Embryonic cell cycles allow the rapid division of cells in the early embryo. These mitotic cell cycles are much shorter in length than the mitotic cell cycles of cells in a mature organism. In the embryonic cell cycles, mitosis takes approximately the same amount of time as it does in the cell cycles of mature cells. What do you think is a result of the embryonic cycle?

Question

A.  Resulting daughter cells are smaller than the mother cell in the embryonic cell cycles.
B.  Resulting daughter cells do not contain the same genetic information as the mother cell in the embryonic cell cycles.
C.  Resulting daughter cells cannot form a mitotic spindle in the embryonic cell cycle.
D.  Mother cells in the embryonic cell cycle spend the majority of their time in G0.

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 the cell cycle? 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

A.  Resulting daughter cells are smaller than the mother cell in the embryonic cell cycles.

Clarify Question
  · What is the key concept addressed by the question?
        o The question asks about the rate of cell division.
· What type of thinking is required?
        o You are being asked to analyze several predictions about what would happen in the cell cycle was shortened.
· What key words does the question contain and what do they mean?
        o Mitotic cell cycle is shorter – This means that the time from G1 through M is shorter.

  Gather Content
  · What do you know about the cell cycle? How does it relate to the question?
        o The cell cycle is made up of four phases; G1 and G2 are gaps where proteins and membranes are made for the newly dividing cells, S where DNA is replicated, and mitosis where the cells divide.
        o The question states that the replication of DNA and mitosis occurs at the normal rate.  However the overall rate of the cell cycle is shorter.

  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?
        o For the daughter cells to survive, they must receive the same amount of DNA as the embryonic stem cell, and to do so they need to be able to form a mitotic spindle.
        o The embryonic stem cells are going through mitosis so they cannot be in Go all the time.

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The embryonic stem cells have a shorter cell cycle, but S and mitosis occur at the same rate, so G1 and G2 must be shorter. As a result, the daughter cells will likely be smaller than the mother cell in the embryonic cell cycles.

  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 predictions of what would happen in embryonic stem cells with shorter cell cycles. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you think that the cells could not be able to divide?  Did you think that the daughter cells would not get as much DNA as the embryonic stem cells.