AP Bio Final

The dashed line on the graph represents the...

'carrying capacity' of the environment

(Respirometer Lab) The rate of oxygen consumption in germinating pea seeds at 26ºC is...

0.05 mL / min

Diapause experiment: The average brood size per mated individual upon reintroduction of food following 30 days of ARD is closest to which of the following?

50

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. If, instead of the bag, a potato slice were placed in the beaker of distilled water, which of the following would be true of the potato slice?

It would 'gain mass'.

The best explanation for the fact that not all points lie on any given line is that...

Organisms within populations show 'variability'

The figure below illustrates a eukaryotic cell. Which of the following best describes how the three structures indicated by the arrows work together?

To synthesize and 'isolate' proteins for secretion or for use in the cell

Site of conversion of chemical energy of glucose to ATP

'A'. Mitochondria

Evolved from a photoautotrophic prokaryote

'B'. Chloroplast

Site of glucose synthesis

'B'. chloroplasts

If the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested, the average time for the disks to float to the surface of the hydrogen peroxide solution would be...

'more' than 30 seconds

The graph indicates that the sheep population most likely is...

'stable' after 1850 under the effects of density-dependent regulating factors

A student studied the effects of light intensity on oxygen production in green algae. The algae were suspended in water inside a sealed glass jar, and the jar was placed into a constant-temperature, lightproof box containing a light source. A probe was inserted into the jar to record the concentration of oxygen. The probe was connected to a recording device. The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. An increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances?

C6H12O6 (product of photosynthesis)

Which point on the curve in the diagram above best represents the carrying capacity of the environment for the population shown?

E; the top point

Based on the data, which of the following behaviors in elk could account for the differences between the percent of aspens browsed by herbivores and the height of aspen trees in riparian and upland environments?

Elk tend to 'avoid riparian areas' where the steep, wooded riverbanks make it difficult to escape predators.

The graph below illustrates a logistic growth curve for a population of Euglena. (point Q is at the top of the S) The population density at point Q indicates that...

the reproductive rate equals the death rate

Site of modification and packaging of proteins and lipids prior to export from the cell

'C'. Golgi Apparatus

Students in a class measured the mass of various living organisms. They then kept the organisms in the dark for 24 hours before remeasuring them. None of the organisms were provided with nutrients during the 24-hour period. The data are as follows. Which of the following is the best explanation for the pattern of change in mass of the organisms over time?

'Cellular Respiration' (because all of the masses went down by 1)

Site of transport of materials into and out of the cell

'D'. Cell Membrane

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. The most probable cause for the difference in mean stem length between plants in dish A and plants in dish B is which of the following?

'Elongation' of seedlings in response to the lack of light

The graph below illustrates a logistic growth curve for a population of Euglena. (point Q is at the top of the S) The population would be most likely to remain at the level shown at Q under which of the following conditions?

'Environmental conditions' do not fluctuate.

Individuals of a particular species of ground beetle are either light tan or dark brown. Light-tan beetles are predominant in habitats with light-colored sandy soils, and dark-brown beetles are predominant in habitats with dark-colored loam soils. In an experiment designed to determine the survival rates of light-tan beetles and dark-brown beetles in different habitats, 500 light-tan beetles and 500 dark-brown beetles were released in each of four habitats. Each beetle had been marked with a small spot of red paint on the underside of its abdomen before it was released. One week after the beetles had been released, any marked beetles that could be found were recaptured. The results are presented in the table below. It is assumed that differences in the numbers of beetles recaptured are directly related to differences in survival rates. Which of the following can be inferred from the data in the table?

'Insectivorous birds are predators' of this species of ground beetle.

A scientist used the amino acid sequence of cytochrome c in different species to consider evolutionary relationships. The data below summarize the number of differences in the amino acid sequences of cytochrome c found in selected species. (small species compared vs number of differences table) Interpretation of the data supports which of the following statements?

'Mammals' are more closely related to reptiles than they are to fish.

Diapause experiment: Which of the following best describes the reproductive ability of C. elegans following the ARD induced in the first experiment?

'Mating' with a well fed male consistently produced more offspring than did reproduction via self fertilization

(ball and graph) In the early 1970s, researchers hypothesized that carbon was the limiting nutrient in many aquatic ecosystems. To test this hypothesis, the researchers divided a small lake in two roughly equal halves with an impermeable curtain that was fastened and sealed to the bedrock of the lake. Beginning in 1971 the researchers treated one side of the lake with sucrose and the other side with both sucrose and phosphate. From 1971 to 1983 the researchers monitored the phytoplankton biomass in both parts of the lake. The results are shown in Figure 1. Which of the following claims is best supported by the data?

'Phosphate' was a limiting factor for phytoplankton in the lake.

A moth's color is controlled by two alleles, G and g, at a single locus. G (gray) is dominant to g (white). A large population of moths was studied, and the frequency of the G allele in the population over time was documented, as shown in the figure below. In 1980 a random sample of 2,000 pupae was collected and moths were allowed to emerge. Which of the following is the most likely reason for the observed differences in the frequency of the G allele between 1965 and 1972?

'Selection against' gray phenotypes

(mouse bar graphs) A group of mice was released into a large field to which no other mice had access. Immediately after the release, a representative sample of the mice was captured, and the fur color of each individual in the sample was observed and recorded. The mice were then returned to the field. After twenty years, another representative sample of the mice was captured, and the fur color of each individual in the sample was again recorded. Which of the following best explains the change in the frequency distribution of fur color phenotypes in the mouse population, as shown in the figures above?

'The field' was composed primarily of light-colored soil and little vegetation, affording gray mice protection from predators.

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. According to the results of this experiment, germination of tobacco seeds during the first week is...

'increased' by exposure to light

A scientist used the amino acid sequence of cytochrome c in different species to consider evolutionary relationships. The data below summarize the number of differences in the amino acid sequences of cytochrome c found in selected species. (small species compared vs number of differences table) Which of the following phylogenetic trees can be supported by the data?

1 and 2 only (no pigs in answer tree)

(ball and graph) In the early 1970s, researchers hypothesized that carbon was the limiting nutrient in many aquatic ecosystems. To test this hypothesis, the researchers divided a small lake in two roughly equal halves with an impermeable curtain that was fastened and sealed to the bedrock of the lake. Beginning in 1971 the researchers treated one side of the lake with sucrose and the other side with both sucrose and phosphate. From 1971 to 1983 the researchers monitored the phytoplankton biomass in both parts of the lake. The results are shown in Figure 1. The average growth rate of the phytoplankton population from 1971 to 1975 in the side of the lake treated with sucrose and phosphate is closest to which of the following?

1,500 (mg/m3) per year

If all insectivorous birds and remaining beetles were removed from habitat 2 and 500 additional dark-brown beetles and 500 additional light-tan beetles were then released into habitat 2, which of the following is the best estimate of the number of additional dark-brown beetles that would be expected to be recaptured in habitat 2 after one more week?

120

The following questions refer to the data presented in the graph below of tobacco cells grown in tissue culture. The numbers on the curves indicate the concentrations of indoleacetic acid (IAA) in milligrams per liter. The optimum concentrations of hormones for promoting maximum tobacco cell growth are...

27 mg/liter of IAA and 0.64 mg/liter of kinetin

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. To model a plant cell, a permeable, non flexible case is placed around each piece of dialysis tubing. The greatest pressure potential will develop within dialysis tube number...

4 (gets to the highest number)

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. The contents of which dialysis tube are initially isotonic to the distilled water in the beaker?

5 (the amount of water stayed the same)

Dialysis tubing is permeable to water molecules but not to sucrose. Four dialysis tubes are half filled with 5 percent, 10 percent, 20 percent, and 40 percent sucrose solutions, respectively, and two dialysis tubes are half filled with distilled water. The dialysis tubes are all sealed at both ends, and the initial masses are determined. Five dialysis tubes are placed into beakers containing distilled water, and the sixth dialysis tube, containing distilled water, is placed into a 40 percent sucrose solution. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. A net movement of water into the beaker occurs in which of the following dialysis tubes?

6 (40% sucrose beaker content) (because the amount of water changed the most)

(Arrow food web with letters instead of animals) A photosynthetic organism would be represented by which species?

A (doesnt need a food source)

Which of the following predictions about the community is most likely true?

A decrease in the wolf population will lead to a decrease in the mean aspen height.

What is the most likely explanation for the change in the slope of the line between 3 and 5 minutes? (3 is in the middle, 5 is at the end of the curving part)

A large amount of the 'substrate' had been consumed.

A tissue culture of vertebrate muscle was provided with a constant excess supply of glucose under anaerobic conditions starting at time zero and the amounts of pyruvic acid and ATP produced were measured. The solid line in the graph above represents the pyruvic acid produced in moles per liter per minute. ATP levels were also found to be highest at points A and C, lowest at B and D. A second culture was set up under the same conditions, except that substance X was added, and the results are indicated by the dotted line. Which of the following best accounts for the shape of the solid line between points A and D?

ATP acted as an 'allosteric inhibitor' on one or more of the enzymes.

(ball and graph) In the early 1970s, researchers hypothesized that carbon was the limiting nutrient in many aquatic ecosystems. To test this hypothesis, the researchers divided a small lake in two roughly equal halves with an impermeable curtain that was fastened and sealed to the bedrock of the lake. Beginning in 1971 the researchers treated one side of the lake with sucrose and the other side with both sucrose and phosphate. From 1971 to 1983 the researchers monitored the phytoplankton biomass in both parts of the lake. The results are shown in Figure 1. Which of the following treatments would have been the best control treatment for the experiment?

An untreated section of the lake

Which of the following models best predicts the effect on the ecosystem if a deadly communicable disease is introduced into the wolf population?

As wolfs decrease elk will increase (graph)

(upside down fishhook graph) Which of the following statements best explains the activity levels of trypsin shown in Figure 1 ?

At extremely low pH values, trypsin is 'denatured' and cannot function efficiently.

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water (pH 7.0) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups V and VI). After exposing the samples to light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of carbon dioxide in the water. For each treatment group, the students calculated the mean pH and standard error, as documented in the table below. Which of the following graphs is the most appropriate representation of the experimental results documented in the table?

Bar graph

Different photosynthetic organisms have different types of chlorophyll molecules. The distribution of chlorophylls in several different groups of organisms is shown in Table 1. A plus sign (+) in the table indicates the presence of a chlorophyll, while a minus sign (−) indicates its absence. Based on the data, which of the following most likely describes the evolutionary relationship among the organisms?

Because all of the organisms contain chlorophyll a, the organisms share a 'common ancestor'.

(Arrow food web with letters instead of animals) Members of which species are most likely to be omnivorous?

C (humans; eats A (a plant) and 2 other animals)

(Arrow food web with letters instead of animals) Which species would most likely represent humans if they were part of this ecosystem?

C (they eat the most food sources)

(Arrow food web with letters instead of animals) Members of which species are herbivores?

D (only eats A; a plant)

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water (pH 7.0) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups V and VI). After exposing the samples to light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of carbon dioxide in the water. For each treatment group, the students calculated the mean pH and standard error, as documented in the table below. The results for treatment groups Vand VI could suggest which of the following questions about the design of the experiment?

Does 'aquarium' water contain living microorganisms?

The diagram below shows energy changes in a specific chemical reaction with and without the addition of an enzyme to the reaction. Which of the following questions can best be answered by the diagram?

Does the addition of an enzyme 'reduce' the activation energy required for a reaction?

In the first step of an experiment, rat liver cells were exposed for 5 minutes to amino acids labeled with a radioactive isotope. The cells were then washed to stop any further incorporation of radioactive amino acids. The cells were sampled periodically thereafter, and the radioactivity of a certain protein (protein X) was measured in various cell components, as shown below. Which of the following correctly shows the order in which protein X moves through the cell?

Endoplasmic reticulum→Golgi apparatus→lysosomes (3 steps)

Testosterone oxido-reductase is a liver enzyme that regulates testosterone levels in alligators. One study compared testosterone oxido-reductase activity between male and female alligators from Lake Woodruff, a relatively pristine environment, and from Lake Apopka, an area that has suffered severe contamination. The graph above depicts the findings of that study. The data in the graph best support which of the following claims?

Environmental contamination 'reduces' total testosterone oxido-reductase activity in 'females'.

(basketball bracket table) Prior to 1960, Lake Washington was highly polluted and underwater visibility was limited to one or two meters. In the late 1960s, a large cleanup effort reduced pollution, resulting in visibility that increased to six to seven meters by 1976. Which of the following best explains how the change in underwater visibility affected armor plating in Lake Washington sticklebacks between 1957 and 1976?

Higher visibility made the sticklebacks 'more susceptible to large-toothed predators' in the lakes, giving complete armor a selective advantage.

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water (pH 7.0) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups V and VI). After exposing the samples to light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of carbon dioxide in the water. For each treatment group, the students calculated the mean pH and standard error, as documented in the table below. To investigate whether an organism in the study is capable of both photosynthesis and respiration, a comparison of which treatment groups is most appropriate?

I and II (light and dark both plants)

(Respirometer Lab) Which of the following conclusions is best supported by the data?

In pea seeds an increase in 'temperature' results in an increase in oxygen consumption.

A student studied the effects of light intensity on oxygen production in green algae. The algae were suspended in water inside a sealed glass jar, and the jar was placed into a constant-temperature, lightproof box containing a light source. A probe was inserted into the jar to record the concentration of oxygen. The probe was connected to a recording device. The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device.

J to K (the line is flat)

The fact that each line on the graph rises from left to right means that...

Larger fish consume 'more oxygen' than smaller fish at all four temperatures

(basketball bracket table) Evolution of a new trait typically takes many generations. Yet a dramatic shift in the extent of armor plating in the Lake Washington stickleback population occurred in the 50 years following the cleanup of the lake. Which of the following best describes the mechanism of the rapid evolution of the armor phenotype in the Lake Washington sticklebacks?

New selective pressures 'favored individuals with the plated phenotype', causing the plated allele frequency in the population to quickly increase.

To refine their model of deep-sea biological communities, the researchers investigated areas of the seafloor that are distant from any active hydrothermal vents. Which of the following is the best interpretation of the observation that some octopus species are only found near active hydrothermal vents?

Octopuses depend 'indirectly' on inorganic compounds in the seawater surrounding hydrothermal vents.

(Large hump and smaller one on a graph) In a species of cactus, the number of spines on a plant is genetically determined. The graph above shows frequency distributions for populations of the cactus species growing in the presence or absence of two herbivores: peccaries (a New World pig) and wasp larvae. Which of the following best accounts for the different frequency distributions in the graph?

Peccaries eat cacti with a 'smaller number of spines', and wasp larvae eat cacti with a greater number of spines.

A student studied the effects of light intensity on oxygen production in green algae. The algae were suspended in water inside a sealed glass jar, and the jar was placed into a constant-temperature, lightproof box containing a light source. A probe was inserted into the jar to record the concentration of oxygen. The probe was connected to a recording device. The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph below shows the results from the recording device. Based on the data shown, changes in the light intensity resulted in changes in the rate of which of the following processes?

Photosynthesis (algae used the o2 to make co2)

Which of the following processes best explains why fewer light-tan beetles than dark-brown beetles were recaptured in habitat 4?

Predation (the predators were more easily able to kill off the light-tan beetles because they didn't blend in with their environment as well)

Based on the data, which of the following is the best explanation for the changes in the elk population size between 2000 and 2005 ?

Predation by 'wolves' was higher than before 1995.

On the basis of the food web, which of the following members of a deep-sea biological community is most likely to also have a symbiotic relationship with chemo-synthetic organisms?

Shrimp (feeds 3 different things)

The food web above represents feeding relationships in a biological community near a deep-sea hydrothermal vent. Hydrothermal vents are geysers on the seafloor that gush super-heated, mineral-rich water. The seawater surrounding hydrothermal vents typically contains carbon dioxide (CO2), molecular hydrogen (H2), hydrogen sulfide (H2S), and methane (CH4). Sunlight, however, fails to reach the seafloor where deep-sea hydrothermal vents are located. As part of an investigation, researchers collected living specimens from an area near a deep-sea hydrothermal vent. Mussels in the collection were found to be dependent on molecular hydrogen in seawater. Also, the researchers discovered multiple species of bacteria living in the gills of the mussels. Mussels use gills for filter-feeding and gas exchange with the surrounding seawater. On the basis of their experimental results, the researchers hypothesized that some bacteria living in the gills of the mussels are capable of chemo-synthesis. Based on an analysis of the food web, an observation that deep-sea bacteria consume molecular hydrogen (H2) is most relevant to resolving which of the following apparent contradictions?

Some deep-sea organisms appear to be primary consumers, but 'no plants live near the hydrothermal vents'.

The food web above represents feeding relationships in a biological community near a deep-sea hydrothermal vent. Hydrothermal vents are geysers on the seafloor that gush super-heated, mineral-rich water. The seawater surrounding hydrothermal vents typically contains carbon dioxide (CO2), molecular hydrogen (H2), hydrogen sulfide (H2S), and methane (CH4). Sunlight, however, fails to reach the seafloor where deep-sea hydrothermal vents are located. Which of the following best explains how biological communities near deep-sea hydrothermal vents can exist in a habitat lacking sunlight?

Some organisms rely on energy captured from 'inorganic' compounds to drive basic biological processes.

Diapause experiment: Based on the experimental results, which of the following is the best evolutionary explanation for the occurrence of ARD in C. elegans ?

The 'ability' to enter ARD provides a strong selective advantage because reproduction can occur despite periods of food scarcity.

Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, paramecia were placed in salt solutions of increasing osmolarity. The rate at which the contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?

The 'contraction rate increases' as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases.

As depicted in the diagram, honeybees communicate the location of flower patches to members of their hives with waggle dances that give information about the direction and distance to the flowers. Which of the following statements about how honeybees communicate the position of flower patches is most consistent with the model?

The 'farther the target flowers' from the hive, the longer the waggle phase.

Students investigated the effect of light on the carbon cycle in aquatic ecosystems by performing the controlled experiment summarized below. The students placed equal amounts of water (pH 7.0) from a large aquarium in glass beakers. The students transferred aquatic plants from the aquarium to several of the beakers, and then they placed equal numbers of the beakers in the light or the dark (Figure 1: groups I and II). Similarly, the students transferred goldfish from the same aquarium to other beakers, and then they placed equal numbers of those beakers in the light or dark (Figure 1: groups III and IV). Finally, the students placed an equal number of beakers containing water only in the light or dark (Figure 1: groups V and VI). After exposing the samples to light or dark for one hour, the students recorded the pH of the water in each beaker. Carbon dioxide dissolved in water will lower the pH of an aqueous solution. In the experiment, the students used changes in pH to monitor changes in the amount of carbon dioxide in the water. For each treatment group, the students calculated the mean pH and standard error, as documented in the table below. Which of the following observations provides the best evidence that photosynthesis occurred in treatment group I?

The 'mean pH' of the sample increased after one hour

A student used a microscope to observe a wet-mount slide of red onion epidermal cells that were suspended in a 1% NaCl solution. The student then added a 15% NaCl solution to the slide and observed the changes that occurred. The student's observations are represented in Figure 1. Which of the following most directly explains the changes in the cells?

The 'movement of water' from the central vacuoles of the cells into the solution

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. From the initial conditions and results described, which of the following is a logical conclusion?

The 'pores' of the bag are larger than the glucose molecules but smaller than the starch molecules.

(ball and graph) In the early 1970s, researchers hypothesized that carbon was the limiting nutrient in many aquatic ecosystems. To test this hypothesis, the researchers divided a small lake in two roughly equal halves with an impermeable curtain that was fastened and sealed to the bedrock of the lake. Beginning in 1971 the researchers treated one side of the lake with sucrose and the other side with both sucrose and phosphate. From 1971 to 1983 the researchers monitored the phytoplankton biomass in both parts of the lake. The results are shown in Figure 1. Which of the following was most likely a direct consequence of the addition of phosphate to the lake?

The amount of 'energy available to consumers' in the lake increased

The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. After 3 hours, glucose can be detected in the water outside the dialysis-tubing bag, but starch cannot. Which of the following best describes the condition expected after 24 hours?

The bag will contain 'more water' than it did in the original condition.

The following is a food web for a meadow habitat that occupies 25.6km2. The primary producers' biomass is uniformly distributed throughout the habitat and totals 1,500 kg/km2 Developers have approved a project that will permanently reduce the primary producers' biomass by 50 percent and remove all rabbits and deer. Which of the following is the most likely result at the completion of the project?

The biomass of coyotes will be 'dramatically reduced'.

Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change?

The coloration in the population 'shifted toward more darker-colored beetles', as in diagram IV (dashed then line). The lighter colored beetles were found more easily by the predators than were the darker-colored beetles. 'Dash then line'

Which of the following best describes why the disks rose to the surface faster in the more concentrated hydrogen peroxide solutions?

The higher 'substrate' concentrations in the more concentrated solutions speeded the reaction.

What can be deduced from graph I?

The maximal flow of water through the stem 'lags' behind the maximal rate of transpiration.

Pacific salmon and black bears have often been cited as examples of keystone species. Pacific salmon spawn in freshwater streams but spend most of their lives at sea. When mature salmon return to the freshwater streams to spawn, they are preyed upon by bears and other predators. When salmon migrate from their marine habitat to the freshwater streams, they bring nitrogen and other marine-derived nutrients that subsequently remain in the areas surrounding the streams—a process called nitrogen influx. In an investigation, the relationship between black bears, salmon, and influx of marine nitrogen into the area around a southwestern Alaskan stream was studied. The investigators established several test plots of the same size along the stream with the following species composition: no salmon or black bears (N), bears but not salmon (B), salmon but not bears (S), and a plot where salmon and bears interact (SB). Nitrogen influx in the different sampling areas was measured as a means of assessing the impact of the different species on the health of the ecosystem. The data are plotted in Figure 1. Which of the following statements is best supported by the data?

The presence of black bears and salmon correlates with a significant increase in nitrogen influx. (addresses everything)

Which of the following statements about the two populations is best supported by the information presented in the graph?

The wolves were 'predators' of the moose, which were otherwise reproductively successful.

To study the actions of the enzyme catalase on hydrogen peroxide, students performed the following experiment. Catalase was extracted from potatoes by blending raw potatoes in a blender with cold distilled water. The filtrate was stored on ice. The following hydrogen peroxide solutions were made: 1 percent, 5 percent, 10 percent, and 15 percent. Filter paper disks were soaked in the catalase filtrate and dropped into beakers containing the various solutions. The activity of the enzyme was measured by the amount of time it took for the disks to float to the surface of the solution on the bubbles produced by the reaction. The following data were obtained. Which of the following best describes why ice was used during this experiment?

To 'retard' the breakdown of the catalase

Assume there are 50,000 joules (J) of energy available in trophic level II in the figure. According to the conventional model of energy flow in ecosystems, which of the following statements correctly describes the flow of energy in the system?

Trophic level 'IV' has approximately 500 J of available energy.

(Food web above) Researchers are investigating the evolutionary relationships among organisms found near deep-sea hydrothermal vents and similar organisms found closer to the ocean surface. Which of the following scientific questions is most relevant to the investigation?

What are the nucleotide sequences of ribosomal 'RNA' genes that are found in the genomes of the different species?

Which of the following scientific questions is most relevant to the model represented in the figure above?

Which molecular substance is 'actively transported' across the plasma membrane?

A tissue culture of vertebrate muscle was provided with a constant excess supply of glucose under anaerobic conditions starting at time zero and the amounts of pyruvic acid and ATP produced were measured. The solid line in the graph above represents the pyruvic acid produced in moles per liter per minute. ATP levels were also found to be highest at points A and C, lowest at B and D. A second culture was set up under the same conditions, except that substance X was added, and the results are indicated by the dotted line. It is most reasonable to hypothesize that, in the breakdown of glucose, substance X is...

an inhibitor

The graph below shows changes in a population of wild sheep that were introduced to the island of Tasmania in the early 1800's. The type of population growth represented by that portion of the graph line enclosed in the bracket is most accurately termed...

exponetial

(basketball bracket table) Which of the following best explains the differences in the armor of the Lake Washington stickleback population summarized in Figure 1 ?

fish exhibiting the low plated phenotype were 'selected against' in the lake Washington stickleback population over the last 50 years

A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below. The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

increasing line: water line strait across: starch

The rate of transpiration, the flow of water through the stem, and leaf water potential are measured in a tree during a 24-hour period under normal environmental conditions. The results from these measurements are shown in the graphs below. All of the following changes would be likely to decrease the rate of transpiration at 8 A.M. EXCEPT

increasing the water potential of the 'soil'

A scientist determined the rate of an enzyme-catalyzed reaction by measuring the amount of product formed over time. The following curve was generated from the data collected. The rate of the reaction could also be determined by...

measuring the change in the amount of substrate

(percent change in the mass of pieces of plant tissue placed in solutions of different sucrose molarities.) Water enters and leaves the plant cells primarily by

osmosis

In the first step of an experiment, rat liver cells were exposed for 5 minutes to amino acids labeled with a radioactive isotope. The cells were then washed to stop any further incorporation of radioactive amino acids. The cells were sampled periodically thereafter, and the radioactivity of a certain protein (protein X) was measured in various cell components, as shown below. In graphing the data from this experiment, the sampling time would be shown on the x-axis because...

sampling time is the 'independent variable'

In the Arctic Ocean, the predominant primary producers are phytoplankton. Phytoplankton are consumed by zooplankton, which in turn are eaten by codfish. In years when there is more open water (less ice coverage), there are more zooplankton and fish than in years with less open water (more ice coverage). Based on the graph above, the difference is most likely because...

the 'ice blocks the light', so in years with more ice coverage, there is less photosynthesis by the phytoplankton

Diapause experiment: Which of the following conclusions is most consistent with the data shown in Figure 2?

the number of days an animal spends in ARD 'does not' significantly affect its time of survival after reintroduction of food

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because...

yellow-leaved seedlings were unable to 'convert light energy to chemical energy'