Let’s say a cell has arrested in the cell cycle due to achromosome being temporarily unable to attach to the microtubulesof the mitotic spindle.
(a) At what stage of the cell cycle is the cellarrested?                   [Select ]                [\"Prophase\", \"Metaphase\",\"Prometaphase\", \"Anaphase\"]    Â
(b) For each of the factors listed below, decide if the factorwould be present in such a cell.
p21Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [Select ] Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [\"PRESENT\", \"NOT PRESENT\"]Â Â Â Â
M-cyclin                   [ Select ]                [\"PRESENT\", \"NOT PRESENT\"]    Â
Cdk                   [Select ]                [\"PRESENT\", \"NOT PRESENT\"]   Â
Securin                   [Select ]                [\"PRESENT\", \"NOT PRESENT\"]   Â
Separase                   [ Select ]                [\"PRESENT\", \"NOT PRESENT\"]    Â
APC/CÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [Select ] Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â [\"PRESENT\", \"NOT PRESENT\"]Â Â Â Â
G1 cyclin                   [ Select ]                [\"PRESENT\", \"NOT PRESENT\"]    Â
(c) Now let’s say that the chromosome finally does attachcorrectly to the spindle, so that all of the chromosomes have nowachieved proper biorientation and congression to the metaphaseplate. Make the correct selections to fill in the blanks regardingthe molecular events that lead to sister chromatid separation:
Proper                   [Select ]                [\"Motor protein activity\",\"Balance\", \"Ndc80 phosphorylation\", \"Tension\"]       on all of the kinetochores causes thespindle assembly checkpoint protein,                   [ Select ]                [\"Cdc20\", \"Aurora B\", \"Mad2\", \"Ndc80\"]       , to be inactivated.                   [ Select ]                [\"APC/C\", \"APC/C-Cdh1\", \"APC/C-Cdc20\",\"SCF\"]       can nowubiquitinate                   [ Select ]                [\"separase\", \"securin\", \"M-cyclin\", \"S-cyclin\"]       , which is then degraded bythe                   [Select ]                [\"Lysosome\", \"Acidhydrolases\", \"ECM protease\", \"Proteasome\"]       , thereby releasingactive                   [Select ]                [\"Microtubules\", \"Motorproteins\", \"Separase\", \"Cohesin\"]       , which cleaves the                   [ Select ]                [\"Cohesin\", \"Condensin\", \"Microtubules\", \"Ndc80proteins\"]       that was holdingthe sister chromatids together.
