L11 + L12 - EUkaryotic RNA transcription and control of gene expression

malra16's version from 2018-01-09 16:42

Section 1

Question Answer
What is an epigenome?It is covalent changed in the DNA structure, which means different genes will be expressed in different cells.
Which pH and which side chains does histones have?They are highly basic, because they have many positively charged amino acid side chains (Arg, Lys)
Which structure does 8 histones create?A nucleosome
What is the smaller units of a chromatin fiber?Nucleosomes
How many base pairs must chromatin include before nucleosomes are present?200 base pairs of DNA.

Section 2

Question Answer
What is specific combinatorial control of transcription?Initiation of transcription
How is initation of transcription enabled?Interactions between transcription factors and specific DNA sequences.
Initiation of transcription allows..Regulatory proteins to have different effect, depending upon their neighboring proteins.
Initiation of transcription is caused by..The ability of one protein to recruit another to a complex.
What is an enhancer?A DNA sequence, which increase the respons or effectivity.
What is an activator?A protein, binding to the DNA and transcriping.
If something recruits other proteins to promote transcription, it is..Both an enhancer and an activator
If they're often redundant (A piece of them can be deleted without loss of functions), they are..An activator

Section 3

Question Answer
Eukaryotic genes that are actively being transcribed are.. Cell-type specific, developmentally regulated and is able to be detected by chromatin immunoprecipitation.

Section 4

Question Answer
The tails of histones..when acetylated have lower affinity for DNA (less supercoiled)
Are involved in recruiting chromatin-remodeling engines that move nucleosomes.
When acetylated, serve as substrates for histone deacetylases
Have their positive charges reduced by acetylation

Section 5

Question Answer
The mechanism behind microRNA posttranslational regulation involves..miRNA binding to at complementary mRNA sequence, to prevent translation.
Argonaute family are RNAses, that cleaves sequences complementary to the microRNA.
miRNA are generated from larger genetically encoded precursors.

Section 6

Question Answer
DNA methylation is involved in gene regulation. What does it require?S-adenosylmethionine as a source of methyl gorups.
Where does it occur?It occurs at 5'-CpG-3' sequences.
How does it act?It acts by converting cytosine in DNA to 5-methylcytosine (marking)
It is less frequent at sites..adjacent to actively transcribed genes.