Gene regulation Flashcards
What is Prokaryotic Gene Regulation?
DNA-binding proteins in prokaryotes regulate genes
by controlling transcription. Energy and resource conserving.
An operon is a group of
genes that are regulated
together.
The genes in an operon
usually have related
functions.
The Lac Operon?
When lactose is not
present, the lac genes
are turned off by
regulatory proteins that
bind to DNA and block
transcription.
What is Promoters
The promoter is a
site where RNA
polymerase can bind
to begin transcription.
What is operator
The operator site is
where a DNA-binding
protein known as the
lac repressor can
bind to DNA.
Promtere and operator are both loacted where
Located in front of the
operon’s three genes
are two regulatory
regions:
What is the Lac Repressor Blocks Transcription
When the lac repressor binds to the O region, RNA polymerase
cannot reach the lac genes to begin transcription.
Lactose Turns On the Operon
When lactose is
added to the
medium, it diffuses
into the cell and
attaches to the lac
repressor.
What is the Eukaryotic Gene Regulation
Eukaryotic genes are controlled individually and have more
complex regulatory sequences than those of the lac
repressor system.
TATA
A typical eukaryotic gene has a TATA box.
TATA box is a short region of
DNA, about 25 or 30 base pairs
before the start of a gene,
containing the sequence TATATA
or TATAAA.
Transcription Factors
By binding DNA sequences in the regulatory regions of
eukaryotic genes, transcription factors control the expression
of those genes.
Cell Specialization
Complex gene regulation in eukaryotes is what
makes differentiation and specialization possible.
Genetic Control of Development
Regulating gene expression is important in shaping
how a multicellular organism develops.
What is Homeotic, Homeobox, and Hox Genes
Homeotic genes reugalte organ develpment
Homeobox genes code for transcprtion factors
Hox genes determine the identies of each body segemnt
Epigenetics
Epigenetic mechanisms control which genes re on and
which are off during each stage of an insect’s life cycle.
Environmental Influences
Environmental factors can
affect gene regulation.
