Chapter 7 and 9 Notes
Chapter 7 and 9 Notes Microbiology 210
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This 7 page Class Notes was uploaded by Jordan Gause on Sunday October 4, 2015. The Class Notes belongs to Microbiology 210 at University of Tennessee - Knoxville taught by Elizabeth McPherson in Fall 2015. Since its upload, it has received 69 views. For similar materials see Microbiology in Biology at University of Tennessee - Knoxville.
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Date Created: 10/04/15
Chapter 9 Controlling Microbial Growth in the Environment in food surfaces etc make bathroom cleaners work A Terminology of Microbial Control suf x mean destructionkilling suf x means not killing heat used to reduce number of spoilage organisms NOT STERILIZATION food preparation removal of pathogens for health standards restaurants destruction of ALL microorganismsviruses in or on an object ex culture media in lab B Microbial Death Rates not all die right away permanent loss of reproductive ability under ideal environmental conditions 2 Death Rate constant over time of speci c species under certain conditions C Action of Antimicrobial Agents two types disrupts integrity of cells by altering cell walls etc interrupt cellular metabolism and reproduction that interfere with protein and nucleic acid structures 1 Alteration of Cell Walls and Membranes counteracts osmosis in hypotonic solution controls passage of chemicals into and out of the cell surrounds some viruses proteins and phosphoipids damage interrupts viral replication nonenveloped has greater tolerance of harsh conditions than enveloped 2 Damage to Proteins and Nucleic Acids proteins regulate cellular metabolism function as enzymes because of 3D shape when damaged protein shape changes denaturation chemicals radiation and heat can alterdestroy nucleic acids 3 Selection of Microbial Control Methods ideally agents should be not a lot of money fastacting stable during storage capable of controlling growth while not being harmful to humans and animals 4 Factors Affecting Efficacy of Antimicrobial Methods site to be treated surgery extreme heat on humans etc relative susceptibility envelope viruses VERY susceptible death rates vary effectiveness of chemical that will kill classi ed as high intermediate and low environmental conditions temp pH organic materials fat blood feces etc a warm works better loweracidic pH better heat related methods time to kill 90 of microbes graph moist heat used to disinfect sanitize sterilize and pasteurize kills by denaturing proteins and destroying cytoplasmic membrane boiling use in labs pasteurization still microbes in it so NOT sterilization ultrahightemp sterilization dry heat aming loop refrigerating and freezing decrease microbial metabolism refrigerating and growth freezing slow freezing better more effective than fast freezing desiccation and lyophilization ltration passage of uid through sieve osmotic pressure hypertonic cell shrivel up radiation UV light affects nucleic acids 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 chromosomes all linear and sequestered with in the membranebound nucleus typically have 2 copies of each chromosome lt chromosome 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 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 phenotype mutations occur naturally in life of organism results from error long DNA move among 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 f Met 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 Second nucleo de base Also codes for 3 22nd amino acid pyrrolysine in some prokaryotes USE THIS CHART TO FIGURE OUT THE GENETIC 2012 Pearson Education Inc CODE LEARNING OBJECTIVES 39 Compare and contrast the structure and function of prokaryotic and cukaryotic DNA UUU Phenylalanine EU a 39 r Tyrosine GU l Cysteine 7 Phe 7 l 7 l UUC r UCC gt Sarina UGC 1i UUA Leucine U011 53quot I 39239 LE l i39 1 E UUG I I uce UGG Tryptophan Trp a r w l l cuu CCU CALI l Hi stidine CG 0 7 39 Hi5 cue Leucine ccc gt Praline GAG EGG Arglinline e CUA Lem can Pro CAA Glutamine CGA M91 as 7 a cue coca GAG 339 CGG In 39 V 7 l AUU I I ACU AAU l Asparagine AG Serine 4 soleu cme 39Asnv 39Ser 7 393 AUG l lie Acc gt Threanine A Ac I I AGO I I 0 hr V 1 it liir i ilgihEliit lijili tllgi ACG J AAG IIIVS AGG M9 L1 i 7 a z GUU ecu GAU Aspartic acid GG Asp k GUC 39Valine Gcc rAlanine GAO GGC Glycine GUA all GCA Na GAA Glummic acid GGA lei GUG GOG GAG 3quot GGG Third nucleotide base 339 position 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