Wk 2 Flashcards
(17 cards)
General process of transcription
Transcription is the process of synthesizing RNA from a DNA template. RNA polymerase binds to the promoter region of DNA and assembles an RNA strand complementary to the DNA template. Transcription ends when RNA polymerase reaches a terminator sequence.
What molecules are involved in transcription?
DNA, RNA polymerase, ribonucleotide triphosphates (ATP, CTP, GTP, UTP), and transcription factors.
What is the role of the promoter in transcription?
The promoter is a DNA sequence where RNA polymerase and transcription factors bind to initiate transcription
What is the role of the terminator in transcription?
The terminator is a DNA sequence that signals RNA polymerase to stop transcription
What is “gene expression” & how does it differ
Gene expression is the process by which information from a gene is used to synthesize a functional product like a protein.Different cell types express different sets of genes based on their function, leading to cellular specialization.
What happens during RNA capping? What the purpose
A modified guanine nucleotide (5’ cap) is added to the beginning of the RNA. It protects the RNA and helps ribosomes recognize the mRNA for translation.
What happens during polyadenylation
A chain of adenines (poly-A tail) is added to the 3’ end of the RNA.
Q9: What is RNA splicing?
A9: Non-coding introns are removed, and coding exons are joined to form a mature mRNA.
Q11: What is the purpose of the poly-A tail?
A11: It stabilizes the RNA and aids in export from the nucleus.
Q12: What are introns and exons?
A12: Introns are non-coding sequences removed from RNA; exons are coding regions that remain.
Q13: How does alternative splicing lead to protein diversity?
A13: It allows different combinations of exons to be joined, making multiple proteins from one gene
Q15: Where does RNA polymerase bind in the operon?
A15: RNA polymerase binds to the promoter.
Q16: What is the function of a repressor in the lac operon?
A16: It binds to the operator to block transcription when lactose is not present.
Q17: What is the role of an activator in gene expression?
A17: Activators help RNA polymerase bind to the promoter, enhancing transcription.
Q18: How can gene expression be repressed or turned off?
A18: A repressor protein binds to the operator and prevents transcription.
Q19: What is the difference between repressible and inducible genes?
A19: Repressible genes are normally on and can be turned off; inducible genes are off and can be turned on.
Q20: How is the lac operon regulated?
A20: It’s inducible. When lactose is absent, a repressor blocks transcription. When lactose is present, it binds to the repressor, inactivating it and allowing transcription to occur.
