MIC 205 1st Edition Lecture 5 Outline of Last Lecture II. Golden Age of MicroIII. StainingIV. TaxonomyV. Cellsa. Prokaryotesb. External Structure of ProkaryotesOutline of Current Lecture VI. Nonmotile ExtensionsVII. Prokaryotic Cell WallsVIII.Bacterial Cell Wallsa. Gram +/- Cell WallsIX. Cell Membrane FunctionX. Passive/Active TransportXI. CytoplasmXII. Prokaryotic Cell DivisionCurrent LectureNonmotile Extensions:Not all cells have them- Fimbriae- sticky protein constructed fibers that stick out of the cell wall and are used for adherence, shorter than flagella, important in biofilms- Pili- extracellular sturctures, long hollow tubes made of pilin, longer than fimbriae shorter than flagellao Mediate transfer of DNA from one cell to another (connect with each other and swap genetic info)o Known as conjugation pili, because they swap DNAProkaryotic Cell Walls: - Provide structure, shape and protect cell from osmotic forcesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Assists in eluding antimicrobial drugs- Rigid structure, but not impermeable (water, nutrients can move through freely)- Animals do NOT have thiso Bacteria Their cell wall is peptidoglycano Archaea Different cell wall chemistryBacterial Cell Walls- Composed of peptide liked chains of carbohydrates o Polysaccharides (carbs) are made of 2 alternating sugars N-acetylgucosamine (NAG) N-acetylmuranic acid (NAM)o NAG and NAM are linked by tetrapeptide crosslinks (4 amino acids) Like rebar in construction sites that are connected by wire (cross bridges) These cross bridges make the walls rigid o Gram + and Gram – cell walls, difference is amount of peptidoglycanGram-Positive Cell Walls- Have tons of peptidoglycan (about 200 layers) this lies outside the cell membrane- Retains the purple dye in Gram staining technique - Has NO outer membrane- Carbohydrate (polysaccharide) surface interactionGram-Negative Cell Walls- Have thin amount of peptidoglycan (about 10-15 layers) also sits outside the cell membrane but under the outer membrane of the cell wall (BETWEEN outer membrane and cell membrane)- Completely different structure when compared to gram-positive- Cells appear pink in Gram stain technique- No one knows why the staining is different between the two gram types- Lipid surface interaction (lipids are hydrophobic) - Outer membrane of cell wall is called lipopolysaccharide (LPS) *Very important molecule later on**Many important antibiotics are inhibitors of peptidoglycan synthesis*Prokaryotic Cell Membrane- Lipid bilayer, dictates what comes in and goes out of cell- Semipermeable membrane, defines the internal part of cell from outside- Proteins in membrane are integral or peripheral (sometimes decorated with sugars for recognition purposes or binding)- These membranes are fluid- “Soap bubble” structure Cell Membrane Function- Transport (move materials across membrane)o Dictates if certain drugs can get in o Transporters help it become selectively permeable (control movement)o Primary functions - Harvest light energy in photosynthetic bacteria and ATP energy in respiring bacteriao Photosynthetic pigments collect the energy o Metabolic enzymes produce ATP synthesisPassive Transport - NO energy needed (ATP)- Move from HIGH to LOW concentration (concentration gradients)o Molecules move to equalize across the spaceo If no gradients materials won’t move across membraneo If materials can’t move, water can move (hypertonic, hypotonic, isotonic)- Typeso Simple diffusion-straight through membrane with small molecules o Osmosis-water moves across membrane Just simple diffusion of water in response to something else Hypertonic solution-water moves out of the cell  Hypotonic solution- water moves into the cell (cell explodes without a cellwall) Isotonic solution-water and solution are equal - These are relative terms with respect to the contents inside the cell or outside the cell depending on the use of the termo Facilitated diffusion- protein carrier/channel  For larger molecules and ionsActive Transport- Use ATP (energy)- Need a carrier protein to move the materials o Move against the gradient of concentrationCytoplasm of Prokaryotes- Contains all the materials inside the cell membrane- “Cytosol” is the liquid inside the cell membrane that is in the cytoplasm- This includes:o Ribosomes-make proteinso Cytoskeleton-structure and shapeo DNA/RNA-genetic info o Inclusions-reserve deposits of chemicalsShape of Prokaryotic Cells**Shape is species-specific**(just be familiar with the terms)- Spherical-cocci- Rodlike-bacillus- Bent rods-vibrio- Corkscrew-spirillum- Variable-pleomorphic--categorized by shape and arrangementArrangement-whether or not the cells divideProkaryotic Cell Division Mechanisms- Divide asexually - Determines cell shape/arrangement- how quickly bacteria can grow-Three mechanisms1. Binary fission2. Snapping division3. Budding-How do bacteria stay agead of the curve genetically? How do they acquire new traits or get rid of the ones they don’t want???- Binary Fission- How nearly all prokaryotic cells divide Replicate DNA, wall off the two copies, divide in half & divide/do NOT divide- Snapping Division- How attached forms come to be1. Parent w/ replicated DNA2. Outer portions of cell wall are still attached, two daughter cellsw/ crosswall3. Walls must be SNAPPED by tension on the outer cell walls, inner cell wall expands4. Daughter cells connected by a hinge of cell wall--Can be V-shaped or Palisade Arrangements- Budding o Copy genetic material and push the copy into a bud, this bud eventually takes on cytoplasm and pinches off from the parental cell Rare in bacterial