1. Human Genome
Genes
DNA

2. ***Does every nitrogen base code for a protein?

3. DNA segment showing that DNA is made up of “junk” segments of DNA.

4. What is cell differentiation?

5. Cell Differentiation
After fertilization the zygote begins to undergo Mitosis to grow.
As the embryo grows cells begin to specialize
After 4 rounds of cell division (mitosis), how many cells will be made? ____
5 rounds? ____
6 rounds? ____
After 2 rounds of cell division the organism would now have 4 total cells 16 32 64

6. Cell Differentiation Watch a single cell become an entire organism

7. How do cells know what type of cell to become?
Cell Differentiation
All multicellular organisms have different types of cells
Muscle
Nervous
Different types of organs
Etc…
Different types of cells have different functions
Cells start to differentiate almost immediately after fertilization
How do cells know what type of cell to become?

8. Regulatory Genes Allow for cell differentiation in eukaryotes
A sort of “on off switch” for gene expression
Turned on and off based on internal and external signal detection
By turning genes on and off cells can specialize

9. Gene Regulation and Expression
What causes these genes to turn on or off?
Environmental factors
Food/Drugs
Human growth hormone. Amplifies the signals that turn on genes that promote growth
Climate/Temperature
Example: Identical rabbits raised in different climates will have different coat colors
Resource availability
Example: certain bacteria will turn on the gene to allow them to digest lactose only if they detect lactose in their environment
Exposure to toxins
Stress

10. Regulatory Gene Example
Hox Genes:
Lay out the basic body forms of many animals, including humans, flies, dogs and worms.
They set up the head-to-tail organization. (What goes where and in what order)

11. Regulatory Gene Example
Mutated Hox genes can lead to body parts being in the wrong place/order

12. NOVA ScienceNOW-Epigenetics