Transcript Gene Regulation

Gene Regulation
How does your body know when to make
certain proteins?
Unit 4 – Chapter 12-5
Gene Regulation Vocab
•RNA Polymerase:Enzyme that makes an
RNA copy of DNA
•lac Operon: a group of genes that operate
together to regulate the production of
lactase
•Lactose: The sugar found in milk
Gene Regulation Vocab
•Active Repressor Protein: when lactose
is not present the repressor protein is
active which means it blocks RNA
polymerase from transcribing the lactase
gene
•Inactive Repressor Protein: when
lactose is present, lactose fits into the
active site of the repressor protein, this
prevents the repressor from blocking
transcription
Gene Regulation Vocab
•Operator: region of chromosome in
an operon to which the repressor
binds when the operon is “turned off”
•Promoter: RNA polymerase binding
site
No Lactose Present:
• Is lactase made? WHY?
• NO, because the repressor protein is blocking
RNA polymerase from copying the gene for
lactase
With Lactose Present:
• What happens to the repressor when lactose is
present?
• Lactose fits into the active site of the repressor
protein, which causes it to release from the operator.
RNA polymerase can copy the gene.
Lactose present: mRNA is made
• What will happen after all the lactose is broken down?
• The repressor protein will grab onto the operator
stopping the production of lactase.
lac Operon from Dolan DNA
Learning Center
• http://teachercenter.insidecancer.org/p/920
• http://www.pbslearningmedia.org/content/tdc02.sci.life.cell.lp_speciali
z/#content/4dd2fd5aadd2c73bce007d55
•
Eukaryote and Prokaryote Gene
Regulation:
1. ___________
Operons generally are not found
in eukaryotes
2. Most eukaryotic genes are controlled
Individually
Regulatory
___________ and have __________
sequences that are much more
Complex
______ than those of the lac operon.
Eukaryote and Prokaryote Gene
Regulation:
3. A typical feature in a eukaryotic cell is
the presence of a gene sequence about
30 base pairs long with a sequence of
TATATA
TATAAA This
___________
or ___________.
sequence is found directly before the
starting point for __________________.
This region
is known as the _______
RNA
Polymerase
TATA Box
Eukaryote and Prokaryote Gene
Regulation:
4. What does the TATA box do?
• Helps position the RNA polymerase by
“marking” the spot just before where
transcription will take place.
5. How do enhancer sequences affect gene
regulation?
• Allow proteins to bind to DNA opening up
tightly packed chromatin so genes can be
copied. Also, some use repressor proteins
to prevent transcription.
Regulation and Development:
1. What are hox genes?
Genes that control organ
and tissue development
in various parts of the
embryo.
Determines organism’s
basic body plan.
Regulation and Development
2. How important are hox genes?
If they are mixed up, an
animal’s body plan will
be mixed up; In the
wrong order.
Regulation and Development
3. What example does the book give as a possilbe
mutation for Drosophila if the hox genes are
mutated?
Repeat in hox genes: Double
Winged Drosophila
Regulation and Development
Side
4. Hox genes are located _______by ______ in a single cluster,
arranged in the _________ order in which they are expressed in the
body.
5. Draw:
Side
Exact