Chapter 16: Control of Gene Expression Flashcards
Controlling gene expression is often accomplished by controlling ______ _______
transcription initation
_______ ________ bind to DNA, modulate binding of RNA polymerase to promoter
regulatory proteins
___________ organisms regulate gene expression in response to their environment
prokaryotic
________ cells regulate gene expression to maintain a constant internal environment in the organism
eukaryotic
What type of regulation is this
- chromatin remodeling to make genes accessible for transcription
-regulatory events at a gene’s promoter and regulatory sequences
transcriptional regulation
What type of transcription is this
- variations in pre-mRNA processing
-removal of making proteins
-variations in rate of mRNA breakdown
-RNA interference
posttranscriptional regulation
What type of regulation is this
- variations in rate of initiation of protein synthesis
translational regulation
What type of regulation is this
- variations in rate of protein processing
-removal of making segments
-variations in rate of protein breakdown
posttranslational regulation
What type of regulation determines which genes are transcribed?
transcriptional
What type of regulation determines types and availability of mRNAs to ribosomes?
posttranscriptional
What type of regulation determines the rate at which proteins are made?
translational
What type of regulation determines the availability of finished proteins?
posttranslational
Gene expression is often controlled by _____ _____ binding to specific DNA sequences
regulatory proteins
______ ______ gain access to the bases of DNA at the major groove
regulatory proteins
Regulatory proteins possess ____-_____ motifs
DNA-binding
What are the two things regulatory proteins can do?
- block transcription by preventing RNA polymerase to bind
- stimulate transcription by facilitating RNA polymerase binding to promoter
Within the ____ groove, nucleotides’ hydrogen bond donors and acceptors are accessible
major
T or F: The unique pattern of accessibility for each base pair combination enables proteins to read the sequence without unwinding DNA
True
What are the regions of regulatory proteins that bind to DNA called?
DNA-binding motifs
What is the two a-helical segments linked by a nonhelical segment called?
Helix-turn-helix motif
What is a special class of helix-turn-helix and is critical in eukaryotic development?
Homeodomain
What type of motif uses zinc atoms to coordinate DNA binding?
Zinc finger
What type of motif has one subunit that interacts with a similar region on another subunit forming a zipper-like connection
Leucine zipper motif
(prokaryotic regulation) ______ _____ can be positively or negatively controlled
transcription initiation`
What type of control increases freqeuncy?
positive
In positive control _______ enhance binding of RNA polymerase to promoter?
activators
What type of control decreases frequency?
negative control
In negative control ____ bind to regulatory sites on DNA called operators that prevent or decrease initiation frequency
repressors
_____ molecules can act on both repressors and activators
effector
______ cells often respond to their environment by changes in gene expression
prokaryotic
genes involved in the same metabolic pathway are organized in ______
operons
In _______ enzymes for a certain pathway are produced in response to a substrate
induction
______ is capable of making an enzyme by does not
repression
____ ______ encodes proteins necessary for the use of lactose as an energy source
lac operon
What are the three genes in the lac operon?
LacZ, lacY, lacA
What gene is linked to the rest of the lac operon?
the lac repressor (lacl)
The promoter for the gene, the gene repressor protein, CAP-binding site, the promoter for the operon, and the operator are all in the _____ region
regulatory
if lactose is absent the lac operon is _____
repressed
if lactose is absent the lac operon is ______
induced
What is the mechanisms for the preferential use of glucose in the presence of other sugars?
glucose repression