1. Chapter 6 Biology – Campbell • Reece
A Tour of the Cell
Chapter 6
Biology – Campbell • Reece

2. How We Study Cells… Microscopes Magnification
Resolving Power or resolution
3 types of microscopes:
Light Microscopes – a beam of light passes through the object, magnify up to 1000x, resolution of 0.2µm
Transmission Electron Microscope (TEM) – passes a beam of electrons through the object, greater magnification, resolution of 2nm
Scanning Electron Microscope (SEM) – passes a beam of electrons over the surface of the object, creates a 3-D image

4. Compound Light Microscope

5. Transmission Electron Microscope

6. Scanning Electron Microscope

7. Isolating Organelles
Cell fractionation – take cells apart and separate the major organelles
Homogenization – the disruption of cells
Centrifuge at low speed – separates the “soup” into a pellet and a supernatant
The supernatant is then centrifuged at higher speed
The process is repeated multiple times at higher speeds

8. Cell Fractionation

9. Prokaryotic vs. Eukaryotic
All cells have: plasma membrane, cytosol, chromosomes, and ribosomes
Prokaryotic cells
No membrane-bound nucleus
Ex. bacteria
Eukaryotic cells
Have a membrane-bound nucleus
Usually larger than prokaryotic cells
Ex. Human skin cell

10. Surface Area vs. Volume
Larger organisms do not generally have larger cells, they have more cells

13. REMINDER:
You are responsible for the information cell parts & organelles (pages )
Questions on the test may come from these pages!!!

14. Extracellular Matrix
Although they do not have a cell wall, animal cells do have an extracellular matrix made up of collagen, proteoglycans, fibronectins, and integrins

15. Intercellular Junctions
Plasmodesmata – channels in cell walls (connects one plant cell to another)

16. Intercellular Junctions
3 types in animal cells
Tight junctions – membranes of neighboring cells are fused
Ex. between skin cells
Desmosomes (anchoring junction) – cells held together by filaments
Ex. attach muscle cells to each other
Gap junctions – cytoplasmic channels between adjacent animal cells (similar to plasmodesmata)

17. Intercellular Junctions (in animal cells)