In the following diagram, each line represents a double-stranded DNA molecule.
a. What type of cell division is being represented, and which stage of that cell division are shown in the two parts of the figure? What is the relationship between the lines drawn in the same shade of blue? Between the lines drawn in different shades of blue?
b. Cohesion is added to chromosomes immediately after S phase. Cohesion complexes are concentrated at the centromeres, but some cohesion complexes are scattered along the chromosome arms. On a copy of the figure, indicate the distribution of cohesion complexes on the chromosomes. Distinguish between cohesion at the centromeres and cohesion along the arms. Your diagram should represent how cohesion might keep DNA molecules together.
c. Look carefully at your drawings. What keeps all the blue lines together at the metaphase plate of this kind of cell division, even though forces are pulling at the kinetochores in opposite directions?
d. Again looking carefully at your drawings, what can you conclude about the function of shugoshin during the type of cell division being depicted? What is the name of the enzyme whose function shugoshin prevents, and what does this enzyme do?