1. Warm-Up (1/11)
On the piece of white paper from the back, answer the following question.
Name
Date
Period
Explain how signal transduction causes a cell to change into different types of cells.

2. 2E.1a: Observable cell differentiation results from the expression of genes for tissue-specific proteins.
3B.1d: Gene regulation accounts for some of the phenotypic differences between organisms with similar genes.
4A.3a: Differentiation in development is due to external and internal cues that trigger gene regulation by proteins that bind to DNA.
4A.3b: Structural and functional divergence of cells in development is due to expression of genes specific to a particular tissue or organ type.

3. Gene Regulation During Development
“Waddington’s Landscape”
Differentiation of a cell means changing its cell type.

4. Cell Differentiation in Development
Differentiation is caused by transcription factors.
2nd messenger P

5. Cell Differentiation in Development
Differentiation is caused by transcription factors.
CELL SIGNALING
INTERNAL ACTIVATION

6. Cell Differentiation in Development
Transcription factors activate tissue-specific genes/proteins.
Na+/K+ pumps
insulin
actin and myosin
pancreatic cell
muscle cell
neuron

7. Critical Thinking Question #1
Discuss this question with your partner and write or represent it. I will call on three people to share their partners’ answers.
Actin and myosin are both proteins that are essential for muscle cells to contract. In development, paraxial mesoderm (PM) cells differentiate when actin and myosin are expressed at high levels. If PM cells have high levels of the transcription factor FOX1A before they differentiate into muscle cells, they will instead differentiate into bone cells.
Create two graphs showing the levels of actin, myosin, and FOX1A over time. In the first graph, show the levels inside a PM cell that becomes a muscle cell. In the second graph, show the levels inside a PM cell that becomes a bone cell.

8. 2E.1a: Observable cell differentiation results from the expression of genes for tissue-specific proteins.
3B.1d: Gene regulation accounts for some of the phenotypic differences between organisms with similar genes.
4A.3a: Differentiation in development is due to external and internal cues that trigger gene regulation by proteins that bind to DNA.
4A.3b: Structural and functional divergence of cells in development is due to expression of genes specific to a particular tissue or organ type.

9. Whole-Organism Phenotypes
Gene regulation causes changes in levels of proteins and numbers of cell types.
These people all have the exact same genes. 1. 2. 3. 4. 5.

10. Whole-Organism Phenotypes
Gene regulation causes changes in levels of proteins and numbers of cell types.
These people all have the exact same genes. 1. 2. 3. 4. 5.

11. Critical Thinking Question #2
Describe, in the context of gene regulation and development, why people have different height.

12. Closure
On the piece of white paper from the back, answer the following question:
Name
Date
Period
Explain how regulation of the gene encoding the Na+/K+ channel protein and the gene encoding insulin contributes to differentiation of embryonic cells into neurons or pancreatic cells.
Scale 1 – 10