Biology 172 Lecture 2

  1. What are the branches on the Tree of Life called?
  2. Ribosomal ribonucleic acid sequences can be used to produce a ____________ _____ showing probable evolutionary relationships
    Phylogenetic tree
  3. Closely related species should have rRNA sequences that are .....
    more similar than those from distantly related species because they share a more recent common ancestor
  4. rRNA performs the same function in all sequences but .....
    the nucleotide sequences differ
  5. Similarities reveal evolutionary relationships. Characteristic; Peptidoglycan in cell wall
    • Bacteria: Present
    • Archaea: Absent
    • Eukaryotes Absent
  6. Similarities reveal evolutionary relationships. Characteristic; RNA polymerase types
    • Bacteria: one
    • Archaea: Several
    • Eukaryotes: Several
  7. Similarities reveal evolutionary relationships. Characteristic; Initiator amino acid for protein synthesis
    • Bacteria: Formyl-methionine
    • Archaea: Methionine
    • Eukaryotes: Methionine
  8. Similarities reveal evolutionary relationships. Characteristic; Response to antibiotics
    • Bacteria: Killed
    • Archaea: Not Killed
    • Eukaryotes: Not Killed
  9. Archaea are more similar to ________
    Eukaryotes than bacteria
  10. What is a cell?
    All cells are enclosed by a plasma membrane that regulates passage of materials in and out of the cell
  11. All cells use ___ for their genetic information
  12. Aristotle
    proposed the concept of "cell" nearly 2000 years before the 1st cells were seen; concluded there must be an ultimate unit of life
  13. Robert Hooke
    1665, the first view of the cell. Hooke looked at oak bark and named the cavities cells. The pore-like compartments are cork cells from oak bark.
  14. Anton von Leeuwenhoek
    1665, was the first to view single-celled "animalcules" in pond water. Shows paramecium, also look at human blood cells, and sperm cells.
  15. Theodor Schwann
    1839, all organisms are composed of cells
  16. Rudolf Virchow
    1858, all cells come from pre-existing cells, not spontaneous generation
  17. Louis Pasteur
    1860, all cells come from pre-existing cells, not spontaneous generation
  18. (most) cells are ________
  19. Four Parts of Cell Theory
    • 1. Cells are the Structural Unit of Life
    • 2. Cells are the Functional Unit of Life
    • 3. All Cells are Fundamentally Similar
    • 4. All Cells come from Pre-existing Cells
  20. 1st Part of Cell Theory
    All organisms are composed of cells
  21. 2nd Part of Cell Theory
    • Cells are the smallest entities that have all the properties of life.
    • Each cell is (or can generate) an entire organism
  22. 3rd Part of Cell Theory
    • similar structure and organization
    • similar metabolic strategies
    • similar hereditary information
    • However specific cell functions can vary Cell Specialization
  23. 4th Part of Cell Theory
    • via cell growth and division
    • life does not arise from non-life
  24. Everything we know about cells was determined _________
  25. Fact
    an observation that has been repeatedly confirmed
  26. Hypothesis
    a proposed explanation, or a testable statement that can be used to build more complex explantations
  27. Law
    about how some aspect of the natural world behaves under stated circumstances, a descriptive generalization; does not explain why something happens - just describes it
  28. Theory
    an overarching explanation that is well-substantiated and that can incorporate facts, laws, inferences, and tested hypotheses
  29. 5 steps of the Scientific Method
    • 1. Make observations, ask questions
    • 2. Form a hypothesis, and don't forget the null hypothesis (consider what are the results when wrong)
    • 3. Make predictions
    • 4. Test predictions, include controls
    • 5. Revise hypothesis based on results and repeat
  30. what can you prove with an hypothesis
    You can never prove a hypothesis; you can only eliminate it by showing that the predictions are false
  31. Image Upload 1
  32. Usually easier to control lab experiments but ....
    but then must consider if lab experiments will be true in real life
  33. Atoms are most stable when ....
    each orbital has two electrons
  34. Covalent Bond
    when each atom's unpaired electrons are shared by nuclei to fill their orbitals, and atoms share pairs of valence electrons
  35. Nonpolar covalent bond
    Electrons are shared equally
  36. Polar covalent bonds
    Electrons are not shared equally so partial charges exist (more electronegative atom has stronger pull)
  37. Ionic Bond
    • Electrons are completely transferred from one atom to another
    • Cation (+) and Anion (-)
    • Ionic compounds are salts
  38. Hydrogen Bond
    • Weak bond
    • Very Important in the chemistry of life
    • Between two atoms with very different electronegativities
  39. Van der Waals Bond
    Transient 'hot spots' of positive and negative charge in a molecule with nonpolar covalent bonds; creates weak interactions when molecules are very close
  40. What is the most abundant molecule in organisms
  41. Properties of Water
    • Great Solvent (substances dissolve easily in it)
    • The H--O bonds in water are polar covalent
    • Water is polar
    • Liquid water is denser than ice
  42. Life originated in and is based on water because ....
    water is a great solvent
  43. _________ bonds from between water molecules
    Hydrogen bonds, which help the substances stay in solutions.
  44. What does and does not dissolve readily in water
    • Polar molecules and ions dissolve readily in water (salt dissolves in water)
    • Nonpolar molecules do not dissolve readily in water
  45. In ice, water molecules form a _______ _________. In liquid water no ______ ______ forms
    crystal lattice
Card Set
Biology 172 Lecture 2
Biology 172 Lecture 2 Exam Review