If a cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?

Question

A.  64
B.  32
C.  16
D.  8

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 mitosis? 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

B.  32

Clarify Question
  · What is the key concept addressed by the question?
        o The question asks about the number of chromosomes following mitosis.
· What type of thinking is required?
        o You are being asked to apply your knowledge of mitosis to predict the number of chromosomes a cell will have.
· What key words does the question contain and what do they mean?
        o 32 chromosomes prior to S phase – this is the diploid number of chromosomes.
        o Mitosis and cytokinesis – after the chromosomes are replicated they are divided evenly between the two daughter cells.

  Gather Content
  · What do you know about mitosis? How does it relate to the question?
        o In mitosis the chromosomes are replicated in S phase and then divide evenly into two daughter cells.
        o Before S phase the cell will be diploid, so there are 32 chromosomes in this diploid cell.

  Consider Possibilities  
  · What other information is related to the question? Which information is most useful?
        o If the diploid number is 32 then a cell with 64 chromosomes is tetraploid.  A cell with 16 chromosomes is haploid.  A cell with 8 chromosomes would not be able to survive.

  Choose Answer
  · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o If a diploid cell has 32 chromosomes and goes through mitosis each of the new daughter cells would also be diploid and have 32 chromosomes.

  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 apply your understanding of mitosis to predict how many chromosomes daughter cells would have. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you recall that the number of chromosomes in the daughter cells does not change following mitosis?  Did you confuse mitosis and meiosis?  Did you think that the number of chromosomes increase after mitosis?