ACT Science : Biology

Study concepts, example questions & explanations for ACT Science

varsity tutors app store varsity tutors android store varsity tutors amazon store varsity tutors ibooks store

Example Questions

Example Question #671 : Biology

Lynx_and_hare

Predator-prey relationships and mechanics are important tools for understanding the ecology of environments. Population cycles were first recorded in Canadian forests by fur trappers. Species interactions are important indicators of the health and economy of a natural environment. A twelve-year study of northern Canada revealed that snowshoe hares and lynxes share highly synchronized and predictable cycles. The lynx's predator populations mimic and mirrors that of their prey, the snowshoe hare. Two scientists express their views on these population patterns below.

Scientist 1

     The observed relationship is best explained by predator-prey relationships and competition for resources. Consumer-resource interactions fluctuate independently of variation within the environment.

Scientist 2

     The observed relationship is produced by environmental changes. Fluctuations in weather patterns and resources manipulate observed predator-prey relationships.

Assume that Scientist 2's reasoning is correct. If snowshoe hares experience a time of plentiful resources, how would the size of the snowshoe hare population be affected?

Possible Answers:

The population would remain the same.

The population would grow due to due to the abundance of available resources.

The population would grow due to a decline in the lynx population and decreased predation.

The population would decline due to increased predation.

Correct answer:

The population would grow due to due to the abundance of available resources.

Explanation:

Scientist 2 believes that the lynx and snowshoe hare populations are affected only by environmental changes. This scientist would expect the snowshoe hare population to increase in correspondence with the amount of resources available to it.

Example Question #671 : Biology

Lynx_and_hare

Predator-prey relationships and mechanics are important tools for understanding the ecology of environments. Population cycles were first recorded in Canadian forests by fur trappers. Species interactions are important indicators of the health and economy of a natural environment. A twelve-year study of northern Canada revealed that snowshoe hares and lynxes share highly synchronized and predictable cycles. The lynx's predator populations mimic and mirrors that of their prey, the snowshoe hare. Two scientists express their views on these population patterns below.

Scientist 1

     The observed relationship is best explained by predator-prey relationships and competition for resources. Consumer-resource interactions fluctuate independently of variation within the environment.

Scientist 2

     The observed relationship is produced by environmental changes. Fluctuations in weather patterns and resources manipulate observed predator-prey relationships.

Climate change has dramatically and detrimentally altered the weather patterns in the Canadian wilderness. How would Scientist 1 expect this to change the species' populations?

Possible Answers:

The hares will decrease and the lynxes will increase in number.

It will have no noticeable effect.

The hares and the lynxes will both decrease in number.

The hares will increase and the lynxes would decrease in number.

Correct answer:

It will have no noticeable effect.

Explanation:

It will have no noticeable effect. Scientist 1 states that the population pattern is the result of predator-prey relationships and independent of environmental variation. The population will follow species specific patterns despite climatic changes in their native environments. 

Example Question #671 : Biology

Lynx_and_hare

Predator-prey relationships and mechanics are important tools for understanding the ecology of environments. Population cycles were first recorded in Canadian forests by fur trappers. Species interactions are important indicators of the health and economy of a natural environment. A twelve-year study of northern Canada revealed that snowshoe hares and lynxes share highly synchronized and predictable cycles. The lynx's predator populations mimic and mirrors that of their prey, the snowshoe hare. Two scientists express their views on these population patterns below.

Scientist 1

     The observed relationship is best explained by predator-prey relationships and competition for resources. Consumer-resource interactions fluctuate independently of variation within the environment.

Scientist 2

     The observed relationship is produced by environmental changes. Fluctuations in weather patterns and resources manipulate observed predator-prey relationships.

According to the information provided, which description of the relationship between hares and lynxes would both scientists accept?

Possible Answers:

Hares and lynxes share interactions that are dependent on each other.

Hares and lynxes share interactions that are completely unrelated.

Hares and Lynxes share interactions that depend upon environmental conditions.

Hares and lynxes share interactions that correlate with one another.

Correct answer:

Hares and lynxes share interactions that correlate with one another.

Explanation:

"Hares and lynxes share interactions that correlate with one another" is the correct answer because it does not side with either scientist. It suggests that factors exist that make the population relationship between the two species comparable. It does not attribute this to the environment or species interactions, as in two of the incorrect answers; furthermore, one cannot deny the existence of a relationship between the two species due to the evidence presented in the graph.

Example Question #672 : Act Science

A mycologist performed an experiment to determine the effect of methanol on the mold Neurospora crassa.

1,500 Neurospora spores were divided evenly into five groups of three large glass test tubes each. Then each test tube was filled with 5.0 mL of liquid nutrient solution and either 0 mL, 0.5 mL, 1.0 mL, 1.5 mL, or 2.0 mL of methanol. The tubes were placed in an incubator at 28oC overnight to germinate, and then their aerial growth was marked beginning the next morning and every twelve hours thereafter for two days.

Table 1 shows the average growth data with  hours representing the morning after germination and  hours representing the end of the two-day experiment.

Table_science

Based on his data, the mycologist concludes that methanol is toxic to Neurospora in liquid culture. You think the mycologist is wrong and repeat the experiment, adding between 0.0 mL and 2.0 mL of distilled water, which is known to have no effect on growth, to each tube. 

Assuming the mycologist is incorrect, what would you expect to be the average growth of cultures in tubes with 2.0 mL of distilled water added after 48 hours?

Possible Answers:

Correct answer:

Explanation:

If adding 2.0 mL of distilled water would have the same effect as adding 2.0 mL of methanol (i.e. 0 mm growth), then the mycologist would be wrong. Therefore, assuming he is wrong, you would expect to show 0 mm average growth.

Example Question #672 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

With which of the following statements would only Scientist 1 agree?

Possible Answers:

The Golgi body efficiently recycles vesicles. 

The Golgi body's compartments form to process and ship specific sets of incoming proteins and travel with them around the cell as vesicles.

The Golgi body's compartments remain intact and in the same place in the organelle as proteins pass through for processing and shipment.

All of the Golgi body’s compartments have the same set of processing enzymes. 

Correct answer:

The Golgi body's compartments remain intact and in the same place in the organelle as proteins pass through for processing and shipment.

Explanation:

"The Golgi body's compartments remain intact and in the same place in the organelle as proteins pass through for processing and shipment" is a summary of Scientist 1's model. "The Golgi body's compartments form to process and ship specific sets of incoming proteins and travel with them around the cell as vesicles" is a summary of Scientist 2's model. Both Scientist 1 and Scientist 2 believe that "the Golgi body efficiently recycles vesicles," however they disagree on how the Golgi body recycles vesicles. Neither scientist directly argues that "all of the Golgi body’s compartments have the same set of processing enzymes," though it can be inferred Scientist 2 is more likely to agree with this statement.

Example Question #671 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

Which scientist(s), if either, would believe that processing enzymes travel with an incoming protein to the Golgi body throughout the cell until it is delivered?

Possible Answers:

Scientist 1

Both Scientist 1 and Scientist 2

Neither Scientist 1 nor Scientist 2

Scientist 2

Correct answer:

Scientist 2

Explanation:

Scientist 2 believes that membranes, with processing enzymes already attached, form a compartment around incoming proteins. After processing, the membrane becomes the vesicle that will help to transport the proteins, and thus the enzymes will travel throughout the cell along with the proteins. 

Example Question #672 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

What criticism of Scientist 2's model is Scientist 1 most likely to make?

Possible Answers:

Scientist 2's model requires all processing enzymes to be present in each compartment, while it has been observed that various compartments contain differing processing enzymes. 

Scientist 2's model does not explain how proteins are received into the Golgi body.

Scientist 2's model does not explain how vesicles are recycled. 

Scientist 2's model does not explain how the proteins are delivered to the appropriate parts of the cell.

Correct answer:

Scientist 2's model requires all processing enzymes to be present in each compartment, while it has been observed that various compartments contain differing processing enzymes. 

Explanation:

Scientist 1 specifically states his or her model is the best because it explains why it has been observed that various compartments contain differing enzymes. It can be assumed that Scientist 2's model is based on the fact that all potentially necessary processing proteins must be available in all compartments, since the proteins only ever reside in one compartment. Neither scientist explains how proteins are received into the Golgi body; however, both explain how proteins are delivered. Scientist 2 provides a clear explanation of how vesicles are recycled.

Example Question #673 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

What criticism of Scientist 1's model is Scientist 2 most likely to make?

Possible Answers:

Scientist 1's model does not explain how vesicles can be recycled or how compartment of the Golgi can be formed in the first place. 

Scientist 1's model does not explain how the Golgi packages proteins for shipment to other parts of the cell.

Scientist 1's model does not tell how protein packages are directed to the correct parts of the cell.

Scientist 1's model does not explain how the processing enzymes are made.

Correct answer:

Scientist 1's model does not explain how vesicles can be recycled or how compartment of the Golgi can be formed in the first place. 

Explanation:

Scientist 2 specifically points out that his or her model is best because it explains how the Golgi compartments are formed, and indicates this is the way that vesicles can be recycled. While Scientist 1 indicates that vesicles are directed back to the Golgi, she or he does not state how they can be reused. She or he also doesn't state how the compartments are formed in the first place. Neither scientist discusses how the processing enzymes are made, or how they are directed to the correct locations in the cell, but both explicitly state how the proteins are packaged for shipment.

Example Question #673 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

If all the enzymes in one compartment were labeled in some way, which of the following statements would support Scientist 2's model? 

Possible Answers:

Later it was found that all the labeled enzymes were still in the same compartment in the same place in the Golgi body.

Later it was found that all the labeled enzymes were still in the same compartment in the same place in the Golgi body.

Later it was found that the labeled enzymes were in several different compartments of the Golgi body.

Later it was found that all the enzymes were unlabeled.

Correct answer:

Later it was found that the labeled enzymes were in several different compartments of the Golgi body.

Explanation:

Scientist 2 predicts that the enzymes, attached to the membrane walls of the compartments, would be incorporated into various vesicles for protein transport. When these vesicles completed their deliver and were broken down, they would be recycled into various new compartments, resulting in that the labeled enzymes could be found in several different compartments. Scientist 1 would have predicted that these enzymes stayed in the same compartment indefinitely. "Later it was found that the enzymes had been delivered to various places around the cell" implies that the vesicles are not recycled upon delivery, as both scientists state they are. "Later it was found that all the enzymes were unlabeled" implies that all the enzymes had degraded in some way, a topic neither scientist discusses.

Example Question #673 : Biology

The Golgi body is an organelle found in most cells. Its function is to package proteins to be sent to various destinations within the rest of the cell. It is comprised of many compartments that contain various enzymes, or agents that catalyze specific chemical transformations, that process proteins to prepare for their delivery to other parts of the cell. There are currently two competing models of how these compartments develop and how they process and package proteins. Two different scientists explain these models below.

 

Scientist 1:

The Golgi body is made up of a set of stable compartments. Each compartment has a unique set of enzymes that carry out specific chemical transformations on the proteins passing through the Golgi body to help process and label them for transport around the cell. In the final compartment, the proteins are packaged in vesicles, or membranes, to be shipped to the rest of the cell. These vesicles are labeled so that when the protein has been delivered to the properly cellular location, they will be shipped back to the Golgi to be recycled.

This model is the best model because the Golgi body has been observed to have uneven distribution of various enzymes throughout the organelle, which can be explained by the specialized compartments.

 

Scientist 2:

The Golgi body is a collection of compartments that are each created for individual sets of proteins and "mature" along with the proteins. First, a membrane is formed around a set of incoming proteins to form a compartment.  Then enzymes attached to the membrane process this specific set of proteins. When the proteins have been fully processed, the compartment's membrane begins to break down to form vesicles around the individual proteins to allow for their transport around the cell. When the proteins are delivered, the vesicles return back to the Golgi body to begin reforming a new compartment around new proteins.

This model is the best because it can explain how compartments in the Golgi body are generated and regenerated, and how vesicles are recycled in the cell.

Based on Scientist 1's model, if a Golgi body processing enzyme could be labeled with a colored molecule and then watched under a microscope to observe its whereabouts in the cell, what results can be expected?

Possible Answers:

The enzyme will travel to various locations in the Golgi body.

The enzyme will stay in the same location in the Golgi body.

The enzyme will travel to various locations in the cell.

The enzyme will travel to another cell. 

Correct answer:

The enzyme will stay in the same location in the Golgi body.

Explanation:

Scientist 1 believes that enzymes stay within stationary compartments, and thus she or he would expect to see the enzyme remain motionless. Scientist 2 would expect to see the enzyme travel to various parts of the cell. Neither discussed enzymes traveling from compartment to compartment or exiting the cell.

Learning Tools by Varsity Tutors