2. Lecture 2 Outline (Ch. 6) I. Cell Background II. Organelles
A. Nucleus, ribosomes
B. Endomembrane System
C. Energy Organelles
i. Mitochondria
ii. Chloroplasts
III. Cytoskeleton
Extracellular Spaces
V. Lecture Concepts

3. How are cells studied?

4. Microscopy Bright field Transmission electron microscopy (TEM)
Contrast
Stained or unstained
Scanning electron microscopy (SEM)
Fluorescence
Laser scanning microscopy

5. Prokaryotes vs. Eukaryotes
- Archae and Bacteria
nucleoid (DNA)
ribosomes
pili
plasma membrane
cell wall
capsule
flagella
1-10μm

6. Prokaryotes vs. Eukaryotes
- Protists, Fungi, Plants, Animals
- Several organelles
- Larger
10-100μm
333 μm

7. Eukaryotic Organelles

8. Eukaryotic Organelles Nucleus – genetic material
• chromosomes (DNA + proteins)
• nuclear envelope
-double
bilayer
• nucleolus -ribosome RNA made
• nuclear pores
• nuclear matrix

9. Ribosomes – protein synthesis
• Made in nucleolus
• Made of RNA & proteins
• Bound or free
• Two subunits

10. Endomembrane System 1. Endoplasmic reticulum (e.r.)
• Extensive membrane
• Continuous with nuclear envelope
• Inside - lumen
• Two types – rough, smooth
– ”bleb” off in vesicles
Rough e.r. – proteins for membrane or secretion
Smooth e.r. – detoxification, lipid and carbohydrate synthesis

11. Endomembrane System 2. Golgi apparatus • Shipping and receiving
• Protein modification & direction
• Flattened sacs
• Vesiscles – transport around cell

12. Endomembrane System 3. Lysosomes • Cellular digestion • Not in plants
“phagocytosis”
“autophagy”
• Bleb off Golgi or cell membrane
• Acidic inside – food particles (a) or old cell parts (b)

13. Endomembrane System 4. Vacuoles • Storage/maintenance compartments
Plant cell
Animal cell
• Central vacuole
• Food vacuole
• Water vacuole
-contractile vacuole
• Disposal for by-products

14. Endomembrane System 5. Plasma membrane
• Lipid bilayer – selective barrier
• Membrane-associated proteins – depend on cell type
• Present in bacteria, animals, and plants

15. Endomembrane System

16. Energy production 1.Mitochondria • energy from nutrients  ATP
• Two membranes, each bilayer
-inner
-outer
• Folds – cristae
• Own DNA!
• Own ribosomes!
• Intermembrane space
• Matrix

17. Energy production 2. Chloroplasts • Light to chemical energy
• Only in plants
• Own DNA
• Own ribosomes
• Outer and inner membranes - bilayer
• Internal membranes – thylakoids, stacks called grana
• Spaces – intermembrane, stroma, thylakoid

18. Organelle summary In animal cells only: Lysosomes (Flagella)
In plant cells only:
Chloroplasts
Central vacuole

19. Self-Check Ribosomes Rough E.R. Smooth E.R. Golgi Plasma Membrane
Organelle Name
Function
Part of Endomembrane System?
In Bacteria? Plants? Animals?
Nucleus
Store genetic info no
P, A
Ribosomes
Rough E.R.
Smooth E.R.
Golgi
Plasma Membrane
Lysosomes
Vacuoles
Mitochondria
Chloroplasts
Cytoskeleton

20. Cytoskeleton overview
• Shape/support
• Cell movement
• Internal transport
• Cell division
Unique to eukaryotic cells - essential to cell survival/function

22. Cytoskeleton Components
Three types of cytoskeletal elements:
• Actin filaments (microfilaments)
• Intermediate filaments
• Microtubules

23. Actin filaments • Localized at membrane • Cell movement
• Muscle fiber contraction
• Cytoplasmic streaming (plants)
• Pseudopodia

24. Microtubules • Radiate from center
• Internal transport, motile structures
• Inside flagella
• Make centrioles
• Inside cilia

25. Intermediate filaments
• Dispersed throughout cell
• Strength/support
keratin
• Animal cells
lamins

26. Extracellular Spaces – Cell wall
• In plants
- made of cellulose
Why?
• plasma membrane
• secondary wall
• primary wall
• Thick
• cells connected

27. Extracellular Spaces – Extracellular Matrix
• Animal cells - glycoproteins
Ex. collagen
• ECM – cell communication, movement

28. Extracellular Spaces – Junctions
• Animal cells - three types
tight junctions
(seal cells)
2. desmosomes
(anchoring)
3. gap junctions
(communicating)

29. Lecture 2 concepts
List at least 3 types of microscopy and pros & cons for each
Explain differences between prokaryotic and eukaryotic cells
*For each organelle mentioned, list the name, function and whether it is present in bacteria, plant, & animal cells*
Name the three fibers of the cytoskeleton and describe the function for each one
Discuss the cell wall in plants, include purpose and material
Explain the extracellular matrix of cells, include purpose and material/composition
Describe how plant and animal cells are connected
Write out a list of new terminology and provide descriptions