1. Gene Regulation and Mutations
TURTLE POWER!
Gene Regulation and Mutations

2. All cells in your body have the same DNA.
So, how do we have so many different types of cells in our bodies?

3. Gene Regulation!
Different genes are turned on and expressed in different types of cells.
In red blood cells, the gene for hemoglobin is expressed. But the gene for hemoglobin is turned off in other types of cells.

4. Cells can respond to their environment by turning genes on and off.
Transcription factor
Regulatory sequence
Genes have regulatory sequences that special proteins can bind to which make transcription of that gene start or stop.

5. The regulatory sequences are kind of like a thermostat
The regulatory sequences are kind of like a thermostat. They turn the gene on and off depending on what the environment is like, just like a thermostat turns the heater on or off depending on the temperature.
Thermostat reads the temp. and turns the heater on
Hot air from heater
Thermostat reads the temp. and turns the heater off
Air cools

6. Depending on the situation or environment that the cell is in, the protein that binds to the sequence could stop or start transcription.
Transcription factor
Regulatory sequence

7. The hormones enter the cells and signal the proteins to attach to DNA
Injury Repair
You are cutting onions and, oops! Your hand slips and you cut yourself.
Proteins attach to DNA at the regulatory sequences of genes that code for clotting factors. The proteins attract RNA Polymerase to the gene and the gene is transcribed and expressed. The cell produces clotting factors which thicken the blood so that the bleeding will stop!
The hormones enter the cells and signal the proteins to attach to DNA
Your body immediately sends signals (hormones) to the cells around the cut.

8. Cell Cycle Genes
Some genes code for proteins that send the cell into different stages of the cell cycle.
When certain genes are turned on, the cell begins to divide. These cells are turned on when the cell is big enough to divide!

9. What do you think might cause a cell cycle gene to be on all the time?
Cancer
When the cell cycle genes are always on, cells divide all the time, and cancer develops.
What do you think might cause a cell cycle gene to be on all the time?

10. Mutations! Mutations are any change in genetic material
Either there is a mutation in the regulatory sequence that keeps a protein from binding to it or there is a mutation in the sequence of a protein that usually binds to a regulatory sequence.

11. Different Kinds of Mutations
Gene Mutations- produce changes in only a single gene
Chromosomal Mutations- produce changes number or structure of the chromosome

12. Gene Mutations
Point Mutations- mutations involving only one or a few nucleotides
Substitution- refers to when one base is changed to another, normally only effect one amino acid
Insertion- an extra base gets added
Deletion- a base gets subtracted

13. Frameshift Mutations
Insertions and deletions can have very bad effects.
Remember the genetic code is read in codons (3 letter words)
This is bad because the codon for each amino acid will be wrong

14. Chromosomal Mutations
Chromosomal mutations involve changes in the number or structure of chromosomes
Deletions- subtractions of all or part of the chromosome
Duplications- extra copies of parts of chromosomes
Inversions- reverse directions of parts of chromosomes
Translocations- one part of chromosomes break off and attach to another

15. Effects of Mutations
Most mutations are neutral meaning that they have little effect on the expression of genes or the proteins for which they code
Harmful mutations are the cause of many genetic disorders
But some mutations also contribute to the genetic variability of a species

16. Beneficial Mutations
Beneficial mutations on the other hand may produce proteins with new or altered activities which can be useful to organisms in changing environments!
Example: plant breeders grow plants with extra sets of chromosomes (polyploidy). This results in the organisms being stronger and larger and also they are infertile meaning they don’t produce seeds!
Seedless watermelon, bananas, and citrus!
Wild Banana