Micro Exam 2 Week 2 Notes
Micro Exam 2 Week 2 Notes 3050
Popular in General Microbiology
Popular in Microbiology
This 9 page Class Notes was uploaded by Luke Holden on Wednesday February 24, 2016. The Class Notes belongs to 3050 at Clemson University taught by Dr. Rudolph in Winter 2016. Since its upload, it has received 34 views. For similar materials see General Microbiology in Microbiology at Clemson University.
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Date Created: 02/24/16
Micro Exam 2 Week 2 Notes 2/12/16 Flagella Structure Gramnegative Filament Flagellin type of protein, the actual whip part Hook the little curve in the flagellum Basal Body o Inculdes Pring Periplasam ring MSRing Membrane (plasma) ring Cring cytoplasm ring MotorSits between the MS and C ring Motor o L+P ring do not rotate/ MS+ C ring o MOT protein surround MS ring and Cring o Fliprotiens commander of the flagellum sit in the MS and Crings o MEMORIZE THIS STRUCTURE BELOW AND KNOW IT VERY VERY WELL o GramPositive Only 2 Rings o Because of the diffrences in the cellular envelope Shown below on the right Flagellum Characteristics How they are Built: o So, it looks like a channel that leads from the cytoplasm to the top of the growing flagellum (Assembly line) o They are channeling up flagellin molecules o CAP proteins stand at the top and direct the flagellin to grow in a circular direction o Imagine you are unscrewing the bolt from the back of your calculator with a screwdriver, as the screw comes out, you notice it looks like it is growing by spinning. This is what the CAP protein does to grow the flagellin. o It just spins in a circle from one point and puts the proteins down in a circular fashion. o How they move: o Gram Negative (Similar to gram positive except a minus a few rings) 2 –part motor that produces torque Rotor This is when the C ring and the MS ring spin and interact with the stator StatorMot A and B proteins Imagine a revolving door, where at the very center and top of the door you hook a flagellum. When you push (H ) on the door (Cring and MS ring) you will rotate the stable column (L and P ring) that holds the flagellum The proton motive force (PMF) (i.e you pushing the door) is the + real star of the show. This works by shuttling H across the membrane between the MOT A protein and the MS and C rings Takes 1000 protons to turn 360 degrees (Monotrichous polar Flagellum (fastest)) How they make the Cell move: o Rotates counter clockwise causes run o Rotates clockwise tumble o Up to 1100 rev/sec o So the way to think about it, bacteria with flagellum don’t have a steering mechanism to direct their movement (inefficient) o So, when their flagellum rotate, they can only go in one general direction, then once they have past their target they have to tumble to change directions o o Peritrichous motility bundled flagella that looks like a spinning ponytail o Spirochete motility Multiple flagellum form an axial fibril and wraps around the cell So, they remain in the periplasmic space (remember they are gram negative so the periplasmic space is bigger). And BOOM they turn into an instant drill bit!!! So their movement is similar to that of a wiggling drill bit: spinning and flexing. o Sticky surface to slide on? No problem! Twitching This goes on with the ends of the cell, involves short jerky motions You know those sticky hands that you would get at like chucky cheese that you could throw out and stick to stuff? (Like these) Well, same concept, in twitching, the pili at the ends of the cell, send out their stick hands (polysaccharide) and stick them to the surface of another cell or the ground. Then they haul them in which causes the cell to move (discontinuous = twitching) Gliding NO PILUS! We think little baby feet move the bacteria. A lot of slime production Gliding motion o Chemotaxis Movement toward a chemical attractant or a way from chemical repellent Concentrations of chemo attractants and chemo repellents detected by the chemoreceptors on the cells Complex but very rapid Response= 20miliseconds 2 +60 cell lengths per second Positive and Negative Bacteria are all or nothing type of folks They will go after something 100 % if they detect it and want it. Or they will try not to go near it in the other case Therefore: o Want it= increase the run= decrease the tumble o Don’t want it= decrease the run= increase the tumble o 2/15/16 Bacterial Endospores (accidental pathogens) (Find them literality everywhere) Complex dormant structures formed by the bacteria typically due to the lack of nutrients in the surrounding environment Can come back to life (germination) Typically occurs in gram positive cells Resistant to o Heat o Radiation o Chemicals o Desiccation (Water loss) Where the endospore is made: o Central center of the cell o Subterminal Kinda close to the end bit not all the way o TerminalRight on the edge of the cell o Swollen sporangiumOMG THE CELL IS A LOLLY POP o Structure of an Endospore o o Goes Like This: Exosporangium Coat Outer Membrane Cortexmade out of pep and less linked than the cell wall Germ cell wall Inner membrane Core ECOCGIC Every Coat On Corn Glows In Cereal What makes the endospore so rock solid? o Core low water content Calcium dipicolinate (CaDPA) SASP ssmall, acid soluble , DNA – binding protiens They are doublestranded DNAbinding proteins that cause DNA to change to an Alike conformation. They protect the DNA backbone from chemical and enzymatic cleavage and are thus involved in dormant spore's high resistance to UV light (radiation). SASP are degraded in the first minutes of spore germination and provide amino acids for both new protein synthesis and metabolism (https://www.ebi.ac.uk/interpro/entry/IPR001448) Lower the pH as well o But the real stars of the show are the Exosporangium and Spore Coat Supreme armor Ok, cool so it can stand up to some stuff but what makes it so great? o The fact that it is an escape pod for the cell that is virtually invincible means that the bacteria can keep on going and doing their thing no matter what o Germination and Sporulation 3 Steps: Activation: o Prepares spores for germination o Often results from treatments like heating Germination: o The nutrients it needs are detected o Spore swelling and rupture of the coat o Loss of resistance but…Increased metabolic activity Outgrowth: o BOOM vegetative cell shows up from the germination process 2/17/16 Chapters 11.1,10.110.4 Microbial Nutrition and Metabolism Requirements for microbial survival and growth (Must haves) o Source of energy Cellular work o Source of electrons Role in energy production Reduce CO2 to form organic molecules o Nutrients Carbon and hydrogen and oxygen Synthesize building blocks for cell to be maintained and grow o Let’s break down energy and electrons Sources Organic and inorganic compounds Energy is obtained through Oxidation of a compound or Sunlight (energy only) Energy is usually reserved in the cell and is used as a currency: ATP Easy to break easy to make How to classify: Different places where organisms get there energy: o Phototrophs: use the sun o Chemotrophs: obtain energy from the oxidation of compounds Different places where organisms get their electrons o Lithotrophs use reduced inorganic substances o Organotrophs obtain electrons from organic compounds Different places where organisms get their Carbon o Heterotroph use of organic molecules as carbon sources (which often serve as energy and as an electron source) o Autotroph use carbon dioxide as their sole or principal carbon source o Must obtain and energy and other electons from other sources o Primary producers Why all the names? SAMPLE EXAM QUESTION Given these three characteristics, classify this organism Uses the sun as energy, digests a lot of organic compounds and make frequent use of carbon dioxide Answer: PHOTOLITHOAUTOTROPH o Photo energy source o Litho electron source o Autotroph carbon source Metabolism Catabolism Anabolism Fueling Reactions Synthesis of complex organic molecules (glucose) from simpler ones (ATP) Energy conserving reaction Requires energy and building blocks from fueling reactions Provide reducing power electrons Generates precursors for biosynthesis ON CONSTANT CYCLE BETWEEN THE TWO
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