Lesson 8: Transcription, Translation, Proteins Processing And Regulation Flashcards
Segment of DNA used to make a functional product called RNA
Gene
__________ of structural genes produces messenger RNA (copy)
Transcription
During ________ mRNA is translated into a sequence of amino acids
Translated
What is central dogma Theory
The path from gene to trait
Encode the information for specific proteins
Structural gene
Site for the binding of regulatory proteins. Role is to influence the rate of transcription
Regulatory sequences
Site where RNA polymerase binds, signaling the beginning of transcription
Promoter
Sequence of DNA that codes for protein
Coding region
The strand that is being coded…
Same as opposite strand accept substitute uracil for thymine in DNA…
Template strand
Sense strand
Five prime for ribosome attachment to begin translation
Ribosome binding site
Three stages in transcription
- initiation (RNA polymerase to bind to DNA)
- Elongation
- five prime to three prime, plumber he’s catalyzes new rTPSs - Termination
- RNA polymerase and RNA transcript dissociate from the DNA
In bacteria, RNA polymerase holoenzyme is made up of:
- Core RNA polymerase -for elongation
- Sigma factor-for initiation (detects consensus sequence (-35 and -10) and promoter
MRNA with multiple ribosomes translating the sequence into proteins
Polysome
The growing RNA transcript will always be synthesized in the __________ Direction which is anti-parallel to the template strand
5’-3’
Coding stand- 5’-3’ (has the same base sequence as the RNA transcript, except T in DNA goes to U in RNA)
Template strand- read 3’-5’
Eukaryotes have three RNA polymerases…
RNA POL 1- RNA genes expect 55
RNA POL 2-mRNA
RNA POL 3- tRNA and 55 rRNA
In eukaryotic,
Located at 25 base pairs
Determines the start start site for transcription
TATA box
Core promoter can produce a low level of transcription on its own
Basal transcription
Regulatory elements:
Acts as activating sequence…
Represses transcription…
Enhancers
Silencers
Often 50 to 100 region, influence the ability of RNA polymerase to recognize the core promoter
Proteins that bind to regulatory regions, located near or at a distance
Have a strong influence on the ability of RNA polymerase to initiate transcription
Regulatory transcription factors
Only influence expression of an adjacent gene on the same DNA. DNA sequences such as TATA box, enhancers, and silencers
Cis-acting elements
Regulatory factors that are not DNA. They bind to the Cis-acting elements on any DNA molecule. Produced by regulatory genes that may be located a distance
Trans-acting elements
When a gene and coding a transacting factor it is expressed it made a few throughout the cell in binding to it’s appropriate Cis-acting element
Adds complementary nucleotides in the growing RNA transcript in the five prime to three prime direction and reads the DNA template strand in the three prime to five prime direction
RNA elongation
Forms between the three hydroxyl in the phosphate of the incoming ribonucleotide triphosphate, releases a diphosphate
Phosphodiester bond
Have signal similar to the Rho- independent mechanism as bacteria
RNA polymerase one and three
More complex. In transcriptional termination, it transcribes a gene pass the polyadnloation signal sequence. RNA Cleve just passed the poly a signal sequence. RNA poly continues transcribing the DNA
RNA pol 2
After passing the poly a signal sequence, RNA pol to is destabilize due to the release of elongation factors binding of termination factors
Allosteric model
An exonuclease binds to the five prime end of the RNA that is still being transcribed and degrades it in a five prime to three prime direction. Exonucleus catches up to RNA polymerase two and causes termination
Torpedo model
In _________,mRNA Is processed before translation
Eukaryotes
- covalently bonded
- allows for the exit of certain RNAs from the nucleus
5’-7-methylguanosine cap
Important for the stability of the mRNA, translocation of the RNA to cytoplasm and regulate translation. Added by the enzyme called poly A Polymerase
3’ ploy-A tail
Endonuclease cleavage occurs about ____ nuclear tides downstream from the AAU AAA sequence.
20
Can prokaryotic or eukaryotic carry out transcription and translation simultaneously?
Bacteria can
Eukaryotes can’t
This is because mRNA must pass through nuclear pores to reach ribosomes in cytoplasm
Two selective targets for antibiotics?
Anabiotic‘s that affect Transcription- Rifamycin B, Actinomycin D
Antibiotics that affect translation-Streptomycin, Tetracycline, Chloramphenicol, Erythromycin
Examples of possible modifications (post transcriptional)
- chaperone proteins for 3-D confirmation
- cleavage
- cofactors added (buying two allosteric or active site of enzyme)
- join with other proteins to form quaternary level of structure
- glycosylation, phosphorylation, acetylation, methylation
Dictate the stability of a protein
Degrons
A type of the degron, the N-terminal amino acid of a proteins directly correlates with it stability
N-terminal rule
Proteins degrading machines in eukaryotes and archaea
Proteasomes
This spans the membrane and is specific for sensing a particular molecule, can sense structural change in the proteins
Sensor kindness protein
Senses changes outside the cell, involves a two components signal transduction system
Activator sequence
Genes that are always turned on and are use continuously
Constitutive genes
Code for endurable enzymes. Only needed under certain conditions often in catabolic pathways
Inducible genes
Encode proteins that structuring in a bio synthetic pathway always present unless than product of the biosynthetic pathway is available
Repressible genes
How are inducible genes organized?
Three basic components that all operons will have at least one
- promoter
- operator( start button to get started)
- structural genes
Regulates the metabolism of lactose
- operator/promoter
- lacZ-in code see Beta galactosidase enzyme, lactose to glucose to galactose
- lacY-specifies the primary structure of permeates enzymes for entry of lactose into bacterial cells
- lacA- encodes transacetylase, enzyme for removal of toxic byproducts of lactose digestion
lac operon
What is Catabolite repression?
-Regulation of transcription by both -repressors and activators
Diauxic growth-byphasic growth pattern
-lac operon turned off in the presence of glucose
Repressible operons are turned off when what is available?
Substrate
_____ operon is repressible
Trp
- regulated by repressor‘s, called in active aporepressors
- corepressor
- complex can bind operator sequence upstream of target gene or operon
The trp operon is involved in the bio synthesis of the amino acid ________
Tryptophan
- attenuation
- negative regulation
^ to shut down expression of these genes
