Study Guide for Test 2 Part 1
Study Guide for Test 2 Part 1 81383 - MICR 3050 - 002
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This 20 page Class Notes was uploaded by Stephanie Erickson on Monday February 29, 2016. The Class Notes belongs to 81383 - MICR 3050 - 002 at Clemson University taught by Krista Barrier Rudolph in Fall 2015. Since its upload, it has received 59 views. For similar materials see General Microbiology in Biological Sciences at Clemson University.
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UNIT 2 STUDY GUIDE Spring 2016 MICR 3050 OBJECTIVES: Chapter 3.1 – 3.5 1. Compare and contrast the structure, composition, and functions of the cell walls of grampositive and gramnegative bacteria. Be able to label them. Composition: Gram positive: plasma membrane surrounded by a thick peptidoglycan wall; 90% of wall is peptidoglycan Large amounts of teichoic acids o Negatively charged – stops some negatively charged particles o Maintains structure of cell envelope o Protects the cell from harmful substances o May bind to host cells (pathogenic bacteria) Lipoteichoic acids o Attached to membrane lipids Some gram positive bacteria have a layer of proteins on surface of peptidoglycan Gram negative: plasma membrane surrounded by a thin peptidoglycan wall, a large periplasmic space, and an outer membrane Thin larger of peptidoglycan (10% of cell wall) Outer membrane composed of lipids, lipoproteins, and lipopolysaccharide (LPS) o Outer membrane is more permeable than the plasma membrane due to presence of porin proteins and transporter proteins Porins form channels through which small, hydrophilic molecules (like sugars) can pass LPS o Three parts Lipid A: fatty acid; only part stuck in the membrane Core polysaccharide : in the middle, always the same O side chain/antigen: at the end, unique for each LPS, causes an immune response in the body, can mutate o Contributes to negative charge on cell surface (core polysacchar.) o Helps stabilize outer membrane structure (lipid A) o May contribute to attachment to surfaces and biofilm formation o Creates a permeability barrier o May mutate to protect from host defenses (O antigen) o Can act as an endotoxin (lipid A) No teichoic acids Periplasmic space makes up 2040% of cell volume o Gellike o Contains enzymes, particularly hydrolytic enzymes which transport materials o Very active; proteins used for nutrient acquisition Braun’s lipoproteins connect outer membrane to peptidoglycan o Anchor phospholipid later in outer layer to peptidoglycan Cell membrane is mainly phospholipids and integral proteins Structure: Both positive and negative have peptidoglycan, a meshlike polymer composed of back bone with two alternating sugars (NAG and NAM) and alternating D and L amino acids Peptidoglycan sugars are held together by 1,4 glycosidic bonds NAM has 4 amino acids coming off of it peptidoglycan chains are crosslinked by peptides (direct and indirect linkages) Amino acid always comes off of NAM 2. Describe the effects of lysozyme and penicillin on a bacterial cell wall. Lysozyme: break down beta 1,4 glycosidic bond between NAG and NAM Pencilin – keeps amino acids from forming linkage between each other **Gram negative less susceptible to lysozyme and pencilin because outer membrane blocks the peptidoglycan layer 3. Explain how bacteria may survive without a cell wall. Mycoplasma has no cell wall, but have more structural stability in their plasma membrane due to presence of sterols 4. Describe capsules and slime layers and discuss their functions. Capsules Usually composed of polysaccharides Well organized and not easily removed from cell Give cell protective advantage o Resistance to phagocytosis Capsule are sticky: helps them stick to each other to form biofilms, helps them stick to host o Protection from desiccation (drying out) Slime Layer Similar to capsules except diffuse, unorganized, and easily removed o No definite shape, easily removed o Only exuded when needed, not a consistent layer Slime may aid in motility by allowing microorganism to glide Chapter 3.6 – 3.9 5. Describe the following bacterial structures and their functions: cytoskeletal proteins, cell inclusions, fimbriae, pili, flagella, and endospores. Cytoskeletal proteins Description: proteins found in the cytoskeleton of a cell Function: play role in cell division, protein localization, and determination of cell shape Cell inclusion aggregates of organic or inorganic material (granules, crystals, globules) found in all cell types might be enclosed by a singlelayered “membrane” or invaginations of plasma membrane different types o Storage inclusions, gas vacuoles, magnetosomes Strorage Inclusion storage of nutrients, metabolic end products, energy, building blocks o carbon (PHB) o phosphate (polyphosphate granules) o sulfur globules o nitrogen (cynaophycin granules) Gas Vacuoles: filled with gases provide buoyancy Magnetosome contain magnetite particles allow for orientation in Earth’s magnetic field Fimbriae and pili short, thin hairlike, proteinaceous appendages mediate attachment to surfaces some required for motility or DNA uptake Sex pili similar to fimbriae except longer, thicker, and less numerous genes for formation found on plasmids required for conjugation (horizontal gene transfer) Flagella threadlike appendages extending outward from plasma membrane and cell wall used for motility and swarming help attach to surfaces may be virulence factors 6. Describe flagella structure and movement. Structure (from cell towards tip of tail basal body (c ring, ms ring, p ring, l ring), hook, filament Basal body is closest to the cell body o Acts as motor o Consists on rings C (in line with Cytoplasm) and MS (in line with Membrane) rings will spin P(in line with Peptidoglycan) and L (in line with LPS layer) will remain stationary P and L rings not present in grampositive cells Hook: curved part that connects the flagella to the motor Filament: actual flagella part o Filament is made of lots of proteins o Proteins added to the tip Movement Flagella is a 2 part motor that produces torque o Rotor: C and M ring turn and interact with stator o Stator Mot A and Mot B (two proteins located in the plasma membrane right on the outside of the basal body) o Membrane has a build up of potential energy due to energy gradient formed by positive charges being stuck on the outside and negative charges being stuck on the inside o To create energy hydrogen ions are moved into the cell Takes 1,000 H+ ions to make flagella rotate one 360 degrees Flagella rotates like a propeller o Counter clockwise rotation causes forward motion (run) o Clockwise rotation disrupts run causing cell to stop and tumble 7. Define chemotaxis and describe how bacteria move toward an attractant (or away from a repellent). Chemotaxis: movement toward a chemical attractant or away from a chemical repellent Cells can’t turn and can not run indefinitely Achieve movement through a series of run and tumbles – referred to as a biased random “walk) Concentration of chemoattracts and chemorepellants detected by chemoreceptors on surfaces of cells To move toward an attractant, cell lowers the frequency of tumbles – runs in direction of attract are longer To move away from a repellent the cell increases the number of tumbles 8. Describe other types of motility (spirochete, twitching, and gliding). Spirochete Multiple flagella ofrm axial fibril which winds around the cell Flagella remain in periplasmic space inside outer sheath Corkscrew shape exhibits flexing and spinning movements Twitching Pili at ends of cell Short, intermittent, jerky motions Cells are in contact with each other and surface May involve Type IV pili Gliding Smooth movements Probably involves slime 9. Understand the structure and functions of bacterial endospores, the basics of sporulation and germination, and endospore resistance. Endospore Complex, dormant structure formed by some bacteria Various locations within the cell Resistant to numerous environmental conditions o Heat, radiation, chemicals, desiccation Sporulation Process through which a vegetative (normally functioning) cell produces a spore Sporulation results in death of original cell Triggered when the cell has a lack of nutrients and is unable to grow Sporulation process o Cytoplasmic membrane folds in on itself to create a pocket, then again to create protoplast o Forespore is created: consists of core (center), inner spore membrane, and outer spore membrane o Forespore is dehydrated and exosporium appears, cortex forms between membrane and exosporium o Spore produces SASPs and dipicolinic acid which protect DNA, spore coat layers are developed o Cell lyses and endospore emerges o Whole processes takes about 10 hours Spore from inside to out o Core: cytoplasm, contains all the structures a normal cell has, just very dehydrated o Inner membrane: becomes plasma membrane o Germ cell wall: becomes outer most part of cell after germination o Cortex: contain peptidoglycan, structural component o Outer membrane o Spore coat: 1415 protein layers thick, make spore impermeable to lots of stuff (house hold cleaners, toxins) o Exosporium: outer protein coating that protects the spore Germination Spore produces a vegetative cell (3 parts) o Activation Prepares spores for germination Often results from treatments like heating o Germination Environmental nutrients are detected Spore swelling and rupture of spore coat Loss of resistance (becomes vulnerable) Increased metabolic activity o Outgrowth Emergence of vegetative cell Spore resistance Spores are resistant to extreme heat, radiation, chemicals, and desiccation Spore is very dehydrated o Resistance to heat (hard to boil) Calcium dipicolinate (CaDPA) and small, acidsoluble, DNA binding proteins SASPs o Protects DNA Slightly lower pH o Keeps enzymes from working and reactions using nutrients Exosporium and spore coat: protein layers o Make spore very impermeable Chapters 11.1, 10.1 – 10.4 10. Know the requirements for microbial survival and growth and their sources. Source of energy i. Needed to complete cellular work ii. Must be able to conserve it for later Source of electrons i. Electrons play a role in energy production (used in electron transport chain to create pmf that results in ATP Ch. 11) ii. Reduce CO2 to form organic molecules Nutrients i. Carbon, hydrogen, and oxygen are used to synthesize organic building blocks needed for cell maintenance and growth 11. Define and recognize the major nutritional types of microorganisms based on their energy source, electron source, and carbon source. Require Energy i. Sunlight: phototrophs ii. Chemical compounds : chemotrophs Require Electrons i. Inorganic substances: lithotrophs ii. Organic substances: organotrophs Require Nutrients/Carbon i. Organic molecules: heterotrophs ii. Carbon dioxide: autotrophs When put all together first part tell you energy, second part tells you electrons, and third part tells you carbon (photolithoautotroph, chemoorganoheterotroph) 12. Define metabolism, catabolism, and anabolism. Metabolism: total of all chemical reactions occurring in the cell Catabolism: breaking down large molecules, releases energy Fuels reactions Energyconserving reactions Provides reducing power (releases electrons) Generates precursors for biosynthesis Anabolism: building of larger molecules, requires energy The synthesis of complex organic molecules from simpler ones Requires energy and building blocks and fueling reactions **Think ANA builds with blocks, CAT comes and knocks it down 13. Understand the concepts of free energy (G) and standard free energy change o ( G ). Free energy (G) amount of energy that is available to do useful work Delta G = change in energy that can occur in chemical reaction o Measure at pH 7, temp 25 C, 1 atm, with reactants and products at 1 M concentration 14. Distinguish between exergonic and endergonic chemical reactions and their o relationship to G . Exergonic reaction (Delta G is NEGATIVE): release energy and proceed spontaneously (catabolism) Endergonic (Delta G is POSITIVE): energy is required and reaction will not proceed spontaneously (anabolism) 15. Explain the importance of ATP. ATP is the energy currency of the cell When phosphate groups are cleaved off of ATP it is turned into ADP and releases energy Doesn’t take a lot of energy to make ATP, but gives away a decent amount when it is broke (easy to make, easy to break!) Cleaving one phosphate releases 31 kJ/mol Cleaving a second phosphate requires more energy because it is less stable, net energy released is less (15 kJ/mol) Cleaving both phosphates releases 46 kJ/mol Combine cleaving ATP with an endergonic reaction in order to make it proceed 16. Be aware of other highenergy compounds, and know the change in standard free energy requirement for cells to use them. Phosphoenolpyruvate: 61.9 kJ/mol 1,3Bisphosphoglycerate: 49.3 kJ/mol Acetyl phosphate: 44.8 kJ ATP: 30.5 kJ/mol (one phosphate cleaved); 45.6kJ/mol (two phosphates cleaved) Acetyl CoA: 31 kJ/mol Glucose 6phosphate: 13.8 kJ/mol 17. Understand redox reactions including the standard reduction potential (E ) o0 half reactions, the electron tower, and their relationship to G . OxidationReduction (Redox) Reaction Many metabolic processes involve redox reaction (electron transfers) One compound is oxidized (electrons are removed) while another compound is reduced (electrons are added) o Oxidation and reduction frequently involve the transfer of not just electrons, but both an electron (e) plus a proton (H+) Electron carriers are often used to transfer from an electron donor to an electron acceptor o Electron carriers (NADH, FADH2, easily add and remove electrons) Can result in energy release, which can be conserved as ATP or another energyrich compound Standard Reduction Potential Equilibrium constant for an oxidationreduction reaction A measure of the tendency of the reducing agent to lose electrons More negative E’ means better electron donor More positive E’ means better electron acceptor HalfReactions All reactions are written as half reaction with acceptor on the left and donor on the right Electron Tower Tower has the compounds with more negative E’ at the top and the most positive E’ at the bottom Compounds at the top are better electron donors, compounds at the bottom are better electron acceptor The greater the difference between the E’ of the donor and the E’ of the acceptor the more negative the DelatG The father down the tower the electron falls the more energy that will be released (NADH to O2 released more energy than FADH2 to O2) As electrons flow down the tower it releases energy; light energy is used to drive electrons up the tower during photosynthesis 18. Describe the location, organization, and functions of the Electron Transport Chains in bacteria. Electron Transport Chain (ETC) Electron carriers organized into ETC with the first electron carrier having the most negative E’ o Potential energy stored in first redox couple is released and used to form ATP o First carrier is reduced and electrons moved to the next carrier and so on **Net energy change of the complete reaction sequence is determine by the difference in reduction potentials between the primary donor and the final acceptor Location Found in mitochondria in eukaryotic cells Found in plasma membrane in prokaryotic cells Function As electrons are carried from electron donors to electron acceptors they fall lower on the electron tower, proton motive force is produced, which makes ATP 19. Define the two classes of electron carriers. Coenzymes Freely diffusible; can transfer electrons from one place to another in the cell (ex. NAD) Prosthetic groups Firmly attached (fixed) to enzymes in the plasma membrane; function in membraneassociated electron transport reactions (ex. Cytochromes) + + 20. Describe how NAD /NADH and NADP /NADPH carry electrons and their roles in metabolism. Act as electron acceptors (NAD+/NADP+) and electron donors (NADH/NADPH) in their different states NADP+/NADPH: used in anabolism NAD+/NADH: used in catabolism, delivers electrons to the electron transport chain *Even if we do not cover these diseases in class, you are still responsible for the information. DISEASES* 46. For each of the microbial diseases listed below, be able to briefly describe the following: a. cause (name of bacterium or virus) b. general characteristics of the microbe (bacteria – Gram reaction and shape, viruses – type of genome and shape) c. route of transmission d. characteristic symptoms. Strep Throat (Streptococcal pharyngitis) Streptococcus pyogenes Grampositive, cocci, link in chains Transmitted through contact with infected throat mucus, nasal discharge, or saliva (coughing, sneezing, or touching) Fever, sore throat, red tonsils, enlarged lymph nodes Cholera Vibrio cholerae Gramnegative, commashaped bacterium Spread mostly by water and food that has been contaminated with human feces, insufficiently cooked food infection of the small intestine, watery diarrhea, vomiting, muscle cramps Bacterial Meningitis (Meningococcal) caused by N. meningitides Neisseria meningitidis Gramnegative, diplococcic Transmitted through saliva and occasionally through close, prolonged general contact with an infected person Acute inflammation of the protective membranes covering the brain and spinal cord; headache and neck stiffness, fever, confusion, altered consciousness, inability to tolerate light or loud noises Lyme Disease Borrelia burgdorferi Diderm (doublemembrane) spirochete Tick bites Expanding area of redness (erythema migrans), loss of ability to move face, joint pains, severe headaches with neck stiffness Infectious Mononucleosis EpsteinBarr virus Herpesvirus, double helix DNA of about 172,000 bp (85 genes) Direct contact with an infected person’s saliva (kissing) Childhood: not noticeable or flulike symptoms; adolescence: fever, sore throat, and fatigue Gas Gangrene (Clostridial Myonecrosis) caused by C. perfringens Clostridium perfringens Grampositive, rodshaped Enter body through significant skin breakage Produces gas in tissues in gangrene, necrosis, bubbles NOTE: Unless otherwise stated, you are responsible for all of the unit objectives even if they are not covered in lecture (see textbook). Unit 2 Test Study Guide Part 2 Chapter 11.2 – 11.8 1. Compare and contrast aerobic respiration, anaerobic respiration, and fermentation in bacteria. Fermentation o uses endogenous organic electric acceptor (pyruvate) o substrate level phosphorylation is primary way or making ATP Aerobic respiration o uses exogenous electron accept (oxygen) o uses oxidative phosphorylation as primary way of making ATP Anaerobic respiration o uses exogenous electron acceptor (not oxygen) o uses oxidative phosphorylation as primary way of making ATP 2. Compare and contrast substratelevel phosphorylation and oxidative phosphorylation. Substratelevel phosphorylation o Used in fermentation and other pathways o ATP is synthesized during steps in the catabolism of an organic compound Oxidative phosphorylation o Used in respiration o ATP is produced by proton motive force produced o Indirect way of making ATP: electron carriers carry electrons to ETC, which makes PMF that makes ATP 3. Describe aerobic catabolism (overview). Stage 1: exoenzymes are released outside the cell to break down polymers into monomers so they can be brought into the cell i. Exoenzymes are inducible (turn on when nutrients are there, turn off when they aren’t) ii. Polysaccharide turned into monosaccharide Stage 2: Endoenzymes break down monomers into small parts i. Endoenzymes are constitutive (always being produced) ii. Monosaccharide (glucose) turned into smaller compound pyruvate) Stage 3: Creb’s Cycle, takes Pyruvate and turns it into CO2 i. Through the process ATP, NADH, and FADH2 are produced Stage 2 and 3 include amphibolic pathways which means they can be reverse 4. Describe the organization and functions of the electron transport chain in aerobic respiration including its role in ATP production. Electron Transport Chain Series of electron carries that operate together Transfer electrons from NADH and FADH2 to a terminal electron acceptor Electrons flow from carriers with more negative E’ to carriers with more positive E’ As electrons are transferred, energy is released to make ATP by oxidative phosphorylation 5. Understand the Chemiosmotic Hypothesis. Movement of protons established PMF ATP synthase uses proton flow down gradient (into the cell) to make ATP 6. Explain the function of ATP synthase. H+ on bottom C protein makes ATP synthase want to spin, but b2 protein holds it in place Instead of spinning it changes conformation In beta conformation Active site is empty – ADP and Pi come in ATP is released – goes back to alpha confirmation 7. Know the functions of proton motive force and how it is established. PMF force is established by Electron transport chain Light from photosynthesis PMF is used To make ATP Rotate bacterial flagella Active transport 8. For aerobic respiration, explain where in the pathway ATP is produced (glycolysis, TCA cycle, and ETC), the methods of ATP production used for each ATP generated, the electron carriers used, and the number of ATPs produced (during the process and the final net yield). Each NADH will make 2.5 ATP Each FADH2 will make 1.5 ATP FADH2 is lower on the electron tower so it will release less energy when it’s electrons are transferred to oxygen Substrate level phosphorylation (7 ATP) 2 NADH (becomes 5 ATP) 2 ATP Bridge Step (5 ATP) 2 NADH (become 5 ATP) TCA Cycle (20 ATP) 6 NADH (becomes 15 ATP) 2 FADH2 (becomes 3 ATP) 2 ATP In all 4 ATP (2 in glycolysis, 2 in TC) 10 NADH (25 ATP) 2 FADH2 (3 ATP) o 28 made in ETC TOTAL = 32 ATP 9. Summarize the major features of the EntnerDoudoroff pathway. used by some soil bacteria yields pyruvate and glyceraldehyde 3P key intermediate i. 2keto3deoxy6phosphogluconate (KDPG) net yield i. 1 ATP ii. 1 NADH iii. 1 NADPH nd (when coupled with 2 half of EmbdenMeyerhof) 10. Describe the process of fermentation, its functions, and its products. Takes place in the absence of an exogenous electron acceptor i. Oxygen not needed Uses pyruvate or derivative as endogenous electron accepto i. Pyruvate is reduced Continues recycling of electron carriers i. NADH from glycolysis is oxidized to NAD+ Forms ATP via substratelevel phosphorylation Produces various fermentation products 11. Know why bacteria produce fermentation products and how these products are useful to humans. Fermentation products are produced as fermentators try to recycle electron carriers Useful to humans because some become food or alcohol ;) i. Ethanol makes breads, wine, beer 12. Distinguish between homolactic and heterolactic acid fermentation. Homolactic: make lactate and no gases i. Cheese, sour cream, yogurt Heterolactic: make lactate and some other things, possibly CO2 i. Sauerkraut, pickles, buttermilk 13. Distinguish between mixed acid and butanediol fermentation. Mixed acid fermentators use several pathways simulataneously Butandiol bacteria only use that one pathway 14. Explain the purpose of the MRVP test and know how it works. If bacteria uses several fermentation pathways, it will create acid byproducts and it’s pH will decrease i. Methyl Red detects pH <5 ii. Positive: turns red if pH less than 5 VogesProskauer tests if bacteria uses 2,3 – butanediol pathway i. Intermediate of this pathway is acetoin, VP tests for its presence ii. Positive: turns red if acetoin is present Chapter 7.1, 7.3 – 7.4, 7.6 – 7.7 35. Describe the growth of bacterial cells (binary fission). Growth Often referring to an increase in the number of cells Study population growth rather than growth of individual cells Binary Fission Two cells arise from one cell Cell elongation o Cellular constituents increase proportionally Genome is replicated and segregated Cell division o Septum formed at midcell Increase in cell number One cell become two cells = one generation 36. Describe in detail the four phases of bacterial growth observed in a batch culture. Lag Phase Cell synthesizing new components o To replenish spent material o To adapt to new medium or other conditions Varies in length o May be short or even absent Exponential Phase/Log Phase Rate of growth is constant and maximal Population is most uniform in terms of chemical and physical properties during this phase Stationary Phase Total number of viable cells remains constant o Metabolically active cells stop reproducing o Reproductive rate is balanced by death rate Possible reasons for this phase o Nutrient limitation o Limited oxygen availability o Toxic waste accumulation o Critical population density reached Death Phase Total number of viable cells is decreasing o Removal of critical nutrients below a threshold level o Metabolic end product reaches toxic level Death o Irreversible loss of ability to reproduce o Lysis may occur 37. Be able to label a growth curve. 38. Define generation time, and be able to calculate it. Generation (doubling) time Time required for the population to double in size Varies depending on species and environmental conditions Exponential growth o Cell number doubles within a fixed time period Calculating n 1. N =tN x02 N ts the population at time t N 0is the original population number n = number of generations for t 2. log N = log N + n log 2 t 0 (note: log 2 = 0.301) 3. n = log Nt – log 0 N 0.301 4. n = 3.3 (log N – tog N ) 0 39. Explain the methods of measuring the growth (number) of microbes (microscopic count, plating methods, turbidity measurements). 40. Describe how water activity, pH, temperature, and oxygen affect microbial growth. At optimal levels of NaCl, pH, temp, and oxygen growth rate will be highest When they are above or below optimum cell will continue to grow but slowly Above or below maximum and minimum level, cell will no longer grow 41. Be able to name, recognize, and define the types of microorganisms that grow in various environments, and know the adaptations they have made to live there. NaCl Nonhalophiles o Does not require NaCl (grow in <1% NaCl) Halotolerant Halophile o Requires NaCl for growth o Grow optimally at >.2M o 115% NaCl Extreme Halophile o Require 26.2 M o 1530% NaCl pH most microbes maintain an internal pH near neutrality use acid shock protein many microbes change the pH of their habitat by producing acidic or basic waste products acidophiles o growth optimum between 0 and 5.5 neutrophiles o growth optimum between 5.5 and 7 alkaliphiles o growth optimum between 8.5 and 11.5 Temperature microbes cannot regulate internal temperature exhibit distinct cardinal growth temperatures (min, max, optimum) psychrophiles (020 C) pyschrotroph (035C) mesophiles (1545 C) thermophiles (4585 C) hyperthermophiles (65113 C) Oxygen aerobe o grows in presence of atmosphere oxygen (20% 02) obligate aerobe o requires 02 anerobe o grows in the absence of o2 obligate anaerobe o killed in presence of o2 microaerophiles o requires 210% O2 facultative aerobe/anaerobe o does not require 02, but grows better in it’s presence aerotolerant anaerob o grows with or without O2 o a – obligate aerobe o b – obligate anaerobe o c – facultative aerobe o d – microaerophiles o e – aerotolerant anerobe 42. Explain how microorganisms protect themselves from the toxic products of oxygen reduction. Oxygen easily reduced to toxic reactive oxygen species (ROS) o Superoxide radical o Hydrogen peroxide o Hydroxyl radical Aerobes produce protective enzymes that break down ROSs o Superoxide dismutase (SOD) o Catalase o peroxidase 43. Describe, in general, microbial growth in natural environments. Microbial environments o Complex o Constantly changing o Often contain low nutrient concentration (oligotrophic environment) Microbial growth depends on o Nutrient supply o Tolerance of environment o Inhibitory substances Most microbes grow attached to surfaces as biofilms 44. Describe biofilms including their characteristics, growth (formation), advantages (for bacteria), and disadvantages (for humans). Biofilm formation Microbes reversibly attach to conditioned surface and release polysaccharides, proteins, and DNA to form the extracellular polymeric substance (EPS) Microbes begin sending chemical signals to each other which causes them to produce even more LPS and attract even more bacteria to join the biofilm Advantages (for bacteria) Heterogeneous community o Metabolic difference Some cells waste will be another cells food o Location Provide protection o Very difficult for antibiotics to get through a biofilm Microbial interaction o Metabolic exchange Some might be fermentator that produce fermentation products that other cells can use o DNA uptake As some cell lyse, other cells will come in and uptake DNA o Quorum sensing Chemical messaging between cells Density dependent: only happens when there are enough cells Disadvantages (for Humans) Medical o Form on medical devices For artificial valves and joints, if infected with a biofilm they have to be removed and replace o Cause disease Cavities form when plaque (biofilm) builds up on teeth Pneumonia: biofilm forms, difficult to kill o Industrial Interfere with fluids distribution Pipes can get clogged if a biofilm forms large enough Corrosion potential DISEASES* 46. For each of the microbial diseases listed below, be able to briefly describe the following: a. cause (name of bacterium or virus) b. general characteristics of the microbe (bacteria – Gram reaction and shape, viruses – type of genome and shape) c. route of transmission d. characteristic symptoms. Strep Throat (Streptococcal pharyngitis) Streptococcus pyogenes Grampositive, cocci, link in chains Transmitted through contact with infected throat mucus, nasal discharge, or saliva (coughing, sneezing, or touching) Fever, sore throat, red tonsils, enlarged lymph nodes Cholera Vibrio cholerae Gramnegative, commashaped bacterium Spread mostly by water and food that has been contaminated with human feces, insufficiently cooked food infection of the small intestine, watery diarrhea, vomiting, muscle cramps Bacterial Meningitis (Meningococcal) caused by N. meningitides Neisseria meningitidis Gramnegative, diplococcic Transmitted through saliva and occasionally through close, prolonged general contact with an infected person Acute inflammation of the protective membranes covering the brain and spinal cord; headache and neck stiffness, fever, confusion, altered consciousness, inability to tolerate light or loud noises Lyme Disease Borrelia burgdorferi Diderm (doublemembrane) spirochete Tick bites Expanding area of redness (erythema migrans), loss of ability to move face, joint pains, severe headaches with neck stiffness Infectious Mononucleosis EpsteinBarr virus Herpesvirus, double helix DNA of about 172,000 bp (85 genes) Direct contact with an infected person’s saliva (kissing) Childhood: not noticeable or flulike symptoms; adolescence: fever, sore throat, and fatigue Gas Gangrene (Clostridial Myonecrosis) caused by C. perfringens Clostridium perfringens Grampositive, rodshaped Enter body through significant skin breakage Produces gas in tissues in gangrene, necrosis, bubbles UNIT 2 ANIMATIONS TO WATCH: http://highered.mheducation.com/sites/0073375268/student_view0/index.html Chapter 3 Bacterial Locomotion Chemotaxis in E. coli (first part only – omit the part discussing the chemoreceptors involved) Bacterial (Endo) Spore Formation http://highered.mheducation.com/sites/0073402400/student_view0/index.html Chapter 11 Electron Transport System and ATP Synthesis Electron Transport System and Formation of ATP How Glycolysis Works How NAD+ Works How the Krebs Cycle Works (just watch for an overview) Chapter 7 Binary Fission Biofilms
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