Cell Communication & Cycle unit test
A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.
Second messenger
Cancer as checkpoint failure
Meiosis I vs meiosis II
Receptor specificity
Calcium as a second messenger
Centrosome and spindle
Sister chromatids vs homologous chromosomes
Meiosis vs mitosis
cAMP pathway
Apoptosis
Signal termination
Cytokinesis
Short answer 1. Define or explain: Synapsis and tetrads
3 ptsShort answer 2. Define or explain: G1 checkpoint
3 ptsShort answer 3. Define or explain: Negative and positive feedback
3 ptsShort answer 4. Define or explain: Lab: Mitosis and Meiosis
3 ptsFree response
9 ptsA growth-factor signaling pathway in epithelial cells works as follows: an extracellular growth factor binds a receptor tyrosine kinase, which activates a series of relay kinases in the cytoplasm; the last kinase phosphorylates a transcription factor that turns on genes promoting progression through the cell cycle. A tumor is found to carry a receptor mutation that locks the receptor in its active conformation even when no growth factor is present.
Describe the three general stages of signal transduction as they apply to this pathway.
Explain how a phosphorylation cascade amplifies the original signal.
Predict the effect of the receptor mutation on cell division in this tissue and justify your prediction.
A drug inhibits a relay kinase downstream of the receptor. Predict whether it would slow the growth of this tumor and explain.
Explain why a drug designed to occupy the growth-factor binding site of the receptor would be ineffective against this particular tumor.