ACT Science : Biology

Study concepts, example questions & explanations for ACT Science

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Example Questions

Example Question #31 : Biology

Passage I

An endocrinologist is a doctor who studies, diagnoses, and treats patients with hormone imbalances. There are many hormones involved in daily functioning. Two of the most important hormones for digestion are insulin and glucagon. These hormones are secreted by the pancreas. Insulin is released after a meal to help body cells take in sugar and covert it to energy. Glucagon is released when the body needs more energy, such as during exercise, and causes body cells to secrete sugar into the blood. A team of endocrinologists performed the following experiments:

Experiment 1

Five participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. All five participants were healthy and had no serious medical conditions. A team of endocrinologists monitored the blood sugar and insulin levels of the participants over time. Figure 1 is a graph of the average levels in the five participants.

Figure_1

Experiment 2

Two participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. One participant was healthy and the other had a hormone disease. Figure 2 is a graph of the blood sugar levels of the participants over time.

Figure_2

At what time after eating would you expect the highest blood sugar level?

Possible Answers:

Immediately

3 Hours

4 Hours

2 Hours

1 hour

Correct answer:

1 hour

Explanation:

This question involves graph interpretation. According to Figure 1, the greatest increase in blood sugar occurs after 1 hour. With the information that the endocrinologists began recording data immediately after participants consumed a tube of sugar, you can expect the greatest increase in blood sugar 1 hour after eating.

Example Question #31 : Act Science

Passage I

An endocrinologist is a doctor who studies, diagnoses, and treats patients with hormone imbalances. There are many hormones involved in daily functioning. Two of the most important hormones for digestion are insulin and glucagon. These hormones are secreted by the pancreas. Insulin is released after a meal to help body cells take in sugar and covert it to energy. Glucagon is released when the body needs more energy, such as during exercise, and causes body cells to secrete sugar into the blood. A team of endocrinologists performed the following experiments:

Experiment 1

Five participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. All five participants were healthy and had no serious medical conditions. A team of endocrinologists monitored the blood sugar and insulin levels of the participants over time. Figure 1 is a graph of the average levels in the five participants.

Figure_1

Experiment 2

Two participants were given 15 grams of pure glucose (sugar). The participants had not eaten for four hours prior to the experiment. One participant was healthy and the other had a hormone disease. Figure 2 is a graph of the blood sugar levels of the participants over time.

Figure_2

Experiment 1 is repeated. The team of endocrinologists also monitors glucagon levels of the participants over time. What would the graph of average glucagon levels over time look like?

Possible Answers:

Inverse of insulin graph

Vertical line

Horizontal line

Exponential increase

Linear increase 

Correct answer:

Inverse of insulin graph

Explanation:

The passage states that insulin and glucagon have opposing functions. Insulin decreases blood sugar levels and glucagon increases blood sugar levels. Therefore, it is most likely that the graph of glucagon would resemble the inverse of the insulin graph. 

Example Question #33 : How To Find Data Representation In Biology

Error bars are utilized in scientific graphs to show the difference between data points. If the error bars of data points overlap then they are not statistically independent from one another; therefore, they can be considered to be similar to one another. Only data points that possess non-overlapping error bars are sufficient to make or support a scientific conclusion.

Error_bars_overlap

Is this data set statistically valid?

Possible Answers:

No, the error bars do not overlap.

Yes, there is significant overlap in error bars.

No, there is too much overlap between error bars.

Yes, the error bars overlap

Correct answer:

No, there is too much overlap between error bars.

Explanation:

No, there is too much overlap between error bars.

The error bars in this data set contain significant overlap. Each point is statistically similiar to the other. Any differences seen in these points could be the result of error or deviation from the mean.

Example Question #31 : Act Science

Error bars are utilized in scientific graphs to show the difference between data points. If the error bars of data points overlap then they are not statistically independent from one another; therefore, they can be considered to be similar to one another. Only data points that possess non-overlapping error bars are sufficient to make or support a scientific conclusion. 

Error_bars_no_overlap

Are these data points statistically independent from one another?

Possible Answers:

No, the error bars overlap

Yes, the error bars overlap

Yes, the error bars do not overlap

No, the error bars do not overlap.

Correct answer:

Yes, the error bars do not overlap

Explanation:

Yes, the error bars do not overlap.

The error bars within the data points of the graph do not overlap. According to the passage, they are statistically independent from one another.

Example Question #31 : Biology

Error bars are utilized in scientific graphs to show the difference between data points. If the error bars of data points overlap then they are not statistically independent from one another; therefore, they can be considered to be similar to one another. Only data points that possess non-overlapping error bars are sufficient to make or support a scientific conclusion.

Error_bars_no_overlap2

Are these data points statistically significant?

Possible Answers:

No, there is overlap between points.

Yes, there is little to no overlap between the points.

Yes, there is overlap between points.

No, there is little to no overlap between points.

Correct answer:

Yes, there is little to no overlap between the points.

Explanation:

Yes, there is little to no overlap between the points.

The data points in the red square possess error bars that do not overlap. These points are statistically independent from one another.

Example Question #36 : How To Find Data Representation In Biology

Error bars are utilized in scientific graphs to show the difference between data points. If the error bars of data points overlap then they are not statistically independent from one another; therefore, they can be considered to be similar to one another. Only data points that possess non-overlapping error bars are sufficient to make or support a scientific conclusion.

Error_bars_bar_graph

Are Samples 3 and 6 statistically valid?

Possible Answers:

Yes, there is significant overlap in error bars.

No, there is significant overlap in error bars.

Yes, there is no error bar overlap.

No, there is no error bar overlap.

Correct answer:

No, there is significant overlap in error bars.

Explanation:

No, there is significant overlap in error bars.

These samples are statistically indistinguishable from one another due to significant error bar overlap.

Example Question #32 : Biology

Error bars are utilized in scientific graphs to show the difference between data points. If the error bars of data points overlap then they are not statistically independent from one another; therefore, they can be considered to be similar to one another. Only data points that possess non-overlapping error bars are sufficient to make or support a scientific conclusion.

Error_bars_bar_graph

Are samples 7 and 8 statistically valid?

Possible Answers:

No, the error bars overlap.

No, there is no error bar overlap.

Yes, the error bars overlap.

Yes, there is no error bar overlap.

Correct answer:

Yes, there is no error bar overlap.

Explanation:

Yes, there is no error bar overlap.

Samples 7 and 8 are statistically valid because their error bars contain no overlap. They are independent sets that may be compared to one another.

Example Question #31 : How To Find Data Representation In Biology

Eukaryotic cells first appeared billions of years ago and were marked by the presence of membrane-bound organelles (organelles with a lipid bilayer surrounding them) similar to the outer and inner membranes of prokaryotes like bacteria. One of these membrane bound organelles is called the mitochondrion, which is responsible for helping generate energy in the form of a nucleotide-sugar molecule called adenosine triphosphate (also known as ATP).

 

By using only oxygen and glucose (a type of sugar composed of a single molecule) as reactants, the mitochondrion is responsible for generating ATP and water. In order to make ATP, animals must eat food products that contain sugars, such as potatoes, which contain molecules called starches that have many sugar molecules linked together. Once the sugar has been processed in the cell by an enzyme called amylase, it undergoes a process called glycolysis, which breaks down glucose into a molecule called pyruvate and provides 2 ATP molecules in the process.

 

After glycolysis, the pyruvate molecule is transported to the mitochondrion, carried across its membrane and then enters a process called the Kreb’s cycle, where a net of 34 ATP are produced. However, the process of transporting the pyruvate molecule into the mitochondrion requires 1 ATP. The ATP produced from both glycolysis and the Kreb’s cycle serves to allow the cell to carry out its housekeeping functions.

According to the passage, what is the net amount of ATP that can be produced by one glucose molecule?

Possible Answers:

2

35

36

34

Correct answer:

35

Explanation:

The passage describes that glucose is first broken down into pyruvate, generating 2 ATP. However, transferring the pyruvate into the mitochondrion for the next step in the process requires one ATP, so our count is back down to 1. The passage then tells us that 34 ATP are produced by the Kreb's Cycle, bringing our count back up to 35. The key to this question was being able to track glucose all the way from entering the cell to being entered into the Kreb's Cycle. 

Example Question #32 : Biology

Eukaryotic cells first appeared billions of years ago and were marked by the presence of membrane-bound organelles (organelles with a lipid bilayer surrounding them) similar to the outer and inner membranes of prokaryotes like bacteria. One of these membrane bound organelles is called the mitochondrion, which is responsible for helping generate energy in the form of a nucleotide-sugar molecule called adenosine triphosphate (also known as ATP).

 

By using only oxygen and glucose (a type of sugar composed of a single molecule) as reactants, the mitochondrion is responsible for generating ATP and water. In order to make ATP, animals must eat food products that contain sugars, such as potatoes, which contain molecules called starches that have many sugar molecules linked together. Once the sugar has been processed in the cell by an enzyme called amylase, it undergoes a process called glycolysis, which breaks down glucose into a molecule called pyruvate and provides 2 ATP molecules in the process.

 

After glycolysis, the pyruvate molecule is transported to the mitochondrion, carried across its membrane and then enters a process called the Kreb’s cycle, where a net of 34 ATP are produced. However, the process of transporting the pyruvate molecule into the mitochondrion requires 1 ATP. The ATP produced from both glycolysis and the Kreb’s cycle serves to allow the cell to carry out its housekeeping functions.

Why might the Kreb's Cycle have been evolutionarily advantageous to developing eukaryotic cells?

Possible Answers:

Increase in Ability to Defend Against Enemies

Increase in Ability to Generate Energy

Increase in Ability to Discard Waste

Increase in Ability to Generate Oxygen

Correct answer:

Increase in Ability to Generate Energy

Explanation:

Indirectly, the passage describes an increased ability to generate ATP per molecule of glucose with the advent of the Kreb's Cycle. The passage states that glycolysis generates only ATP. However, when the glucose derivative pyruvate enters into the Kreb's Cycle, 34 more ATP can be produced. The question tells us that is was evolutionarily advantageous to develop the Kreb's Cycle, so the logical conclusion is that it was able to provide more energy per unit of glucose for the organism.

Example Question #32 : Act Science

Eukaryotic cells first appeared billions of years ago and were marked by the presence of membrane-bound organelles (organelles with a lipid bilayer surrounding them) similar to the outer and inner membranes of prokaryotes like bacteria. One of these membrane bound organelles is called the mitochondrion, which is responsible for helping generate energy in the form of a nucleotide-sugar molecule called adenosine triphosphate (also known as ATP).

 

By using only oxygen and glucose (a type of sugar composed of a single molecule) as reactants, the mitochondrion is responsible for generating ATP and water. In order to make ATP, animals must eat food products that contain sugars, such as potatoes, which contain molecules called starches that have many sugar molecules linked together. Once the sugar has been processed in the cell by an enzyme called amylase, it undergoes a process called glycolysis, which breaks down glucose into a molecule called pyruvate and provides 2 ATP molecules in the process.

 

After glycolysis, the pyruvate molecule is transported to the mitochondrion, carried across its membrane and then enters a process called the Kreb’s cycle, where a net of 34 ATP are produced. However, the process of transporting the pyruvate molecule into the mitochondrion requires 1 ATP. The ATP produced from both glycolysis and the Kreb’s cycle serves to allow the cell to carry out its housekeeping functions.

The funtion of amylase is most likely to:

Possible Answers:

Generate ATP in Glycolysis

Break Down Starch

Transport Oxygen into the Cell

Generate ATP in the Kreb's Cycle

Correct answer:

Break Down Starch

Explanation:

Using context clues in the passage, we see that starch must be broken down into individual glucose molecules. The passage tells us that "once [starch] has been processed in the cell by an enzyme called amylase," it undergoes glycolysis. Also from the passage, we see that only the individual molecules of glucose can enter into glycolysis. Thus, the "processing" that the enzyme amylase does must be to break it down into individual glucose molecules.

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