Regulation Of Gene Expression Flashcards
What is post-transcriptional regulation of gene expression?
A: The control of gene expression at the mRNA level, including mRNA stability, translation initiation, and degradation.
How is translation initiation regulated in eukaryotes?
A: Through the action of translation initiation factors, repressor proteins, and microRNAs that modulate ribosome assembly on mRNA.
What is the function of iron-response elements (IREs) in ferritin mRNA regulation?
A: IREs bind Iron Regulatory Proteins (IRPs) to inhibit translation when iron levels are low.
How do microRNAs regulate translation?
A: They bind to complementary sequences in the 3’ untranslated region (UTR) of mRNA, leading to translational repression or mRNA degradation.
What is the role of eIF2 phosphorylation in translation control?
A: Phosphorylation of eIF2 inhibits translation initiation, preventing GDP-GTP exchange necessary for ribosome assembly.
mRNA degradation can be regulated by
deadenylation and removal of the 5’ cap.
MicroRNAs (miRNAs) regulate up to
60% of human gene transcripts.
Translation can be inhibited globally or specifically through
repressor proteins.
eIF4E-binding proteins (4E-BPs) block
translation initiation in response to stress.
Ferritin translation is controlled by
iron availability.
MicroRNAs promote translation of their target mRNAs.
False – They inhibit translation or promote mRNA degradation.
The phosphorylation of eIF2 enhances translation initiation.
False – It inhibits translation initiation by preventing ternary complex formation.
RNA-binding proteins (RBPs) influence mRNA stability.
True – They bind to AU-rich elements (AREs) and regulate mRNA degradation.
The poly-A tail of mRNA increases its stability.
True – It protects mRNA from degradation.
The enzyme responsible for removing the 5’ cap from mRNA is called __________.
A: Decapping enzyme.
The interaction between microRNAs and the RISC complex leads to __________.
A: Translational repression or mRNA degradation.
The __________ complex is required for translation initiation in eukaryotic cells.
A: eIF4F complex.
The sequence elements that bind RNA-binding proteins for mRNA degradation are called __________.
A: AU-rich elements (AREs).
Which of the following mechanisms contributes to translation repression?
A) DNA methylation
B) miRNA binding to the 3’ UTR
C) Enhancer activation
D) Histone acetylation
A: B) miRNA binding to the 3’ UTR.
What is the role of eIF4E-binding proteins (4E-BPs)?
A) Promote translation by recruiting ribosomes
B) Inhibit translation by preventing eIF4E-eIF4G interaction
C) Stimulate ribosome assembly
D) Facilitate mRNA splicing
A: B) Inhibit translation by preventing eIF4E-eIF4G interaction.
How do cells regulate translation in response to stress?
A) Activation of miRNAs
B) Phosphorylation of eIF2
C) Increasing ribosomal binding
D) Strengthening mRNA stability
A: B) Phosphorylation of eIF2.
Which of the following is a mechanism by which microRNAs affect gene expression?
A) Enhancing ribosomal recruitment
B) Targeting mRNA for degradation
C) Increasing transcription rates
D) Promoting alternative splicing
A: B) Targeting mRNA for degradation.
A patient with iron-deficiency anemia shows low levels of ferritin. What molecular mechanism is likely responsible?
A: IRPs binding to ferritin mRNA’s IREs, blocking translation initiation.
A researcher observes that stress conditions reduce protein synthesis in cultured cells. What is a likely mechanism?
A: Phosphorylation of eIF2, inhibiting translation initiation.
