In contrast to prokaryotes, eukaryotes have membrane-bound organelles that allow their cell(s) to compartmentalize different cellular functions. These different functions, which occur only within membrane-bound organelles, include the synthesis and breakdown of different macronutrients fatty acids and proteins. Other processes like glycolysis (the breakdown of carbohydrates) and nucleic acid breakdown can occur outside membrane-bound organelles. Synthesizing different macronutrients is known as anabolism, while breaking down these same nutrients into Adenosine Tri-Phosphate (ATP) is called catabolism.

Macronutrient anabolism and catabolism are balanced by the supply of available energy. In the fed state, where a high concentration of sugar is dissolved in your blood stream, the body prefers to use glucose as its energy source through a pathway called glycolysis. When the supply of glucose in the blood runs low, however, the liver is able to synthesize new glucose in a process called gluconeogenesis. In gluconeogenesis, oxaloacetate, the product of another cycle called the Krebs Cycle is used as the starting point to run glycolysis in reverse, making a new glucose molecule. When these precursors needed to initiate gluconeogenesis run low, the body then turns to the catabolism of proteins and free fatty acids.

Proteins, composed of strands of amino acids, are broken down to generate ATP and oxaloacetate. People who have not eaten for an extended period of time experience low muscle mass due to catabolism of skeletal muscle proteins. Only after available protein is broken down does beta oxidation of free fatty acids begin.

Beta oxidation uses free fatty acids floating in the blood to generate the greatest amount of ATP per gram of starting material of any of the macronutrients. Carried out by enzymes called lipases, beta oxidation splits a long fatty acid chain into two carbon units called acetyl-CoA. Per acetyl-CoA that enters the Krebs Cycle, three NADH and one FADH₂ are produced that enter the Electron Transport Chain to drive ATP production. 1 NADH molecule can generate 3 ATP, while 1 FADH₂ molecule can generate 2 ATP. Lipases continue to cleave acetyl-COA units off the parent lipid chain until it either produces its last acetyl-CoA molecule or ends in a 3 carbon molecule called propyl-CoA. Propyl-CoA can further undergo catabolism to yield one final acetyl-CoA molecule.

A 6-carbon free fatty acid could be expected to produce how many NADH? 

A researcher studies the olfactory (scent-related) senses of the giant forest ant, Camponotus gigas. The researcher places 120 ants in a three-chambered cell. The cell has an end section with a cotton ball soaked in a saline solution and another end with a cotton ball soaked in a glucose solution. The ants are placed in the middle and timed for 15 minutes. Their initial and final positions in the cell are recorded (see Table 1). The researcher's null hypothesis states that the distribution of ants across the three chambers will be equal to one another. In other words, the glucose solution will have no effect and there will be no significant difference in the distribution of the insects.

                                 Table 1

The researcher decides to perform a statistical test known as a Chi-squared test of independence to interpret the experiment's results. The test is performed by calculating a Chi-squared statistic by utilizing observed and expected values for distribution (see Table 2). If the sum of the Chi-squared test statistic is higher than the critical value, then the null hypothesis can be rejected. This indicates that the distribution of insects is not random and the variable in question has a pronounced effect on the subjects. A critical value is calculated by determining the degrees of freedom, which in this experiment is equal to the number of categories in the study minus one, and then locating the proper number on a table (see Table 3). There are three possible categories in this experiment: the glucose end, the control end (with the saline-solution soaked cotton ball), and middle portion of the chamber.

                                 Table 2

                                 Table 3

If the null hypothesis for this study were supported, what could be said about the ants' distribution?

A researcher studies the olfactory (scent-related) senses of the giant forest ant, Camponotus gigas. The researcher places 120 ants in a three-chambered cell. The cell has an end section with a cotton ball soaked in a saline solution and another end with a cotton ball soaked in a glucose solution. The ants are placed in the middle and timed for 15 minutes. Their initial and final positions in the cell are recorded (see Table 1). The researcher's null hypothesis states that the distribution of ants across the three chambers will be equal to one another. In other words, the glucose solution will have no effect and there will be no significant difference in the distribution of the insects.

                                 Table 1

The researcher decides to perform a statistical test known as a Chi-squared test of independence to interpret the experiment's results. The test is performed by calculating a Chi-squared statistic by utilizing observed and expected values for distribution (see Table 2). If the sum of the Chi-squared test statistic is higher than the critical value, then the null hypothesis can be rejected. This indicates that the distribution of insects is not random and the variable in question has a pronounced effect on the subjects. A critical value is calculated by determining the degrees of freedom, which in this experiment is equal to the number of categories in the study minus one, and then locating the proper number on a table (see Table 3). There are three possible categories in this experiment: the glucose end, the control end (with the saline-solution soaked cotton ball), and middle portion of the chamber.

                                 Table 2

                                 Table 3

What should be done with the null hypothesis based on the results of this experiment?

A researcher studies the olfactory (scent-related) senses of the giant forest ant, Camponotus gigas. The researcher places 120 ants in a three-chambered cell. The cell has an end section with a cotton ball soaked in a saline solution and another end with a cotton ball soaked in a glucose solution. The ants are placed in the middle and timed for 15 minutes. Their initial and final positions in the cell are recorded (see Table 1). The researcher's null hypothesis states that the distribution of ants across the three chambers will be equal to one another. In other words, the glucose solution will have no effect and there will be no significant difference in the distribution of the insects.

                                 Table 1

The researcher decides to perform a statistical test known as a Chi-squared test of independence to interpret the experiment's results. The test is performed by calculating a Chi-squared statistic by utilizing observed and expected values for distribution (see Table 2). If the sum of the Chi-squared test statistic is higher than the critical value, then the null hypothesis can be rejected. This indicates that the distribution of insects is not random and the variable in question has a pronounced effect on the subjects. A critical value is calculated by determining the degrees of freedom, which in this experiment is equal to the number of categories in the study minus one, and then locating the proper number on a table (see Table 3). There are three possible categories in this experiment: the glucose end, the control end (with the saline-solution soaked cotton ball), and middle portion of the chamber.

                                 Table 2

                                 Table 3

What is the critical value of this experiment?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

According to Figure 3, what happens to the tick population from the months of January to December?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

According to Figure 2, what happened to the wolf population from the months of January to December?

Population dynamics can be described as the intricate relationships and mechanics of a given ecological community. Ecology attempts to study the interactions between organisms and between organisms and their environments. Populations of organisms may be impacted by abiotic (nonliving) and biotic (living) factors within their environment. These factors may or may not depend on population densities. Density-independent factors such as weather patterns can affect a population of any size. Conversely, density-dependent factors such as predation have differing effects on populations based on the number of individuals present.

Utilizing this information, consider the following scenario.

An island contains several wolf and moose populations. Ecologists studied these populations through several generations and made observations on each population's size and relative fitness. In the initial years of the investigation, wolf populations declined due to a disease known as canine parvovirus. Due to decreased predatory pressures, the moose population rose to higher numbers than seen in previous years. Several years later, environmental temperatures rose dramatically in the area. Increased environmental temperatures resulted in reduced fitness and health within the island's moose population. Individuals were exposed to rising tick populations that caused blood loss and spread disease. Likewise, increased temperatures induced weight loss in the moose population; moose cannot perspire and must cool themselves by resting in the shade, and this detracts from their ability to forage and gain weight and insulation for the colder winter months. The weakened moose population became susceptible to increased predation by wolves, which resulted in an increase in the wolf population. (See Figures 1, 2, and 3.)

According to Figure 1, what happened to the moose population from the months of January to December?

Background

Plants take in nutrients through extensive root systems, as well as from the air through leaves or needles. Many coniferous evergreens are able to survive for a few weeks after being cut down due to their water-saving needles.

A group of students investigated the properties of several types of coniferous evergreens once they had been extracted from their environments. The students compared the length of time before needles (modified leaves) began to fall from the trees. They placed recently severed, seven-foot trees in spaces with controlled temperature and environmental conditions, and then monitored them closely over several days.

Experiment 1

The students placed representative samples of several varieties of coniferous evergreen in a controlled environment: 20°C, 1 atm, and 35% humidity. They recorded the number of days before needles began to fall for each species.

Results: Experiment 1

Experiment 2

The students used the Douglas Fir to conduct a second experiment. They placed new trees in enclosed spaces, varied the temperature and humidity of the trees' environments, and recorded the number of days before needles began to fall.

Results: Experiment 2 

Based on the results of Method 1, which species of tree is able to conserve the most water after the root system has been severed?

Background

Plants take in nutrients through extensive root systems, as well as from the air through leaves or needles. Many coniferous evergreens are able to survive for a few weeks after being cut down due to their water-saving needles.

A group of students investigated the properties of several types of coniferous evergreens once they had been extracted from their environments. The students compared the length of time before needles (modified leaves) began to fall from the trees. They placed recently severed, seven-foot trees in spaces with controlled temperature and environmental conditions, and then monitored them closely over several days.

Experiment 1

The students placed representative samples of several varieties of coniferous evergreen in a controlled environment: 20°C, 1 atm, and 35% humidity. They recorded the number of days before needles began to fall for each species.

Results: Experiment 1

Experiment 2

The students used the Douglas Fir to conduct a second experiment. They placed new trees in enclosed spaces, varied the temperature and humidity of the trees' environments, and recorded the number of days before needles began to fall.

Results: Experiment 2 

 Based on the results of Method 2, what effect does humidity have on the water retention of Douglas Firs?

Background

Plants take in nutrients through extensive root systems, as well as from the air through leaves or needles. Many coniferous evergreens are able to survive for a few weeks after being cut down due to their water-saving needles.

A group of students investigated the properties of several types of coniferous evergreens once they had been extracted from their environments. The students compared the length of time before needles (modified leaves) began to fall from the trees. They placed recently severed, seven-foot trees in spaces with controlled temperature and environmental conditions, and then monitored them closely over several days.

Experiment 1

The students placed representative samples of several varieties of coniferous evergreen in a controlled environment: 20°C, 1 atm, and 35% humidity. They recorded the number of days before needles began to fall for each species.

Results: Experiment 1

Experiment 2

The students used the Douglas Fir to conduct a second experiment. They placed new trees in enclosed spaces, varied the temperature and humidity of the trees' environments, and recorded the number of days before needles began to fall.

Results: Experiment 2 

 Based on the results of Experiment 2, what value would you expect for the number of days until needle drop at 20°C and 75% humidity?