Topic 24: Regulation of Gene Expression - Eukaryotes Flashcards
What is heterochromatin and euchromatin? Explain how cells regulate gene expression at the level of chromatin.
Heterochromatic is when chromatic is highly packed in histones, preventing transcription from occurring. Induced my methylation
Euchromatin is when chromatin is loosely packed on chromatin allowing transcription to occur because a DNA sequence is exposed. Induced by Acetylation
Even if some DNA sequences are not altered can be passed on through epigenetic inheritance
Define general and specific transcription factors, what are their roles in eukaryotic gene expression? Explain how transcription factors can lead to differential gene expression.
General transcription factors are important for the transcription of protein coding genes by binding to the promoter. They are required in every gene that ia transcribed, without them it won’t work.
Specific transcription factors are really important because hey are specific to genes depending which ones need to be turned on. They will bind to enhancers to try to turn the gene on.
Transcription factors can lead to gene expression because they turn on genes to express the gene expression. Turn on genes to express the correct function for the cell.
Contrast repressors and activators for specific transcription factors. What is an enhancer?
Activators bind to enhancer to make transcription of the gene happen.
Repressors bind to silencers to preventing DNA from transcribing to mRNA.
Specific transcription factors bind to enhancers to turn on genes for different cell type or environments.
Enhancer enhance the transcription of a certain gene.
Describe how gene expression can be regulated post-transcriptionally in eukaryotes.
Gene expression can be regulated post-transcriptionally by alternative splicing and mRNA stability.
In RNA Stability: balance of transcription and RNA decay.
What is the advantage of alternative splicing?
In alternative splicing to make different kinds of proteins from the same gene. When it occurs as we know introns are spliced out and all the exons join back together but sometimes the mRNA pairs differently allowing the there to be a different proteins.
Explain how gene expression can be regulated by miRNAs
Rna Stability: ex, miRNAs
miRNAs codes for tiny RNAs, they can bind to an mRNA by blocking translation or even cut off the mRNA.
Negatively regulates gene expression. Decreasing frequency of gene expression.
How is gene expression regulated at the level of translation and after translation
Gene expression regulates after translation by controlling gene expression by altering the longevity of the protein.
