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
IV. Extracellular Spaces
V.
Lecture Concepts
How are cells studied?
Microscopy
Bright field
Transmission electron
microscopy (TEM)
Stained or unstained
Contrast
Scanning electron
microscopy (SEM)
Fluorescence
Laser scanning microscopy
Prokaryotes vs. Eukaryotes
Prokaryotes:
- Archae 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
Nucleus – genetic material
• chromosomes
(DNA +
proteins)
• nucleolus
-ribosome
RNA made
• nuclear pores
• nuclear matrix
Ribosomes – protein synthesis
• Made in nucleolus
• Made of RNA
& proteins
• Bound or free
• Two subunits
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
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 – food particles (a) or old cell parts (b)
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 bacteria, animals, and plants
Endomembrane System
Energy production
1.Mitochondria • energy from nutrients  ATP
• Two membranes, each bilayer
-inner
• Folds – cristae
-outer
• Own DNA!
• Intermembrane space
• Own ribosomes!
• Matrix
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
Organelle summary
In animal cells only:
Lysosomes
(Flagella)
In plant cells only:
Chloroplasts
Central vacuole
Self-Check
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
Cytoskeleton overview
• Shape/support
• Cell movement
• Internal transport
• Cell division
Unique to eukaryotic cells - essential to cell survival/function
Cytoskeleton Components
Three types of cytoskeletal elements:
• Microtubules
• Actin filaments
(microfilaments)
• Intermediate
filaments
Actin filaments
• Localized at membrane
• Cell movement
• Muscle fiber contraction
• Pseudopodia
• Cytoplasmic streaming (plants)
Microtubules
• Radiate from center
• Internal transport, motile structures
• Inside flagella
• Inside cilia
• Make centrioles
Intermediate filaments
• Dispersed throughout cell
• Strength/support
keratin
• Animal cells
lamins
Extracellular Spaces – Cell wall
• In plants
- made of cellulose
Why?
• plasma
membrane
• secondary wall
• primary wall
• Thick
• cells
connected
Extracellular Spaces – Extracellular Matrix
• Animal cells - glycoproteins
Ex. collagen
• ECM – cell communication, movement
Extracellular Spaces – Junctions
• Animal cells - three types
1. tight junctions
(seal cells)
2. desmosomes
(anchoring)
3. gap junctions
(communicating)
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