1. Cell Differentiation
Mrs. Harlin

2. 1.1.3
Explain how instructions in DNA lead to cell differentiation and result in cells specialized to perform specific functions in multicellular organisms.

3. Specialized Cells
Multicellular organisms begin as undifferentiated masses of cells and variation in DNA expression and gene activity determines the differentiation of cells and ultimately their specialization.

4. Differentiation
Only specific parts of the DNA are activated; the parts of the DNA that are activated determine the function and specialized structure of a cell.
Because all cells contain the same DNA, all cells initially have the potential to become any type of cell; however; once a cell differentiates, the process cannot be reversed.

5. DNA
Nearly all the cells in an organism contain the same chromosomes and DNA.
Different parts of the genetic instructions are used in different types of cells, influenced by the cell’s environment and past history.

6. Hormones
Hormones are chemical signals that are released by cells that influence the development and activity of other cells.

7. Stem Cells
Unspecialized cells that continually reproduce themselves and have, under appropriate conditions, the ability to differentiate into one or more types of specialized cells.

8. Types of Stem Cells Embryonic stem cells
Adult stem cells- found in bone marrow
Research has demonstrated both types of stem cells can be differentiated into specialized cells.

9. Specialized cells in Animals
Nerve cells- eukaryotic, but have dendrites and axons for electrochemical communication in the body.
They are never replaced when they die.

10. Specialized cells in Animals
Muscle cells- eukaryotic; used for movement.
Skeletal muscles contain many nuclei and are striated- voluntary movement.
Smooth muscles only have 1 nucleus- involuntary movement

11. Specialized cells in Animals
Blood cells
Red blood cells- the hemoglobin protein transports oxygen and carbon dioxide (influenced by temperature and pH)
Do not divide
No mitochondria or nucleus
Plasma- transports materials
Insulin regulates glucose levels
Lipids, amino acids, and other ions also transported from digestive system.
White blood cells- protects the body from infection
Has a nucleus

12. m

13. Specialized cells in Animals
Gametes- Sperm and egg cell
Used in sexual reproduction
Only contain half the DNA as the rest of the cells in an organisms.
Haploid number for humans= 23 chromosomes

14. Specialized Cells in Plants
Xylem- transports water from roots
Phloem- transports water and sugars

15. References
heal-thyself.us
health-niche.com
ap-bio-patrick-steed.wikispaces.com