Microbiology 204; Waldmann: Exam 3 – Flashcards
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| replication |
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| a process that produces an exact copy; in molecular biology, this is a process that produces two DNA molecules that are exact copies of the starting DNA molecules |
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| DNA polymerase |
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| the enzyme that links together nucleotides to make new strands of DNA |
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| origin of replication |
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| a location on a chromosome where replication begins |
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| semi-conservative |
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| half of the original (in particular, one whole strand of the original helix) is intact in each new helix at the end of replication (the other strand is newly synthesized) |
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| polymerase chain reaction (PCR) |
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| the amplification of small amounts of DNA using repeated rounds of replication; a lab technique used to make many copies of a DNA segment |
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| primer |
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| a short single-stranded nucleic acid molecule that serves as the beginning of a strand during synthesis |
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| Central Dogma of Biology |
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| States there is a one-way flow of information from DNA to protein; this was believed to be correct from 1950s to the 1980s. |
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| reverse transcription |
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| the flow of information from RNA to produce DNA |
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| promoter |
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| a site on a DNA molecule that promotes the binding of RNA polymerase and points the direction for transcription |
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| messenger RNA (mRNA) |
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| an RNA molecule that encodes a protein |
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| ribosomal RNA (rRNA) |
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| an RNA molecule that is used to build a ribosome |
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| transfer RNA (tRNA) |
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| an RNA molecule that carries an amino acid into a ribosome |
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| base pair |
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| two nitrogenous bases which associate via hydrogen bonds |
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| complementary |
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| an adjective referring to either -two nitrogenous bases that form a base pair or to -two nucleic acid strands that can form base pairs along their entire length |
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| reanneal |
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| reform the hydrogen bonds between the base pairs |
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| transcription |
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| the process in which one strand of DNA is used as a template to synthesize a complementary RNA molecule |
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| -transcription (DNA to RNA) -translation (RNA to amino acid) |
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| the process involving -initiation -elongation -termination |
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| translation |
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| a cellular process in which the sequence of nitrogenous bases in an mRNA molecule determines the sequence of amino acids linked together to make a protein |
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| codon |
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| a group of three nitrogenous bases in an mRNA molecule that are used as a code for one amino acid |
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| anti-codon |
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| a group of three nitrogenous bases in a tRNA molecule that base pair to a codon |
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| stop codon nonsense codon terminator codon |
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| a group of three nitrogenous bases that do not encode an amino acid and serve as a stop signal, ending translation |
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| reading frame |
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| the grouping of the bases into codons |
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| gene |
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| a segment of DNA which encodes one RNA molecule |
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| AUG |
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| the start-codon in translation |
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| operator |
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| a segment of a DNA molecule that controls the transcription of a neighboring segments |
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| operon |
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| a cluster of genes whose expression is controlled by a single operator |
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| repression |
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| (in genetics) the inhibition of transcription of a gene when a compound interferes with the binding RNA polymerase to the gene's promotor |
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| induction |
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| (in genetics) the enhancement of transcription of a gene when a compound increases the rate at which RNA polymerase initiates transcription of the gene |
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| mutations |
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| permanent changes in the sequence of nitrogenous bases in a DNA molecule |
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| genotype |
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| the genetic make-up of one trait of an organism |
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| genome |
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| the genetic make-up of an organism |
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| phenotype |
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| the observable traits of an organism |
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| mutant |
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| an organism that differs from its parent due to a mutation |
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| silent mutation |
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| a mutation that does not change the phenotype |
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| deleterious mutation |
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| a mutation that slows the growth and/or reproduction of an organism or is lethal |
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| beneficial mutation |
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| a mutation that enhances an organism's ability to survive and reproduce |
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| spontaneous mutation |
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| a naturally-occurring mutation (most occur when DNA polymerase makes a mistake during replication; can also occur when a virus inserts its nucleic acid into the chromosome of the host cell) |
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| induced mutation |
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| a mutation that occurs due to human activities or man-made chemicals |
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| mutagen |
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| an agent that causes mutation; can include -physical agents (xray, UV radiation) -chemical agents (nitrous acid; base analog) |
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| base analog |
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| a compound that is structurally similar to one of the common nitrogenous bases. Some cause mutations when they are incorporated into strands of DNA during synthesis. |
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| point mutation |
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| a change in a single base, e.g., substitution, deletion of one nucleotide, or addition of a nucleotide |
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| insertion |
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| when a longer segment of nucleotides is added; also occurs when a virus or a plasmid inserts its nucleic acid in the chromosome |
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| deletion |
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| when a longer segment of nucleotides is deleted |
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| frameshift mutation |
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| a mutation that changes the reading frame |
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| reverse mutation |
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| a mutation occurring in a mutant that restores the original phenotype |
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| obligate intracellular parasite |
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| an organism that survives only by living inside a host cell |
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| virion |
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| a fully-assembled extra-cellular virus |
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| capsid |
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| a viral protein coat |
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| nucleocapsid |
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| the protein coat along with the nucleic acid core of a virus |
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| viral envelope |
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| a phospholipid bilayer surrounding a viral capsid |
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| spikes |
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| functional molecules that project out from the surface of a viral particle (usually protein or glycoprotein in composition) |
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| receptor |
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| a molecule that acts as a recognition and binding site for another molecule |
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| filamentous |
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| long and thin; aka helical |
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| icosahedral |
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| having 20 triangular sides |
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| complex |
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| bacterial viruses that have an icosahedral head on a filamentous body; also includes any other unusual shapes |
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| neurotropic |
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| a virus that infects the nervous system |
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| dermotropic |
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| a virus that infects the skin |
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| pneumotropic |
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| a virus that infects the lungs and/or respiratory system |
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| viscerotropic |
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| a virus that infects the blood & a variety of organs |
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| bacteriophage |
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| a virus that infects bacteria |
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| lysis |
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| bursting |
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| lytic cycle |
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| a viral replication cycle in which a virus penetrates a host cell, replicates, and lyses the host cell, releasing numerous viral particles |
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| lysogenic |
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| capable of becoming lytic |
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| lysogenic cycle |
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| a viral replication cycle in which a viral genome is integrated into the host cell's chromosome, and, along with the rest of the chromosome, the viral genome is copied and passed to daughter cells; if stressed, this cycle can convert to the lytic cycle |
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| provirus |
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| a viral genome that is located in a eukaryotic chromosome |
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| prophage |
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| a viral genome that is inserted in a bacterial chromosome |
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| virulent |
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| harsh, or having a severe effect |
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| virulent phage |
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| phage that have a drastic effect on the host cell because they can replicate via the lytic cycle, lysing the host cell after release |
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| temperate phage |
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| phage that have a relatively mild effect on the host cell because they can replicate via the lysogenic cycle |
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| budding |
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| 1) cell division in which one daughter cell is much smaller than the other daughter cell 2) release of viral particles from a host cell without lysis of the cell |
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| interferons |
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| compounds produced by virally-infected cells. The compounds are secreted from the cells and bind to nearby cells where they activate antiviral mechanisms. Used to treat MS, some cancers, herpes, HIV, & hepatitis |
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| vesicle |
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| an elevation of skin filled with serous fluid |
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| papule |
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| an elevation of skin, reddened, solid, & circumscribed |
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| macule |
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| a discoloration of skin, neither raised nor depressed |
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| Koplik's spots |
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| a series of bright red patches with white pimple-like centers located on the buccal mucosa opposite the 1st and 2nd molars. Appear several days before the skin rash of measles |
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| Negri bodies |
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| dark cytoplasmic granules seen in the brain stem cells of rabid animals |
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| Downey cells |
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| enlarged lymphocytes with lots of vacuoles characteristic of Epstein-Barr virus infections |
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| antibody |
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| a glycoprotein produced by a white blood cell that binds to a specific foreign molecule |
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| free antibodies |
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| antibody molecules which are free in the blood serum and not attached to a cell surface |
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| hemagglutination |
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| clumping of red blood cells |
