Which of the following is likely to occur if you were to prevent cyclin B from associating with its cyclin-dependent kinase near the end of meiosis I?

Question

A.  failure to maintain sister chromatid cohesion at the centromere
B.  failure to form initiation complexes necessary for DNA replication to proceed
C.  suppression of DNA replication
D.  activation of DNA replication

Clarify Question
  · What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

  Gather Content
  · What do you know about cyclins and cell check points? How does it relate to the question?

  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?  

  Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  activation of DNA replication

Clarify Question
  · What is the key concept addressed by the question?
        o The question asks about the effect of loss of cyclin on a kinase activity.
· What type of thinking is required?
        o You are being asked to analyze several statements that predict what would happen if a cyclin cannot bind a kinase.
· What key words does the question contain and what do they mean?
        o Cyclin B associating with its cyclin-dependent kinase – when cyclin B binds its kinase then the kinase is active and the cell will progress into the next checkpoint in the cell cycle.  For the cell to progress further, the cyclin needs to be degraded.

  Gather Content
  · What do you know about cyclins and cell check points? How does it relate to the question?
        o There are three main check points in the cell cycle.  G1/S, G2/M and one in mitosis/meiosis to check for proper spindle formation.  Cyclins need to be degraded and stop binding to their associated kinase for the cell to progress through the next check point.

  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?
        o During mitosis, the destruction of mitotic cyclin is necessary for a cell to enter another division cycle. The result of this maintenance of cyclin B between meiotic divisions in germ-line cells is the failure to form initiation complexes necessary for DNA replication to proceed. This failure to form initiation complexes appears to be critical to suppressing DNA replication.

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?  
        o Since cyclin B suppresses a cell from replicating DNA, loss of cyclin B would lead to an increase in DNA replication.

  Reflect on Process
  · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to analyze different statements explaining what would happen if cyclin B was inhibited in a cell. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you recall that cyclin B needs to be degraded for a cell to replicate DNA?  Did you realize that the cyclin B would not affect the steps in chromosome separation of meiosis?