1. How does your body know when to make proteins?
Gene Regulation
How does your body know when to make proteins?

2. Gene Regulation Terms
RNA polymerase – The enzyme used to transcribe a gene.
lac Operon – Section of DNA containing binding sites for the promoter, operator, and the lactase gene.

3. Gene Regulation Terms
Lactase – The enzyme used to break down the sugar in milk
Lactose – The sugar found in milk

4. Gene Regulation Terms
Repressor Protein – Prevents RNA polymerase from making the mRNA strand
Operator – Section of the DNA the repressor binds to.
Promoter – Section of the DNA that RNA polymerase binds to

5. When NO Lactose Present:
RNA Polymerase
Repressor protein
Is lactase made? WHY?
NO, because the repressor protein is blocking RNA polymerase from copying the gene for lactase

6. When Lactose IS 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.

7. Lactose is present: mRNA is made
mRNA strand that will be translated to make Lactase.

8. And Back to No Lactose Present:
RNA Polymerase
Repressor protein
What will happen after all the lactose is broken down?
The repressor protein will grab onto the operator stopping the production of lactase again.

9. Ameoba Sisters video

10. lac Operon from Dolan DNA Learning Center

11. Eukaryote and Prokaryote Gene Regulation:
Operons
___________ generally are not found in eukaryotes
Most eukaryotic genes are controlled ___________ and have __________ sequences that are much more ______ than those of the lac operon.
Individually
Regulatory
Complex

12. Eukaryote and Prokaryote Gene Regulation:
A typical feature in a eukaryotic cell is the presence of a gene sequence about 30 base pairs long with a sequence of ___________ or ___________. This sequence is found directly before the starting point for __________________. This region is known as the _______
TATATA
TATAAA
RNA Polymerase
TATA Box

13. Amoeba Sisters