If one were to inject cytoplasm containing Bicoid into the middle of a Drosophila egg immediately prior to fertilization, the embryo would

Question

A.  try to form anterior structures in the middle of its body.
B.  try to form posterior structures in the middle of its body.
C.  not develop at all.
D.  develop normally.

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 already know about bicoid?

  Consider Possibilities
· Consider the different answer options. Which can you rule out?

  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.  try to form anterior structures in the middle of its body.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses bicoid.
· What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.
· What key words does the question contain and what do they mean?
        o Bicoid is a gene that is necessary for specifying anterior development.

  Gather Content
· What do you already know about bicoid?
        o Bicoid is a gene that is expressed in the nurse cells of the ovary, then mRNA is deposited into the anterior of the egg, where it leads to anterior development.

  Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o If Bicoid was injected, would the embryo try to form posterior structures in the middle of its body? No, that doesn’t make sense because bicoid specifies anterior structures.
        o If Bicoid was injected, would the embryo not develop at all? No, the cells would just develop according to the signals they received.
        o If Bicoid was injected, would the embryo develop normally? No, because bicoid is a powerful morphogen, it would have an effect.

  Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o If Bicoid was injected, would the embryo try to form anterior structures in the middle of its body? Yes, because the cells in the middle would receive the anterior-specifying morphogen.

  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 what would happen if you injected Bicoid into the middle of an embryo.
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that Bicoid would induce determination of anterior structures?