Gene Regulation Flashcards
In eukaryotes, how many polypeptide chain can be translated from a processed mRNA molecule?
Only a single polypeptide chain
Regulatory sites for transcription in prokaryotes?
- promoters
- operators and regulators are small
- near to and usually upstream from start point
Regulatory regions in eukaryotes
- much larger
- hundreds of bases away
- no operons
A large fraction of the base sequences in eukaryotic mRNA is ________
untranslated
It is present in eukaryotic genes
Introns
Spliced in eukaryotes
eukaryotic mRNA
In eukaryotes, it is synthsized
RNA
In eukaryotes, RNA is synthesized where?
nucleus
Where does the synthesized RNA in the nucleus must be transported?
transported throught the nuclear membrane to the cytoplasm where it is translated
After the synthesized RNA is transported to the nuclear membrane, it is translated in?
Cytoplasm
In prokaryotes, there is no _____ _____
nuclear membrane
In prokaryotes translation of ______ ____ can occur even before transcription has been completed
nascent mRNA
There is _____ _____ and more _____ ____ of gene regulation in eukaryotes than in prokaryotes
- great number
- more complex levels
What is gene expression?
A biological processes that yield a gene product
It is expressed when its biological product is present and active
Gene
When is gene expressed?
When its biological product is present and active
Gene expression is regulated at ______ levels
multiple levels
Each cell in your body expresses only a _____ ____ of genes at any time
small subset
During development, what cells expresses sets of genes?
different cells expresses different sets of genes
Gene regulation is express in what way?
A precisely regulated fashion
What level does gene regulation occurs?
- transcription
- production of mRNA
A given cell transcribes what
only a specific set of genes and not others
Gene products should be what?
released at the right time, in the right place and in the right amounts
Gene regulation in prokaryotes is mainly for?
- growth
- response to environment
Who first proposed the theory of Operon?
- Francis Jacob
- Jacques Monod
A cluster of genes encoding related enzymes that are regulated together
Operon
What is an Operon?
A cluster of genes encoding related enzymes that are regulated together
Two Categories of Gene Control
- Negative Regulation
- Positive Regulation
What is a Negative regulation?
A process of regulating gene expression by inhibiting the expression of that specific gene
What is present in the cell in Negative regulation?
an inhibitor (repressor) that keeps transcription turned off
What is called for an anti-inhibitor?
Inducer
What is inducer for?
needed to turn the system on
Example of Negative Regulation
Lactose operon
What is a Positive regulation?
Initiates the transcription process on the presence of proteins
An effector molecule
- protein
- small molecule
- molecular complex activates a promoter
Example of Positive regulation
Lactose operon (cAMP-crp)