MICR J210 1st Edition Lecture 4 Outline of Last Lecture I. Structure of Prokaryotic cellsII. Gram StainingIII. Structure of Peptidoglycana. Liposaccharides and their Medical RelevanceIV. EndosporesV. Spore formation in FungiVI. Cyst Formation in ProtozoaVII. VirusesVIII. Binomial naming systemOutline of Current Lecture I. Metabolisma. Aerobicb. AnaerobicII. DNA Replication in Prokaryotesa. Protein Synthesis III. Bacterial GrowthIV. Bacteria and Patient CareCurrent LectureMetabolismThese 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.- Metabolism: sum of all biochemical reactionso Catabolism: break down of molecules Releases energyo Anabolism: build up of molecules  Requires energy- Cellular metabolismo Proteases are secreted digestive enzymes that break down nutrientsnutrients are then able to enter into the bacterial cello The cellular respiration of sugar is the most efficient pathway- Nutritional Classification of Microbeso Autotroph use CO2 as C source, non-organic source for energy Self-feeding organismso Heterotroph use preformed organics as C source and energy source Other-feedingo Fastidious require specific nutritional supplement Hard to please Some require Feo Side note: not all pathogens are easy to culturethey are fastidious and require specific nutrients i.e. Blood agar - Cellular Respiration overviewo Aerobic respiration: most common heterotrophic reaction O2 is the electron acceptor in order to produce ATPo Anaerobic respiration For obligate anaerobes, O2 is toxic Nitrate, carbonate, or sulfate is the electron acceptoro Fermentation Facultative anaerobes are at their best when using O2 but can survive without O2 by undergoing fermentation Use organic molecules at the electron acceptor There are a lot of industrial uses such as cheese, beer, acetone, and rubbing alcohol- Three Distinct Pathwayso Glycolysis: converts glucose to pyruvateo Krebs cycle: pyruvates make lots of electronso Electron transport chain: requires O2 to accept superfluous electrons Harvest the energy of Hydrogen atoms reentering the cell and utilize that energy to produce ATPDNA Replication- Nearly all enzymes are proteinso Encoded for in the DNAo However, not all enzymes are present in ALL organisms- Substrates are what go into the reactionthe Product is the end result of the reaction- Base Pairso Adenine (A) is always paired with Thymine (T)o Guanine (G) is always paired with Cytosine (C) - Riboseo 5 carbon sugar with an oxygen molecule on the 2’ (2 prime) carbon- Deoxyriboseo 5 carbon sugar with NO oxygen molecule on the 2’ carbon- DNA binds 5’ to 3’o Base Pairs are linked together at the 5’ carbon of one sugar to the 3’ carbon of another sugar- DNA Replication Forko DNA replication only starts in ONE place (origin of replication)o Helicase: untwists the double helix of DNA  Does so by breaking Hydrogen bonds that bind the complimentary base pairs- Hydrogen bonds are electrostatic forces- Can be broken with the input of energy or with heato DNA Polymerase: form the complimentary strand Joins together nucleotides together with strong covalent phosphodiester bonds to form the new complimentary strand Replication runs from 5’ to 3’ (5 prime carbon to 3 prime carbon)o The speed of replication is much faster in prokaryotes Prokaryotes only have 5,000 base pairs Takes approx. 40 minutes- PCR: Polymerase Chain Reactiono Serves as a diagnostic technique to detect and diagnose infectious diseaseso Allows DNA to be replicated rapidly in laboratory settings Kary Mullis discovered bacteria polymerase that lived in hot springs Used this heat stable polymerase in PCR Protein Synthesis- Transcription of DNAo Occurs in the cytoplasm of Prokaryoteso DNA is transcribed onto mRNA (Messenger RNA)- Translation of mRNAo mRNA runs through ribosomes and the ribosomes read the mRNA strando tRNA (transfer RNA) with a specific 3 base code (codon) carries the specific coded amino acid to the ribosome- In prokaryotes transcription and translation happen almost simultaneously due to the fact that everything is freely floating in the cytoplasmBacterial Growth- Undergoes Binary Fission—Does NOT undergo MITOSIS!!o Single Strand of DNA replicates and associates with the cell membraneoo Fissure splits the mother cell into two daughter cellso Doubling time: amount of time to replicate and double the number of bacteria present- Phases of Growtho LAG Phase: growth is slow as adaptation to environment occurso LOG Phase (Exponential phase): multiply exponentially, doubling in number every few minuteso STATIONARY Phase: bacteria begin competing for nutrients and waste begins tobuild upo DEATH Phase: toxic waste and depleted food eventually kills the bacteria- Oxygen Requirementso Obligate aerobe: bacteria will gather at the top of the test tube in order to absorb maximal amount of O2o Obligate anaerobe: bacteria will gather at the bottom of the test tube because oxygen is toxic to themo Facultative anaerobes: primarily use oxygen but can also be anaerobic through fermentation if necessary—most of the bacteria will be at the top of the tube but some will be spread throughout the tube as wello Microaerophiles: need oxygen but at a smaller concentration—bacteria will be close to the top but not right on the surfaceo Aerotolerant anaerobes: bacteria will be evenly spread through the test tube because these bacteria do not use oxygen and the oxygen is not toxic to them- Air Toxicityo Oxygen with extra electronsuperoxide (also known as ROS-reactive oxygen species) ROS attack other molecules to “ditch” their extra electron These molecules then are damagedo Two types of antioxidants to eliminate ROS Superoxide dismutase: reacts with H2O to form Hydrogen Peroxide Catalase and Glutathione Peroxidase: reacts with Hydrogen peroxide to render the free radical harmless- Catalase test: whether the bacteria contain the antioxidant catalase or noto Helps differentiate between Staph and Strep- Temperature-dependent growtho Psychrophile: grow in cold environmentso Mesophile: body temperature Most pathogens are mesophileso Thermophile: heated environmentso Extreme thermophile: extreme (either really hot or really cold)Bacteria and Patient Care- Nosocomial infectionso Infections that appear within 48 hours or more after hospital admission