Flashcards in 9.6 Chromatin, Transcription, RNA Processing Deck (21):
the "poly-A addition signal" is integral for the 3' processing. What other sequence is?
a string of U or GU nucleotides
what disease is associated with incorrect splicing? (bood cells - incorrect expression of globin genes)
a nucleosome has _______ histone proteins, which forms a disk-like structure. The _____ is wrapped around the outside of this histone core and is held in place by histone _______.
8, DNA, histone H1
The exposed 5' end of the new RNA is modified by a methylated nucleotide (5' 7-methyl guanosine). What is this called?
the mRNA cap
how does a single gene generate multiple different proteins?
at the extreme 5' end of an intron, there is usually a "___-___" (nucleotide sequence)
what are the three functions of the mRNA cap?
1. binds to a protein complex which is important for translation
2. allows for recognition of mRNAs vs. other RNAs without caps
3. helps to protect the 5' end of the RNA from degradation
what is the "poly-A addition signal"
5' - AAUAAA - 3'
on the intron sequence, there is always an "_____" that signifies the branch point
a small family of basic proteins. They have a positive charge and thus interact strongly with the negative outside of DNA
at the extreme 3' end of the intron, there is always a "__-__" (nucleotide sequence)
proteins that help facilitate splicing are called: _______
nucleosomes themselves are wrapped into a more elaborate structure/sprial called a _________
the solenoid structure decreases DNA length by ____ fold
a _________ is added at the 3' end of a transcript
describe the two main steps in the splicing of introns from transcripts
1. the branch point nucleotide attacks the 5' splice junction and cleaves the backbone at this point
2. The 3' OH of the first exon sequence then reacts with the 5' end of the next exon, to precisely excise the intron
the nucleosome decreases DNA length by ____ fold
the process of transcription starts with DNA and makes ____
in a gene, the __________ are expressed and the ________ are intervening regions, not expressed.
what protein lies outside the histone and is thought to hold the DNA in place?