Chapter 10 Flashcards
What is the main difference between prokaryotic and eukaryotic RNA polymerases?
Prokaryotic organisms only have one RNA polymerase while eukaryotes have three.
Where are eukaryotic RNA polymerases found?
In the nucleus.
Where is RNA Pol I found?
In the nucleolus of eukaryotes.
Where is RNA Pol II found?
In the nucleus of eukaryotes.
Where is RNA Pol III found?
In the nucleus of eukaryotes.
How do we know we have three different RNA polymerases in eukaryotes?
They can be separated using ion exchange chromatography.
What is the purpose of anion-exchange chromatography?
To separate negatively-charged substances.
What is the purpose of cation-exchange chromatography?
To separate positively-charged substances.
Describe the experiment used to determine how many polymerases are found in eukaryotes.
Sea urchin extracts were applied to an anion-exchange column and fractionated. These fractions were tested for polymerase activity by testing their ability to incorporate labeled UMP.
What does Pol I do?
Synthesizes large RNA precursors, which become rRNAs
What does Pol II do?
Synthesizes hnRNA which become mRNA, snRNA, and miRNA.
What does Pol III do?
Synthesizes tRNA, U6 RNA, 5S RNA, and other, lesser known RNAs.
