BSI Lectures 7-10 Gene Expression Flashcards
True or False? The DNA in every cell contains all the genes to make a complete human.
True
If every cell contains all genes to make a human why does each cell have a specific function?
Because only certain genes are expressed in each cell
What are the 6 steps at which gene expression can be controlled?
- Transcription
- RNA processing (splicing)
- RNA transport and localization
- Translational control
- mRNA degradation
- Control of protein activity
DNA methylation
long tails on the histones contain lysine, which has a positive charge. These tails form ionic bonds with the negative charges on the DNA. These bonds pull the histones together and tightly pack the chromosome preventing RNA polymerase from completing transcription
Histon acetylation
Acetylation of lysine residues on histone tails leads to looser packaging of genes; therefore, RNA polymerase can make mRNA (turns genes on)
What leads to the tighter packing of genes?
methylation
T or F; Gene regulatory sequences for a specific gene can be thousands of base pairs away from the promoter.
True
_____ promote assembly of transcription initiation complex.
Activators
What effect does methylation of DNA typically have on gene expression?
It shuts genes off; leads to tighter packaging of genes
Do transcription regulators repress or stimulate transcription?
They can do both
What do transcription regulators bind to in order to regulate transcription?
Gene regulatory sequences
Are most genes regulated by one transcription regulator or many?
Many
What are the 3 ways that the process of translation can be regulated?
Translation initiation via phosphorylation of eIF-2 inhibits translation; mRNA stability/degradation;miRNA
Define: Epigenetics
Heritable changes in the genomes that are NOT due to changes in the DNA sequence
What are the types of modifications to turn off or on genes?
DNA Methylation turns genes off and Acetylation usually turns genes on
What are transcription regulators?
aka Transcription factors or gene regulator proteins are proteins that bind to gene regulatory sequences to stimulate or repress transcription.
Each gene has its own set of gene ________ sequences associated with it.
Regulatory
Phosphorylation of _____ inhibits translation initiation.
eIF-2