Bio 205 Topic 2 - Study Guide PDF

**BIO 205 Topic 2 - Study Guide** **Chapter 4- Microbial Growth** - Agar Agar is not a nutrient Robert Kuch: developed methods for pure culture techniques, agar=ideal for solidifying media due to chemical and physical properties that make it neutral and remain solid at room tem...

**BIO 205 Topic 2 - Study Guide** **Chapter 4- Microbial Growth** - Agar Agar is not a nutrient Robert Kuch: developed methods for pure culture techniques, agar=ideal for solidifying media due to chemical and physical properties that make it neutral and remain solid at room temperature - Bacterial reproduction known as Binary Fission - Biofilms Most microbes live in poly saccharide-encased communities termed biofilms, may enhance bioremediation efforts and protect organisms against harmful chemicals - **Define Pure culture and a colony** **All the bacterial cells that result from the replication of a single original bacteria species/organism** **Colony= visible cluster of microorganisms that originate from single parent cell on growth medium** - Method for isolating bacteria Streak-plate method - How are Bacterial cultures stored? Agar slant in refrigerator, frozen in glycerol solution or freeze dried - **Explain the stages of Bacterial growth curve and characteristics of these stages:** **Lag:** - **Introduction to sterile medium, maturing but not dividing, begin synthesizing enzymes required for growth, \*metabolically active cells** **Exponential/log:** - **Bacteria are rapidly increasing in number, most susceptible to antibiotics, primary metabolites like amino acids and ethanol, important commercially and formation of endospores, capsules etc.** **Stationary:** - **Nutrient level=low to sustain growth, total number remains constant, become more resistant to drugs** **Death:** - **Total number of viable cells decline** **Prolonged decline:** - **Some survive, adapted to tolerate worsened conditions** - During which phase of growth are bacteria most susceptible to antibiotics? Exponential - In which phase bacterial population rapidly multiply and cell numbers increase? Exponential - All the different types of bacterial groups based on temperature, pH and oxygen preference. Temperature: Psychrophiles: -5 to 15 degrees Celsius, found in artic regions Psychrotrophs: 20 to 30 degrees Celsius, food spoilage Mesophiles: 25 to 45 degrees Celsius, PATHOGENS: 35 to 40 degrees Celsius Thermophiles: 45 degrees to 70 degrees Celsius (hot springs) Hyperthermophiles: 70 to 110 degrees Celsius, members are Archaea, hydrothermal vents, can only survive those temps - Temperature and food preservation: refrigeration SLOWS spoilage by limiting growth of fast-growing mesophiles - Psychrophiles and trophs still grow but slowly - Freezing preserves but does not kill microbes - Temperature and disease: Hansen's disease/leprosy: coolest regions (ears, hands, feet and fingers) due to preference of MYCOBACTERIUM LEPRAE Oxygen: Shake tube growth demonstrates organisms' oxygen requirements Obligate aerobe: grows ONLY when oxygen is available, requires oxygen for respiration, produces superoxide dismutase and catalase Facultative anaerobe: grows BEST when oxygen is available but can grow without it (alternatives), uses O2 for resp. of available, produces superoxide dismutase and catalase Obligate anaerobe: CANNOT grown when oxygen is present, does not use O2, does not produce superoxide dismutase and catalase Microaerophile: grows ONLY if SMALL amounts of oxygen are available, requires O2 for respiration, produces some superoxide dismutase and catalase Aerotolerant anaerobe: Grows equally well with or without oxygen, does not use oxygen, produces superoxide dismutase but not catalase PH -Most microbes=neutrophils Range of pH 5 to 8, OPTIMUM near pH 7 Acidophiles= optimally at pH below 5.5 Alkaliphiles= optimally at pH above 8.5 - Proteins of thermophiles Resist denaturing, PCR = polymerase chain reaction - Human pathogens prefer which temperature range? 35 to 40 degrees Celsius (human body=37) - Optimum pH for most bacteria NEAR pH 7 - The enzymes that deal with toxic oxygen-containing molecules is/are Superoxide dismutase and catalase deal with ROS (o2 in cells) - How does an aerobic organism protect itself from the action of Reactive Oxygen Species (ROS)? By using those enzymes bruh - Fastidious? - Chemotrophs, heterotrophs, autotrophs. - Aerobes, anaerobes, microaerophiles - Food preservation Dissolved salts, sugars make water unavailable to cell = used to preserve food **Chapter 6** - Metabolism Anabolic and catabolic reactions - Anabolism vs. Catabolism Ana=building up of molecules, forming bonds between molecules, dehydration synthesis, Monomer + monomer=Polymer and Glucose + glucose=Maltose, ENDERGONIC reaction Cat= breaking down of molecules, EXERGONIC reactions = energy is released - potential energy vs. Kinetic energy Potential=at rest Kinetic=movement - Exergonic vs. Endergonic - Oxidation vs. reduction Oxidation= atom is loses an electron = oxidized, exergonic, supply of oxygen and removal of electron Reduction= atom gains an electron = reduced due to negative charge, endergonic REDOX= couple to make ATP Electron acceptor = oxygen PRESENCE of hydrogen = reduced No hydrogen = oxidized - ATP - Electron carriers - Enzymes- Speed up conversions of substrate into product by lowering activation energy - structure - function - activity- activation energy -energy needed to start a chemical reaction - regulation- allosteric, competitive, non-competitive Allosteric: enzyme activity controlled by end-product binding to allosteric site Competitive: binds to active site of enzyme, chem. Structure similar to substrate Example: Sulfa drugs blocking folic acid synthesis (mimics PABA, needed for folate -\> amino acid required for growth Non-competitive: inhibitor binds to a different site than the active site = reversible - What is Feedback Inhibition? Show it schematically. Regulating the amount of product produced and often involves the use of allosteric enzymes, end-product INHIBITS enzyme 1 - Cofactors Assist enzymes - What are electron carriers give 2 examples. NAD, FAD AND NADP - Coenzymes ORGANIC FACTORS: FAD, NAD and NADP - Glycolysis - Which central metabolic pathway generates most of the reducing power? Krebs cycle - TCA cycle In aerobic= pyruvate carbons become CO2 In anaerobic fermentation= carbon atoms stay in lactate or ethanol + co2 End= no more carbon - Electron Transport chain Requires a membrane and generates a concentration gradient of protons, oxygen serves as the terminal electron acceptor - ATP synthase Ready to use energy 1. Substrate level phosphorylation = gain phosphate given by substrate 2. Oxidative phosphorylation= oxygen donation 3. Photophosphorylation : light energy donation - Proton Motive force Flow of protons, drives ATP synthase - Chemiosmosis Hydrogen flow down concentration gradient - aerobic vs. anaerobic respiration - fermentation alternative to cellular respiration if oxygen is not available - Catabolism of: Proteins, lipids and polysaccharides