Download Prokaryotic and Eukaryotic Cells Two Main Classes

Prokaryotic and Eukaryotic
Cells
Two Main Classes of Cells
• Prokaryotic (Bacteria and Archaea)
– Pro = “Before”; Karyon = “Kernel”
– No nucleus, DNA coiled up inside cell
• Eukaryotic (Everything else)
– Eu = “True”
– DNA inside membrane bound organelle inside
cell, the nucleus
3 Domains of Life
Eukaryotic Cell (non bacterial)
Prokaryotic Cell (bacteria)
Cell Size: Prokaryotes and eukaryotic cell
Size Differences
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Prokaryotic Diversity: K. Monera
Prokaryotic Cell
• 4000 described species
– Estimated range 400,0004 million sp.
• Minimal structural
diversity
• Tremendous metabolic
diversity
• Ecological roles and
pathogenesis
Bacterial Size, Shape and Arrangement
Coccus
Bacillus
Spiral
The Capsule: Frederick Griffith, 1928
Prokaryotic Cell
Gram staining: A clinical tool for distinguishing cell wall composition
(Gram-positive and gram-negative bacteria)
• Enhances virulence: attachment and resistance
• Forms the foundation of “biofilms”
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Common bacterial CELL WALL
structures as revealed by Gram staining:
Bacterial Motility: Flagella
Gram positive:
thick peptidoglycan
cell wall
Gram negative:
thin peptido. wall +
outer memb.
Bacterial Growth: Binary fission
a simple division process
Ecological Importance Bacteria and
Cyanobacteria
• Nutrient Cycling:
–
–
–
–
Decomposers
Carbon fixation
Nitrogen fixation
Others
• Symbioses:
– Mutualistic: +/+
– Commensalistic: +/o
– Parasitic: +/-
Movie 1
• Foreign pathogens
• Opportunistic pathogens
Movie 2
Prokaryotes
• Low morphological diversity (how they looks)
• HUGE metabolic diversity!
All organisms can be divided into either of two major
groups based upon their pattern of cell structure:
Characteristic Prokaryotic Cell
size
ave. size 1-10 µm
nucleus
nucleoid
(no membrane)
single circ. loop of
naked DNA
absent
chromosomes
organelles
ribosomes
flagella
cell wall
cell reproduction
present as smaller 70S
form
Solid core made of
flagellin
present in most sp. as
peptidoglycan
binary fission
Eukaryotic Cell
ave. size 10-100 µm
membrane bound
linear, arranged with
histones in pairs
present, vary with
cell function
present as larger 80S
form
9+2 arrangement of
microtubules
absent or different in
composition
mitosis and sexual
reproduction
3
Animal Cell
Plant Cell
Evolution of Eukaryotic Cells
Eukaryotic Cell Structure: The Factory
• Limits of the P.M.
– Surface area revisited
• Differentiation of P.M.
• Formation of Organelles
–
–
–
–
Compartmentalized Reaction centers
Increase Membrane Surface area
More efficient Metabolism
Increase DNA…which means?
• Leads to Eukaryotic cells…
• Plant and Animal Cell Structure
– Nucleus: the control center
– Cytoplasm and Ribosomes: site of protein synthesis
– Endoplasmic Reticulum: plumbing, lipid and protein
synthesis
– Golgi Apparatus and the secretory pathway
– Lysosomes: digestive activity
– Chloroplasts and Mitochondria: food and ATP energy
– Vacuoles: storage/digestion
– Cytoskeleton: structure and movement
– Plant Cell Wall: structure, osmosis and turgor pressure
• Family Photos-- structural and functional
specializations
Animal Cell
The Nucleus
•Chromatin= DNA +
proteins
•Nucleolus= site of
ribosome production
•Endomembrane
system
•Interrelated
membrane
“network” inside
of cell
4
The Nucleus and Protein Synthesis
Ribosomes
The “real” Ribosomes
• Protein Synthesis
• Free- endogenous proteins
• Bound- secretory and membrane bound proteins
The Endoplasmic Reticulum
How the Rough ER Works
• Huge Surface Area
• General functions
• Rough endoplasmic
reticulum (RER)
– Makes more membranes,
– Modifies proteins
• Smooth endoplasmic
reticulum (SER)
– Makes lipids, steroids,
hormones, etc
– Detox in the liver
– Storage
5
The Golgi Apparatus
ER and Golgi complex
Storage, refinement, and shipping of ER
products
Works in partnership with ER
Lysosomes
Figure 4.10 Lysosome formation
•Sacks of digestive
enzymes which break
down molecules and
organelles in the cells
•Digest food, fight
invaders, clean house
•pH of 5
•Apoptosis
•Disorders
Vacuoles
Plant Cell
• Sacks which can store enzymes, proteins,
water, and cellular byproducts, waste.
• Plants cells often have large Central
Vacuole which holds water and other stuff
• Vacuoles also transport things from one
organelle to another within
the cell
6
Vacuoles
Mitochondria and Chloroplasts
• Role in Energy Transformation
– Photosynthesis
– Cellular respiration
• Evolution
– Endosymbiosis Theory
The Chloroplast
•Most of the
living world
depends on
chloroplasts for
its energy!
The Mighty Mitochondria
Sites of cellular respiration and ATP
synthesis
•Two membranes
on outside
•Complex
membrane
structure on inside
The Cytoskeleton
Cilia and Flagella
The “skeleton, muscles and highway” of a cell
7
A comparison of the beating of flagella and cilia
Support and Joining of Cells
Support and Joining of Cells
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