8. Transcription and processing in prokaryotes Flashcards
The central dogma
Flow of genetic info from DNA to RNA (transcription) to proteins (translation)
RNA self-replication
RNA- dependent RNA polymerase activity in RNA viruses
RNA can be retrotranscribed to DNA
Retrotranscriptase activity in retroviruses
Protein + infection
= prion
E.g., self-reproducing pathogenic proteins
Primary function of DNA
Store genetic info.
Primary function of RNA
Transducer DNA messages into protein
Primary functions of proteins
Read info. And catalyze reactions as ribosozymes
Transcription and translation in prokaryote vs eukaryotes
Prokaryotes can’t regulate RNA and protein synthesis
In eukaryotes nucleus divided transcription and translation=greater control of RNA and protein synthesis
RNA molecules involved in transcription
MRNA SnRNA TRNA RRNA MiRNA
RNA polymerase
Highly conserved proteins (so function stays same)
Steps for DNA info transmission to protein:
- Gene expression
- MRNA processing
- MRNA transport
- MRNA translation
Spiegelman’s experiments
Rapid switch from transcription of E.coli genes to phage genes;
phage hijacks cells transcription machinery, but cells then actively destroy messenger
Pulse-chase labeling experiments
Prove RNA synthesized in nucleus and then transported to cytoplasm
RNA ribonucleotides
- Adenosine
- Guanosine
- Cytidine
- Uridine
RNA vs. DNA
1. Single vs. double More options for shape 2. OH groups in position 2 3. Uracil pairs with A during transcription pairs with A or G when folding 4. RNA can catalyze reactions
