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Subject Test Biology

Question 2 of 5

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SAT Subject Test

The graph below illustrates the data obtained from reactions at various temperatures of an enzyme with its specific substrate at pH 6.

The figure presents a graph in the first quadrant. The horizontal axis is labeled Temperature in degrees Celsius and is numbered, from left to right, from 0 to 100 in increments of 10. The vertical axis is labeled Product. The 7 dots shown in the graph rise and then fall with increasing temperature. Each of the first 4 dots, starting near the horizontal axis at 10 degrees, is at a higher level on the vertical axis than the previous dot, up to a temperature of 40 degrees Celsius. For temperatures of 50, 60, and 70 degrees Celsius, each of the dots is at a lower level on the vertical axis than the previous dot, ending close to the horizontal axis at 70 degrees.

Based on the data, what results could be predicted if the experiment were repeated at pH 4?

Select an Answer

The available data are insufficient to make a reliable prediction.

Correct Answer: 
Yes

An amount of product equal to that at pH 6 would be formed.

Correct Answer: 
No

An amount of product less than that at pH 6 would be formed.

Correct Answer: 
No

An amount of product more than that at pH 6 would be formed.

Correct Answer: 
No

Little or no product would be formed.

Correct Answer: 
No

The correct answer is that for this question there are insufficient data to make a prediction, (A). Unlike the previous question, which called for an extrapolation within a small range of the obtained data, this question calls for a prediction at a pH 100 times as acidic (remember that pH is a logarithmic scale). We have no information on the optimal pH of this enzyme, so choices (B), (C), (D), and (E) are all inappropriate.

Question Difficulty: 
hard