydroxide ions (\(\mathrm{OH^-}\)).
  • What is the pH scale?
    A logarithmic scale from 0 to 14 that measures the concentration of hydrogen ions in a solution.
  • What pH range is considered neutral?
    A pH of 7 is neutral, where hydrogen ion and hydroxide ion concentrations are equal.
  • What role do buffers play in biological systems?
    Buffers minimize pH changes by accepting or donating hydrogen ions to maintain homeostasis.
  • What are the four major classes of biological macromolecules?
    • Carbohydrates
    • Lipids
    • Proteins
    • Nucleic acids
  • What is a polymer?
    A large molecule made by linking many similar or identical monomers through covalent bonds.
  • How are polymers formed and broken down?
    Formed by dehydration synthesis (removal of water) and broken down by hydrolysis (addition of water).
  • What is the basic structure of a carbohydrate?
    Composed of carbon, hydrogen, and oxygen with a general formula \((CH_2O)_n\).
  • What are monosaccharides?
    Simple sugars like glucose that serve as fuel and building blocks for carbohydrates.
  • What distinguishes starch from cellulose?
    Starch is a storage polysaccharide in plants; cellulose is a structural polysaccharide in plant cell walls.
  • What are lipids and their main function?
    Hydrophobic molecules including fats, phospholipids, and steroids; they store energy and form membranes.
  • Describe the structure of a fat molecule.
    Composed of glycerol linked to three fatty acids via ester bonds.
  • What is the difference between saturated and unsaturated fatty acids?
    Saturated fatty acids have no double bonds; unsaturated have one or more double bonds causing kinks.
  • What is the role of phospholipids in cells?
    They form the bilayer of cell membranes with hydrophilic heads and hydrophobic tails.
  • What are proteins made of?
    Polymers of amino acids linked by peptide bonds.
  • Name the four levels of protein structure.
    • Primary: amino acid sequence
    • Secondary: alpha helices and beta sheets
    • Tertiary: 3D folding
    • Quaternary: multiple polypeptides
  • What is the function of nucleic acids?
    Store and transmit genetic information (DNA and RNA).
  • What are the components of a nucleotide?
    A nitrogenous base, a pentose sugar, and one or more phosphate groups.