Honeybees can detect a variety of odorants through olfactory receptors on their antennae. You genetically engineer a receptor to be gated by the explosive chemical TNT, and use a transgene to express the receptor in honeybee olfactory neurons. What would this provide to the bee?

Question

Honeybees have an incredible ability to distinguish thousands of different odorant molecules, using their large repertoire of olfactory receptors. A wide variety of different types of chemicals can be detected as odorants -- they simply require olfactory neurons with a receptor that can bind the chemical and transduce that stimulus into a receptor potential.

A.  the ability to taste TNT
B.  it would have no effect
C.  the ability to smell TNT
D.  the ability to collect TNT molecules
E.  the ability to see TNT


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 olfaction? 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 ability to smell TNT

Clarify Question
What is the key concept addressed by the question?
        · What would a transgenic receptor in antennae provide?
What type of thinking is required?
            o This is an analyze question because you have to break sensory (olfaction) signaling into different stages and understand the effect of a novel transgenic receptor on olfaction sensation in honeybees.

Gather Content
What do you already know about olfaction? What other information is related to the question?
        · You already know that olfaction detects odorants when odorants bind to specific olfactory receptors and opening up ion channels, producing receptor potentials. What would happen if you express a novel olfactory receptor for TDT on honeybee antennae? The honeybee would be able to sense or smell the TDT.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Since the TDT receptor that you have genetically engineered in the honeybee antennae is an olfactory receptor, and olfaction is the sense of smell, then the honeybee will have the ability to smell the TDT, not taste or see TNT. These receptors would bind to TDT, not collect TDT.

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 Answering this question correctly depended not only on understanding the steps of the sensory pathway of olfaction, but on your ability to understand how a change in this system by genetic engineering can change the perception of the honeybee. If you got an incorrect answer, did you get confused with the definition of olfaction thinking that it was referring to taste, which also uses a similar receptor system? Did you think that TDT does not have a smell? Although we might not be able to detect TDT readily, many animals can. Dogs, for example, can be trained to detect things like explosives via smell.