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Biology: What is Life? life study of Properties of Life
Cellular Structure: the unit of life, one or many Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy Growth: cell enlargement, cell number Movement: intracellular, movement, locomotion Reproduction: avoid extinction at death Behavior: short term response to stimuli Evolution: long term adaptation
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Cell Structure Prokaryotic before nucleus Eukaryotic true nucleus
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Comparing Cell Sizes Mycoplasma 0.3-0.8 µm E. coli 1x2 µm
Cyanobacteria 10 µm diam Plant Cell 30x75 µm Obviously eukaryotic Nucleus present Mitochondrion Bacterium Chloroplast Cyanobacterium
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Cell Structure: Boundary
Mycoplasma Water and enzymes for fermentation, glycolysis, Kreb’s cycle, Calvin cycle, naked circular DNA for transcription, 70S ribosomes for translation cell membrane bilayer glycolipid, sulfolipid transport proteins cytosol regulates input/output ETS for PSN, Resp Gram Positive Gram Negative cell wall-murein peptidoglycan muramic acid - peptide prevents dye release prevents bursting turgor pressure penicillin sensitive additional membrane bilayer glyco- sulfo-lipids releases dye
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Prokaryotic Cell Shapes
Coccus - cocci Bacillus - bacillus Spirillum - spirilli Vibrio - vibrios
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Scanning Electron Microscope (SEM) image..the shape?
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? ? Transmission Electron Microscope (TEM) image..the shape?
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Sulfolobus acidocaldarius
TEM or SEM? Of Archaeon Extremophile Sulfur metabolism pH 1 to 6 75°C Optimum Strict aerobe Partial monolayer (C40) membranes Multiple DNA Circles Introns in DNA DNA binding proteins rRNA similarity RNA synthase similarity Operon style regulation 70S ribosomes Shape?
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Bacterium of the Genus: Leptospira
TEM or SEM? Shape? Bacterium of the Genus: Leptospira
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What are the shapes of these disease bacteria?
Vibrio cholerae Helicobacter pylori Are they motile? If so, by what mechanism?
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Cell Structure: Movement
hook directional rotation? basal rings and rod anchorage rotation stiff helical flagellum flagellin protein is rotated by “motor apparatus” in the membrane by H+ ATPase at rates of rps (>12,000 rpm!) Taxis: movement toward stimulus Exceptions: myxomycetes, some cyanobacteria use slime, but how? spirochetes have flexible internal microtubules (endosymbiotic source of flagella in eukaryotes?) ((gut parasite in termites have spirochete symbiosis)) phototaxis: movement toward light chemotaxis: movement to chemicals
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Prokaryotic Growth Cells are generally very small
Cells may double in size but only before binary fission Growth mostly in terms of cell number or colony size, etc. Doubling time in cell numbers may be 20 minutes in ideal conditions Could quickly take over the earth if conditions could remain ideal Very competitive in ideal environments Ultimate survivors billion years!
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Cell Structure: Nucleoid
Nucleoid - genome one circular DNA molecule no histone protein association attached to cell membrane transcription by RNA polymerase replication by DNA polymerase separation of chromosomes cytokinesis by furrowing 70S Ribosome Process called binary fission NOT mitosis! Genome and copy are identical Genome is haploid There is no synapsis There is no recombination rRNA + protein + ribozymes translation of mRNA into protein
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Cell Associations ? Coccus Diplococcus Streptococcus - filamentous
Staphylococcus - colonial ? Streptobacillus
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What shapes and associations are shown in these SEMs?
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An artificially colored TEM of a cyanobacterium.
Thylakoids contain chlorophyll a (green) Metabolism? Association? Shape?
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Anabaena --a cyanobacterium w/ division of labor Vegetative Cells
(Photosynthesis) Akinete (hypnospore) Heterocyst (N2 fixation)
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Cyanobacterial Vegetative Cell (photosynthesis)
cell wall mesosome cell membrane cyanophycean starch cyanophycin vacuole lipid droplet polyphosphate granule thylakoids nucleoid polyhedral body
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Cyanobacterial Heterocyst (N2 fixation)
cell wall O2 block cell membrane nucleoid mesosome ETS for O2 reduction cytosol Nitrogenase reduces N2 (requires anaerobic conditions) pore in wall fuel input for respiration
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Cyanobacterial Akinete (hypnospore)
cell wall cell membrane cyanophycean starch polyhedral body lipid droplet polyphosphate granule vacuole cyanophycin thylakoids nucleoid
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Germinating akinetes (producing vegetative filaments)
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Cell Structure Prokaryotic before nucleus Eukaryotic true nucleus
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How Many Kingdoms? Extant Eukaryotes ARE Chimeras! Extinct
Multicellular Animals Myxozoans Protozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes Euglenoids Archezoans Archaea Bacteria Eukaryotes ARE Chimeras! Cyanobacterium endosymbiosis Extinct Eubacterium endosymbiosis Though sketched here as single events, these endosymbioses were very likely multiple events! Original Cell
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Archezoans “Protozoan parasites without mitochondria or Golgi”
Oldest nucleated cells Diverged from other Eukaryotes 2bybp… prior to ER and Golgi evolution Lack peroxisomes Ribosomes are 70S but NOT 80S 400 species (many more likely unknown parasites!) Three phyla: Archaeamoebae/Pelobiontida (Pelomyxa) Metamonada (Giardia) Microsporidia
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Pelomyxa palustris Pseudopodia Endosymbiotic bacteria
Free-living in freshwater sediment (microaerophilic) Phagocytosis active Uroid Accumulate glycogen reserves At least 3 species of endosymbiont in each cell…two species are methanogenic archaeons! Glycogen body Anterior uroid (macropseudopodium) for amoeboid movement Vacuoles Smaller pseudopodia do not enlarge
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Reproduction: Mitosis of nucleus Cytokinesis by furrowing Nuclei
“Daughter” Amoeba What would you suggest has been a large component of this individual’s phagocytosis diet?
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wood particles and bacteria
Trichonympha Termite gut protist symbiont lacking mitochondria Protist has bacterial endosymbionts making cellulase for digesting wood particles taken in by phagocytosis And spirochete ectosymbionts for motility spirochetes nucleus wood particles and bacteria
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Euglenozoa Flagellated protists which can be photosynthetic
Odd features Protein pellicle instead of cell wall Odd mitochondria (discoid cristae) so unique endosymbiont Chromosomes remain condensed during interphase 400 species (many more likely unknown parasites!) Two sub-phyla: Kinetoplasta (Trypanosoma gambiense) sleeping sickness Euglenoida (Euglena) photosynthetic, chlorophyll a,b, paramylum
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Euglena gracilis Posterior extension Mitochondrion Pyrenoid Nucleus
Chloroplasts Paramylon grain Protein pellicle (striations) Contractile vacuole Eyespot Anterior invagination With internal short flagellum Long flagellum rooted here also (not shown)
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How Many Kingdoms? Extant Euglenoid mitochondria are unique!
Multicellular Animals Myxozoans Protozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes Euglenoids Archezoans Archaea Bacteria Chlorophyte algal endosymbiosis Euglenoid mitochondria are unique! Eukaryotes ARE Chimeras! Cyanobacterium endosymbiosis For euglenoids, the chloroplast is a secondary endosymbiosis. Extinct Eubacterium endosymbiosis Though sketched here as single events, these endosymbioses were very likely multiple events! Original Cell
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How Many Kingdoms? Extant Eukaryotes ARE Chimeras! Extinct rough ER
Multicellular Animals Myxozoans Protozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes Euglenoids Archezoans Archaea Bacteria Chlorophyte algal endosymbiosis For brown algae, the chloroplast is also a secondary endosymbiosis. rer Eukaryotes ARE Chimeras! Cyanobacterium endosymbiosis Extinct Eubacterium endosymbiosis rough ER nucleomorph phaeoplast Original Cell
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Comparing Cell Sizes Mycoplasma 0.3-0.8 µm E. coli 1x2 µm
Cyanobacteria 10 µm diam Plant Cell 30x75 µm Obviously eukaryotic Nucleus present Mitochondrion Bacterium Chloroplast Cyanobacterium
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Eukaryotic Cell Structure
Middle Lamella-pectin glue Cell Wall-cellulose+protein Cell Membrane-phospholipid -transport proteins Chloroplast -photosynthesis 70S ribosomes naked, circular DNA Cytosol-enzymes for -fermentation -glycolysis Mitochondria -respiration 70S ribosomes naked, circular DNA Nucleus-DNA linear histone bound -transcription -replication Vacuole -toxic waste processing Endoplasmic Reticulum -internal transport 80S Ribosomes -protein synthesis -translation Vesicles -import/export package Golgi Apparatus -sorting -packaging Other eukaryotic organelles have been omitted here!
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Protist, Plant, Animal, Fungus?
TEM, SEM, Light Microscopy? Natural or Artificial Coloring? cell wall cellulose + protein + wax chloroplast photosynthetic endosymbiont nucleus RNA transcription, DNA replication vacuole toxic waste processing cytosol fermentation, glycolysis, etc. gas space cooling and gas exchange
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TEM or SEM? of a Plant or Animal Cell?
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? Cell: a mesophyll protoplast
(Cell wall was digested off by cellulase) TEM, SEM, or Light? cell membrane import/export chloroplast photosynthesis ? nucleus transcription replication vacuole toxic waste processing cytosol fermentation glycolysis natural or artificial coloring?
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? ? ? Protist, Plant, Animal, Fungus? endoplasmic reticulum
endoplasmic reticulum internal transport ? 80S ribosome translation nucleus transcription, replication RNA ? ? DNA cytosol fermentation, glycolysis zymogen granule protein storage enzyme secretion mitochondrion respiration
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Saccharomyces: yeast from kingdom? Fungi Mitosis nearly complete
Cytokinesis via furrowing (budding!) ? ? Cell wall: chitin not cellulose ? ?
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