Forelimbs form at the junction of the neck and thoracic vertebrae, the position of which is controlled by HoxC-6 genes. Several kinds of vertebrates from different classes are limbless, including limbless lizards, and amphibians known as caecilians. All descended from limbed forms. On the basis of recent research in genetics, what would you conclude about the functioning of their HoxC-6 genes?
A. Their HoxC-6 gene has mutated and serves a different function than in limbed vertebrates.
B. The site of expression of their HoxC-6 genes may have moved anteriorly until the level of expression has eliminated the neck region.
C. The site of expression of their HoxC-6 genes would be the same as that of limbed vertebrates but is simply turned off early in development.
D. The effect of the HoxC-6 gene is masked by another gene that is dominant to it.
Answer: B
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You stain a cell with a dye that reacts with an enzyme found in the lysosome. You would also expect to see this dye in the:
A. nucleus. B. mitochondria. C. endoplasmic reticulum. D. cytoplasm. 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 lysosome proteins? 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?
9. Earthworms exhibit segmentation, defined as the
(a) division of the body into a series of similar segments. (b) presence of a true coelom. (c) difference in size of the male and female. (d) presence of a “head” equipped with sensory organs.
Which concept represents the lowest degree of certainty?
a. hypothesis b. conclusion c. fact d. principle e. theory
Which of the following antibacterial drug groups does not target protein synthesis?
A. Tetracyclines B. Aminoglycosides C. Oxazolidinones D. Sulfonamides E. Macrolides