history the cell chapter 1 invention of the microscope hans and zacharias janssen - 1590 galileo galilei - 1609 giovanni faber robert hooke -1665 - Micrographia anton van leewenhoek - 1676 schleiden & schwann cell theory basic properties of cells three basic tenets all organisms are composed of cells cell is the structural unit of life cells only arise from division of other cells cells can be cultured HeLa cells Torsten Wittmann / Photo Researchers, Inc. complex but organized cells from different species share characteristics each type of cell exhibits structural consistency cells are structurally conserved possess genetic information can produce proteins can copy themselves acquire and utilize energy MI Walker / Photo Researchers, Inc.
basic properties of cells carry out chemical reactions metabolism have mechanical activity motor proteins can respond to stimuli robustness cells evolve all cells evolved from LCA two main types of cells prokaryotic Archaea and Bacteria eukaryotic Eukarya Fungi, Animalia, Plantae, Protists scale prokaryotic microns (micrometers, µm) nanometers (nm) size constraints surface area-to-volume ratio no nucleus DNA packaged up in unbound nucleoid region single circular DNA no true membrane-bound organelles reproduction by binary fission most diverse and numerous cells Ribosome Bacterial flagellum DNA of nucleoid Plasma membrane Cell wall Capsule Pilus Cytoplasm
eukaryotic nucleus separated by complex nuclear membrane complex chromosomes complex organelles complex cytoskeletal system possess ability to phagocytize particles cellulose cell wall in plants divide through mitosis/ cytokinesis 5 different RNA polymerases plant cell nuclear envelope nucleoplasm nucleolus rough endoplasmic cell wall plasma membrane plasmodesmata mitochondrion ribosomes vesicle cytosol chloroplast smooth endoplasmic peroxisome golgi complex tonoplast microtubules animal cell cytoplasm cytoskeleton: microtubule microfilament intermediate filament microvilli centrosome: pericentriolar material microtubule secretory vesicle lysosome smooth endoplasmic peroxisome mitochondrion microtubule flagellum cilium proteasome free ribosomes nucleus: chromatin nuclear pore nuclear envelope nucleolus glycogen granules cytosol rough endoplasmic bound ribosome golgi complex microfilament prokaryota relatively simple eukaryota cytosol cytoskeleton ribosomes From O. Medalia, et al, Science 298:1211, 2002, Figure 3a. 2002, reprinted with permission from AAAS. Photo provided courtesy of Wolfgang Baumeister
organelles prokayotes none eukaryotes membrane bound organelles nucleus ER golgi apparatus mitochondria chloroplasts vacuoles cellular reproduction prokaryotes eukaryotes involves mitosis / meiosis spindle fibers Courtesy Conly Rieder Courtesy Charles C. Binton, Jr., and Judith Carnahan flagella prokaryotes simple protein filaments that rotate quickly eukaryotes complex Courtesy of Charles C. Brinton, Jr., and Judith Carnahan From Bernhard R Gerber, et al, J.Mol. Biol.,71:317-323. 1972, with permission from Elsevier Courtesy ML DePamphillis and Julius Adler prokaryotic diversity Archaea often extremophiles Bacteria includes mycoplasma includes cyanobacteria general diversity identified by specific DNA sequences species concepts perhaps not appropriate
prokaryotic diversity identification culture - only 0.1% identifiable by traditional means DNA sequencing metagenomes eukaryotic origins Eukaryotic diversity endosymbiont theory -- symbiogenesis mitochondria - eubacteria chloroplasts - cyanobacteria heterotrophic eukarya autotrophic eukarya eukarya fungi, protista, plantae, animalia unicellularity protist groups, algae multicellularity evolved multiple times specialization of cells differentiation Carolina Biological Supply / Phototake
Eukaryotic diversity sponges Osculum Flagellum Choanocyte Collar Food particles in mucus Choanocyte Eukaryotic diversity Spongocoel Individual choanoflagellate Pore Spicules Phagocytosis of food particles Amoebocyte Choanoflagellates Epidermis Water flow OTHER EUKARYOTES Sponges Mesohyl Amoebocytes Animals Collar cell (choanocyte) Other animals model organisms reductionism genome size chromosome number number of genes SPECIES haploid number of chromosomes mosquito 3 house fly 6 Escherichia coli (bacterium) Saccharomyces (yeast) Arabidopsis (mustard plant) frog (Rana pipiens) 13 mouse 20 human 23 cattle 30 dog 39 goldfish 47 Caenorhabditis elegans (nematode) Drosophila (fruit fly) Mus musculus (mouse) carp 52
viruses? viruses virions structure DNA or RNA surrounded by capsid some surrounded by lipid envelope living? viruses? viruses (cont.) lytic lysogenic viroids potato spindle-tuber disease prions