Microbiology Chapter 9 Vocab

Genetics
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Terms in this set (89)
Genetics
the science of heredity
Heredity
genetic inheritance
Genome
the complete set of chromosomes and genes in an organism
Genomics
the systematic study of an organism's genes and their functions
Chromosome
the tightly coiled bodies in cells that are the primary sites of genes
Gene
a site on a chromosome that provides information for a certain cell function, a specific segment of DNA that contains the necessary code to make a protein or RNA molecule
Protein
predominant organic molecule in cells, formed by long chains of amino acids
Genotype
the genetic makeup of an organism of an organism, this is ultimately responsible for an organisms phenotype, or expressed characteristics
Phenotype
the observable characteristics of an organism produced by the interaction between its genetic potential (genotype) and the environment
Nucleotide
the basic strucutral unit of DNA and RNA; each nucleotide consists of a phosphate, a sugar (ribose in RNA, deoxyribose in DNA) and a nitrogenous base such as adenine, guanine, cytosine, thymine or uracil
Phosphatean acidic salt containing phosphorus and oxygen that is essential inorganic component of DNA, RNA, and ATPDeoxyribosea 5-carbon sugar that is an important component of DNANitrogenous Basea nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code, adenine, guanine, and cytosine are found in both DNA and RNA while thymine is found only in DNA and uracil is found only in RNAPurinea nitrogen base that is an important encoding component of DNA and RNA, the two most common purines are adenine and guaninePyrimidinenitrogen bases that help form the genetic code on DNA and RNA, uracil, thymine, and cytosine are the most importantAdenineone of the nitrogen bases found in DNA and RNA with a purine formThymineone of the nitrogen bases found in DNA but not in RNA, in a pyrimidine formGuanineone of the nitrogen bases found in DNA and RNA in the purine formCytosineone of the nitrogen bases found in DNA and RNA with a pyrimidine formAntiparallela description of the two strands of DNA, which are parallel to each other, but the orientation of the deoxyribose and phosphate groups run in the opposite directions with the 5' carbon at the top of the leading strand and the 3' carbon at the top of the lagging strandSemiconservative Replicationin DNA replication, the synthesis of paired daughter strands, each retaining a parent strand templateReplication Forkthe Y-shaped point on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNAPrimerssynthetic oligonucleotides of known sequence that serve as landmarks to indicate where DNA amplification will beginLeading Strandthe newly forming 3' DNA strand that is replicated in a continuous fashion without segmentsLagging Strandthe newly forming 5' DNA strand that is discontinuously replicated in segmentsOkazaki Fragmentin replication of DNA, a segment formed on the lagging strand in which biosynthesis is conducted in a discontinuous manner dictated by the 5' -> 3' DNA polymerase orientationTelomeresareas of repeating DNA sequences at the ends of a linear chromosome that protect the chromosome from being deteriorated during rounds of DNA replicationTranscriptionmRNA synthesis, the process by which a strand of RNA is produced against a DNA templateTranslationprotein synthesis; the process decoding the messenger RNA code into a polypeptideProteomicsthe study of an organisms complement of proteins, and functions mediated by the proteinsUracilone of the nitrogen bases in RNA but not in DNA, uracil is in a pyrimidine formRibosea 5 carbon monosaccharide found in RNAMessenger RNAa single-stranded transcript that is a copy of the DNA template that corresponds to a geneCodona specific sequence of three nucleotides in mRNA that constitutes the genetic code for a particular amino acidTransfer RNAa transcript of DNA that specializes in converting RNA language into protein languageAnticodonthe trinucleotide sequence of transfer RNA that is complimentary to the trinucleotide sequence of messenger RNARibosomal RNAa single-stranded transcript that is a copy of part of the DNA templateRNA Polymeraseenzyme process that translates the code of DNA to RNATemplate Strandthe strand in a double-stranded DNA molecule that is used as a model to synthesize a complementary strand of DNA or RNA during replication or transcriptionTranscripta newly transcribed RNA moleculeRedundancythe property of the genetic code that allows an amino acid to be specified by several different codonsWobblea characteristics of amino acid codons in which the third base of a codon can be altered without changing the code for the amino acidStart Codonthe nucleotide triplet AUG that codes for the first amino acid in protein sequencesStop Codonone of the codons UAA, UAG, and UGA, which have no corresponding tRNA and thus signal the end of transcription; nonsense codonNonsense Codona triplet of mRNA bases that does not specify an amino acid but signals the end of a polypeptide chainTranslocationthe movement of the ribosome from one codon to the next during translation of the mRNA sequence after the peptide bond has been formed between amino acidsPosttranslationalreferring to modifications to the protein structure that occur after protein synthesis is complete, including removal of formyl methionine, further folding of the protein, addition of functional groups, or addition of the protein to a quaternary structurePolyribosomal Complexan assembly line for mass production of proteins composed of a chain of ribosomes involved in mRNA transcriptionIntronsthe segments on split genes of eukaryotes that do not code for polypeptide, they can have regulatory functionExona stretch of eukaryotic DNA coding for a corresponding portion of mRNA that is translated into peptides, intervening stretches of DNA that are not expressed are called introns, during transcription, these are separated from introns and are spliced together into a continuous mRNA transcriptSpliceosomea molecule composed of RNA and protein that removes introns from eukaryotic mRNA before it is translated by forming a loop in the intron, cutting it from the mRNA, and joining exons togetherOperonsa genetic operational unit that regulates metabolism by controlling mRNA production, in sequqnce the unit consists of a regulatory gene,inducer or repressor control sites, and structural genesLactose Operoncontrol system that manages the regulation of lactose metabolism, it is composed of three DNA segments, including a regulator, a control locus, and a structural locusRegulatorDNA segment that codes for a protein capable of repressing an operonRepressorthe protein of a repressor gene that combines with the operator and arrests the transcription and translation of structural genesPromoterpart of an operon sequence, the DNA segment that is recognized by RNA polymerase as the starting site for transcriptionOperatorin an operon sequence, the DNA segment where transcription of structural genes is initiatedAllostericpertaining to the altered activity of an enzyme due to the binding of a molecule to a region other than the enzymes active siteInducera molecule in an inducible operon responsible for initiating transcription of the operon by removing the repressor from the operator section of the DNA, allowing transcription to proceedCorepressora molecule that combines with inactive repressor to form active repressor, which attaches to the operator gene site and inhibits the activity of structural genes subordinate to the operatorPhase Variationthe process of bacteria turning on or off a group of genes that changes its phenotype in a heritable mannerRecombinationa type of genetic transfer in which DNA from one organism is donated to anotherRecombinantan organism that contains genes that originated in another organism, whether through deliberate laboratory manipulation or natural processesHorizontal Gene Transfertransmission of genetic material from one cell to another through nonreproductive mechanisms, such as from one organism to another living in the same habitatConjugationin bacteria, the contact between donor and recipient cells associated with the transfer of genetic material such as plasmids, can involve special sex piliTransformationin microbial genetics, the transfer of genetic material contained in naked DNA fragments from a donor cell to a competent recipient cellTransductionthe transfer of genetic material from one bacterium to another by means of a bacteriophage vectorFertility Factordonor plasmid that allows synthesis of a pilus in bacterial conjugation, presence of the factor is indicated by F+ and lack of the factor is indicated by F-Piluslong, tubular structures made of pillin protein produced by gram-negative bacteria and used for conjugationResistance Factorplasmids, typically shared among bacteria by conjugation that provide resistance to the effects of antibioticsCompetentreferring to bacterial cells that are capable of absorbing free DNA in their environment either naturally or through induction by exposure to chemicals or electrical currentsTransfectionthe introduction of DNA into eukaryotic cells from the environment by exposing cells to chemicals or electrical currentsTransposona DNA segment with an insertion sequence at each end, enabling it to migrate to another plasmid, to the bacterial chromosome or to a bacteriophageInsertion Elementsthe smallest transposable elements, consisting only of tandem repeats that are capable of inserting themselves into DNA but do not carry any genesRetrotransposona transmissible element capable of translating itself from DNA to RNA to make many copies of itself and then translating itself back into DNA in order to insert itself into a new location on the chromosomePathogenicity Islandsareas of the genome containing multiple genes that contribute to a new trait for the organism that increases its ability to cause diseaseMutationa permanent inheritable alteration in the DNA sequence or content of a cellWild Typethe natural, nonmutated form of a genetic traitMutant Straina subspecies of microorganism that has undergone a mutation, causing expression of a trait that differs from other members of the speciesSpontaneous Mutationa mutation in DNA caused by random mistakes in replication and not known to be influenced by any mutagenic agent, these mutations give rise to an organisms natural, or background rate of mutationInduced Mutationany alteration in DNA that occurs as a consequence of exposure to chemical or physical mutagensMutagenany agent that induces genetic mutationPoint Mutationa change that involves the loss, substitution, or addition of one or a few nucleotidesMissense Mutationa mutation in which a change in the DNA sequence results in a different amino acid being incorporated into a protein, with varying resultsNonsense Mutationa mutation that changes an amino acid producing codon into a stop codon, leading to premature termination of a proteinSilent Mutationa mutation that, because of the degeneracy of the genetic code, results in a nucleotide change in both the DNA and mRNA but not the resultant amino acid and thus, not the proteinBack-Mutationa mutation that counteracts an earlier mutation, resulting in the restoration of the original DNA sequenceFrameshift Mutationan insertion or deletion mutation that changes the codon reading frame from the point of the mutation to the final codon, almost always leads to a nonfunctional proteinAmes Testa method for detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria