1. Controls over Genes

2. Eukaryotic
Gene Regulation

3. Have you ever wondered?
Every cell in our bodies has exactly the same DNA… and DNA makes everything in our bodies…
How does it know when to be a skin cell and when to be a stomach cell or a neuron?
THE ANSWER IS… _________________

4. When are genes controlled?
In Eukaryotes genes can be controlled at any of the steps of protein synthesis…
During ______________
________________
Even _______________ proteins can be stored before activating them because they are waiting for some modification (ex. phosphorylation) to get active

5. During Transcription
During transcription enzymes called ___________ __________ are used to regulate gene expression
Transcription factors can be
____________: proteins that bind to enhancer sequences on the DNA speeding up transcription
____________: proteins that bind to silencer sequences on the DNA slowing down transcription

6. Transcription continued
To begin transcription, general transcription factors need to help ____________ bind to the ______________
This gets the gene ready to be transcribed but __________________must be added to completely start or turn off transcription

7. Special gene packaging and transcription
To turn UP transcription __________ bind to _______________________ _________________strand
To turn DOWN OR OFF transcription _______________________ bind to ___________________ on the DNA.
Eukaryotes bend so the same enhancers are around ALL of the genes that need for a specific function
This is accomplished by winding the DNA around proteins, called ______________
This also keeps them organized and the appropriate enhancer or repressor around the gene(s) they control

8. During Processing
Different splicing or processing affects where, within the cell, the protein is made and in what order.

9. Translation
Some RNAs last longer and get copied multiple times before they are broken down by the cell’s enzymes (_____________).
RNA interference is when __________ ________________________________________with their sequence.

10. Cancer… when gene regulation goes wrong
In healthy cells there is an inhibitor for cell reproduction
When that inhibitor gets broken the cell starts to divide uncontrollably
Oncogene
Genes we know have the potential to mutate but are currently normal are proto-oncogenes
Also there are cells that are supposed to stop excess growth (tumor suppressor genes) but they also become mutated to no longer suppress it.

11. Cancer Causes
Because of the combo of things that cause cancer it is not usually a single event that gives you cancer
The more you can avoid potential carcinogens (things that cause the mutations that cause cancer) the lower your risk.

12. Outcomes of gene controls: x-inactivation
Clearly, we learn from males, ______________
What do we do with the other ones?
Mammals undergo ________ ___________
The inactivated X in balled up in a barr body where it is not used at all except during interphase. _____________ __________________
This is rarely visible… one notable exception is the tortoise shell cat where fur color is controlled by the X

13. Master Genes
The expression of some “Master Genes” starts a cascade of activity in other genes.
The protein produced by a master gene generally acts as _________________ ___________________________________________________

14. Homeotic Genes (Eukaryotes)
In Eukaryotes all of the Master genes are collectively called ___________________ _______________
These genes ______________ ______________________________such as eye formation, limb production, segmentation etc.
They have been extensively studied in many species.

15. Knockout Fruit Flies
Homeotic genes were primarily discovered in ___________________________.
When a gene is suspected of being a ‘master gene’ scientist perform a Knockout Experiment on them
A knockout experiment is when _________________________________________________________ ______________________________
The role of the gene is then found by observing what ‘problem’ it caused in the organism
They are named accordingly– wingless, minibrain etc.

16. Prokaryotic
Gene Regulation

17. Basics of PROKARYOTIC gene regulation
Before any specific region of DNA that is transcribed there is a ___________
Then there is an _________… this is an on off switch for the gene
____________________________________ ________________________________________________________________________

18. Repressors (positive control… presence activates)
Take the lac operon in e.coli (what’s e. coli?)
The lac operon is ________ __________________________________… then it turns on to make the enzyme that breaks down lactose.
The thing that keeps it turned off is called a repressor (made by the regulatory gene upstream of the promoter)

19. Another repressor (negative control… presence inhibits)
The trp operon also only turns on when it is necessary
Trp operon makes tryptophan (an amino acid)
If the organism is ingesting trp, it won’t use the energy to make it from scratch… so _____________________________ __________________________________________________________________
activated
repressed