Name_____________________________ Date/Class Period____________________
GENE REGULATION/CELL DIFFERENTIATION ACTIVITY (TEKS 6D, 5C)
Notice the “STEM CELL DNA” sequence below. Recall that stem cells are unspecialized cells; they can become any type of cell (including bone, muscle, nerve, epithelial, blood, etc.). As a cell becomes specialized, however, some genes are turned on (“expressed”), and some genes are turned off. Your job is to investigate the expressed DNA, transcribe it to mRNA, translate it into a protein, and then use the information included on the next page to determine to which protein / specialized cell the expressed gene belongs. In the specialized cell DNA sequences, the
expressed genes are bold. Good luck, scientist! 
STEM CELL DNA (unspecialized):
TAC – GCC – AAT – ACT – TAC – CTA – ATA – ACG – TAC – GGG – ACC – ATT – TAC – CGG – CAG – ATC
SPECIALIZED CELL DNA 1:
TAC – GCC – AAT – ACT – TAC – CTA – ATA – ACG – TAC – GGG – ACC – ATT – TAC – CGG – CAG – ATC mRNA PRODUCED BY TRANSCRIPTION:
________________________________
SPECIALIZED CELL DNA 2:
AMINO ACIDS:
__________________
PROTEIN/CELL TYPE:
____________/____________
TAC – GCC – AAT – ACT – TAC – CTA – ATA – ACG – TAC – GGG – ACC – ATT – TAC – CGG – CAG – ATC mRNA PRODUCED BY TRANSCRIPTION: AMINO ACIDS: PROTEIN/CELL TYPE:
_______________________________ __________________ ____________/____________
SPECIALIZED CELL DNA 3:
TAC – GCC – AAT – ACT – TAC – CTA – ATA – ACG – TAC – GGG – ACC – ATT – TAC – CGG – CAG – ATC mRNA PRODUCED BY TRANSCRIPTION:
_______________________________
AMINO ACIDS:
__________________
PROTEIN/CELL TYPE:
____________/____________
SPECIALIZED CELL DNA 4:
TAC – GCC – AAT – ACT – TAC – CTA – ATA – ATT – TAC – GGG – ACC – ATT – TAC – CGG – CAG – ATC mRNA PRODUCED BY TRANSCRIPTION: AMINO ACIDS: PROTEIN/CELL TYPE:
_______________________________ __________________ ____________/____________

Name_____________________________ Date/Class Period____________________
PROTEIN & SPECIALIZED CELL INFORMATION
Myosin is a protein involved in muscular contraction (muscle cells). In this activity, myosin is represented by the amino acids
methionine,
asparagine, & tyrosine.
Insulin is produced by the pancreas and is involved in a cell’s ability to absorb glucose, which your mitochondria need for cellular respiration.
Insulin contains the amino acids
methionine, alanine, &
valine.
Hemoglobin is a protein found in red blood cells that is responsible for carrying oxygen throughout the body. In this activity, hemoglobin is represented by the amino acids
methionine, arginine, &
leucine.
Myelin is found in nerve cells. It creates a coating around nerve axons, called a myelin sheath, which acts as an insulator and speeds up nerve impulses. Its amino acids are methionine, proline,
& tryptophan (trp).

Name_____________________________ Date/Class Period____________________
Conclusion Questions:
1.
Explain the difference between a stem cell and a specialized cell.
2.
What is different about the DNA of a specialized cell when compared to a stem cell?
3.
Explain what it means for a gene to be “expressed.”
4.
Are the proteins of one specialized cell made in specialized cells of a different type? (For example, are blood cell proteins made in nerve cells, etc) Why or why not?
5.
What does it mean to say that genes are “regulated?”
6.
What would a scientist have to do in order to turn a specialized cell back into a stem cell?
7.
Cell differentiation is critical during embryonic development. The process of cell differentiation results in the production of many types of cells, including germ, somatic, and stem cells. Cell differentiation is most directly regulated by—
A ATP
B DNA
C lipids
D sugars

Name_____________________________ Date/Class Period____________________
KEY
1.
MET-ARG-LEU-STOP (Hemoglobin/Blood cell)
2.
MET-ALA-VAL-STOP (Insulin/Pancreatic Beta cell)
3.
MET-PRO-TRP-STOP (Myelin/Nerve cell)
4.
MET-ASP-TYR-STOP (Myosin/Muscle cell)