Unit 3: Regulating Translation of mRNA in Eukaryotes Flashcards
MCB 181R University of Arizona
Why is iron essential for humans? Approximately how much do humans use per day?
Iron is essential for humans to make new red blood cells. Human use approximately 20mg per day.
How is iron safety transported in the bloodstream? What protein is involved in taking iron into cells?
Iron is safely transported in the bloodstream when bound to a protein called transferrin. Transferrin-bound iron is taken into cells by binding to a cell surface protein called the transferrin receptor.
Why is too much free iron dangerous for cells? How do cells safely store extra iron?
Too much free iron is toxic. Cells can safely store extra iron by binding to a protein called ferritin.
Where is the iron response element (IRE) located in the ferritin mRNA?
The ferritin has an iron response element (IRE) in the 5’ UTR (5’ untranslated region).
What happens to the translation of ferritin mRNA when the IRE- binding protein is bound to the IRE?
When the IRE-binding protein is bound to the IRE in the 5’ UTR of ferritin mRNA, it blocks the translation of the mRNA.
Under what cellular condition does the IRE- binding protein bind to the IRE on ferritin mRNA? What is the result?
The IRE-binding protein binds to the IRE on ferritin mRNA when intracellular iron levels are low. This blocks the translation of ferritin mRNA, preventing the synthesis of the ferritin protein when iron storage is not needed.
Under what cellular condition does the IRE- binding protein not bind to the IRE on ferritin mRNA? What is the result?
When intracellular iron levels are high, iron ions bind to the IRE-binding protein. This causes a conformational change in the IRE-binding protein, preventing it from binding to the IRE on the ferritin mRNA. As a result, ferritin mRNA is translated, and the ferritin protein is produced to store the excess iron.
Some features of mRNA affect translation pt.1
Some features of mRNA affect translation pt.2
