1. Department of Cancer and Cell Biology
Principles of Cell Biology for Engineers I 20-MECH-871       Section 023    Call #
Sarah Pixley
Univ. of Cincinnati
College of Medicine
Department of Cancer and Cell Biology

3. Dr. Pixley (UC)

5. NSF funded Engineering Research Center: Revolutionizing Metallic Biomaterials
Partners: North Carolina A&T State Univ.; Univ. of Pittsburgh; Univ. of Cincinnati (Engineering & Medical Schools)
Global Partner: Hannover Medical School, Germany
Outreach Partners: California State Univ., Los Angeles; Edmunds Community Col., WA; Guilford County Community Col., NC
Global Outreach/Cultural Partner: Indian Institute of Technology, Madras, India

6. What is a Cell?
The cell is a glorified soap bubble! So, what is the difference?

7. Cells defy Entropy!

8. & a bunch of organelles (Structural & Functional Compartmentalization)
A typical animal cell
& a bunch
of organelles
(Structural
&
Functional
Compartmentalization)
Cytoplasm
(cytosol+
Organelles)
Size : s mm
Lodish 5e

9. The basic structure of the cell membrane is a
phospholipid (fat) bilayer:
two layers of lipid (fat)
molecules.
Figure Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)

10. Lipids with a polar head group (hydrophilic) (red ovals) and one fatty acid tail
(hydrophobic) (red stick) form “cone” shapes and form micelles in water.
Lipids with two fatty acid tails have an effective “cylinder” shape and form bilayers.
Figure Molecular Biology of the Cell (© Garland Science 2008)

11. Figure 2-22 Molecular Biology of the Cell (© Garland Science 2008)

12. Figure 10-8 Molecular Biology of the Cell (© Garland Science 2008)

13. But it is a long way from a simple lipid bilayer to the cell!
Let’s get going!
Figure Molecular Biology of the Cell, Fifth Edition (© Garland Science 2008)

14. Cellular world
Prokaryotic - No nucleus, simple organization (ex: bacteria)
Eukaryotic - well-defined nucleus and other organelles (ex: yeast, fly, mammals, etc….)
In all cases: cellular contents are surrounded by a lipid bilayer called: The unit membrane = plasma membrane = cell membrane

15. (building block: DNA) Structure of a Prokaryotic Cell chromosome
E-Coli (1-2 mm)
Lodish 5e

16. Electron micrograph of a bacterium
Lodish 5e

17. Membrane bilayer Plasma membrane Chromosome (building block: DNA)
Structure of an Eukaryotic Cell
Membrane bilayer
Plasma membrane
Chromosome
(building block: DNA)
ribosome
cytosol
Size : s mm
Lodish 5e

18. Electron micrograph of an eukaryotic cell
Lodish 5e

19. Let’s look at
Sizes!
Figure Molecular Biology of the Cell (© Garland Science 2008)

20. 25 µm
100 µm
Figure Molecular Biology of the Cell (© Garland Science 2008)

21. Figure 9-1 Molecular Biology of the Cell (© Garland Science 2008)

22. Figure 9-2 Molecular Biology of the Cell (© Garland Science 2008)

23. Visualizing Cells Microscopy:
Light microscopy (LiteM): In theory, resolution limit is ~0.2 µm = 200 nm, but practical limit is ~0.4 µm.
Resolution: you can distinguish 2 points (not 1) if they are 0.2 µm apart.
Regular microscopy: uses regular light sources
Confocal microscopy: uses laser light sources
Electron microscopy (EM): practical limit of resolution: ~0.1 nm. “Light” source: electrons
Transmission EM: electrons go through specimen
Scanning EM: electrons bounce off surfaces of structures

24. LiteM
Figure 9-3b Molecular Biology of the Cell (© Garland Science 2008)

25. Stained (after fixation)
Unstained (live)
Nucleus
Cells B A
LiteM
Two cells in B are packed with pigment granules in their cytoplasm,
so you can see the entire cell. Otherwise, you can only vaguely see nuclei.

26. Procedures to visualize unstained (live) cells
differential interference (Nomarski)
conventional
phase-contrast
LiteM

27. LiteM

28. Hematoxylin and Eosin (H&E)
dyes
staining
Hematoxylin and Eosin (H&E)
Hematoxylin is a positively charged blue dye, that will bind to negatively charged (acidic) cell structures (e.g. DNA, RNA). Structures that bind hematoxylin are referred to as basophilic (base dye-loving (philic)).
Eosin is a negatively charged red/pink dye, that will bind to positively charged (basic) cell structures (e.g. proteins, mitochondria). Structures that bind eosin are referred to as acidophilic ( acidic dye-loving).

29. Hematoxylin and Eosin (H&E)
Nuclei (blue)
Cytoplasm
(red/pink)
LiteM

30. Cytoplasm
(red/pinkish)
Whole Cell
LiteM
Nuclei (blue)

31. Immunofluorescence More complicated (more details later in course).
Basically: Use the immune system to find molecules (antibodies) that bind to just one cell type or just one protein, organelle or type of molecule in a cell.
Fix a fluorescent molecule on the binding molecule (antibody with attached fluorescent molecule).
Use a light microscope, but to visualize the fluorescence, add filters that only let one wavelength of light through to your eye or the camera (you only see the color put out by the fluorescent molecule).
You can combine 2 or more colors in one view.

32. Immunofluorescence Microscopy
This is ONE cell!
Blue = nucleus
Green = the
microtubules
inside the cell
(cytoskeleton)
Red = the
microfilaments
inside the same
cell.
LiteM
Figure Molecular Biology of the Cell (© Garland Science 2008)

33. Electron microscopy
transmission electron microscopy (TEM)
scanning electron microscopy (SEM)
SEM
TEM

34. TEM In TEM, proteins and DNA/RNA Appear dark. Most fatty substances
Are washed out and appear light.
No colors at the EM level.

35. TEM

36. TEM Ergastoplasm (old name) is now called: endoplasmic reticulum (ER).
Shown is
rough ER (RER)

37. SEM

38. SEM LiteM TEM unstained
Figure Molecular Biology of the Cell (© Garland Science 2008)