Welcome to BSCI 230
Spring, 2001

(Please be certain to purchase the syllabus/lab manual in the Stamp Union Book Center!)

Your BSCI 230 Staff:
 

  •     Dr. Reid Compton, Course Coordinator
  •     Mr. James Carpenter, Laboratory Coordinator


    • Graduate Teaching Assistants

  •     Ahmed Hafez (1104 & 1108)
  •     Ernie Hixon (1102 & 1107)
  •     Juliet Healy (1103 & 1105)
  •     Shelly Grow (1101 & 1106)


    • Dr. Know-it-all
    William J. Higgins
    Associate Professor of Biology
    Associate Dean, LFSC

    And in some future lecture, Dr. Higgins will discusses his research...
    Testosterone makes you stupid !
            (Higgins's Rule #1)

    Higginsís Rule #2
            Running is bad for you!

    and now, we review the syllabusÖ.

  •     If youíre not registeredÖÖ..
  •     Attendance, lecture tapes and conversation
  •     Visiting with Dr. Know-it-all
  •     Examination dates
  •     Regrade policy
  •     Make Up examinations
  •     If youíre not dead, youíre taking the exam.
  •     Grading contract
  •     Optional Recitation sections
  •     Lecture policies
  •     Web site and notes
  •     Entertainment


    • Life is Everywhere!
            (Just an observation which has always fascinated your Professor.)

    Higginsís Rule # 3:
    In the end, entropy always wins. Organisms are organized entities that constantly combat it.
     

    Every cell faces three problems relating to size:

  •     Surface Area to Volume ratio
  •     Diffusion distances

    •  
  •     What is the relationship between a linear dimension and surface area?
  •     What is the relationship between a linear dimension and volume?

    •  
    [Figures Included:  Circle vs. Cube]
  •     Concentration of required substances in intracellular fluids

    •  

     

    Diffusion across cell membrane depends upon surface area

    Diffusion:  J = -DA Dc/Dx

  •     J = Rate of diffusion in moles per unit time
  •     D = diffusion coefficient of the membrane
  •     A = area of the membrane
  •     Dc = concentration difference across the membrane
  •     Dx = thickness of the membrane

    •     Think of examples in the human body where cells and tissues have specific modifications designed to maximize rate of diffusion.
     

    What about cell size and diffusion?

    How does distance effect the rate of diffusion?

    Diffusion velocity increases with the square of the distance:
     
     
    Diffusion Distance (mm)
     Time Required
    1 
    0.5 msec
    10
    50 msec
    100
    5 sec
    1000 (1mm)
    8.3 min
    10,000 (1 cm)
    14 hours

     

    Cell solute concentration:
    Cells must accumulate certain solutes at specific concentrations
    Large cells (large intracellular volumes) would require large amounts of solutes
     

    Every cell faces three problems relating to size:

  •     Surface Area to volume ratio
  •     Diffusion distances
  •     Concentration of required substances in intracellular fluids

    •  

     

    Prokaryotes and Eukaryotes
    Prokaryotes (bacteria)

    Eukaryotes

    Prokaryotes vs. Eukaryotes
    See Table 4-1 for summary of differences

    Basically:

  •     Size
  •     Intracellular membrane-bounded structures
  •     Intracellular filaments
  •     Method of cell division
  •     Structure of ribosomes
  •     DNA - protein complexes
  •     Processing of RNA
  •     Prokaryotes and Eukaryotes

    • You should read the chapter and know this stuff!

    Five Important Principles from Chapter 2

  •     Why Carbon?
  •     Whatís so special about water?
  •     Selective permeability
  •     Polymerization of small molecules
  •     Self assembly of macromolecules


    • Why Carbon?
    Versatile structure due to 4 unpaired outer shell electrons - 4 bonds
    Easily forms bonds with H, O, and N
    Bonds form at different angles for molecules of different shapes
    See Figures 2-2 and 2-3 for energetic considerations

    Why Carbon?
    Adding O and/or N gives us functional groups:
    -OH - Hydroxyl
    CH3 - Methyl
    NH2 - Amino
    see Figure 2-5 and know these groups!
    Water

    Properties of Water
    Hydrogen bonds (polar interactions as opposite charges attract) hold it together
    Water molecules are cohesive

    Properties of Water
     

  •     Itís a liquid at most surface temperatures on Earth
  •     Surface tension and capillary action
  •     High boiling point (high specific heat)
  •     High heat of vaporization
  •     Good solvent for other polar molecules
  •     Forces nonpolar molecules to adhere together in an organized structure
  •     @ 4oC it is most dense so it freezes from top down
  •     It ionizes


    • It ionizes!!!
    Ionization of Water
    H2O <----> H+ + OH-

    In pure water, [H+ ] = [OH-]
    [H+] in solution
    [H+] in pure water =0.0000001M
    or 10-7 moles/liter

    so: Log10 [H+ ] = -7

    and: - Log10 [H+ ] = 7
    [H+ ] or pH
    pH is a way to express the [H+ ]
    pH = -Log10 [H+ ]

    Add a base, [H+] decreases and pH increases
    Add an acid, [H+] increases and pH decreases

    pH Quiz:

    If [H+ ] = 0.001 M, pH = ????

    If [H+ ] = 10-5 M, pH = ???

    If Log of [H+ ] = - 10, pH = ????

    pH of Various Solutions:
     

  •     Stomach acid = pH of 1
  •     Coca Cola = pH of 3
  •     Water = pH of 7
  •     Baking soda = pH of 9
  •     Oven cleaner = pH of 13
  •     Drain cleaner = pH of 15

    •  

     

    Why is pH (i.e., [H+ ]) Important?

    Next time in BSCI 230:

  •     The Higgins Plan for doing well in this course
  •     The remaining 3 Principles from Chapter 2
  •     Introduction to the macromolecules of the cell
  •     Structure and function of proteins
  •     Chapters 2 and 3