1. Lecture 2 Monday, January 26, 2004 Survey Introduction continued :CSK, tensegrity. Basic cellular components

3. Geodesic- Buckminster Fuller A geodesic dome uses a pattern of self-bracing triangles in a pattern that gives maximum structural advantage, thus theoretically using the least material possible. (A "geodesic" line on a sphere is the shortest distance between any two points.)

4. Nucleus connected to the CSK, modeled with straws.

5. Tensegrity

6. How does the CSK provide structure? Some results are not compatible with tensegrity model Signals travel at speed of sound, as expected for a tensegrity model. With or without microtubules

7. Percolation: an alternate theory

8. Malines, BelgiumFibroblast

9. Pulling out the chromosomes A micropipet can suck up the end of a chromosome and then the entire 23 Can be pulled out, indicating they are all connected.

10. Cells incorporate into Nano-fabricated devices Attaching to needles Stretching on a cantilever Growing on electrodes

11. The generic cell Basic structure And components

12. Building blocks Water Cl, Na, K, Ca, Mg (50) - Electrolytes Fatty acids-lipids- (200) Phospholipids Amino Acids- (115) Proteins Sugars- (100) Carbohydrates Sugars + Bases (200) Nucleotides 30-200 Daltons 10 3 -10 6 Daltons I.e number of aa’s for spectrin = 230,000 D 115 H2OH2O

13. CompoundFraction in Cell (%) Relative Size of molecule Polarity of molecule Water70-80SmallPolarized Protein (Polypeptide) 10-20LargeRegionally polarized Lipid (Fat) 2-20MediumNon-Polarized Carbohydrate (Sugars) 1-2Medium to large Regionally polarized Salts (Electrolytes) 1SmallPolarized

15. Lipid vesicles are ghost-like 3. Vesicles pass through each other. 2. Pipet pushes vesicle out. 1. Vesicles make contact

20. Proteins Primary, secondary, tertiary, quaternary structures Make filaments: rods, tubes, Flexural Stiffness

26. Rod Bending

27. Polymer Length-stiffness Persistence length

28. Acid-base reactions determine charge, that determines mechanical properties. HA pKa=pH +log[HA] [A-] H + + A -

29. Cartilage Cell inside is a gel : a state of matter whereby electro-osmosis produced by charged polymers causes water pressure inside.

30. Structure by light & immunofluorescence PMT Filter

31. Fibroblasts are stained with Phallacidin green for F actin, Texas red for microtubules, and DAPI for nucleic acid. F actin microtubules

32. F actin is green with Phalloidin, G actin is red with Texas red. Nucleus has fewer stress fibers, but is thicker than rest of cell, so red is diffuse. F actinG actin

33. Studying the CSK: “Knock-out” methods Spectrin Actin Microtubules Intermediate Filaments Heat Cytochalasin Nocodazole Acyrlamide

34. Swelling and Lysis to measure membrane strength RBCs Muscle 3% 50% Frog

35. Pipet Aspiration Neutrophils are WBCs involved in immune response. The source of cortical tension is unknown, but may be from actin tangential to surface.

37. Cells are Wiggly and Soft New ways to describe softness- difference between cooked and uncooked noodles: thermal fluctuations. Neutrophils are WBCs involved in immune response. The source of cortical tension is unknown, but may be from actin tangential to surface.

38. Fibroblast dividing