The year is 2442. Protein engineering and molecular biology have became incredib
ID: 260676 • Letter: T
Question
The year is 2442. Protein engineering and molecular biology have became incredibly powerful and all diseases are cured. You previously sabotaged your rival lab mate's setup for cytoskeletal racing by sneaking into his supplies and switching chemicals. Because of your rivalry, he has grown increasingly suspicious of you and comes to confront you. Unfortunately, he finds you when you are alone in lab and in the process of adding another lucrative chemical to your microtubules to cheat even more. You scramble the supplies on your benchtop to try to look innocent, and pretend that you are doing research in hope that he doesn't press you too hard.. 4. A. "What are you working on?" he asks condescendingly. "Uhhh, you know, just studying M-Phase with my microtubules," you lie "Sure is pretty exciting stuff, wanna see some videos of the-" "Really?" he snaps, interrupting you. "If you know so much about the cell cycle, then tell me this: . At what specific phase can chromosomes first attach to spindle microtubules? What part of the chromosome mediates the attachment to the microtubule? Would vou expect the microtubules to be more or less stable than normal during this phase?". You respond with scientific accuracy:Explanation / Answer
Answer:
A.1) The chromosomes attach to the microtubule spindles at the pro-metaphase.
A.2) The microtubules attach to the chromosomes at their kinetochores.
A.3) The microtubules are less stable in this dynamic state since they are involved in degradation during the seperation of sister chromatids..
B.1) Nuclear lamins in their unphosphorylated state help in maintaining the integrity of the nuclear membrane. When this protein is phosphorylated, it causes the nuclear membrane to break down into numerous small vesicles, thereby allowing a direct access between the microtubules and the chromosomes. This allows the cell to proceed from prophase to the metaphase. A mutation in this phosphorylation process thus disrupts the advancement of cell cycle from prophase to metaphase.
C.1) During cytokinesis, a contractile ring is formed which involves F-actin and myosin II. If actin does not interact with myosin, then the contractile ring does not perform its function of contraction which leads to the ingression of the plasma membrane. The force required for the contractile process is generated by movements along actin by the motor protein myosin II.
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