Living Environment Regent August 2019
Base your answers to questions 36 through 39 on the information and photograph below and on your knowledge of biology.
Scientists Investigate Sex Determination in Alligators
The sex of some reptiles, including the American alligator, is determined by the temperature at which the eggs are incubated. For example, incubating them at 33°C produces mostly males, while incubation at 30°C produces mostly females.
Scientists recently discovered a thermosensor protein, TRPV4, that is associated with this process in American alligators. TRPV4 is activated by temperatures near the mid-30s, and increases the movement of calcium ions into certain cells involved with sex determination.
36. The results of this scientific investigation will most likely lead other scientists to hypothesize that
(1) human sex cells also contain the TRPV4 protein
(2) other reptiles may have the TRPV4 protein in their eggs
(3) the TRPV4 protein affects the growth of plants
(4) the TRPV4 protein is present in all of the foods eaten by alligators
Answer: The passage tells us that the sex of some reptiles is determined by the temperature at which eggs are incubated. Furthermore, specifically in alligators, TRPV4 protein has been discovered that is linked to this process. We can eliminate choices 1 and 3 since the passage is about reptiles and not humans or plants. We can also eliminate choice 4 because the passage did not talk about the foods eaten by alligators. Choice 2 is the correct answer choice because the passage talks about realties, and it is plausible to extrapolate that the protein present in alligators may be present in other replies as well.
37 Which information was most essential in preparing to carry out this scientific investigation?
(1) a knowledge of the variety of mutations found in American alligator populations
(2) the arrangement of the DNA bases found in the TRPV4 protein
(3) the effects of temperature on the incubation of alligator eggs
(4) a knowledge of previous cloning experiments conducted on alligators and other reptiles
To answer this question we should again eliminate any answer choices that are not connected to the passage. Thus choice 1 and 4 can be eliminated. Choice 3 is the only choice described in the passage, and is therefore the correct answer. Indeed, the passage describes the importance of the effects of temperature on the incubation of alligator eggs.
38 The movement of the calcium ions into certain cells is most likely due to
(1) the destruction of the TRPV4 when it contacts the cell membrane
(2) the action of TRPV4 proteins on the cells involved with sex determination
(3) the sex of the alligator embryo present in that particular egg
(4) the action of receptor proteins attached to the mitochondria in alligator sex cells
In order to answer this question correctly, lets go back to the passage and learn more about TRPV4 protein. This protein is a thermosensor protein, which means it is regulated by the temperature changes. We also know that it is activated by the mid30s temperatures and when it is activated the movement of calcium ions into sex determining cells increases. Therefore, choice 2, the action of TRPV4 proteins on the cells involved with sex determination, is the correct answer choice since it follows the passage most closely.
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