AP Bio Chapter 18 Part 2 Flashcards
What can eukaryotes do (w regulation)
Regulate gene expression and therefore their metabolism at every step of protein synthesis from pre-transcription to post translation
What are telomeres, what do they replace, and what are they there for, and who fixes when shortened
End pieces of DNA, repeating units
There to protect functional genes
When the chromosomes get shortened, telomerase adds more telomerase
What does the decoupling of transcription and translation add for more
Control points
What are the five ways eukaryotes regulate genes
DNA access Pre transcription Post transcription Pre translation Post translation
What is the DNA of eukaryotes not associated w
Proteins
How are genes regulated at the DNA access level
Only keep necessary genes accessible
In eukaryotes, DNA is “wound” around histone proteins
The addition of Acetyl groups (-CH3CH3) to histones causes them to become less tightly packed, allowing for access to the DNA
Heterochromatin
More tightly packed DNA, unavailable for transcription
Euchromatin
Muss less tightly packed DNA available for transcription
What does recent put research show regarding “loose” chromosomes in interphase
Even the loose chromosomes occupy distinct nuclear regions
Transcription factories
Areas of nucleus where active regions of different chromosomes interface, may be associated with common functions
Thousands of transcription factories in any nucleus
What is the biggest way eukaryotes regulate gene expression
Through pre transcription
What basic fact does pre transcription play off of
All the actors need to be present for the play to begin
What in pre transcription do many eukaryotic genes interact with
And what are these proteins
Many “upstream” regulatory elements. These are DNA sequences that precede a transcription unit that need to have specific proteins present for RNA polymerase to begin transcription.
These proteins that mediate RNA polymerase are known as transcription factors
What is one of the two major ways that cells of a multicellular organism accomplish differential gene expression
Control of a transcription factor
What does differential gene expression allow cells to do
Differentiate to serve different functions in the organism
Post transcription has ______________ outcomes
Oh so many
Following transcription, what is necessary for eukaryotic mRNA to remain functional and to be transported to the cytoplasm for translation
Following transcription, 5’ capping and 3’ poly adenylation
What does alternative splicing of exons allow for
Multiple functional (or not functional) gene products to be made from a single primary transcript.
Anywhere from 75-100% of human genes with multiple exons probably underwent
Alternative splicing
What is the major rule behind POST translation
Don’t let unnecessary proteins hang around
What is RNA interference (RNAi)
Things interfering with RNA messages
What is RNA interference mediated by
A group of tiny RNA molecules (micro RNA/miRNA)
What are the miRNAs produced after
The transcript for them is cleaved into multiple fragments by a dicer protein
What are the miRNAs complex with
Protein
What happens to any mRNA with a sequence complementary to an miRNA
It’s tagged with the miRNA protein complex
What is special about tagged proteins
They aren’t translated
What happens to the proteins in post translation
Chopped up
