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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

Cell Structure Prokaryotic before nucleus Eukaryotic true nucleus

Antonie van Leeuwenhoek 1632-1723 Developed microscopes for observing living organisms 1674 discovered live protist cells 1677 discovered spermatozoa 1682 discovered striated muscle fibers http://www.ndpteachers.org/perit/Leeuwenhoek.JPG

http://www. molecularexpressions http://www.molecularexpressions.com/primer/images/introduction/leeuwenhoek.jpg http://www.cartage.org.lb/en/themes/Sciences/Physics/Optics/OpticalInstruments/Microscope/GlassSphere/usph_01.gif http://cell.sio2.be/introduction/images/microleeuw.jpg http://students.ou.edu/J/Renee.E.Jones-1/Van%20leeuwenhoek%20Scope.jpg

Mouth “animalcules” (bacteria) 1684 http://en.citizendium.org/images/thumb/9/94/Leeuwenhoek.jpg/300px-Leeuwenhoek.jpg

Cell Theory 1839 Theodor Schwann Prussian Zoologist 1810-1882 http://content.answers.com/main/content/img/scitech/HSmatthi.jpg http://home.tiscalinet.ch/biografien/images/schwann.jpg Theodor Schwann Prussian Zoologist 1810-1882 Matthias Schleiden German Botanist 1804-1881 1. All living organisms consist of one or more cells. 2. Some organisms are unicellular, so cells are the fundamental unit of life. 3. New cells come from pre-existing cells by cell division. We can now add: 4. Cells must show all the properties of life. 5. All cells are basically similar in chemical and structural composition.

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 Endosymbiosis: Eukaryotes are Chimeras!

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

Prokaryotic Cell Shapes Coccus - cocci Bacillus - bacillus Spirillum - spirilli Vibrio - vibrios

Scanning Electron Microscope (SEM) image..the shape? http://www.up.ac.za/academic/electron/bacteria.jpg

Light microscopy would be even less detailed! Ribosomes This is a cartoon image created by an artist to emphasize certain structures. Plasmids Cytoplasm Chromosome Flagellum This is a transmission electron microscopy image that inspired the cartoon. Light microscopy would be even less detailed! Plasma membrane Cell wall Figure 7-1 Page 120

The cytoplasm area shows the nucleoid (DNA) area at the top. This cartoon is not labeled, so it merely acts as a key, to orient the viewer to the enlarged portion of the TEM image. Cytoplasm The cytoplasm area shows the nucleoid (DNA) area at the top. The cell membrane shows that it is a bilayer. The cell wall shows that it is multilayered. Plasma membrane Cell wall Figure 7-2 Page 121

This diagram shows you a further enlargement of a TEM. The DNA double helix is further twisted to form the coils you are seeing here. DNA Supercoiled DNA in chromosome Figure 7-3 Page 121

Those found in the eukaryotic cytosol are 80S in “size.” Ribosomes are 70S in “size” in prokaryotes, mitochondria, and plastids. Those found in the eukaryotic cytosol are 80S in “size.” Ribosome Large subunit of ribosome Small subunit of ribosome Figure 7-4 Page 121

Cyanobacteria carry out photosynthesis with chlorophyll bound to proteins in thylakoid membranes Photosynthetic membranes Figure 7-5 Page 122 This is an artificially-colored micrograph from transmission electron microscopy (TEM)

Cyanobacterial Vegetative Cell (photosynthesis) cell wall mesosome cell membrane cyanophycean starch cyanophycin vacuole lipid droplet polyphosphate granule thylakoids 70S ribosome nucleoid polyhedral body http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/CBDivideTEM.jpg

? ? Transmission Electron Microscope (TEM) image..the shape? http://library.thinkquest.org/3564/Cells/cell91.gif

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 http://web.pdx.edu/~kstedman/MEDIA/Sulfolobus.jpg Shape?

Bacterium of the Genus: Leptospira TEM or SEM? Shape? Bacterium of the Genus: Leptospira http://phil.cdc.gov/PHIL_Images/02142002/00001/PHIL_138.tif

What are the shapes of these disease bacteria? http://microbewiki.kenyon.edu/images/a/a8/V_cholerae.jpg Vibrio cholerae Helicobacter pylori Are they motile? If so, by what mechanism? http://www.cab.unimelb.edu.au/images/helico.jpg

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 200-1700 rps (>12,000 rpm!) Taxis: movement toward stimulus Exceptions: phototaxis: movement toward light 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)) chemotaxis: movement to chemicals

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 - 3.5 billion years!

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

Cell Associations ? Coccus Diplococcus Streptococcus - filamentous Staphylococcus - colonial ? Streptobacillus

What shapes and associations are shown in these SEMs? http://www.hhs.gov/asphep/presentation/images/bacteria.jpg

An artificially colored TEM of a cyanobacterium. Thylakoids contain chlorophyll a (green) Metabolism? Association? Shape? http://genome.jgi-psf.org/anava/anava.jpg

Anabaena --a cyanobacterium w/ division of labor Vegetative Cells (Photosynthesis) Akinete (hypnospore) Heterocyst (N2 fixation) http://www.ac-rennes.fr/pedagogie/svt/photo/microalg/anabaena.jpg

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 http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/Heterocyst.jpg

Cyanobacterial Akinete (hypnospore) cell wall cell membrane cyanophycean starch polyhedral body lipid droplet polyphosphate granule vacuole cyanophycin thylakoids nucleoid http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/AkineteEMBlue400.jpg

Germinating akinetes (producing vegetative filaments) http://www-cyanosite.bio.purdue.edu/images/lgimages/oreg4.jpg

Internal Membranes and Organelles How do Prokaryotic and Eukaryotic Cells Differ? Location of DNA Internal Membranes and Organelles Cytoskeleton Overall Size Bacteria and Archaea In nucleoid area but may have plasmids or replicons Mesosomes, thylakoids, vacuoles Limited except in spirochetes Normally about size of mitochondrion Eukaryotes In nucleus surrounded by envelope, but also in mitochondrion, chloroplast Large number of and kinds of organelles, endomembrane system Extensive microtubules and microfilaments Most are much larger than any prokaryotic cell Adapted from: Pearson Benjamin Cummings © 2008 Figure 7-5-Table 7-1 Page 122