AP Bio - Gene Regulation and OPERON
The "araC" gene represents....
a gene that is a switch that will only allow the GFP gene to be expressed in the prescence of arabinose
The genes trpA - trpE code for proteins which ...
make tryptophan
When there is NO lactose present, is the operon on or off?
off
Transformation is taking a _____ and inserting it into a _______.
plasmid, bacteria
The repressor is an example of what?
a regulatory protein
When DNA is tightly coiled around the histone proteins, what happens to the rate of transcription of the genes?
decreases
Which of the statements is true?
- lactose binds to the repressor, changing its shape (an allosteric interaction) - transcription can go ahead when the repressor is not bound to the operator - the presence of lactose inactivates the repressor
1) Petri Dish: LB 2) Bacteria: No plasmid added Petri Dish: LB/Amp 3) Bacteria: Plasmid added Petri Dish: LB/Amp 4) Bacteria: Plasmid added Petri Dish: LB/Amp/Ara
1) lawn 2) No growth 3) Colonies 4) Colonies
Which of the following mechanisms control gene expression AFTER transcription occurs?
Alternative splicing, RNA interference
Regulation of gene expression at the transcriptional level is control of what step?
DNA --> RNA
What is the order of information flow in gene expression?
DNA --> RNA --> protein
Histone acetylation impacts DNA coiling in what manner?
DNA is more loosely coiled around the proteins so RNA polymerase can interact with the gene and allow for transcription.
What part of DNA does RNA polymerase bind?
Promoter
When lactose is bound to the repressor, the repressor changes shape and can't bind to the operator anymore. What happens next?
RNA polymerase can now bind to the promoter and transcribe the genes
When DNA is packed tightly into nucleosomes...
RNA polymerase is unable to bind and transcribe DNA
What is the role of miRNAs?
They digest mRNA or prevent translation of mRNA, thus controlling the amount of protein expressed by a gene.
All the cells have the same genes but they are not expressing all of the genes at the same time.
True
Epigenetics allows change in the phenotype of an organism without changing the underlying genes.
True
Epigenetics is taking the genes that we have and manipulating them.
True
For a gene to be expressed as a protein, it must be transcribed and then translated
True
Lifestyle can change what genes you express.
True
What is a promoter sequence of DNA?
Where RNA polymerase binds to start transcription
The GFP gene represents...
a gene that produces green flourescent protein, that will allow the bacteria to glow.
What is an example of a regulatory sequence?
a promoter
What is found just "above" or before a gene?
a promoter, a regulatory sequence
The "amp" gene on the plasmid represents...
an ampicillin resistant gene
What is true of gene regulation in eukaryotes?
it is more complex than in prokaryotes, it may involve transcription factors from outside the nucleus
What gene that code for the repressor protein?
lacI
What is a gene coding for the metabolism of lactose?
lacY, lacA, lacZ
Gene X is transcribed into mRNA X which is translated into Protein X. Gene Y is transcribed into mRNA Y which is translated into Protein Y. If mRNA X is degraded quickly by miRNAs and mRNA Y is degraded slowly by miRNAs, then
less Protein X will be synthesized compared to Protein Y
Bacteria contain the following
loose DNA (that codes for proteins for the bacteria) small ribosomes cell walls plasmids (that code for additional proteins)
The agouti mutation causes mice to have what phenotype (physical appearance)?
obese and light colored
When the lactose bind to the repressor protein, the operon is switched.....
on
What is the function of Operator?
the binding site for repressor protein to switch off the gene regulation
Which operon is a repressible operon (the operon is repressed - turned off)
the tryp operon
which operon do you think is called an "inducible" operon?
the lac operon
Where does RNA polymerase first bind to start transcription?
the promoter
The "ori" on the plasmid represents...
the promoter, or the TATA box
Which of the following are performed on the bacteria to make them more competent to taking in the foreign plasmid?
CaCl, heat
Which of the following mechanisms control gene expression BEFORE transcription occurs?
DNA packing, Transcription factors
When methyl groups are added to the cytosine nucleotides in DNA, what happens?
Genes are turned off which means transcription decreases.
Nucleosomes consist of DNA wound around proteins called
Histones
When the repressor protein is bound to the operator can RNA polymerase bind to the promoter?
No
What is the name of the nucleotide sequence common to the promoter region in eukaryotes?
TATA box (TATAAAAA)
How does alternative splicing increase variation in phenotypes?
The same gene can be expressed as several different proteins depending on which introns are removed from the initial mRNA transcript
Lactose is breakdown into...
glucose + galactose