welcome to bioengineering 555courses.washington.edu/bioe555/lecture1.pdfpollack, cells, gels and the...
TRANSCRIPT
Welcome to Bioengineering 555 !!
Main Text:
Pollack, Cells, Gels and the Engines of Life
Optional texts:
Alberts et al., Molecular Biology of the CellLing, G.N., A Revolution in the Physiology of the Living CellHoward, J., Mechanics of Motor Proteins and the CytoskeletonPollack, Muscles and Molecules:
Uncovering the Principles of Biological Motion
Grading:
Homework
25%Presentation(s) 20%Classroom participation
10%Midterm exam
20%Final Exam
25%
Session Date
Topic
Reading Due
Week 1
3/30
Introduction: scope of course4/01
Pumps, channels and membranes
Ch 1, 2 <http://uwtv….>4/03
Student presentations
A
Hillman, 1994B
Schiff, 1994C
Kolata, 1976+Ling, 1997
Week 2
4/06
Cytoplasm, Cell water
Ch. 3; Ch. 4 to p. 624/08
Cell water
Rest of Ch. 44/10
Student presentations
A
Vybiral, 2005B
Pashley and Kitchener, 1979C Granick, 1991
Format
Due at Friday sessions:
Short summary of reading assignment (several paragraphs)
A, B, or C
Class website
http://courses.washington.edu/bioe555/ind ex.shtml
Grader:
Marisa Sylvester -
• Questions?
• Presentation assignments
• Book distribution
• Introductions
A sampling of things to come…
Sustenance
Cell movement…
Cut cell experiment:(Maniotis and Schliwa, 1991) Anomalies:
Why does leading edge keep moving?
How does cell survive without membrane?
.
.Cell-membraneIntegrity…
additional examples of cell function w/o intact membrane
How could membrane integrity be less than essential?
If cytoplasm is a gel
The cell is long known to be a gel…
What is a gel?
elastic modulus > viscous modulus;can sustain steady shear without flow;Supreme Court definition
How the cell’s gel-like nature will help in understanding its function
• movement
• contraction (muscle)
• division
• electrophysiology
• secretion
• etc.
What holds the water inside the gel?
• osmotic theory* *read in chem book
• ordered water theory
Water is a dipole
water molecule
polymer
liquid crystal(excludes solutes)
2009 To here….
gel
200 µm
PAAPAA gel
Nafluorescein
nafion
may extend far
IMPLICATION:
Gel contains polymers + liquid crystalline water
Why doesn’t Jello (95% water) leak?
• Water dipoles stick to surface, and stick to one another
What do you think is the maximum water / polymer ratio
in a gel?
10,000 : 1 (Osada and Gong, 1993)
.
First part of course:
• gels
• water
• role of gels and water in fundamental biological processes, particularly movement and mechanics
• phase transition…
temperature, solvent composition, pH, ions, electric field, UV light, specific molecules or chemicals
Polymer gel phase transition
gel
Implications for movement, muscle contraction
Some mysteries associated with water
• hydrated wedge cracks rock
• egg white excludes dyes
• torsion pendulum shows progressive resistance
• freezing time (boiled vs. stagnant)
• “Jesus Christ”
Lizard
• water memory
brain stimulation…
end