1. http://www.pbs.org/wgbh/nova/teachers/interactives/regulating-
genes/index.html
http://www.sumanasinc.com/webcontent/animations/content/lacoperon.html
http://www.teachertube.com/viewVideo.php?title=Lac_operon&video_id=21717
4

2. Warmup
• What are the 4 levels of protein structure?
• What are 2 reasons why proteins are important?
• Factor 8 is a blood clotting protein that most
hemophiliacs lack. How would you make and
purify large quantities of factor 8?

3. Do you have the same
DNA in all of your cells?
Yes! All cells from an
organism has the same
DNA.

4. How is it possible that we have different
types of cells?
(What makes these cells different?)

5. What makes these cells different?
Hint: DNA Transcription RNA Translation Protein
Proteins make cells look different. In
different types of cells, some proteins are
made and other proteins are not made,
changing their phenotype.

6. What makes these cells different?
DNA Transcription RNA Translation Protein
(Gene)
Genotype Phenotyp
e
Gene On Protein/Phenotyp
e
Gene Off No
Protein

7. How do cells control what protein is made and
what protein is not made?
Cells control the process gene expression (how proteins
are made from DNA ) by gene regulation (how some
genes get turned on and other genes get turned off).
Gene regulation allows for cell differentiation (when cells only
express certain proteins to help them perform a specific function).
Protein
Gene Regulator
Interactive: http://www.pbs.org/wgbh/nova/teachers/interactives/regulating-
genes/index.html

8. The lac operon regulates genes by turning
on the genes to digest lactose only when
there is lactose around it.

9. lac operon animation
Lac operon video 2

10. Gene regulation in
Prokaryotes
An operon is a link of genes that code for proteins
that perform a similar function

11. General diagram of lac
operon

12. Diagram of lac operon when lactose is NOT
present

13. Diagram of lac operon when lactose IS
present

14. Gene Regulation in
Eukaryotes
Gene regulation in eukaryotes is complex! It can
occur at different steps along the gene expression
process.

15. Regulation of DNA Packing
When DNA is tightly wrapped in chromatin,
RNA polymerase cannot bind to transcribe the
gene.
Ex: X chromosome inactivation
Oswald and Sisters!

16. Initiation of Transcription
Similar to how prokaryotes regulate transcription.
- Has regulator genes that code for activator proteins (Turn on)
and repressor proteins (Turn off) to bind operator
- Usually one promoter and operator for each gene. (few operons)
- Uses transcription factors to help RNA polymerase transcribe

17. RNA Processing and Breakdown
Alternative splicing is when different exons are cut to form
the mRNA making different proteins from the same gene

18. Regulation of Translation
mRNA gets degraded before it is translated to a
protein

19. Protein Alteration and Breakdown
Proteins can be cut or degraded

20. Why Regulate Genes?