What is a likely explanation for why nothing happened in your experiment?

Question

Sometimes the most practical way to do an experiment is not to perform it in an animal, but to look at cell responses in culture. Cells from mice, humans, and other mammals have been used to establish cell culture lines that have been very important for research. You are studying a novel water-soluble mouse hormone. You know cell culture can be a practical model to reveal protein function, so you apply the hormone to yeast cells, but nothing happens.

A.  Yeast have a cell wall, so the molecule cannot pass through the cell membrane as it would in mice.
B.  Water-soluble hormones are lipids, not proteins.
C.  You need to apply the hormone in large amounts to see an effect.
D.  Yeast may lack the receptor required for the hormone to act.

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 hormones? 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

D.  Yeast may lack the receptor required for the hormone to act.

Clarify Question
What is the key concept addressed by the question?
        · What is the cause of species specific reactivity of hormones?
What type of thinking is required?
            o This is an analyze question because you have to understand differences between water soluble and lipid hormones and then seek logical explanations for why mouse hormones may not affect yeast cells.

Gather Content
What do you already know about hormones? What other information is related to the question?
        · The question already tells you that you are dealing with a cell culture of yeast that you are applying a water-soluble mouse hormone to. You know that hormones can be either lipid-based or water-soluble. Lipid hormones like steroids can pass through the cell membrane while water-soluble ones cannot- they must first bind to a receptor on the outside of target cells before signal changes can be changed within the cells. Yeast receptors and mouse receptors may not be the same.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Yeast do not have cell walls like plant cells or bacteria do, so that cannot be the reason. Water-soluble hormones are not lipids, as lipids are hydrophobic and water-soluble molecules are hydrophilic. Hormones do not need to be applied in large amounts before an effect is seen, but receptors for that specific hormone is needed to see effects and yeast likely do name have the proper receptor for a mammalian hormone.

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 on realizing that the water-soluble hormone being applied cannot diffuse across the cell membrane and thus need a proper receptor, and figuring out that yeast may not have proper receptors for mouse hormones. Did you select the correct answer? If so, great! If not, which concept did you get confused on? Did you think that water-soluble hormones are lipids that can diffuse across the cell membrane? Did you think that yeast have cell walls like bacteria?