Week 5 - Translation Flashcards
What is the central dogma of molecular biology?
DNA – RNA - Protein
What are the main processes involved in gene expression?
- Transcription
- mRNA processing
- Translation
What is the primary function of RNA polymerases?
Incorporate nucleotides into strand of RNA from a DNA template
What is the structure of bacterial RNA polymerase?
- Two alpha subunits
- One beta subunit
- One beta prime subunit
- One omega subunit
- One sigma subunit
What are the conserved sequence regions in prokaryotic promoters?
- -35 element
- -10 element (Pribnow box)
How does transcription initiation occur in prokaryotes?
Sigma subunit interacts with -35 and -10 promoter elements, polymerase unwinds DNA and transcription begins
What signals transcription termination in prokaryotes?
A G-C rich inverted repeat followed by 7 A residues
What is one alternative method of transcription termination in prokaryotes?
Termination protein (Rho)
How many subunits does yeast RNA polymerase II have?
12-17 subunits
What is the role of TFIID in eukaryotic transcription?
Binds to promoter consensus sequences and initiates transcription
What modifications occur during eukaryotic mRNA processing?
- 5’ cap addition
- 3’ poly A tail addition
- Intron splicing
What is the purpose of the 5’ cap in eukaryotic mRNA?
Stabilizes mRNA and plays a role in translation initiation
What enzyme cleaves pre-mRNA downstream of the AAUAAA sequence?
Endonuclease
What is the function of poly-A polymerase?
Adds a poly-A tail to the 3’ end of mRNA
What complex removes introns from pre-mRNA?
Spliceosome complex
What are the components of the spliceosome complex?
- Small nuclear RNAs (snRNAs)
- Small nuclear ribonuclear particles (snRNPs)
What is the role of ribosomes in translation?
Interpret the mRNA code and facilitate protein synthesis
What are the sites available on a ribosome for tRNA binding?
- A site
- P site
- E site
Fill in the blank: The process of linking an amino acid to tRNA is catalyzed by _______.
[aminoacyl tRNA synthetases]
True or False: Eukaryotic mRNAs undergo processing before translation.
True
What is the function of the ribosomal RNA in ribosomes?
Provides structural scaffold and catalytic activity
What is the typical length of tRNA molecules?
70-80 nucleotides long
What is the significance of the AAUAAA sequence in mRNA processing?
It signals the site for cleavage by endonuclease
