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