Working in an experimental fertility clinic, a researcher removes one cell from an 8-cell stage chimpanzee embryo. What is the likely result?

Question

A.  Both the cell and the blastula will die.
B.  All the cells are already committed and therefore are not viable.
C.  The embryo from which the cell was removed still remains viable and can form a normal chimp.


Clarify Question
What is the key concept addressed by the question?

What type of thinking is required?


Gather Content
What do you already know about early development? What other information is related to the question?


Choose Answer
Given what you now know, what information 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

C.  The embryo from which the cell was removed still remains viable and can form a normal chimp.

Clarify Question
What is the key concept addressed by the question?
     · This question is asking about the effects of the removal of a blastomere from a mammal embryo.

What type of thinking is required?
     · Apply level:
       o You are being asked to take what you already know and use, or apply, it to the fate of a mammalian blastomere.


Gather Content
What do you already know about early development? What other information is related to the question?
     · Early cells that form from the divisions of a fertilized egg are called blastomeres.
     · In mammals, regulative development is present.
     · With regulative development, blastomeres are not pre-determined to be specific tissue.


Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
     · A blastula is not present until multiple cell divisions result in a hollow ball of cells.
     · In a mammal, these early cells are not yet committed to a developmental pathway.
     · Since mammals exhibit regulative development, the seven cells that remain could still form all of the necessary germ layers and resulting structures. This embryo could survive.


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?
     · Apply level:
       o Answering this question correctly depended on your ability to use early development in a new situation. If you got an incorrect answer, did you remember that mammal development is regulative, or that regulative development means that early cells are not predetermined to be a specific type of tissue?