Class Notes Chapter 6, 13, and 7
Class Notes Chapter 6, 13, and 7 Microbiology 210
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This 14 page Bundle was uploaded by Jordan Gause on Wednesday September 23, 2015. The Bundle belongs to Microbiology 210 at University of Tennessee - Knoxville taught by Elizabeth McPherson in Fall 2015. Since its upload, it has received 229 views. For similar materials see Microbiology in Biology at University of Tennessee - Knoxville.
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Date Created: 09/23/15
CHAPTER 6 l Microbial Nutrition and Growth A Growth Requirements use passive and active transport organisms use variety of nutrients for their energy needs microbes obtain nutrients from variety of sources B Sources of Carbon Energy and Electrons inorganic source of carbon C02 make organic compounds from carbon dioxide catabolize reduced organic molecules dependent on other life forms acquire energy from redox reactions involving inorganic and organic chemicals use light as their energy source Energy source Light photo J Chemical compounds chemoJ Carbon Photoautotrcphs Chemloautotrophs dioxide 0 Plants algae and cyanobacteria Hydrogen sulfur and nitrifying autoJ use H20 to reduce 02 producing bacteria some archaea 02 as a tryproduct Green sulfur bacteria and purple sulfur bacteria do not use H20 nor produce 02 Organic Photoheterotrophs Chemoheterotrophs com ou ds Green nonsulfur bacteria and Aerobic respiration most animals 91 9quot purple nonsulfur bacteria some fungi and protozoa and many archaea bacteria Anaerobic respiration some animals protozoa bacteria and archaea 39 Fermentation some bacteria yeasts and archaea Carbon source 2012 P eeee on Education Inc C Oxygen Requirements oxygen is essential for obligate aerobes nal electron acceptor in ETC but deadly for anaerobes reason is because forms of oxygen that are toxic are highly reactive and also excellent oxidizing agents molecular oxygen with electrons boosted to higher energy state contains carotenoids what distinguishes this from the other 3 forms form during oxygen as nal electron acceptor and anaerobic metabolism occurring in the presence of oxygen very reactive aerobes must produce enzyme to detoxify them anaerobes lack superoxide dismutase and die formed during reactions catalyzed by superoxide dismutase and other reactions contain either catalase or peroxidase to break down the peroxide anion results from ionizing radiation and from incomplete reduction of hydrogen peroxide MOST REACTIVE OF THE FOUR FORMS OF OXYGEN all four strip electrons can maintain life via fermentation or anaerobic respiration or by aerobic respiration ie EColi do not undergo aerobic respiration but have some enzymes that detoxify oxygen s poisonous forms aerobes that require oxygen levels from 210 and have a limited ability to detoxify hydrogen peroxide in stomach Oxygen Looscy JIM Ml WI concentration 1quot fitting I i l J High cap a a Obfigate b Obligate c Facultative d Aerototerant aerobes anaerobes anaerobes anaerobes D Nitrogen Requirements anabolism often ceases due to insufficient nitrogen needed for proteins and nucleotides reduction of nitrogen gas to ammonia by certain bacteria is essential to life on Earth bc nitrogen is made available to living organisms in a usable form acquired from organic and inorganic nutrients all cells recycle nitrogen from amino acids and nucleotides Other Chemical Requirements phosphorus sulfur trace elements and growth factors Temperature temperature between 5 and 20 C temperature between 20 and 50 C humans temperature between 50 and 80 C temperature between 80 and 110 C 390 I measure of the concentration of H in a solution pH around 6575 or neutral pH around 3 bc acidic pH around 115 very basic Physical Effects of Water osmotic pressure and hydrostatic pressure can have huge effects on a cell hypotonic solution have lower solute concentrations cells will burst hypertonic solution have greater solute concentrations cells will shrink helps preserve some food Associations and Bio lms one organism either harms or kills another organism virus quotbad personquot is an antagonist receive bene ts from living with other members but could live separately if they want do better living together symbiotic relationships rarely live outside the relationship of their group primary residence of microbes in nature cells with bio lms communicate and coordinate with each other may allow members of the bio lms to concentrate and conserve digestive enzymes gooey extracellular bio lm slim Reason bio lms form start out as one then increase concentration increases as well Ex fans in stadium example one fan tries to make noise by himself not a lot of sound and energy 100000 fans try and have a lot of energy microbes respond to the density of nearby microorganisms J Generation Time vary among population How to gure I Generation Time 1 out generation time 39 The time reQuired for a bacterial cell or population of cells to grow and divigg 39 ary among populations Mr m f an on c embargnd physmal conditions NM juw 2quot w iauf to memoirs in 9W6 I V b w 39 5 a l V quot ff I a W a j m 1 ll W I K Phases of Microbial Population Growth like you when alarm goes off awake but not moving replicating cells are adjusting to new environment equivalent to of deaths binary ssion splitting occurs here cells begin to enter period of growth growth is greater than deaths population more susceptible to antimicrobial drugs that interfere with metabolism new cells dying cells happens because if not Earth would be overwhelmed with bacteria endospores created now because realize they are dying deaths greater than replication many assume unusual shapes CHAPTER OBJECTIVES 0Compare the four basic categories of organisms based on their carbon and energy source ODistinguish among anaerobes aerobes aerotolerantanaerobes facultative anaerobes and microaerophiles Explain how oxygen can be fatal to organisms by discussing singlet oxygen superoxide radical peroxide anion and hydroxyl radical and describe how organisms protect themsel ves from toxic forms of oxygen Explain the importance of nitrogen fixation Explain how extremes of temperature pH and osmotic and hydrostatic pressure limit mi crobial growth Describe binary fission as a means of reproduction Explain what is meant by the generation time of bacteria Explain logarithmic growth Describe a bacteria growth curve and explain what occurs at each phase of a population s growth CHAPTER 13 l Characterizing and Classifying Viruses Viroids and Prions we need to understand vira structure to understand disease not living A Characteristics of Viruses caused by aceuar noncellular agents very simple no cell structure can t carry out metabolic pathway cant reproduce independenUy use prokaryotes and eukaryotes to reproduce cause most of disease cures very difficult because viruses live inside us so we would attack ourselves receptors only accept very speci c viruses all cells have DNA or RNA no cytoplasmic membrane metabolism etc 1 capsid removed virus exists as nucleic acid 2 protein surrounding nucleic acid core 3 Differences Between Viruses more variety of genomes than cells DNA OR RNA can be ssDNA dsDNA dsRNA or ssRNA never have doublestranded RNA in cells only viruses have singlestranded DNA much smaller genome than cell B Hosts of Viruses most only infect particular hosts humans infect many kinds of cells in many different hosts Ecoli all cells susceptible to viral infection virus infecting bacteria outnumber a bacteria prokaryotes and eukaryotes combined C Sizes of Viruses none have ribosomes very very small 1 Capsid Morphology protein coat that provides protection for viral nucleic acid similar to cytoplasmic membrane eitheror situation either have it or don t acquires it from host cell s cytoplasmic membrane composed of phospholipid bilayer and proteins play role in host recognition Red blood cell 39 quot A 10000 nm in diameter E coli bacterium 1000 nm x 3000 nm 300 nm ucation Inc 1 Bacterial ribosomes Smallpox Virus 200 nm x 300 nm Poliovirus 30 nm Bacteriophage T4 50 mm x 225 nm Bac eriolfhzge M32 Tobacco mosaic virus n 15 nm x 300 nm D Viral Replication 1 Lytic Lysogenic 2 in lawn of bacteria T4 phage happens very quick Only for bacteriophage Steps include attachment entry synthesis assembly and release Replication Cycle of Bacteriophages Attachment random meeting like meeting boyfriend for rst time Entry viruses enzyme produced degrades cell wall Synthesis degrade bacterial DNA make more viruses Assembly viruses created Release lysosome from entry nished degrading cell wall plaques area of disintegrating bacterial cells cell doesn t blow up right away unlike entry step of ytic attachment same inserted into DNA of host cell bacterial virus during Entry may remain a part of bacterial chromosomes forever E Replication of Animal Viruses same basic replication as bacteriophages differences because more animal viruses have envelopes they are eukaryotic and they lack cell wall 1 Attachment don t have tails chemical attraction dependent may have spikes or other molecules on surface 2 Entry different extra step direct penetration membrane fusion and endocytosis used by nakednonenvelope viruses attaches and sinks into cytoplasmic membrane creates pore where genome enters capsid remains on the outside entire capsid and contents enter host cell capsid released into cytoplasm capsid removedviral genome released a this MUST happen when capsid intact used by most enveloped viruses host cell engulfs it into an endosome uncoating F Synthesis of Animal Viruses dependent on type of nucleic acid it has DNA nucleus RNA cytoplasm How is messenger RNA synthesized Template for nucleic acid replication G Assembly of Animal Viruses in nucleus from there to cytosol RNA created here takes more time than replication of bacteriophages naked viruses extruded by release of material from eukaryotic cell enveloped viruses released via budding H Latency of Animal Viruses like lysogenic except for name called differences some become incorporated into host chromosome BUT OTHERS DON T when incorporated into host DNA becomes physical part of host chromosome CHAPTER OBJECTIVES ODiscuss Viral genomes in terms of dsDNA ssDNA ssRNA dsRNA and number of seg ments of nucleic acid Explain the mechanism by which Viruses are specific for their host cells 0Compare and contrast Viruses of fungi plants animals and bacteria Discuss the structure and function of the Viral capsid Discuss the origin structure and function of the Viral envelope Sketch and describe the five stages of the lytic replication cycle as it typically occurs in bacteriophages 0Compare and contrast the lysogenic replication cycle of Viruses With the lytic cycle Explain the differences between bacteriophage replication and animal Viral replication 0Compare and contrast the release of Viral particles by lysis and budding 0Compare and contrast latency in animal Viruses With phage lysogeny CHAPTER 7 l Microbial Genetics A Structure and Replication of Genomes study of inheritance and inheritable traits as expressed in an organism s genetic material its genetic complement entire including its genes speci c sequence of nucleotides 1 Structure of Prokaryotic Genomes main portion of DNA also have RNA in chromosomes single copy of each typical chromosome consists of circular molecule of DNA located in the nucleoid small molecules of DNA that replicate independently of the chromosome circular carry info required for own replication typically not essential for normal metabolism growth reproduction etc 2 Structure of Eukaryotic Growth typically have more than one nuclear chromosome in their genome chromosome chromosomes all linear and sequestered with in the membranebound nucleus typically have 2 copies of each chromosome lt DNA molecules of mitochondria and chloroplasts are circular and resemble circular chromosomes of prokaryotes nuclear DNA codes for 95 of RNA and proteins B DNA Replication talked about this in class occurs during polymerization anabolic polymerization process that allows a cell to make copies of its genome requires monomers and energy key to replication is complementary structure of the two strands AT and CG replication is new strands composed of one original strand and one daughter cell KNOW HOW TO FIND GENETIC CODE USING CHART EX TAC GAA ATA ATG CTT TAT C Relationship Between Genotype and Phenotype set of genes in genome consists of all the series of DNA nucleotides that carry instructions for an organism s life physical features and functional traits of an organism genotype determines phenotype by specifying what kinds of RNA and which protein molecules are produced not all genes are active all the time genotypes not always expressed as phenotypes D Transfer of Genetic Information info in DNA is copied as RNA nucleotide sequences polypeptides synthesized from RNA DNA transcribed to RNA RNA translated to form polypeptides E Events in Transcription 1 Prokaryotes occurs in cytosol nucleoid single type of RNA polymerase single transcription factor required to bind RNA to DNA 2 Transcriptional Differences in Eukaryotes occurs in nucleus mitochondria and chloroplast 3 types of nuclear RNA mRNA processed before translation F Regulation of Genetic Expression most bacterium s genes expressed at all times constantly transcribed and translated other genes regulated so polypeptides they encode are synthesized only in response to environmental change allows cells to conserve energy regulation of protein synthesis may stop transcription of mRNA doesn t require as much energy because happens before translation one way to regulate can stop translation directly one way to regulate G Mutations of Genes change in nucleotide base sequence of genome almost always dangerousbad evolution something good comes out of mutation 1 Types of Mutation single base pair is affected include pair substitutions and frameshift change in genotype but phenotype stays the same I change in genotype and stop codon gets inserted when it s not supposed to affect proteins much more seriously than substitutions because frameshift affects all codons insertions and deletions AAG changed to GAAC is insertion and AAG changed to AA is deletion mutations occur naturally in life of organism results from error long DNA move among mutations phenotype chromosomes viruses etc physical or chemical agents include radiation and several types of DNA altering chemicals induce mutations 3 Frequency of Mutations uncommon very rare 110 million many are harmful because they code for nonfunctional proteins or stop translation entirely change in evolution H Genetic Recombination and Transfer exchange of nucleotide sequences between 2 DNA molecules cells with DNA molecules that contain new arrangements of nucleotide sequences 1 Horizontal Gene Transfer process by which prokaryotes and eukaryotes replicate their genomes and supply copies donor cell contributes part of genome to recipient cell recipient cell takes up DNA from environment transfer of DNA from one cell to another via replicating viruses limited by availability of virus capable of infecting both donor and recipient cells carries random DNA segment only certain donor DNA donor cell remains alive requires physical contact between donor and recipient mediated by pili prokaryotes start with AUG called fMet eukaryotes start with AUG called Met STOP amino acids in genetic code tells ribosomes to stop Any other time AUG appears it s just methionine USE THIS CHART TO FIGURE OUT THE GENETIC CODE Second nucleoliidle base First nucleotide base 539 position Al so codes for a 22nd amino acid pyrroliysine in some prokaryotes 2012 Pearson Education Inch LEARNING OBJECTIVES 39 Compare and contrast the structure and function of prokaryotic and eukaryotic DNA 0 Describe the structure and function of plasmids Explain Why DNA replication is said to be a semiconservative process 0 Explain how the genotype of an organism determines its phenotype Explain the central dogma of genetics and explain the roles of DNA and RNA in polype ptide synthesis 0 Contrast the basic tenets of bacterial transcription With those of eukaryotic transcription Describe the genetic code in general and identify the relationship between codons and a mino acids 0 Describe in general how cells regulate protein synthesis 0 Define mutation 39I39lhli l nucleotide base 339 positiun
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