Chapter 16 - Mechanics Of DNA Regulation Flashcards
aka posttranslational regulation
enzyme/protein function regulation
two approaches of regulation
gene expression, enzymes and protein function
genes that are expressed only when specific substances are present in the environment
inducible gene
inducible genes are most common in blank
catabolism
genes that are normally expressed but repressed when certain substances are present in the environment
repressible gene
repressible genes are most common in blank
biosynthesis
if the blank is bound to blank, no transcription can occur
repressor, operator
tightly blank chromatin prevents blank
condensed, transcription
only a low level of transcription occurring
constitutive synthesis
proteins that inhibit transcription are called blank control
negative
proteins that promote transcription is called blank control
positive
induction and repression occur because of the activity of blank proteins and blank binding
regulatory, DNA
repressor proteins are blank because they have a blank and blank form
allosteric, active, inactive
anything that turns up transcription
inducer
three structural genes coding for lactose uptake and metabolism
inducible genes
lac blank binds lac operator which inhibits transcription by blank access to promoter for genes
repressor, blocking
if glucose is present, blank does not get used by the cell because it isn’t as easy
lactose
the lac repressor blank DNA
bends
this consists of 5 structural genes which code for enzymes needed to synthesize tryptophan
trp operon
differences between lac operon and trp operons slides
okay
eukarya use regulatory blank factors to regulate transcription blank
transcription, initiation
most prevalent form of gene in nature
wild gene
gene with variation of sequence compared to wild type
mutant type
wild type to mutant type is blank
forward mutation
mutant phenotype to wild type is blank
reversion mutation
occurs when the second mutation is at a different site than the original mutation
suppressor mutation
these mutations can affect structure but does not usually have an effect on function
point mutations
change nucleoside sequence of codon but not the encoded amino acid
silent mutation
mutations in blank sequences do not affect blank structure but might affect blank
regulatory, protein, regulation
enzymatic repair to any damage in dna
dna repair
corrects damage that causes distortions in double helix
excision repair
excision repairs remove the damaged portion of dna strand and use the intact blank strand as a template to blank new dna
complementary, synthesize
used to directly repair thymine dimers
photoreactivation
synthesis allows dna to be synthesized with no template
translesion synthesis
when dna damage is large scale the cell may need to use a different type of repair system and this system is more blank
error prone
inducible repair system used to repair excessive damage that halts replication, leaving many gaps
sos response
these dna polymerases are very error prone
4, 5
this protein initiates recombination repair
RecA
this protein acts as protease, destroying LexA repressor protein, increasing production of oxcision repair enzymes
RecA
mutations bring new blank to populations
genetic diversity
mutations are subject to blank
selective pressure
process in which one or more nucleic acids are rearranged
recombination
transfer of genes from parents to progeny
vertical gene transfer
sexual reproduction is accompanied by genetic recombination in blank
eukaryotes
this transfer of genes from one independent, mature organism to another followed by recombination
horizontal gene transfer
three mechanisms of horizontal gene transfer
transformation, transduction, conjugation
most common form of recombination that usually involves a reciprocal exchange between pair of DNA molecules with very similar nucleotide sequence
homologous
these enzymes play a role in recombination
RecA
uptake of naked dna released into medium by donor cell by a competent recipient cell followed by incorporation of the dna into the recipient cell’s genome
bacterial transformation
transfer of bacterial genes from a donor bacterium to a recipient bacterium by a virus
transduction
these can carry out the lytic cycle in which the host cell is destroyed or the viral dna can integrate into the host genome, becoming a latent prophage
bacteriophage
any part of bacterial genome can be transferred
generalized transduction
carried out by only temperate phages that have established lysogeny and only a specific portion of bacterial genome is transferred
specialized transduction
small, autonomously replicating dna molecules that can exist independently in cytoplasms, or as episomes, integrate reversibly into the host chromosome
bacterial plasmids
this is the conjugative plasmid that contains the information of formation of sex pilus in E. coli
F factors
conjugative plasmid in E. coli
f factor
cells with free f plasmid
f+
cells which have no f plasmid and are always the recipient cells
f -
gene transfer can be blank or blank directions
clockwise, counterclockwise
a blank copy of the f factor usually is not blank
transferred
direct cell to cell contact and is the transfer of genes between two bacteria
conjugation
conjugation is mediated by blank
f pilus
this transfers the most genes out of all the forms of genetic transfer
conjugation
donor HFr cell has f factor integrated into its blank
chromosome
segments of dna that move themselves to somewhere else in the genome in a process called blank
transposition
these are simple transposable that only contain genes for transposition
insertion sequences
these are transposable elements which contain genes other than those used for transposition like genes for antibiotic resistance
composite transposons
