ACT Science Practice Test - 9 - online test

The bacterial strain SN2 (Alteromonas naphthalenivorans) is known to contaminate both tidal flats and seawater. The graphs in Figure 1 show the results of an experiment intended to measure the cell growth of SN2 in a tidal flat environment with added Naphthalene (TF-N) and a tidal flat environment with added Pyruvate (TF-P). The concentration of Naphthalene and Pyruvate were also measured within this experiment. Additionally, changes in the optical density of seawater was measured when both Naphthalene and Pyruvate were added. The goal of this experiment was to better understand the Eco physiological behavior of SN2 in contaminated environments. The graphs in Figure 2 depict levels of correlation in level of gene expression between conditions.

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Figure 1

Science lesson Science Practice Test 9 exam questions 1. question pragraph

Figure 2

Figures adapted from Genome-wide transcriptional responses of Alteromonas naphthalenivorans SN2 to contaminated seawater and marine tidal flat sediment by Hyun mi Jin et al.

In Figure 1, what is the relationship between Pyruvate concentration and Naphthalene concentration?

As Pyruvate decreases, Naphthalene increases.

As one decreases, the other does as well.

As Pyruvate increases, Naphthalene decreases.

There is no clear relationship between concentrations of Pyruvate and Naphthalene in Figure 1.

(B) As one decreases, the other does as well. Consider only the top graph in Figure 1. The trend in the strain SN2 in both conditions should be ignored given the question inquires about concentrations of Pyruvate and Naphthalene specifically. The dashed lines indicate change in their concentrations.

After 12 hours of incubation, how many copies/g of sediment of the 16S rRNA gene are there of the SN2 strain in the TF-N condition?

Greater than 108

Between 106 and 107

Between 107 and 108

Less than 106

(C) There are between 107 and 108 gene copies/g of sediment of SN2 in both conditions after the 12-hour timestamp. Consider only the top graph. The trend in Pyruvate and Naphthalene concentrations should be ignored given the question inquires about SN2 specifically. The solid lines indicate change in their concentrations.

In Figure 1, what is the relationship between Pyruvate concentration and strain SN2 in TF-P?

As one decreases, the other increases.

As one decreases, the other does as well.

As one increases, the other does as well.

There is no clear relationship between concentrations in Figure 1.

(A) In Figure 1, as Pyruvate concentration decreases, SN2 TF-P concentration increases. Consider only the top graph and points that are shaded white. During all time intervals Pyruvate concentration was measured, SN2 TF-P concentration increased while Pyruvate concentration decreased.

The highest optical density of the SW-N condition occurs closest to which incubation time?

0 hours

12 hours

16 hours

20 hours

(C) The highest optical density in the SW-N period occurs closes to 16 hours. Consider only the bottom graph of Figure 1 and the points that are shaded white. Though measurements taken past 20 hours, values peaked closest to 16 hours of incubation.

Which answer most closely represents the number of hours a decrease in optical density was observed during the seawater conditions?

4

16

20

(B) A decrease in optical density was observed during approximately 4 hours of incubation in the seawater conditions. Consider only the bottom graph of Figure 1. There is no observable decrease in SW-P during any time interval, but SW-N clearly decreases in optical density around the 16-hour mark. This continues for the remainder of the graph. Though the exact amount of time of decrease is unclear, the best answer available is 4 hours.

In Figure 2, which conditions had the highest correlation?

TF-N and TF-P

TF-N and SW-N

TF-P and SW-P

SW-N and SW-P

(D) SW-N and SW-P had the highest correlation. The graph comparing these conditions provides an r value (correlation coefficient) of .8214. Given this is the highest r value in the figure, the optical density of both the SW-N and SW-P conditions are most correlated.

In figure 2, which conditions had the lowest correlation?

SW-N and SW-P

TF-N and TF-P

TF-P and SW-N

TF-N and SW-P

(C) TF-P and SW-N had the lowest correlation. The graph comparing these conditions provides an r value (correlation coefficient) of .6592, Given this is the lowest r value in the figure, the results of these conditions are the least correlated.

Researchers studied a species of hibernating black Bears. Each year the Black Bears go into hibernation for a 5-7 month period. During this time, they do not consume any food. Researchers explored the metabolic processes that allow black Bears to survive for so long without eating.

Science lesson Science Practice Test 9 exam questions 8. question pragraph

Figure 1

Science lesson Science Practice Test 9 exam questions 8. question pragraph

Figure 2

Figures adapted from Hibernation in Black Bears: Independence of Metabolic Suppression from Body Temperature by Oivind Toien et al.

Study 1

Researchers gathered black Bears and transported them to facilities in Alaska where they were placed in wooden box habitats. The researchers prepared to measure the Black Bears core body temperature and oxygen consumption during hibernation. Core body temperature was measured through implanted radio transmitters, and oxygen consumption was measured through the constant collection and analysis of air in the habitat. EMG was also surgically implanted to measure electrical activity. Results representative of a typical six-day period during hibernation can be observed in Figure 1.

Study 2

Researchers had additionally installed devices to track the hibernating Black Bears movements including infrared cameras. Once awake, the researchers continued to analyze the Black Bears metabolisms to better understand the process of recovering from hibernation. After having done so, the researchers decided to graph the last several months of hibernation and the post hibernation period, as can be seen in Figure 2. The legend indicates different individual Black Bears. The dashed line indicates the average date the Black Bears woke up from hibernation.

What is the lowest core body temperature observed during hibernation (Figure 2)?

Between 30 and 31 degrees Celsius

Between 31 and 32 degrees Celsius

Between 32 and 33 degrees Celsius

Between 33 and 34 degrees Celsius

(A) According to Figure 2, the lowest core body temperature observed during hibernation was between 30 and 31 degrees Celsius. Only consider the bottom graph. Though some Black Bears were observed to have their lowest core body temperature at higher temperatures, the lowest was observed of BB97-02F.

What is the highest core body temperature observed during hibernation for BB99-01M (Figure 2)?

Between 30 and 32 degrees Celsius

Between 32 and 34 degrees Celsius

Between 34 and 36 degrees Celsius

Between 36 and 38 degrees Celsius

(C) The highest core body temperature observed during hibernation for BB99-01M was between 34 and 36 degrees Celsius. Only consider the bottom graph. Though some Black Bears were observed to have their highest core body temperature during hibernation at higher temperatures, the highest for BB99-01M fell with the 34 and 36-degree range. After hibernation ended, the bear had an even higher core body temperature, but temperatures after the dashed line should be ignored.

Why was it important that the researchers tracked the hibernating bear’s movements in study 2?

It allowed the researchers to identify the Black Bears eating habits.

It allowed the researchers to better track the Black Bears core body temperature.

It allowed the researchers to better identify the Black Bears oxygen consumption.

It allowed the researchers to identify when the Black Bears awoke from hibernation.

(D) It was important that researchers tracked the bear's movements so that they could determine when the Black Bears awoke from hibernation. Knowing the exact moment of awaking can prevent hibernation data from being confounded with data from the recovery period. Tracking the bear’s movements did not inform the researchers further on the bear’s oxygen consumption or core body temperature. Additionally, the Black Bears did not eat during hibernation making their eating patterns irrelevant.

What is suggested by the differences in core body temperature between all three Black Bears in Figure 2?

Black Bears either have a lower core body temperature during hibernation than recovery, or a similar one.

Black Bears are similar in hibernation and in recovery from hibernation.

Black Bears differ more in hibernation than in recovery from hibernation.

Black Bears either have a higher core body temperature during hibernation than recovery, or a similar one.

(C) Black Bears differ more in hibernation than recovery from hibernation in core body temperature according to Figure 2. Consider only the bottom graph. Core body temperatures rise and fall at different points in different Black Bears while hibernating, and do so while being several degrees Celsius apart. During the recovery period temperatures fluctuate in a more similar manner and are less degrees Celsius apart.

Once awoken, what happens to the Black Bears?

Their average oxygen consumption increases.

Their average oxygen consumption decreases.

Their average oxygen consumption remains the same.

Their average core body temperature decreases.

(A) Once awoken, the average oxygen consumption of Black Bears increases. In all three Black Bears oxygen consumption increases significantly upon awakening. It does not decrease or remain the same, and average core body temperature does not decrease for any of the three Black Bears.

One of the researchers hypothesized that if the same study were performed again the following year with three new Black Bears instead of the Black Bears from the current studies, the pattern of oxygen consumption would be relatively the same. Do the results of the study support this hypothesis?

Yes, all three Black Bears experienced a consistent decrease in oxygen consumption, magnifying as more time passed.

Yes, all three Black Bears experienced a similar trend in oxygen consumption at all time intervals suggesting individual Black Bears do not differ

No, some Black Bears had several degrees higher body temperature than others at the same point in time.

No, oxygen consumption as observed in the current study has no clear pattern and is not replicable.

(B) Yes, all three Black Bears experienced a similar trend in oxygen consumption at all time intervals suggesting individual Black Bears do not differ in this regard. The question only inquires about oxygen consumption, so only consider the top graph of Figure 2. Because all three Black Bears followed a similar trend and there was no evidence to dispute that individual variance between Black Bears is important in determining oxygen consumption during hibernation, it is supported by the study that Black Bears are generally the same in this regard.