RNA Synthesis and Transcription in Bacteria Flashcards
Two parts of gene expression
- DNA –> RNA = TRANSCRIPTION
2.RNA –> protein = TRANSLATION
Pulse-chase method
Infecting nucleotides with radioactive components and traced in cells
Difference between RNA and DNA
RNA:
- thymine replaced by uracil
- ribose sugar instead of deoxyribose. Ribose has one more OH group
What form is RNA in?
A type. DNA IS B TYPE HELIX
Where does RNA synthesis take place on the strand?
between 3’ hydroxyl of one nucleotide and 5’ phosphate on adjacent one
mRNA
Messenger RNA produced by protein producing genes. Intermediate between DNA and protein. Only type of RNA that undergoes translation
What are the functional RNAs?
Transfer RNAs (tRNAs) and Ribosomal RNA (rRNA)
Which of the following RNA are involved in the process that leads to protein synthesis?
mRNA, tRNA, rRNA
How long is the transcription bubble of unwound DNA?
14 bp. ~8 RNA nucleotides paired with DNA inside transcription bubble
Transcription vs Replication?
Transcription:
- DNA-dependent RNA polymerases
- DNA unwinding is minimal
- Some regions copied at high levels; some low. Level of expression can be changed
How are bacterial genes expressed?
In groups called OPERONS consisting of genes relating to similar metabolic function
Where does RNA transcription begin?
Promoter upstream (5’)
Where does RNA transcription end?
Terminator region downstream (3’) from coding segment of gene
What catalyzes transcription in RNA?
RNA polymerase. Makes RNA from DNA but does not bind promoter or initiate RNA synthesis
Consensus sequences
Promoter– 5’ to 3’ coding strand sequence
