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Copyright Notice! This PowerPoint slide set is copyrighted by Ross Koning and is thereby preserved for all to use from plantphys.info for as long as that website is available. Images lacking photo credits are mine and, as long as you are engaged in non-profit educational missions, you have my permission to use my images and slides in your teaching. However, please notice that some of the images in these slides have an associated URL photo credit to provide you with the location of their original source within internet cyberspace. Those images may have separate copyright protection. If you are seeking permission for use of those images, you need to consult the original sources for such permission; they are NOT mine to give you permission.
Cellular Structure: the unit of life, one or many Biology: life study of What is Life? Growth: cell enlargement, cell number Evolution: long term adaptation Behavior: short term response to stimuli Reproduction: avoid extinction at death Metabolism: photosynthesis, respiration, fermentation, digestion, gas exchange, secretion, excretion, circulation--processing materials and energy Movement: intracellular, movement, locomotion Properties of Life
Antonie van Leeuwenhoek Developed microscopes for observing living organisms 1674 discovered live protist cells 1677 discovered spermatozoa 1682 discovered striated muscle fibers
Mouth animalcules (bacteria) 1684
Theodor Schwann Prussian Zoologist Matthias Schleiden German Botanist 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. Cell Theory 1839
Scanning Electron Microscope (SEM) image..the shape?
Figure 7-1 Page 120 Ribosomes Plasmids Flagellum Cell wall Plasma membrane Chromosome Cytoplasm This is a cartoon image created by an artist to emphasize certain structures. This is a transmission electron microscopy image that inspired the cartoon. Light microscopy would be even less detailed!
Figure 7-2 Page 121 Plasma membrane Cell wall Cytoplasm This cartoon is not labeled, so it merely acts as a key, to orient the viewer to the enlarged portion of the TEM image. 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.
Figure 7-3 Page 121 Supercoiled DNA in chromosome DNA 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.
Figure 7-4 Page 121 Large subunit of ribosome Small subunit of ribosome Ribosome Ribosomes are 70S in size in prokaryotes, mitochondria, and plastids. Those found in the eukaryotic cytosol are 80S in size.
Figure 7-5 Page 122 Photosynthetic membranes Cyanobacteria carry out photosynthesis with chlorophyll bound to proteins in thylakoid membranes This is an artificially-colored micrograph from transmission electron microscopy (TEM)
? ? Transmission Electron Microscope (TEM) image..the shape?
Sulfolobus acidocaldarius 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 TEM or SEM? Of Archaeon Shape?
Bacterium of the Genus: Leptospira TEM or SEM?Shape?
Vibrio cholerae Helicobacter pylori What are the shapes of these disease bacteria? Are they motile? If so, by what mechanism?
Cell Structure: Movement anchorage rotation basal rings and rod stiff helical flagellum is rotated by motor apparatus in the membrane by H+ ATPase at rates of rps (>12,000 rpm!) hook directional rotation? flagellin protein 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)) Taxis: movement toward stimulus phototaxis: movement toward light 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 billion years!
Cell Structure: Nucleoid transcription by RNA polymerase one circular DNA molecule no histone protein association attached to cell membrane separation of chromosomes replication by DNA polymerase Nucleoid - genome translation of mRNA into protein rRNA + protein + ribozymes 70S Ribosome cytokinesis by furrowing Process called binary fission NOT mitosis! Genome and copy are identical Genome is haploid There is no synapsis There is no recombination