Inducible Operon
Is the inducible operon typically ON or OFF?
Is the repressible operon usually ON or OFF?
What is positive gene regulation?
the system is already ON, BUT we are increasing and decreasing the intensity of gene expression
What occurs during DNA methylation?
the attachment of methyl groups to DNA (condenses) and prevents transcription
What is RNA Processing?
Post-transcriptional addition of 5' guanine cap and 3' poly-adenine tail to help guide mRNA out of the nucleus and into the cytoplasm
What pathways is it assosciated with (anabolic or catabolic)?
Catabolic
What pathways is it assosciated with (anabolic or catabolic)?
Why do bacteria favor using glucose in the presence of both glucose and lactose?
Glucose is a simple sugar and easier to utilize
What occurs during histone acetylation?
attachment of acetyl groups to histone proteins, causing the histone proteins to grip the DNA less tightly. this opens up the DNA and allows for higher transcription levels
What is the wobble?
relaxed base pairing rule on the 3rd base
allows tRNA to bind to more than 1 codon
What does the inducible operon rely on the presence of? (substrate or product?)
Substrate - when the molecule that NEEDS to be broken down is PRESENT, the operon is turned ON.
What does the repressible operon rely on the presence of (substrate or product)?
Product; if there is ENOUGH product, synthesis may be REPRESSED (saves resources) if there ISN'T enough product, the operon functions normally (activated)
When does cAMP build up in the cell?
During the absence of glucose
what does the promoter do?
the promoter is a regulatory sequence of DNA that regulates transcription by the binding of transcription factors
How does termination occur?
When the stop codon is in the A site of the ribosome, a release factor enters and binds to the stop codon, finishing the protein polypeptide
What is the lac operon's substrate?
Lactose
What is the TRP operon's product?
Tryptophan (amino acid)
What is a plasmid?
extra circular chromosomal DNA molecule
what is alternative rna splicing?
posttranscriptional; some rna segments can be treated as exons or introns
What is a polyribosome/polysome?
Many ribosomes translating the same mRNA simultaneously
Does Lactose act as an activator/inducer or a corepressor?
Inducer/Activator; because it binds to the repressor protein, deactivating it.
genes are being expressed
Does Tryptophan act as an activator/inducer or corepressor?
what is the function of restriction enzymes?
creates a dna fragment; can allow for the insertion of genes
what is the function of nuclease?
nuclease breaks down mRNA starting at the 5' end
In what direction is the DNA template READ to produce mRNA?
3' -> 5' to create an mRNA strand 5' -> 3'