Test 2 – Microbiology – Flashcards
Unlock all answers in this set
Unlock answersquestion
| Genetics |
answer
| The science of heredity. |
question
| genome |
answer
| the genetic information in a cell |
question
| what two things make up the genome? |
answer
| chromosomes and plasmids |
question
| chromosomes |
answer
| structures containing DNA that physically carry hereditary information |
question
| genes |
answer
| segments of DNA (or RNA in some viruses) that code for functional products |
question
| DNA |
answer
| a macromolecule composed of repeating units called nucleotides |
question
| nucleotide |
answer
| consists of a nuclease, a deoxyribose, and a phosphate group |
question
| what is the structure of DNA? |
answer
| long strands of nucleotides twisted together to form a double helix |
question
| what are the DNA base pairs? |
answer
| adenine - thymine cytosine - guanine |
question
| genetic code |
answer
| the set of rules that determines how a nucleotide sequence is converted into the amino acid sequence of a protein |
question
| genotype |
answer
| an organism's genetic makeup |
question
| phenotype |
answer
| actual, expressed properties; a manifestation of the genotype |
question
| what do the phenotypic properties derive from? |
answer
| the structure and function of protein |
question
| in microbes, most proteins are: (2) |
answer
| enzymatic: catalyze particular reactions structural: participate in large functional complexes |
question
| bacteria |
answer
| single circular chromosome consisting of a single circular molecule of DNA with associated proteins |
question
| short tandem repeats (STRs) |
answer
| noncoding regions that occur in most bacterial genomes |
question
| genomics |
answer
| the sequencing and molecular characterization of genomes |
question
| what happens first: cell division or DNA replication? |
answer
| DNA replication |
question
| what is the ultimate goal of DNA replication? |
answer
| one parental double-stranded DNA molecule is converted to 2 identical daughter molecules |
question
| function of DNA gyrase, topoisomerase |
answer
| relaxes supercoiling ahead of the replication fork |
question
| function of DNA ligase |
answer
| makes covalent bonds to join DNA strands; joins Okazaki fragments and new segments in excision repair |
question
| function of DNA polymerase |
answer
| synthesizes, proofreads, and repairs DNA |
question
| function of endonucleases, transposase |
answer
| cut DNA backbone in a strand of DNA and facilitate repair |
question
| function of helicase |
answer
| unwinds double-stranded DNA |
question
| function of methylase |
answer
| adds methyl group to selected bases in newly made DNA |
question
| function of photolyase |
answer
| uses visible lights energy to separate UV-induced pyrimidine dimers |
question
| function of ribozyme, snRNP |
answer
| RNA enzyme that removes introns and splices exons together |
question
| function of RNA polymerase |
answer
| copies RNA from a DNA template |
question
| function of RNA primase |
answer
| an RNA polymerase that makes RNA primers from a DNA template |
question
| replication fork |
answer
| the point at which replication occurs |
question
| semiconservative replication |
answer
| the process of replication in which each new double-stranded DNA molecule contains one original strand and one new strand |
question
| what is the numerical structure of DNA? |
answer
| 5' --> 3' |
question
| on which end of the numerical DNA structure can DNA polymerases add new nucleotides? |
answer
| 3' |
question
| where does energy for replication come from? |
answer
| nucleotides |
question
| what synthesizes DNA? |
answer
| deoxyribose (sugar) |
question
| what synthesizes RNA? |
answer
| nucleoside triphosphates with ribose |
question
| transcription |
answer
| the synthesis of a complementary strand of RNA from a DNA template |
question
| ribosomal RNA (rRNA) |
answer
| forms ribosomes (where protein synthesis occurs) prokaryotic transcription |
question
| messenger RNA (mRNA) |
answer
| carries the coded information for making specific proteins from DNA to ribosomes prokaryotic transcription |
question
| process of prokaryotic transcription (3) |
answer
| 1) strand of mRNA is synthesized using a DNA template 2) RNA polymerase binds to DNA site called a promoter 3) this continues until RNA polymerase reaches DNA site called a terminator |
question
| translation |
answer
| protein synthesis --> converts the "language" of nucleic acids and converts it to the "language" of proteins |
question
| what is the "language" of mRNA? |
answer
| codons |
question
| what does the codon sequence do? |
answer
| determines the sequence of amino acids that will be in the protein being synthesized |
question
| degeneracy |
answer
| allows for a certain amount of mutation in the DNA without affecting the protein produced |
question
| t/f: there is only one possible codon sequence for each amino acid |
answer
| false |
question
| sense codons |
answer
| code for amino acids |
question
| nonsense codons |
answer
| signal the end of the protein molecule's synthesis (UAA, UAG, UGA) |
question
| what is the start codon for protein synthesis? |
answer
| AUG |
question
| what is the process of prokaryotic translation? (6) |
answer
| 1) mRNA codons converted to protein 2) the codons are read and amino acid chains are formed 3) translation occurs at ribosome 4) tRNA recognize the codons and transport appropriate amino acids 5) the amino acids are lined up and form peptide bonds 6) stops when nonsense codon is reached |
question
| where does transcription occur in eukaryotes? |
answer
| nucleus |
question
| what are genes composed of? |
answer
| exons and introns |
question
| exons |
answer
| the areas of DNA expressed |
question
| introns |
answer
| the intervening regions of DNA that do not encode protein |
question
| constitutive genes |
answer
| their products are constantly produced at a fixed rate |
question
| what is the default position of constitutive genes? |
answer
| on |
question
| why are constitutive genes always activated? |
answer
| they are needed in large amounts for major life processes |
question
| repression |
answer
| the regulatory mechanism that inhibits gene expression and decreases the synthesis of enzymes |
question
| what mediates repression? |
answer
| repressors |
question
| what do repressors do? |
answer
| block the ability of RNA polymerase to initiate transcription |
question
| what is the default position of repression? |
answer
| on |
question
| induction |
answer
| the process that turns on the transcription of a gene |
question
| what is the default position of induction? |
answer
| off |
question
| inducer |
answer
| a substance that acts to induce transcription of a gene |
question
| inducible enzymes |
answer
| enzymes synthesized in the presence of inducers |
question
| who is associated with the Operon Model of gene expression? |
answer
| Francois Jacob and Jacques Monod |
question
| promoter |
answer
| region where RNA polymerase initiates transcription |
question
| operator |
answer
| acts as a stop/go signal for transcription of the structural genes |
question
| is the lac operon inducible or repressible? |
answer
| inducible |
question
| cyclic AMP (cAMP) |
answer
| a substance derived from ATP that serves as a cellular alarm signal |
question
| alarmone |
answer
| a chemical alarm signal that promotes a cell's response to environmental or nutritional stress |
question
| catabolite repression |
answer
| inhibition of the metabolism of alternative carbon sources by glucose |
question
| when glucose is available, cAMP levels are ____________. |
answer
| low |
question
| how can eukaryotes and bacterial cells turn genes off? |
answer
| by methylating certain nucleotides (epigenetic inheritance) |
question
| microRNA (miRNA) |
answer
| single-stranded DNA molecules of 22 nucleotides |
question
| what 2 things does miRNA do? |
answer
| inhibits protein production in eukaryotic cells allows different cells to produce different proteins |
question
| mutation |
answer
| a permanent change in the base sequence of DNA |
question
| base substitution |
answer
| a single base at one point in the DNA sequence is replaced with a different base |
question
| missense mutation |
answer
| when the base substitution results in an amino acid substitution in the synthesized protein |
question
| example of a missense mutation? |
answer
| Sickle cell anemia |
question
| nonsense mutation |
answer
| caused when a nonsense codon is created in the middle of an mRNA molecule |
question
| frameshift mutation |
answer
| one or a few nucleotide pairs are deleted or inserted in the DNA |
question
| which type of mutation results in a long stretch of altered amino acids? |
answer
| frameshift |
question
| example of a frameshift mutation disease? |
answer
| Huntington's |
question
| spontaneous mutation |
answer
| occur even in the absence of mutation-causing agents |
question
| mutagens |
answer
| agents in the environment that directly or indirectly bring about mutations |
question
| what type of mutagen is nitrous acid? |
answer
| chemical |
question
| nitrous acid |
answer
| makes A pair with C |
question
| nucleoside analog |
answer
| alters base pairing properties |
question
| 2 types of radiation mutagens |
answer
| UV light X rays/ gamma rays |
question
| what do x-rays and gamma rays do? |
answer
| ionize atoms and molecules |
question
| what does UV light do? |
answer
| causes formation of harmful covalent bonds |
question
| photolyases |
answer
| light repair enzymes that use visible light energy to separate the dimer back to 2 original thymines |
question
| nucleotide excision repair |
answer
| enzymes cut out the incorrect base and fill in the gap with newly synthesized DNA that is complementary to the correct strand |
question
| methylases |
answer
| enzymes that add a methyl group to selected bases soon after a DNA strand is made |
question
| mutation rate |
answer
| the probability that a gene will mutate when a cell divides |
question
| auxotrophs |
answer
| any mutant microorganism having a nutritional requirement absent from parent |
question
| carcinogens |
answer
| substances that cause cancer |
question
| Ames test |
answer
| preliminary screening of potential carcinogens using bacteria |
question
| genetic recombination |
answer
| the exchange of genes between 2 DNA molecules to form new combinations of genes on a chromosome |
question
| crossing over |
answer
| a process during which a cell picks up foreign DNA, some of which inserts into the cell's chromosome |
question
| vertical gene transfer |
answer
| occurs when genes are passed from an organism to its offspring |
question
| horizontal gene transfer |
answer
| occurs when genes are passed from an organism to other microbes of the same generation |
question
| which organism practices horizontal gene transfer? |
answer
| bacteria |
question
| how are genes transferred from bacteria to another cell? |
answer
| as naked DNA in solution |
question
| what was Frederick Griffith known for? |
answer
| the experiment with dead encapsulated bacteria and live nonencapsulated (non virulent) bacteria, in which the virulence was transferred from dead bacteria to the live. |
question
| competence |
answer
| when a recipient cell is in a physiological state in which it can take up the donor DNA |
question
| conjugation requires __________________. |
answer
| cell-to-cell contact |
question
| what happens during the conjugation of gram-negative bacteria? |
answer
| genes code for the synthesis of sex pili and projections from the donor cell surface pull it and the recipient together |
question
| what happens during the conjugation of gram-positive bacteria? |
answer
| sticky surface molecules cause cells to come in direct contact with each other --> "mating bridge" |
question
| F (fertility) Factor |
answer
| first plasmid observed to be transferred between cells during conjugation |
question
| HFr (high frequency of recombination) cell |
answer
| when a cell carrying an F factor integrates that factor into the chromosome |
question
| specialized transduction |
answer
| only certain bacterial genes are transferred |
question
| what do plasmids and transposons do? |
answer
| provide additional mechanisms for genetic change |
question
| conjugative plasmid |
answer
| carries genes for sex pili and the transfer of the plasmid to another cell |
question
| dissimilation plasmid |
answer
| code for enzymes that trigger the catabolism of certain unusual sugars and hydrocarbons |
question
| bacteriocins |
answer
| toxic proteins that kill other bacteria |
question
| resistance (R) factors |
answer
| plasmids that have significant medical importance |
question
| resistance transfer factor |
answer
| includes genes for plasmid replication and conjugation |
question
| r-determinant |
answer
| production of enzyme that inactivate certain drugs/ toxic substances |
question
| transposons |
answer
| small segments of DNA that can move from one region of a DNA molecule to another |
question
| what is Barbara McClintock known for? |
answer
| the theory of transposons |
question
| insertion sequences |
answer
| contain only a gene that codes for an enzyme (transposes) and recognition sites |
question
| recognition sites |
answer
| short inverted repeat sequences of DNA that the enzyme recognizes as recombination sites between the transposon and chromosome |
question
| mycorrhizae |
answer
| symbiotic fungi which help plants' roots absorb minerals and water from the soil |
question
| mycology |
answer
| the study of fungi |
question
| thallus |
answer
| body of fungi |
question
| what is the thallus of molds and fleshy fungi composed of? |
answer
| long filaments of cells joined together (hyphae) |
question
| hyphae |
answer
| long filaments of cells joined together |
question
| septa |
answer
| cross-walls which divide hyphae into distinct, uninucleate cell-like units called septate hyphae |
question
| coenocytic hyphae |
answer
| hyphae with no septa |
question
| how do hyphae grow? |
answer
| by elongating at the tips |
question
| vegetative hyphae |
answer
| the portion that obtains nutrients |
question
| reproductive/ aerial hypha |
answer
| reproduction |
question
| mycelium |
answer
| a filamentous mass sometimes formed by hyphae |
question
| yeasts |
answer
| nonfilamentous, unicellular fungi |
question
| how do budding yeasts divide? |
answer
| parent forms bud parent nucleus divides and 1 goes to bud cell wall laid between and divide |
question
| fission yeasts |
answer
| divide evenly in half |
question
| what kind of growth do yeasts exhibit? |
answer
| facultative anaerobic |
question
| dimorphic fungi |
answer
| exhibit 2 forms of growth (mold or yeast), depending on temperature |
question
| how do filamentous fungi reproduce? |
answer
| asexually- hyphae fragmentation, spores (identical parent/daughter) sexually- spores result from the fusion of nuclei from 2 opposite mating strains of fungus |
question
| how are asexual fungal spores produced? |
answer
| mitosis and cell division |
question
| conidiospore |
answer
| a unicellular or multicellular spore that is not enclosed in a sac |
question
| arthroconidia |
answer
| conidia formed by the fragmentation of a septate hyphae into single, slightly thickened cells |
question
| blastoconidia |
answer
| consists of buds coming off parents cell |
question
| chlamydoconidium |
answer
| a thick-walled spore formed by rounding and enlargement within a hyphal segment |
question
| sporangiospore |
answer
| formed within a sporangium sac at the end of an ariel hypha called a sporangiophore |
question
| production of sexual spores (3) |
answer
| 1) plasmogamy 2) karyogamy 3) meiosis |
question
| plasmogamy |
answer
| a haploid nucleus of a donor cell (+) penetrates the cytoplasm of a recipient cell (-) |
question
| karyogamy |
answer
| (+) and (-) nuclei fuse to form a diploid zygote nucleus |
question
| meiosis |
answer
| diploid nucleus gives rise to form a haploid nuclei |
question
| how do fungi obtain nutrients? |
answer
| chemoheterotrophs- they absorb it |
question
| t/f: molds are aerobic |
answer
| true |
question
| zygomycota |
answer
| conjugation fungi-- they are saprophytic molds that have coencytic hyphae |
question
| how do zygomycota reproduce? |
answer
| sexual or asexual |
question
| microsporidia |
answer
| eukaryotes that lack mitochondria and microtubules |
question
| t/f: microsporidia can exists freely in the environment |
answer
| false, they are obligate intracellular parasites |
question
| ascomycota |
answer
| sac fungi |
question
| basidiomycota |
answer
| club fungi with septate hyphae |
question
| basidium |
answer
| a base pedestal on which basidiospores grow |
question
| teleomorphs |
answer
| produce both sexual and asexual spores |
question
| anamorphs |
answer
| asexual fungi |
question
| mycosis |
answer
| any fungal infection |
question
| systemic mycoses |
answer
| fungal infections deep within the body |
question
| subcutaneous mycoses |
answer
| fungal infections beneath the skin caused by saprophytic fungi that live in soil and on vegetation |
question
| dermatophytes (cutaneous mycoses) |
answer
| fungi that affect only the epidermis, hair, and nails |
question
| superficial mycoses |
answer
| affect hair shafts and surface epidermal cells |
question
| opportunistic pathogen |
answer
| usually harmless, but becomes pathogenic in a host who is susceptible |
question
| lichen |
answer
| a combination of a green algae and a fungus (mutualistic relationship) |
question
| 3 categories of lichen |
answer
| crustose: encrust foliose: leaflike fruticose: fingerlike |
question
| medulla |
answer
| lichen algal cells around which fungal hyphae grow, creating the thallus |
question
| rhizines |
answer
| holdfasts |
question
| cortex |
answer
| a protective covering over the lichen algal layer, created by the fungal hyphae |
question
| algae |
answer
| photoautotrophs that lack the tissues of plants |
question
| how does algae get nutrients? |
answer
| absorbs nutrients from the water over the whole surface; photosynthetic; some are chemoheterotrophs |
question
| pneumatocist |
answer
| a floating, gas-filled bladder than may help buoy algae |
question
| how do algae reproduce? |
answer
| asexually (fragmentation or cell splits in 2) sexually for some |
question
| chlorophyll |
answer
| a light-trapping pigment found in algae |
question
| brown algae (kelp) characteristics |
answer
| macroscopic; fast growth |
question
| red algae characteristics |
answer
| delicately branched thalli; deeper depths |
question
| green algae characteristics |
answer
| cellulose cell walls |
question
| diatoms |
answer
| unicellular or filamentous algae with complex cell walls that consist of pectin and a layer of silica |
question
| dinoflagellates |
answer
| unicellular algae collectively called plankton |
question
| dinoflagellate characteristics |
answer
| rigid structure; neurotoxins |
question
| red tide |
answer
| forms when large concentrations of dinoflagellates amass |
question
| water molds (oomycota) |
answer
| decomposers that form cottony masses on dead things |
question
| how is algae beneficial in nature? |
answer
| it fixes carbon dioxide into organic molecules that can be consumed by chemoheterotrophs and produce oxygen for us |
question
| algal blooms |
answer
| periodic increases in numbers of planktonic algae that may indicate pollution |
question
| protozoa |
answer
| unicellular, eukaryotic organisms |
question
| trophozoite |
answer
| the feeding and growing stage of a protozoa |
question
| how do protozoa reproduce? |
answer
| asexually (fission, budding, schizogony) some sexually (conjugation, gametes) |
question
| schizogony |
answer
| multiple fission (nucleus divides many times before the cell divides, producing many daughter cells) |
question
| what is the purpose of a protozoa cyst? |
answer
| a protective capsule that sometimes forms under adverse conditions, allowing parasites to survive outside host |
question
| how do protozoa get nutrients? |
answer
| mostly aerobic heterotrophic (some anaerobic) |
question
| pellicle |
answer
| a protective covering that makes it necessary to reacquire specialized structures in protozoa to take in food |
question
| cytosome |
answer
| a mouth-like opening of protozoa toward which ciliates wave their cilia in order to take in food |
question
| how do amoebas eat? |
answer
| engulf food by surrounding it with pseudopods and phagocytize it |
question
| vacuoles |
answer
| where digestion takes place in protozoa |
question
| what are feeding grooves? |
answer
| spindle-shaped protozoa that have flagella and an undulating membrane |
question
| euglenozoa |
answer
| photoautotrophic protozoa that have rRNA sequences, disk-shaped mitochondria, and are asexual. |
question
| eyespot |
answer
| a carotenoid-containing organelle that senses light and directs the cell in the appropriate direction using a preemergent flagella (characteristic of euglenozoa protozoa) |
question
| hemophlagellates (blood parasites) |
answer
| transmitted by bites of blood-feeding insects |
question
| how do amoebae move? |
answer
| extend pseudopods |
question
| apicomplexa |
answer
| non-motile, obligate intracellular protozoan parasites. |
question
| what causes malaria? |
answer
| plasmodium |
question
| definitive host |
answer
| harbors the (sexually) reproducing stage |
question
| intermediate host |
answer
| the host in which a parasite undergoes asexual reproduction |
question
| slime molds |
answer
| closely related to amoebae; phylum amoebozoa |
question
| cellular slime molds |
answer
| typical eukaryotic cells that resemble amebae |
question
| plasmodial slime molds |
answer
| exist as masses of protoplasm with many nuclei |
question
| helminths (parasitic worms) |
answer
| multicellular, eukaryotic animals with a complex life cycle |
question
| dioecious |
answer
| male organs in 1, female in another (helminths) |
question
| momoecious/ hermaphroditic |
answer
| one animal has both male and female reproductive organs (helminths) |
