Unformatted text preview: BICD110 PS4 SSII 09 Kai Q1. Microtubules are made up of 13 __________________, which consist of ______________ dimers. Microtubules polymerize from the microtubule-organizing center (MTOC), also known as the ______________in animal cells. The MTOC has 2 centrioles and consists of many ______________ which cap the ______ end. As they polymerize, they have a GTP cap on the _______ end to temporarily stabilize it. When the GTP cap falls off, the microtubules begin to _______________________. This rapid change is known as _____________________. The re-addition of the GTP cap re-initiates polymerization, this process is known as __________________. This entire process of repeated polymerization and depolymerization is known as "____________________________". Q2. How does DNA damage activate p53 to block cell division? Q3. Explain the idea of "checkpoint" in cell cycle and why it is necessary to have them. Name the three checkpoints. Q4 What are Cdks (including full name and function)? What protein is most important in regulating the activity of Cdks? Name and briefly describe the four classes of this regulatory protein. Q5 Cdks activity is also regulated by phosphorylation. Name three proteins that regulate Cdks by phosphorylation/dephosphorylation and briefly state their functions. Q6 Describe the roll of the three cyclins involved in cell division and the timing at which they become activated. Q7 What happens in situations where DNA damage is detected in G1 or G2 phase? Q8 What molecule is responsible for ensuring only one round of DNA replication? Q9 Describe the signaling that promotes chromosomal segregation at anaphase.
Q10 What are the contractile units within muscle cells which allow the cells to contract? a. What are the "thin filaments" of this structure composed of? b. When sarcomeres shorten, do the lengths of the filaments within it change? c. Ca2+ influx into a muscle cell causes the cell to contract, what protein complex binds to Ca2+ to allow for the movement of myosin heads along the actin filament? Q11 What motor protein is involved in ciliary and flagellar movement? Q12 A mutation in ciliary dynein can cause a disease which is characterized by male sterility, an increased probability for lung infections, and defects in the left/right asymmetry of the human body. Explain these phenotypes. Q13 What is the general term for the "leading edge" of a moving cell? . d. What is the general term for protrusions from the "leading edge"? Q14 Define Chemotaxis Q15 CDC42 activation triggers what? Q16 Rac activation triggers what? Q17 Rho activation triggers what? Q18 CDC42, Rac, and Rho are all part of what protein family? Q19 What occurs during S-Phase; Q20 Myosins usually walk toward the _____ end of _____________. Kinesins usually walk toward the _____ end of ___________. Dyneins only walk toward the ______ end of _____________. __________ and __________ are believed to have a common evolutionary origin.
Q21 List the regulatory proteins present and their functions, as well as the relative amount present. Protein and Function: Presence
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