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Test 2
Chapters 8, 12-13
212
Microbiology
Undergraduate 2
03/24/2015

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Term
Genetics
Definition
The science of heredity.
Term
genome
Definition
the genetic information in a cell
Term
what two things make up the genome?
Definition
chromosomes and plasmids
Term
chromosomes
Definition
structures containing DNA that physically carry hereditary information
Term
genes
Definition
segments of DNA (or RNA in some viruses) that code for functional products
Term
DNA
Definition
a macromolecule composed of repeating units called nucleotides
Term
nucleotide
Definition
consists of a nuclease, a deoxyribose, and a phosphate group
Term
what is the structure of DNA?
Definition
long strands of nucleotides twisted together to form a double helix
Term
what are the DNA base pairs?
Definition
adenine - thymine
cytosine - guanine
Term
genetic code
Definition
the set of rules that determines how a nucleotide sequence is converted into the amino acid sequence of a protein
Term
genotype
Definition
an organism's genetic makeup
Term
phenotype
Definition
actual, expressed properties; a manifestation of the genotype
Term
what do the phenotypic properties derive from?
Definition
the structure and function of protein
Term
in microbes, most proteins are: (2)
Definition
enzymatic: catalyze particular reactions
structural: participate in large functional complexes
Term
bacteria
Definition
single circular chromosome consisting of a single circular molecule of DNA with associated proteins
Term
short tandem repeats (STRs)
Definition
noncoding regions that occur in most bacterial genomes
Term
genomics
Definition
the sequencing and molecular characterization of genomes
Term
what happens first: cell division or DNA replication?
Definition
DNA replication
Term
what is the ultimate goal of DNA replication?
Definition
one parental double-stranded DNA molecule is converted to 2 identical daughter molecules
Term
function of DNA gyrase, topoisomerase
Definition
relaxes supercoiling ahead of the replication fork
Term
function of DNA ligase
Definition
makes covalent bonds to join DNA strands; joins Okazaki fragments and new segments in excision repair
Term
function of DNA polymerase
Definition
synthesizes, proofreads, and repairs DNA
Term
function of endonucleases, transposase
Definition
cut DNA backbone in a strand of DNA and facilitate repair
Term
function of helicase
Definition
unwinds double-stranded DNA
Term
function of methylase
Definition
adds methyl group to selected bases in newly made DNA
Term
function of photolyase
Definition
uses visible lights energy to separate UV-induced pyrimidine dimers
Term
function of ribozyme, snRNP
Definition
RNA enzyme that removes introns and splices exons together
Term
function of RNA polymerase
Definition
copies RNA from a DNA template
Term
function of RNA primase
Definition
an RNA polymerase that makes RNA primers from a DNA template
Term
replication fork
Definition
the point at which replication occurs
Term
semiconservative replication
Definition
the process of replication in which each new double-stranded DNA molecule contains one original strand and one new strand
Term
what is the numerical structure of DNA?
Definition
5' --> 3'
Term
on which end of the numerical DNA structure can DNA polymerases add new nucleotides?
Definition
3'
Term
where does energy for replication come from?
Definition
nucleotides
Term
what synthesizes DNA?
Definition
deoxyribose (sugar)
Term
what synthesizes RNA?
Definition
nucleoside triphosphates with ribose
Term
transcription
Definition
the synthesis of a complementary strand of RNA from a DNA template
Term
ribosomal RNA (rRNA)
Definition
forms ribosomes (where protein synthesis occurs)

prokaryotic transcription
Term
messenger RNA (mRNA)
Definition
carries the coded information for making specific proteins from DNA to ribosomes

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