Week 7 - Regulation Of Gene Expression Flashcards
What is gene expression?
Control at multiple steps
Define an operon.
A functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter
What is the function of the E. coli lac operon?
Control of gene expression for efficient substrate use
What induces the synthesis of enzymes for lactose metabolism in E. coli?
Presence of lactose
How is the lac operon expression inhibited?
By a repressor protein
What is the role of allolactose in the lac operon?
Binds to repressor protein and blocks its action
What type of expression system is the lac operon an example of?
Inducible expression system
What is the function of the trp operon?
Codes for genes responsible for synthesis of amino acid tryptophan
What happens to the trp operon when tryptophan levels are low?
Repressor is inactive, operon expressed, tryptophan synthesized
What happens to the trp operon when tryptophan levels are high?
Tryptophan binds to repressor, operon expression inhibited
What are regulatory transcription factors (TFs)?
Proteins that activate or inhibit transcription
What is the difference between transcriptional activators and repressors?
Activators promote transcription, repressors inhibit transcription
What is chromatin remodeling?
Alteration of chromatin structure to regulate transcriptional activity
What is euchromatin?
Open chromatin structure that is transcriptionally active
What is heterochromatin?
Condensed chromatin that is normally transcriptionally silent
What role do histone modifying enzymes play?
Catalyze histone modifications that affect chromatin structure
How does acetylation affect transcriptional activity?
Tends to increase transcriptional activity
What is DNA methylation?
Addition of methyl groups to DNA, typically resulting in transcriptional silencing
What is alternative splicing?
Process by which genes can encode more than one protein through different mRNA transcripts
What is the role of translation initiation factors?
Mediates the process of translation initiation
What is the function of micro RNAs (miRNAs)?
Regulate gene expression by binding to target mRNAs and inhibiting translation
What happens to translation initiation in low iron levels?
IRP binds to IRE, interferes with translation initiation
What is the action of eIF2 in translation regulation?
Active eIF2-GTP escorts initiator Met-tRNA to ribosome
What occurs when growth factors stimulate 4E-BPs?
Phosphorylation of 4E-BPs dissociates them from eIF4E, allowing translation to proceed
What initiates mRNA degradation in eukaryotes?
Deadenylation of the poly-A tail followed by exonuclease digestion
What are AU-rich elements (AREs)?
Sequences in mRNA that serve as binding sites for RNA-binding proteins (RBPs)
In prokaryotes, what is the typical half-life of mRNA?
Minutes
What is the primary role of RNA-binding proteins (RBPs)?
Influence mRNA fate by binding to regulatory sequences
What is the key outcome of transcriptional control in eukaryotes?
Gene expression is chiefly controlled by transcription factors and chromatin remodeling
What is the title of the book authored by Alberts et al. in its 6th edition?
Molecular Biology of the Cell
Published by Garland Science in 2015
What is the URL for the online resource provided by the DNA Learning Centre?
http://www.dnalc.org/
This is a Cold Spring Harbor online DNA learning resource
What is the focus of the ‘DNA from the Beginning’ resource?
An animated primer of 75 experiments that made modern genetics
This resource helps in understanding fundamental concepts in genetics
What type of content does Bozeman Science provide?
Basic video tutorial on Transcription and translation
Includes educational resources for molecular biology
Fill in the blank: The 6th edition of ‘Molecular Biology of the Cell’ was published by _______.
Garland Science
True or False: The DNA Learning Centre is a resource for learning about RNA synthesis.
False
The DNA Learning Centre focuses on DNA and genetics, not specifically on RNA synthesis.
List the online resources mentioned for molecular biology education.
- DNA Learning Centre
- DNA from the Beginning
- Bozeman Science