Station A

1. Which molecule (RNA polymerase or repressor) activates gene expression? How does this work?

2. Which molecule (RNA polymerase or repressor) turns off gene expression? How does this work?

3. If one cell has genes A, B, and E activated, what is the cell’s phenotype?

4. If another cell has genes B, C, and D activated, what is the cell’s phenotype?

5. How do two cells with the same genes have different phenotypes? Use the words “express,” “protein,” and “combination” in your answer.

RNA polymerase

repressor

phenotypeobserved as a result of the different proteins produced

Station B

Stomach Cell

Also called parietal cells, stomach cells attach to other cells in an epithelium lining

the gastric pits. Stomach cells release acid into the stomach to help digest food and

protect against harmful bacteria. Stomach cells die often, and dead stomach cells

frequently shed off into the stomach and are replaced by newly made stomach cells

undergoing the cell cycle.

Station B

Nerve Cell

Also called neurons, nerve cells stretch from one end of the body to the spinal cord,

or from the spinal cord to the brain. They send pulses of electricity through their

long axons to send signals of sensation or to command the muscles to contract.

Nerve cells are some of the only post-mitotic cells in the body, which means they

do not undergo the cell cycle and never divide.

Station B

Based on the data table below, predict which THREE genes are most likely expressed in stomach cells, and which THREE genes are most likely expressed in nerve cells, and justify your prediction.

Gene Name Protein Function

Laminin Helps cells attach to each other

GluR Creates electricity inside the cell

HolA Repairs errors after DNA replication

ATP synthase Creates ATP in the mitochondria

Aqp1 Transports water into and out of the cell

NFM1 Helps to make the cell stretch longer

ATP4A Pumps acid from the cytoplasm to outside of the cell

Xyr1 Enzyme which breaks down cellular waste

FAS Creates membranes

AP2M1 Helps the cell perform endocytosis

Station C

Station C

1. Explain why it is important to express the Par gene just before cytokinesis.

2. Explain why it is important for the Condensin gene to be expressed after S phase.

3. During G2 phase, the cell doubles in size so that the two daughter cells produced after cytokinesis will be normal-sized. Predict what would happen if the AP2 gene was constantly expressed at all stages of the cell cycle. Justify your prediction.

Station D

Based on the data table and the graph below, predict which THREE genes are most likely expressed in during July-September and which THREE genes are most likely expressed in December-February, and justify your prediction.

Gene Name Protein Function

Lhx2 Promotes growth of hair follicle cells

CA12 Regulates pH of sweat glands

Trex Transports mRNA from nucleus to ribosome

BAF60c Coverts excess nutrients into fat

Tubulin Helps to synthesize cytoskeleton proteins

DIXDC1 Slows brain activity

T1R Increases taste sensitivity

Foxn1 Decreases rate of fur production

Gja10 Enhances vision in bright light

Myosin Increases heart rate

Station E

Station E

1. Explain why checkpoints are important in the cell cycle.

2. Explain why a mutation preventing the PolI gene from being expressed would lead to rapid cell division.

3. Explain why overexpression of the Cdk gene would lead to rapid cell division.

4. Describe what happens as the result of uncontrolled cell division.

Station F

Note: “Optimal” means “best” or “ideal”

Station F

1. Predict which THREE genes are most likely to be expressed in the winter months. How do you know?

2. Predict which THREE genes are most likely to be expressed in the summer months. How do you know?

3. Predict which gene most likely encodes a protein which grows fur. Explain.

4. Justify this statement:

“Gene A is most likely expressed in a plant’s leaves, while Gene B is more likely to be expressed in a plant’s roots.”

I know gene A is more likely to be expressed in a plant’s leaves because…, whereas gene B is more likely to be expressed in a plant’s roots because…