1. Ch. 7: A tour of the cell

2. So, how do we know what we know about cells?????
Methods of study cells and cellular components
Microscopes
Resolving Power
LM vrs EM (TEM, SEM)
isolation of organelles
cell fractionation techniques

3. Prokaryote

4. Eukaryotes, Plant or Animal

5. So, why aren’t there huge cells out there?????
The ratio of cell surface to cell volume determines how large a cell can be.
Sufficient surface area to serve their volume
e.g. RBC - functional advantage of size

6. Plasma Membrane Lipid Bilayer (phospholipids) Proteins Carbohydrates
Fluid Mosiac Model

7. Nucleus and Ribosomes Nucleus: Ribosomes Genes, DNA
Double membrane (each a lipid bylayer)
Nuclear Lamina (mesh lining for shape)
Pores, Pore Complex
Chromatin
Chromosomes
Nucleolus (ribosomal RNA made)
Ribosomes
Build cell proteins (Protein Synthesis)
Ribosomal RNA and Proteins
Free Ribosomes: suspended in cytosol
Bound Ribosomes: attached to outside of ER or Nuclear Envelope.
Free R = use inside cytosol
Bound R = organelle w/ protein or export

8. Endomembrane System System of interactive organelles
Direct physical contact or
Transfer of membrane bound vesicles
Nuclear Envelope ER
Golgi
Lysosomes
Vacuoles
Plamsa membrane

9. Endoplasmic Reticulum
½ the total membrane of the cell
Network of tubules and cisternae (sacs)
Continuous with nuclear membrane
Smooth ER
Synthesis of lipids
Enzymes for detoxification of drugs (liver)
Drug Tolerance due to stimulation of sER
Rough ER (bound ribosomes)
Secretory proteins wrapped in membrane of vesicles
Transport Vesicles
Makes membrane phospholipids

10. Golgi Apparatus Manufacturing, warehouse, sorting, and shipping center
Receives products of ER
Polarity of membrane sacks
Cis Face: near ER, receiving side
Trans Face: shipping side
Modification occur between Cis and Trans
Identification Tags added to product

11. Lysosomes Membrane bound sacks of hydrolytic enzymes Lysosomal Enzymes
Low pH (cytosol neutral pH)
Phagosytosis
Autophagy: recycle their own organic material
Apoptosis (programmed cell death)
Tadpole’s tail
Human fingers

12. Mitochondria Cellular Respiration (all euK’s)
Catabolic process (ATP production
Free ribosome make membrane
Own DNA for own proteins
2 lipid bilayer membranes
Inner membrane w/ folds called Cristae (increase surface area)
Intermembrane space
Mitochondrial Matix
Outer membrane: Smooth

13. Chloroplasts Stacks of organelles (plastids)
Contains pigment, enzymes, for photosynthesis (Chloroplasts have chlorophyll pigment)
Thylakoids
Granum: stacks of thylakoids
Stroma: fluid outside of thylakoids

14. Peroxisomes Transfer H to O producing H2O2
Contains peroxidase to break down toxic H2O2
Liver: detoxifies alcohol

15. Cytoskeleton Structural Support Cell Motility Three main Molecules
Movement of cell
Movement of organelles
Three main Molecules

16. Cilia and Flagella Core of microtubules sheathed in plasma membrane.
“9+2” pattern
Dynein Arms
Radial Spokes
Basal Bodies: anchorage to cell

17. ECM Extracellular Matrix: glycoproteins secreted by the cell.
Collagen: ½ total protein of the body
Proteoglycans: embedded in collagen, rich in carbohydrates.
Fibronectin: glycoprotein of ECM, binds to receptor called Integrins found in cell membrane (in/out).
Communication from inside cell to ECM

18. Intercellular Junctions
Cells organized into tissue, organs b/c of Junctions.
Types:
Plasmodesmata: channels allows for cytosol to pass, unifies plant.
Tight Junctions: membranes of neighboring cells fused. Prevents leakage of extracellular fluids.
Desmosomes: (anchoring junctions) like rivets. Strong sheet w/ intermediate filaments extending in.
Gap Junctions: (communication junction) cytoplasmic channels, proteins around pores to control border.

19. Lysosome

20. Cytosol

21. Nucleus

22. Ribosomes

23. Plasma Membrane

24. Golgi Apparatus

25. Endoplasmic reticulum

26. Intercellular junctions: “Just try and figure out who we are!”
1. We are protein “belts” that hold cells so tightly together that we prevent the movement of things between our cells.
2. We are rivets that join cells together in strong sheets, but still allow things to pass between cells. We made of glycoprotein filaments.
3. We allow things to transport between the cytoplasm of adjacent cells. We are membrane proteins. We allow your heart to beat as a unit.
Tight junctions
Desmosomes
Gap Junctions