Proten synthesis, prions, gene regulation, and epigenetics Flashcards
What are the two different ways an enhancer can act
Cis or trans (local or long distance)
What was the point of the olfactory receptor enhancer lesson
Different olfactory receptors may have had different sequences but the same enhancer sequence for all
What is a ortholog
Same gene found in two different species
How many reading frames do you need to determine if there is a protein-encoding sequence present
6
What is most cellular RNA made of
rRNA and tRNA
How much GTP is used in peptide growth
4 PO4 bonds: 2 loading A.A. onto tRNA, 1 when freeing elongation factor, 1 during peptide translocation
What two modifications are typically made if a gene is silenced
Heavy methylated or bound by histones
Define epigenetic
A change in phenotype brought about by heritable changes in gene regulation rather than the genotype itself
What does constitutive mean
always on
Does H3K9 turn on or off when methylated
5’ end= activation Farther 3’= deactivation
Definition of monocistronic
mRNA that caries the genetic information to translate a single protein chain (usually eukaryotes)
What are some of the ways gene expression is regulated
- Transcriptional level
- Transript processing and stability
- Way protein is folded
- Export out of nucleus
- Assembly of ribosomes at 5’ end
- Transnational control
How much of a cell’s RNA is mature (%)
3-5%
Does H3K4 turn on or off when trimethylated
On
What do insulators do
prevent enhancers from up regulating irrelevant promoters
What is a gene
Complete chromosomal segment responsible for making a functional product
Does AcH3 histone turn off or on when acetylated
On
What is the most important level of gene regulation
Transcription
T/F: the lowest free energy state of protein is always the best to be in
False
What does a chaperone do
Sequesters polypeptide away from other proteins to prevent aggegation
Is a vaccinia virus in DNA in the cytoplasm part of your genome
No
How transmissible are TSE’s
Very, transmitted by blood or can grow inside of a plant that has been exposed to the disease
What is a clinical significance of histone bookmarking
Environmental exposures that affect epigenetic marks may affect phenotype for future generations (Rat vinclozolin example)
What are transmissible spongiform encephalopathies
inappropriate chaperone-like activity.
What is histone bookmarking
Histone modifications may stay in the same place into next generation
What is stochastic gene expression
Random intrinsic noise involving expression of different proteins that are not made at the same levels within individual cells
Where does transcription start
transcription start site
Why is there so little mature RNA in a cell
most fails to mature, and it’s short lived
What is the mode of action for AZT
Inhibits DNA synthesis by terminating biosynthesis of nascent DNA molecule
What mechanism do humans use to amplify the number of proteins
Alternative splicing
What is primary protein structure
Linear sequence of amino acids
What is a homolos
Similar gene
What is secondary protein structure
Simple folds/coils
what does an enhancer do
organize transcription factors and RNA polymerase on the promoter
What is cachexia
Wasting away: rapid cellular proliferation, increased metabolisim
Definition of polycistronic
mRNA that can encode more than one polypeptide separately within the same RNA molecule. (usually bacteria)
Where does elongation factor load onto
‘A’ site of ribosome
How can we take advantage of self-assembling nature of PrPsc
Amplify samples to detectable levels
What does the promoter do
Assembly of RNA polymeraze complex with transcription. 5’ end
What are some transcriptional control elements (5)
- Promoters 2. Enhancers 3. Silencers 4. DNA-binding proteins 5. Insulators
What is a paralog
Multiple genes within a specie derived from ortholog
Where does transcription stop
terminator
What turns a promoter on
Enhancer
Do epigenetic effects often have memory
Yes
What is tertiary protein structure
overall conformation made up of multiple primary and secondary structures
Why is stochastic gene expression significant
tumor suppressor genes if they are too variable my not produce enough at the right time losing regulation ability
T/F: Some modifications of proteins are more resistant to TSE than the wild types
True
What is quaternary protein structure
Multi-subunit associations of sub-units to make complete protein
