NB CH24,25 - Gene Regulation Flashcards
Promoter
Special type of regulatory sequence that comes before the gene. RNA polymerase binds to promoters
What types of promotors can increase or decrease transcription?
Increase: strong promoters
Decrease: weak promoters
Regulatory sequence
Regions of DNA with specific sequences that can, when bound by a transcription factor, help increase or decrease gene expression
What types of regulatory sequences can increase or decrease transcription?
Increase: enhancer
Decrease: silencer, operator (only in prokaryotes)
Transcription factor
What are the two types?
Proteins that bind to regulatory sequences
Activators, repressors
Activators
What regulatory sequences do they bind to?
Transcription factors that bind to enhancers or weak promoters
Repressors
What kinds of regulatory sequences can it bind to?
Transcription factors that bind to silencers, operators, or strong promoters
Effector
Small molecules that bind to transcription factors to change transcription
Examples of effectors are inducers, inhibitors, and corepressors
Allosteric regulation on transcription factors
Small molecules can bind to transcription factors, activating or inactivating them
What kinds of bonds do transcription factors make with DNA?
Specific amino acids in them will form hydrogen bonds with specific nucleotides in the DNA
How do transcription factors produce positive vs. negative regulation?
Positive: increases transcription by binding to a regulatory element
Negative: decreases transcription by binding to a regulatory element
Inducer
A molecule that binds to repressors to deactivate them (prevent binding to DNA) or
binds to activators to activate them (allow binding to DNA)
Inhibitor
A molecule that binds to activators and prevents from binding to DNA (opposite of inducer)
Corepressor
A molecule that binds to repressors and allows binding to DNA (opposite of inducer)
Operator
It is a regulatory sequence to which a repressor can bind
Only found in prokaryotic cells
The association of DNA with histones typically affects transcription by
Decreasing transcription of a few genes, while not influencing most others
What does ∆ mean when placed before a gene?
That specific gene has been deleted
