Untitled Deck Flashcards
What is the central dogma of molecular biology?
DNA → RNA → Protein
What catalyzes the polymerization during transcription in prokaryotes?
RNA polymerase
What are the four stages of transcription?
- Recognition and binding
- Initiation
- Elongation
- Termination and release
What are the main components of RNA polymerase?
- 2 α subunits
- β subunit
- β’ subunit
- σ subunit
What is the difference between the core enzyme and holoenzyme in RNA polymerase?
Holoenzyme = Core + σ
What direction does RNA polymerase proceed during transcription?
5’ to 3’ direction
What is the role of the σ factor in transcription?
Essential for recognition of the promoter
What are intrinsic terminators in transcription?
Sequences that cause termination without additional factors
What is the role of the rho (ρ) factor in transcription termination?
Catalyzes unwinding of RNA:DNA hybrid
What is the primary function of mRNA?
Transcribe message from DNA to protein synthesis machinery
How does bacterial mRNA differ from eukaryotic mRNA?
Bacterial mRNA is polycistronic, while eukaryotic mRNA is monocistronic
What is the function of the 5’ cap in eukaryotic mRNA?
Protects mRNA from degradation and assists in ribosome binding
What are introns and exons?
- Introns: Untranslated intervening sequences
- Exons: Translated sequences
What is the GU-AG rule in RNA splicing?
Introns contain invariant 5’-GU and 3’-AG sequences at their borders
What are the three classes of RNA polymerases in eukaryotes?
- RNA Polymerase I
- RNA Polymerase II
- RNA Polymerase III
What is a key feature of eukaryotic promoters?
They can have core and upstream elements
What is the purpose of alternative splicing?
Allows different proteins to be produced from a single transcript
What does the term ‘post-transcriptional modification’ refer to?
Changes made to the RNA transcript after transcription, such as splicing and capping
Fill in the blank: RNA splicing is the removal of ______ sequences that interrupt the coding region of a gene.
intervening
What is the significance of the TATA box in eukaryotic transcription?
It is a core promoter element that helps initiate transcription
What is the typical transcription rate for RNA polymerase?
50 to 90 nucleotides per second
What are the roles of rRNA and tRNA in the cell?
- rRNA: Structural component of ribosomes
- tRNA: Adapters that carry amino acids to ribosomes
What is a primary transcript in eukaryotic cells?
Heterogeneous nuclear RNA (hnRNA)
What happens to RNA polymerase after termination of transcription?
RNA polymerase and RNA are released, DNA duplex reforms
