Transcription Flashcards
Give some differences between prokaryotic and eukaryotic transcription.
In prokaryotes:
-occurs in cytoplasm, transcription and translation are coupled, no definite phase of occurence, one single form of RNA polymerase, no initiation factors, polycistronic
In eukaryotes:
-occurs in nucleus, no coupling, occurs in G1 and G2, 3 forms of RNA polymerase, multiple general transcription factors, monocistronic
What is the difference between polycistronic and monocistronic mRNA?
Polycistronic mRNA produces several proteins, monocistronic mRNA produces a single protein
What are control elements?
Non-coding DNA segments that regulate transcription by binding transcription factors
What are promoters?
Sequences of DNA bound by the first component(s) of the Pre-Initiation Complex
What are enhancers?
Short nucleotide sequences that influence the rate of transcription.
What can enhancers be bound by?
Silencer/repressor proteins
What are introns?
Segments of DNA that interrupt the coding sequences
What is transcription?
The process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA)
Where is the mRNA exported for translation?
The cytoplasm
Why is RNA processing necessary before pre-mRNA is exported?
There are enzymes in the cytoplasm that could degrade pre-mRNA
Give the 8 different RNA products
-non-coding mRNAs (ncRNA)
-small nucleolar RNA (snoRNA)
-micro RNA (miRNA)
-small interfering mRNA (siRNA)
-small nuclear RNA (snRNA)
-ribosomal RNAs (rRNA)
-transfer RNAs (tRNA)
-messenger RNA (mRNA)
Which enzyme produces pre-rRNA?
RNA polymerase I
Which enzyme produces pre-mRNA?
RNA polymerase II
