Genetics

• Where does transcription occur in eukaryotic cells?

  In the nucleus

  
• What are the two main components of a eukaryotic gene?

  Introns and exons
• What is the role of transcription factors in transcription?

  They regulate the transcription process
• How many types of RNA polymerase are there in eukaryotes?

  Three RNA polymerases
• What is the function of enhancers in gene transcription?

  They influence the rate of transcription
• What is pre-mRNA processing in the nucleus?

  Modification of pre-mRNA before translation

  
• What is the difference between prokaryotic and eukaryotic transcription?

  Eukaryotes have RNA processing; prokaryotes do not

  
• What is the process of transcription?

  Copying DNA information into mRNA

  
• What is the role of the 5' cap in mRNA processing?

  It protects the transcript and aids export

  
• What is the purpose of polyadenylation in mRNA processing?

  To stabilize the transcript and aid export
• What are introns and exons?

  Introns are non-coding; exons are coding sequences
• What is the spliceosome's role in mRNA processing?

  It removes introns and splices exons together

  
• What is the function of RNA polymerase I?

  Transcribes pre-rRNA

  
• What does RNA polymerase II transcribe?

  Pre-mRNA and various non-coding RNAs
• What is the role of RNA polymerase III?

  Transcribes pre-tRNA and 5S rRNA

  
• What happens during the initiation phase of transcription?

  RNA polymerase binds to the template strand

  
• What is the transcription bubble?

  A region where DNA is unwound for transcription

  
• What is the significance of the TATAA box?

  It is a recognition site for TBP in the promoter
• What is the role of the mediator complex in transcription?

  It binds to DNA regulatory elements

  
• How does RNA polymerase II function during elongation?

  It synthesizes pre-mRNA while processing it

  
• What is the direction of RNA synthesis during transcription?

  5' to 3' direction

  
• What is the purpose of the poly-A tail?

  To stabilize the mRNA and aid in export

  
• What are polyadenylation signals?

  Sequences that signal for the addition of a poly-A tail

  
• What is the least understood mechanism of transcription termination?

  Termination in eukaryotes
• How does RNA Pol I terminate transcription?

  Using transcription termination factors and bending
• What is the role of the poly-A tail in RNA Pol II termination?

  It doubles as a termination signal

  
• How does RNA Pol III terminate transcription?

  Using a thymine-rich terminator sequence
• What is the significance of alternative splicing?

  It allows one gene to produce multiple proteins
• What are the steps involved in pre-mRNA processing?

  1. 5' capping
  2. Splicing (removal of introns)
  3. Addition of poly-A tail

  
• What is the role of the spliceosome in mRNA processing?

  • Removes introns
  • Splices exons together
  • Composed of snRNAs and protein factors

  
• What are the functions of the 5' cap in mRNA processing?

  • Regulation of nuclear export
  • Prevention of degradation by exonucleases
  • Promotion of translation
  • Promotion of intron excision
• What are the mechanisms of transcription termination for different RNA polymerases?

  • RNA Pol I: Uses TTF1 and bending
  • RNA Pol II: Poly-A tail as termination signal
  • RNA Pol III: Thymine-rich terminator sequence

  
• Why are introns important in gene expression?

  • Allow for alternative splicing
  • Enable generation of diverse proteins
  • Contribute to chromatin assembly
• What is the significance of the transcription bubble during transcription?

  • Region where DNA is unwound
  • Allows RNA polymerase to read the template strand
  • Essential for RNA synthesis

  
• What is the role of the mediator complex in transcription initiation?

  • Binds to DNA regulatory elements
  • Facilitates interaction between transcription factors
  • Enhances transcription efficiency

  
• What is translated into protein during translation?

  mRNA
• In which direction does translation proceed on mRNA?

  From 5’ to 3’ end
• What are the two components of ribosomes?

  RNA and protein
• What does tRNA do during translation?

  Matches codon to the correct amino acid
• What are the stages of translation?

  • Initiation
  • Elongation
  • Termination