Lecture 2 Outline (Ch. 6)
I. Prokaryotes vs Eukaryotes
II. Organelles Overview
III. Endomembrane System
IV. Energy Organelles
VI. Cytoskeleton
VII. Extracellular Structures
VIII. Summary
Prokaryotes vs. Eukaryotes
Prokaryotes:
- Archaea and Bacteria
nucleoid (DNA)
ribosomes
plasma membrane
cell wall
capsule
pili
flagella
1-10μm
Eukaryotes:
- Protists, Fungi, Plants, Animals
- Several organelles
- Larger
Prokaryotes vs. Eukaryotes
10-100μm
333 μm
Eukaryotic Organelles
Eukaryotic Organelles Nucleus – genetic material
• chromosomes (DNA + proteins)• nuclear envelope
-double bilayer
• nuclear pores• nuclear matrix
Nucleolus makes rRNA
Chromosomes/DNA
Eukaryotic Organelles Nucleus – genetic material
Ribosomes – protein synthesis
• Made in nucleolus
• Bound or free • Two subunits
• Made of RNA & proteins
• Free – make cytoplasmic proteins
Bound Ribosomes Build Membrane & Exported Proteins
Ribosomes – protein synthesis
Ribosomes – protein synthesis
Eukaryotic Endomembrane System
Endomembrane System – shipping and transport in cells
Lipid SynthesisDetoxify Drugs
Membrane FactoryAdds Carbohydrates to
Glycoproteins
Endomembrane System
1. Endoplasmic reticulum (e.r.)
• Two types – rough & smooth
Endomembrane System
”bleb” off in vesicles
• Extensive membrane
• Continuous with nuclear envelope
• Inside is the lumen
2. Golgi apparatus• Shipping and receiving
• Flattened sacs
• Vesiscles – transport around cell
• Protein modification & direction
Endomembrane System
3. Lysosomes
• Cellular digestion
• Not in plants
• Bleb off Golgi or cell membrane
• Acidic inside – break down (a) food particles or (b) old cell parts - both by HYDROLYSIS
Endomembrane System
“phagocytosis” “autophagy”
Plant cell
4. Vacuoles • Storage/maintenance compartments
• Food vacuole
• Water vacuole
-contractile vacuole
• Disposal for by-products
• Central vacuoleAnimal cell
Endomembrane System
5. Plasma membrane
• Lipid bilayer – selective barrier
• Membrane-associated proteins – depend on cell type
Endomembrane System
• Present in ALL CELLS
MitochondriaHarvest Chemical Energy
ribosomes and own DNA
ribosomesand own DNA!
ChloroplastLight to Chemical
Energy
Question: Why do mitochondria and chloroplasts have their own DNA and ribosomes?
Cytoskeleton - Eukaryotes
Thick!
Thin!Intermediate filaments – Intermediate!
• Radiate from center
• Internal transport, motility, cell division
Cytoskeleton - Microtubules
• Inside flagella
• Inside cilia • Make centrioles
• Localized at membrane
• Cell movement
Cytoskeleton - Actin filaments
• Muscle fiber contraction
• Pseudopodia
• Cytoplasmic streaming (plants)
• Throughout cell to support shape
• make up nuclear lamina, and mesh outside nucleus
Example: keratins
Cytoskeleton - Intermediate filaments
• fibers linked into sheets, then ropes
Extracellular Spaces – Cell wall
• In plants
- made of cellulose
• Thick
• cells connected through cell wall
• plasma membrane
• cell wall
• cell wall
• Animal cells - glycoproteins Ex. collagen
• ECM – cell communication, movement
Extracellular Spaces – Extracellular Matrix (ECM)
• Animal cells - three types
1. tight junctions (no-leak)
2. desmosomes (flexible)
3. gap junctions (communication)
Extracellular Spaces – Junctions
Organelle 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
Cytoskeleton
Cell Wall
ECM