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General Biology: Water, Carbon, and Biomolecules

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Terms in this set (28)

  • Why is water essential for life?

    Water's unique chemical and physical properties arise from its molecular structure and polarity, enabling key biological functions.

  • What causes water molecules to be polar?

    Water molecules have a partial negative charge near oxygen and partial positive charges near hydrogen atoms, creating polarity.

  • What is hydrogen bonding in water?

    Hydrogen bonds form between the polar water molecules, leading to cohesion, adhesion, and surface tension.

  • Why does ice float on liquid water?

    In ice, stable hydrogen bonds form a lattice that makes ice less dense than liquid water, allowing it to float and insulate aquatic life.

  • Define temperature in terms of molecular motion.

    Temperature is the average kinetic energy of molecules in a substance.

  • What is water's specific heat and its biological importance?

    Water has a high specific heat, requiring much energy to change temperature, which helps maintain homeostasis.

  • Explain heat of vaporization of water and its role in cooling.

    Water absorbs significant heat when evaporating, aiding cooling mechanisms like sweating.

  • What is a solution in biological terms?

    A solution is a mixture of a solute (dissolved substance) and a solvent (dissolving substance), often water.

  • Differentiate hydrophilic and hydrophobic substances.

    Hydrophilic substances are polar or charged and dissolve in water; hydrophobic substances are nonpolar and do not dissolve.

  • How do acids and bases affect hydrogen ion concentration?

    Acids increase hydrogen ion (\(H^+\)) concentration; bases decrease it.

  • What does the pH scale measure?

    The pH scale is a logarithmic measure of hydrogen ion concentration in a solution.

  • What is the role of buffers in biological systems?

    Buffers resist pH changes by absorbing or releasing hydrogen ions to maintain stable conditions.

  • Why is carbon central to organic molecules?

    Carbon forms four covalent bonds, allowing diverse molecular structures essential for life.

  • What are hydrocarbons?

    Hydrocarbons are molecules composed only of carbon and hydrogen.

  • Name three ways carbon bonding varies in organic molecules.

    Variation occurs in backbone length, double-bond position, and branching or ring formation.

  • List key functional groups and one property each imparts.

    Methyl (-CH3): nonpolar, affects gene expression.
    Hydroxyl (-OH): polar, forms alcohols.
    Carboxyl (-COOH): acidic.
    Amino (-NH2): basic.
    Phosphate (-PO4): negative charge.
    Sulfhydryl (-SH): forms disulfide bonds.

  • How are biological macromolecules formed and broken down?

    Formed by dehydration synthesis (removing water) and broken down by hydrolysis (adding water).

  • What are the monomers and bond types of carbohydrates, proteins, and nucleic acids?

    Carbohydrates: monosaccharides, linked by glycosidic bonds.
    Proteins: amino acids, linked by peptide bonds.
    Nucleic acids: nucleotides, linked by phosphodiester bonds.

  • What are the main functions of carbohydrates?

    Energy storage and structural components, e.g., starch for energy and cellulose for structure.

  • Describe the four levels of protein structure.

    Primary: amino acid sequence.
    Secondary: alpha-helix and beta-sheet.
    Tertiary: 3D shape from R group interactions.
    Quaternary: multiple polypeptide chains.

  • What causes protein denaturation?

    Loss of structure due to heat, pH changes, or salt concentration.

  • What role do chaperone proteins play?

    Chaperones assist in refolding denatured proteins to restore function.

  • What are nucleotides composed of?

    A phosphate group, a pentose sugar (ribose or deoxyribose), and a nitrogenous base.

  • Which nitrogenous bases are purines and which are pyrimidines?

    Purines: adenine and guanine.
    Pyrimidines: cytosine, thymine, and uracil.

  • How do base pairs pair in DNA?

    In DNA, adenine pairs with thymine and cytosine pairs with guanine.

  • What are the main types of lipids and their functions?

    Triglycerides store energy; phospholipids form membranes; steroids like cholesterol aid structure and signaling; waxes provide protection.

  • What is the structure of triglycerides?

    One glycerol molecule linked to three fatty acids, used for energy storage.

  • Why are phospholipids amphipathic?

    They have hydrophilic heads and hydrophobic tails, making them ideal for cell membranes.