1. Topic 1.2 – Ultrastructure of Cells
PART 1
Comparing microscopes
Prokaryote structure and ultrastructure

2. NOS- Invention of Electron Microscope
Most progress in biology is due to the invention and improvements to microscopes
Compound Light Scopes:
Second half of 19th century
Larger (> .2 µm) cell structures were now clear and visible
Chromosomes (mitosis, meiosis)
Mitochondria, chloroplasts
Electron Microscopes:
Developed in 1930’s, regular use by 40’s and 50’s
Clear images produced for objects as small as .001µm
Dark green areas of chloroplasts were found to be small stacks of membranes (grana)
Mitochondria has intricate membrane structure
These structures are called “ultrastructures” because they are so small
Other things discovered- Ribosomes, lysosomes, and ER

3. Picture of Electron Scope
Video of crazy images

4. NOS- Your turn
Discuss how developments in scientific research follow improvements in an apparatus:

5. Comparing resolutions of Light vs Electron scopes
Define Resolution: Making the separate parts of and object distinguishable by the eye
Light
Electron
Visible light has a longer wavelength
Maximum res is .2µm (200 nm)
Limited by wavelength of light which is nm
Making stronger lenses doesn’t help because we cant’ change the wavelength
Electron beams have a shorter wavelength
Maximum res is .001µm (1 nm)
Why do electron microscopes have a stronger resolution at higher magnifications?
ans. Electron beams have a shorter wavelength allowing for higher resolution

6. Prokaryotic Cell Structure
Prokaryotic Cell Structure

8. What are the characteristics of a PROKARYOTIC cell?
No nucleus- DNA is “free floating” in a nucleoid
Found everywhere on Earth
Cell Membrane
Cell wall made of peptiodoglycan
Cytoplasm fills entire cell interior
NO compartments (compartmentalization)
Ribosomes are the only ultrastructure
70S (Svedburg units), smaller than those found in a eukaryote

10. 70S

11. 70S

13. 70S

16. Topic 1.2- Ultrastructure of Cells
Part 2: Eukaryotic Cells

17. Label the animal cell below

18. Eukaryotic cells are complex
What does it mean for a cell to be compartmentalized:
The cell is divided up into partitions composed of single or double membranes. Organelles are located in these compartments
Most important compartment is the nucleus
Compartments are known as organelles
What are the advantages of compartmentalization?
Enzymes and substrates are less spread out making reactions more efficient
Damaging substances can be kept within a certain area so they won’t harm the cell
Optimum pH for certain processes can be maintained in a specific location
Organelles can be moved around within the cell

19. How did eukaryotic cells evolve?

20. Note how it ACTUALLY LOOKS in the micrograph

21. Using your text p21-23 Label and bullet the job and description of the following structures in the diagram:
Nucleus-
Rough ER-

22. ER and ribosomes

23. Organelles con’t……
vesicle
Golgi Apparatus-
Lysosome-
Golgi
Lysosome

24. Organelles con’t……
Mitochondrion-
Free ribosomes-

25. Organelles con’t……
Chloroplast
Vacuoles-

26. Organelles con’t……
Microtubules-
Centrioles-

27. Organelles con’t….
Cilia-
Flagella-

30. Skills: Identifying ultrastructures in a micrograph; Drawing the ultrastructures based on a micrograph
Directions:
Using the handout provided, you will develop skills identifying and drawing eukaryotic cell ultrastructures

31. Exocrine Gland of Pancreas
Exocrine glands secrete digestive enzymes into small intestine
Enzymes are proteins, so which structures would we expect to see a lot of in these cells?

32. Exocrine gland cell of pancreas - Label the cell

33. Palisade mesophyll Cell -Label the visible structures

34. Comparing Eukaryotes and Prokaryotes:

35. Label the parts of the plant cell