Exam 1 Test

Chapter 1

  • Scientific data supports or refutes a hypothesis.
  • Independent variables are manipulated; dependent variables are measured.
  • Null hypothesis: no effect of the independent variable on the dependent variable.
  • Scientific method order: Observation, Hypothesis, Prediction, Experiment, Conclusion.
  • Scientific literacy: understanding of basic scientific fundamentals.

Chapter 2

  • Phosphorus (P) with 5 outer shell electrons wants to share 3 electrons to form covalent bonds.
  • All matter is made up of atoms.
  • Subdividing an atom results in loss of essential properties.
  • Water has polarity due to oxygen's electronegativity, leading to dipole formation.
  • Bond strength ranking: Covalent > Ion-dipole > Hydrogen > Induced dipole-induced dipole.
  • Uncharged atom: protons = electrons.
  • Atomic weight: weighted average of atomic masses of isotopes.
  • pH decreases as [H+][H^+] increases.
  • Sodium (Na) electron distribution: 2 in the first shell, 8 in the second, 1 in the third.
  • Buffers absorb/release H+H^+ to maintain pH.
  • Atomic particles: Protons determine the element; electrons form ions; neutrons form isotopes.

Chapter 3

  • Enzymes decrease activation energy, increasing reaction rate.
  • Side chain determines unique amino acid properties.
  • 20 amino acids commonly in proteins; 9 are dietary essentials.
  • Cholesterol and sex hormones are sterols.
  • Plasma cell membranes are mostly phospholipids.
  • DNA contains 4 nucleotides: adenine, cytosine, thymine, guanine.
  • Excess glucose converts to glycogen for short-term storage.
  • Eggs are a complete protein.
  • All macromolecules contain carbon.

Chapter 4

  • Tight junctions form water-tight seals.
  • Desmosomes hold cells together but allow fluid passage.
  • Gap junctions allow direct molecule movement between cells.
  • Bacteria are NOT eukaryotic.
  • Large molecules enter cells via endocytosis.
  • Hypertonic solution: higher solute concentration outside the cell.
  • Prokaryotic cells lack a nucleus.
  • Plant cells (not animal cells) contain chloroplasts and a cell wall (cellulose).
  • Plasma membrane components: Glycerol, Phosphate (hydrophilic), and Fatty acids (hydrophobic).
  • Transport types: Primary active transport (ATP needed directly), Osmosis (no ATP), Simple diffusion (no ATP), Secondary active transport (ATP needed indirectly), Facilitated diffusion (no ATP).
  • Cytoskeleton:
    • Microfilaments: cell contraction and division (smallest diameter).
    • Microtubules: intracellular movement (largest diameter).
    • Intermediate filaments: durable, provide cell strength (intermediate diameter).
  • Organelle Functions:
    • Nucleus: genetic control center.
    • Ribosome: protein synthesis.
    • Smooth ER: lipid synthesis and detoxification.
    • Rough ER: modifies proteins.
    • Golgi Body: packages molecules for export.
    • Lysosome: waste breakdown and recycling.
    • Mitochondria: ATP production.