Cells and Mitosis
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Transcript of Cells and Mitosis
© 2004 Wadsworth – Thomson Learning
Prokaryotic and Eukaryotic Prokaryotic and Eukaryotic CellsCells
© 2004 Wadsworth – Thomson Learning
PROKARYOTIC VS. EUKARYOTIC
Prokaryotic No nucleus No membrane-
bound organelles Cell wall contains
peptidoglycan Size: less than
several micrometers
Eukaryotic Nucleus Membrane-bound
organelles No peptidoglycan if
cell wall even present Size: may be 10 times
larger
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PROKARYOTES--CELL STRUCTURE
Appendages on outside Capsule and envelope
outer membrane (some) periplasmic space
between two membranes cell wall (most) cytoplasmic membrane
Cytoplasm nucleoid ribosomes storage granules Figure 4.3
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PROKARYOTES: OUTER MEMBRANE
Lipid bilayer phospholipid lipopolysaccharide (LPS)
endotoxin lipid A porins lipoprotein
anchors to cell wall unique to bacteria
Figure 4.5
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PROKARYOTES: CELL WALL Provide shape Withstand turgor pressure
(osmotic pressure) Composition
peptidoglycan: murein part protein (peptido-) part polysaccharide (-glycan) chains of alternating
polysaccharide N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM)
cross-linked with peptidesFigure 4.6
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SPHERICAL BACTERIA
Cocci (Coccus) single pair
diplococcus group of four
tetrads chain
streptococcus clusters
staphylococcus
Figure 4.7
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ROD-SHAPED BACTERIA
Bacilli (Bacillus) Arrangement
single pair
diplobacillus chain
streptobacillus
Figure 4.7
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SPIRAL AND OTHER SHAPED
Spiral shaped spirilla (spirillum)
Comma shaped vibrio
Other Square Star-shaped
Figure 4.7
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CYTOPLASMIC MEMBRANE Contain the cytoplasm Both Eucaryotic and Procaryotic regulate passage into and out of cell Components
phospholipid bilayer proteins
transmembrane cytoplasmic peripheral
Fluidity of membrane
Figure 4.8
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PROKARYOTES: APPENDAGES
Pili (Pilus) or fimbriae attachment
Flagella (flagellum) locomotion
propeller-like motion structure
helical-shaped filament hook
attached to anchor basal body
anchors in membrane Figure 4.10
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PROKARYOTES: MOVEMENT
Chemotaxis sense chemicals
Phototaxis sense light intensity
Aerotaxis favorable oxygen
concentrations Magnetotaxis
move along magnetic lines
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PROKARYOTES: CHEMOTAXIS Run: swimming motion
propelled by flagella working in unison Tumble: senses the chemical concentration
flagella loosen apart repeat actions changing direction slightly
Figure 4.12
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PROKAYROTES: OUTERMOST LAYER
Capsule, slime layer, glycocalyx Slimy or gummy substance Composition varies Most made of polysaccharides
Function Protection
Against drying out Against phagocytosis
Adhere to surface pathogenesis
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PROKARYOTES: CYTOPLASM Primarily water Site of metabolism Nucleoid
region contains DNA Ribosomes
site of protein synthesis Inclusion bodies
storage granules Gas vacuoles Chlorosomes magnetosomes
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PROKARYOTES: ENDOSPORES
Resting structures formed inside cell Conditions unfavorable for growth
extreme heat dehydration toxic chemicals radiation
Long-term survival hundreds of years
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SPORULATON
Unequal cell division begins
Cytoplasm divides vegetative cell forespore
DNA in both parts
Figure 4.15
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SPORULATION Thick protective wall forms
peptidoglycan--different than vegetative cell keratinlike
Spore body contains all essential cell components
Vegetative cell lyses--releases endospore Germinates when conditions become favorable
Figure 4.15
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STRUCTURE OF ARCHAEA
Cell walls archaea have protein or
pseudomurein Plasma membrane
fatty acids attached to glycerol differently bacteria--ester bond archaea-ether bond
stronger bond withstand harsh
conditions
Figure 4.16
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EUKARYOTES: APPENDAGES
Flagella Purpose
motility wave-like motion (not propeller-like)
Composition microtubules
9 pair surrounding 2 central
Cilia shorter more numerous
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EUKARYOTES: CELL WALL AND CYTOPLASMIC MEMBRANE
Cell wall great diversity many cells don’t have (animal cells) composition varies
Cytoplasmic membrane similar to prokaryotes
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EUKARYOTES: CYTOSKELETON Function
structure movement
cytoplasmic streaming transport of molecules
cell division Fibrous protein
structures three types
Microtubules Microfilaments Intermediate filaments
Figure 4.17a
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EUKARYOTES: NUCLEUS
Function contain the DNA
Nuclear membrane lipid bilayer surrounding nucleus nuclear pores
passage of material Nucleoplasm
gelatinous matrix of nucleus Nucleoli
dense masses of RNA and protein
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EUKARYOTES:CYTOMEMBRANE SYSTEM
Function sorting and transport
of synthesized molecules
Components Endoplasmic reticulum
(ER) rough ER
ribosomes attached smooth ER
no ribosomes Figure 4.21
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EUKARYOTES:CYTOMEMBRANE SYSTEM
Golgi apparatus stacks of flattened
membrane sacs molecules are
modified
Vessicles transport from ER to Golgi from Golgi to final
destination inside the cell outside the cell
Figure 4.22
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EUKARYOTES:MITOCHONDRIA AND CHLOROPLASTS
Energy production Double membrane system
outer membrane--separate from rest of cell inner membrane--highly folded
Mitochondria respiration
Chloroplasts photosynthesis
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CELL DIVISION: MITOSIS
Cell division ending in two identical cells Stages:
Interphase DNA decondenses DNA replicated
Mitosis Prophase Metaphase Anaphase Telophase
Figure 4.19
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CELL DIVISION: MITOSIS
Early prophase double number of
chromosomes chromosomes condense
Late prophase spindle forms chromosomes condensed
Figure 4.19
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CELL DIVISION: MITOSIS
Metaphase chromosomes attach to
spindle fibers chromosomes line up
middle of cell
Anaphase chromosomes moved to
opposite ends of cell
Figure 4.19
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CELL DIVISION: MITOSIS
Telophase chromosomes
decondense nuclear membrane
reforms cell separation occurs
Interphase identical daughter cells
Figure 4.19