28.1: The Challenges of Peacetime
The decade and a half immediately following the end of World War II was one in which middle- and working-class Americans hoped for a better life than the one they lived before the war. These hopes were tainted by fears of economic hardship, as many who experienced the Great Depression feared a return to economic decline. Others clamored for the opportunity to spend the savings they had accumulated through long hours on the job during the war when consumer goods were rarely available.
African Americans who had served in the armed forces and worked in the defense industry did not wish to return to “normal.” Instead, they wanted the same rights and opportunities that other Americans had. Still other citizens were less concerned with the economy or civil rights; instead, they looked with suspicion at the Soviet presence in Eastern Europe. What would happen now that the United States and the Soviet Union were no longer allies, and the other nations that had long helped maintain a balance of power were left seriously damaged by the war? Harry Truman, president for less than a year when the war ended, was charged with addressing all of these concerns and giving the American people a “fair deal.”
DEMOBILIZATION AND THE RETURN TO CIVILIAN LIFE
The most immediate task to be completed after World War II was demobilizing the military and reintegrating the veterans into civilian life. In response to popular pressure and concerns over the budget, the United States sought to demobilize its armed forces as quickly as possible. Many servicemen, labeled the “Ohio boys” (Over the Hill in October), threatened to vote Republican if they were not home by Christmas 1946. Understandably, this placed a great deal of pressure on the still-inexperienced president to shrink the size of the U.S. military.
Not everyone wanted the government to reduce America’s military might, however. Secretary of the Navy James Forrestal and Secretary of War Robert P. Patterson warned Truman in October 1945 that an overly rapid demobilization jeopardized the nation’s strategic position in the world. While Truman agreed with their assessment, he felt powerless to put a halt to demobilization. In response to mounting political pressure, the government reduced the size of the U.S. military from a high of 12 million in June 1945 to 1.5 million in June 1947—still more troops than the nation ever had in arms during peacetime. Soldiers and sailors were not the only ones dismissed from service. As the war drew to a close, millions of women working the jobs of men who had gone off to fight were dismissed by their employers, often because the demand for war materiel had declined and because government propaganda encouraged them to go home to make way for the returning troops. While most women workers surveyed at the end of the war wished to keep their jobs (75–90 percent, depending on the study), many did in fact leave them. Nevertheless, throughout the late 1940s and the 1950s, women continued to make up approximately one-third of the U.S. labor force.
Readjustment to postwar life was difficult for the returning troops. The U.S. Army estimated that as many of 20 percent of its casualties were psychological. Although many eagerly awaited their return to civilian status, others feared that they would not be able to resume a humdrum existence after the experience of fighting on the front lines. Veterans also worried that they wouldn’t find work and that civilian defense workers were better positioned to take advantage of the new jobs opening up in the peacetime economy. Some felt that their wives and children would not welcome their presence, and some children did indeed resent the return of fathers who threatened to disrupt the mother-child household. Those on the home front worried as well. Doctors warned fiancées, wives, and mothers that soldiers might return with psychological problems that would make them difficult to live with.
The GI Bill of Rights
Well before the end of the war, Congress had passed one of the most significant and far-reaching pieces of legislation to ease veterans’ transition into civilian life: the Servicemen’s Readjustment Act, also known as the GI Bill (Figure 28.1.2). Every honorably discharged veteran who had seen active duty, but not necessarily combat, was eligible to receive a year’s worth of unemployment compensation. This provision not only calmed veterans’ fears regarding their ability to support themselves, but it also prevented large numbers of men—as well as some women—from suddenly entering a job market that did not have enough positions for them. Another way that the GI Bill averted a glut in the labor market was by giving returning veterans the opportunity to pursue an education; it paid for tuition at a college or vocational school, and gave them a stipend to live on while they completed their studies.
The result was a dramatic increase in the number of students—especially male ones—enrolled in American colleges and universities. In 1940, only 5.5 percent of American men had a college degree. By 1950, that percentage had increased to 7.3 percent, as more than two million servicemen took advantage of the benefits offered by the GI Bill to complete college. The numbers continued to grow throughout the 1950s. Upon graduation, these men were prepared for skilled blue-collar or white-collar jobs that paved the way for many to enter the middle class. The creation of a well-educated, skilled labor force helped the U.S. economy as well. Other benefits offered by the GI Bill included low-interest loans to purchase homes or start small businesses.
However, not all veterans were able to take advantage of the GI Bill. African American veterans could use their educational benefits only to attend schools that accepted black students. The approximately nine thousand servicemen and women who were dishonorably discharged because they were gay or lesbian were ineligible for GI Bill benefits. Benefits for some Mexican American veterans, mainly in Texas, were also denied or delayed.
The Return of the Japanese
While most veterans received assistance to help in their adjustment to postwar life, others returned home to an uncertain future without the promise of government aid to help them resume their prewar lives. Japanese Americans from the West Coast who had been interned during the war also confronted the task of rebuilding their lives. In December 1944, Franklin Roosevelt had declared an end to the forced relocation of Japanese Americans, and as of January 1945, they were free to return to their homes. In many areas, however, neighbors clung to their prejudices and denounced those of Japanese descent as disloyal and dangerous. These feelings had been worsened by wartime propaganda, which often featured horrific accounts of Japanese mistreatment of prisoners, and by the statements of military officers to the effect that the Japanese were inherently savage. Facing such animosity, many Japanese American families chose to move elsewhere. Those who did return often found that in their absence, “friends” and neighbors had sold possessions that had been left with them for safekeeping. Many homes had been vandalized and farms destroyed. When Japanese Americans reopened their businesses, former customers sometimes boycotted them.
For more on the experiences of Japanese Americans after internment, read about their return to communities in Oregon after World War II.
THE FAIR DEAL
Early in his presidency, Truman sought to build on the promises of Roosevelt’s New Deal. Besides demobilizing the armed forces and preparing for the homecoming of servicemen and women, he also had to guide the nation through the process of returning to a peacetime economy. To this end, he proposed an ambitious program of social legislation that included establishing a federal minimum wage, expanding Social Security and public housing, and prohibiting child labor. Wartime price controls were retained for some items but removed from others, like meat. In his 1949 inaugural address, Truman referred to his programs as the “Fair Deal,” a nod to his predecessor’s New Deal. He wanted the Fair Deal to include Americans of color and became the first president to address the National Association for the Advancement of Colored People (NAACP). He also took decisive steps towards extending civil rights to African Americans by establishing, by executive order in December 1946, a Presidential Committee on Civil Rights to investigate racial discrimination in the United States. Truman also desegregated the armed forces, again by executive order, in July 1948, overriding many objections that the military was no place for social experimentation.
Congress, however, which was dominated by Republicans and southern conservative Democrats, refused to pass more “radical” pieces of legislation, such as a bill providing for national healthcare. The American Medical Association spent some $1.5 million to defeat Truman’s healthcare proposal, which it sought to discredit as socialized medicine in order to appeal to Americans’ fear of Communism. The same Congress also refused to make lynching a federal crime or outlaw the poll tax that reduced the access of poor Americans to the ballot box. Congress also rejected a bill that would have made Roosevelt’s Fair Employment Practices Committee, which prohibited racial discrimination by companies doing business with the federal government, permanent. At the same time, they passed many conservative pieces of legislation. For example, the Taft-Hartley Act, which limited the power of unions, became law despite Truman’s veto.
Section Summary
At the end of World War II, U.S. servicemen and women returned to civilian life, and all hoped the prosperity of the war years would continue. The GI Bill eased many veterans’ return by providing them with unemployment compensation, low-interest loans, and money to further their education; however, African American, Mexican American, and gay veterans were often unable to take advantage of these benefits fully or at all. Meanwhile, Japanese Americans faced an uphill struggle in their attempts to return to normalcy, and many women who had made significant professional gains in wartime found themselves dismissed from their positions. President Harry Truman attempted to extend Roosevelt’s New Deal with his own Fair Deal, which had the goal of improving wages, housing, and healthcare, and protecting the rights of African Americans. Confronted by a Congress dominated by Republicans and southern Democrats, however, Truman was able to achieve only some of his goals.
Review Questions
Truman referred to his program of economic and social reform as the ________.
New Deal
Square Deal
Fair Deal
Straight Deal
C
Which of the following pieces of Truman’s domestic agenda was rejected by Congress?
the Taft-Hartley Act
national healthcare
the creation of a civil rights commission
funding for schools
B
How did the GI Bill help veterans return to civilian life? What were its limitations?
The GI Bill provided returning veterans with a year of unemployment compensation, so they did not have to worry about finding jobs immediately. It allowed them to receive low-interest loans to buy homes or start businesses, and it paid for tuition for those who wished to attend college or vocational school. However, African American veterans could use their educational benefits only to attend schools that accepted black students, and some Mexican American veterans had difficulty gaining access to their benefits.
Glossary
- Fair Deal
- President Harry Truman’s program of economic and social reform
- GI Bill
- a program that gave substantial benefits to those who served in World War II


3.7: Undercut
This section requires you to be able to solve “large” systems of equations. You will be using the matrix techniques from Section 3.6 . You are encouraged to use technology such as a graphing calculator or Sage.
As we saw in Section 3.5 , an important part of game theory is the process of translating a game to a form that we can analyze.
Each player chooses a number \(1\)-\(5\). If the two numbers don't differ by \(1\), then each player adds their own number to their score. If the two numbers differ by \(1\), then the player with the lower number adds both numbers to his or her score; the player with the higher number gets nothing. (From Douglas Hofstadter's Metamagical Themas .)
For example, suppose in round one Player 1 chooses \(4\); Player 2 chooses \(4\). Each player keeps their own number. The score is now \(4\)-\(4\). In the next round, Player 1 chooses \(2\), Player 2 chooses \(5\). The score would now be \(6\)-9. In the third round Player 1 chooses \(4\), Player 2 chooses \(5\). Now Player 1 gets both numbers, making the score \(15\)-\(9\).
Choose an opponent and play Undercut several times. Keep track of the outcomes.
After playing Undercut with an opponent, try to devise a good strategy.
Just from playing Undercut several times, can you suggest a strategy for Player 1? What about for Player 2? For example, what number(s) should you play most often/least often, or does it matter? Are there numbers you should never play? Does this game seem fair, or does one of the players seem to have an advantage? Explain your answers.
As we've seen before, a payoff matrix can help with analyzing a game.
Create a payoff matrix for Undercut. Note that your payoffs should have a score for each player.
Is this a zero-sum game? Explain.
Does there appear to be a pure strategy equilibrium for this game? Explain.
Let's assume we are going to play Undercut repeatedly. By the time you and your opponent are done playing, what should it mean to win the game?
How might we determine a “winner” for Undercut after playing several times?
Most likely, you said that someone will win the game if they have the most points. In fact, we probably don't care if the final score is \(10\)-\(12\) or \(110\)-\(112\). In either case, Player 2 wins. Since we will play this game several times, we do care about the point difference. For example, a score of \(5\)-\(1\) would be better for Player 1 than \(5\)-\(3\). So let's think about the game in terms of the point difference between the players in a given game. This is called the net gain . For example, with score of \(5\)-\(1\), Player 1 would have a net gain of \(4\).
Calculate the net gain for Player 1 for each of the three rounds in Example \(3.7.1\) in the beginning of this section.
Create a new payoff matrix for Undercut which uses the players' net gain for the payoff vectors.
Is this now a zero-sum game? Explain.
The method of using net gain to describe the payoffs to each player should be familiar from some of the really early examples where we turned constant-sum payoff vectors into zero-sum vectors. But note that the original form of this game wasn't even a constant-sum game! What we are really doing here is thinking about our payoffs not as points, but a win or loss relative to our opponent. Now that we have reframed Undercut as a zero-sum game, we can apply our methods for solving the game that we have seen in this chapter.
Is there a pure strategy equilibrium for this game? Explain.
- Answer
-
Rather than looking at each option, you could compare the values for the pure maximin/minimax strategies.
This game has one additional property that will help simplify our analysis. This game is symmetric , meaning the game looks the same to Players 1 and 2.
Give an example of another game which is symmetric. Give an example of a game which is not symmetric.
What is the expected payoff for a symmetric game? Explain your answer.
- Answer
-
You might think about whether it is possible for a player to have an advantage in a symmetric game.
Hopefully, you determined that there is not a pure strategy equilibrium for Undercut. Thus, we would like to find a mixed strategy equilibrium. Since this is a \(5 \times 5\) game, we cannot use our graphical solution. We will need to rely on our expected value solution. We want to decide with what probability we should play each number. Let \(a, b, c, d, e\) be the probabilities with which Player 2 plays 1-5, respectively. For example, if Player 1 plays a pure strategy of \(2\), then the expected value for Player 1, \(E_1(2)\text{,}\) is \(-3a+0b+5c-2d-3e\text{.}\)
Write down the five equations that give Player 1's expected value for each of Player 1's pure strategies.
In Exercise \(3.7.12\), you should have determined that since this is a symmetric game, the expected value for each Player should be \(0\). Modify your equations to include this piece of information. It is important to recognize that this step greatly simplifies our work for the expected value method since we don't need to set the expected values equal to each other. HOWEVER, we can ONLY do this since we know the game is symmetric!
If we use that the game is symmetric, and hence the expected value of the game for each player must be \(0\) since neither player can have an advantage over the other, we do not need to set the equations equal to each other. We could not use this method earlier since we had no way of knowing the expected value of a general game.
We now have five equations and five unknowns. There is a sixth equation: we know that the probabilities must add up to \(1\). We can now solve for the equilibrium strategy!
Use matrices to solve the resulting system of six equations. Give the mixed strategy equilibrium for Player 2. What is the mixed strategy for Player 1?
- Answer
-
Should it be different than the strategy for Player 2?
Based on your answer to Exercise \(3.7.15\), which number(s) should you play the most often? Which should you play the least? Are there any numbers that you should never play? Compare the mathematical solution to your conjectured solution for Exercise \(3.7.2\). Is there an advantage to knowing the mathematical solution?
You have now solved a rather complex two-person game. Try playing it with your friends and family. It may be difficult (or even impossible) to play randomly with the exact probabilities. It is also unlikely that your opponent will also be playing the equilibrium strategy, but can you use the solution to assure an advantage, or at least assure that your opponent doesn't have an advantage? Can you see the difference between an exact theoretical solution to a game, and a practical strategy for playing the game? In the next chapter, we will see even more differences between theoretical and practical solutions to a game.


11.6: Sublimation and Fusion
Sublimation
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation . At room temperature and standard pressure, a piece of dry ice (solid CO 2 ) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublime at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes and a vivid purple vapor forms (Figure \(\PageIndex{6}\)). The reverse of sublimation is called deposition , a process in which gaseous substances condense directly into the solid state, bypassing the liquid state. The formation of frost is an example of deposition.
Figure \(\PageIndex{6}\): Sublimation of solid iodine in the bottom of the tube produces a purple gas that subsequently deposits as solid iodine on the colder part of the tube above. (credit: modification of work by Mark Ott)
Like vaporization, the process of sublimation requires an input of energy to overcome intermolecular attractions. The enthalpy of sublimation, ΔHsub, is the energy required to convert one mole of a substance from the solid to the gaseous state. For example, the sublimation of carbon dioxide is represented by:
\[\ce{CO2}(s)⟶\ce{CO2}(g)\hspace{20px}ΔH_\ce{sub}=\mathrm{26.1\: kJ/mol}\]
Likewise, the enthalpy change for the reverse process of deposition is equal in magnitude but opposite in sign to that for sublimation:
\[\ce{CO2}(g)⟶\ce{CO2}(s)\hspace{20px}ΔH_\ce{dep}=−ΔH_\ce{sub}=\mathrm{−26.1\:kJ/mol}\]
Consider the extent to which intermolecular attractions must be overcome to achieve a given phase transition. Converting a solid into a liquid requires that these attractions be only partially overcome; transition to the gaseous state requires that they be completely overcome. As a result, the enthalpy of fusion for a substance is less than its enthalpy of vaporization. This same logic can be used to derive an approximate relation between the enthalpies of all phase changes for a given substance. Though not an entirely accurate description, sublimation may be conveniently modeled as a sequential two-step process of melting followed by vaporization in order to apply Hess’s Law .
\[\mathrm{solid⟶liquid}\hspace{20px}ΔH_\ce{fus}\\\underline{\mathrm{liquid⟶gas}\hspace{20px}ΔH_\ce{vap}}\\\mathrm{solid⟶gas}\hspace{20px}ΔH_\ce{sub}=ΔH_\ce{fus}+ΔH_\ce{vap}\]
Viewed in this manner, the enthalpy of sublimation for a substance may be estimated as the sum of its enthalpies of fusion and vaporization, as illustrated in Figure \(\PageIndex{7}\). For example:
Fusion
When we heat a crystalline solid, we increase the average energy of its atoms, molecules, or ions and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state, or melting . At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is melted. Only after all of the solid has melted will continued heating increase the temperature of the liquid (Figure \(\ PageIndex {5}\).
Figure \(\PageIndex{5}\): (a) This beaker of ice has a temperature of −12.0 °C. (b) After 10 minutes the ice has absorbed enough heat from the air to warm to 0 °C. A small amount has melted. (c) Thirty minutes later, the ice has absorbed more heat, but its temperature is still 0 °C. The ice melts without changing its temperature. (d) Only after all the ice has melted does the heat absorbed cause the temperature to increase to 22.2 °C. (credit: modification of work by Mark Ott).
If we stop heating during melting and place the mixture of solid and liquid in a perfectly insulated container so no heat can enter or escape, the solid and liquid phases remain in equilibrium. This is almost the situation with a mixture of ice and water in a very good thermos bottle; almost no heat gets in or out, and the mixture of solid ice and liquid water remains for hours. In a mixture of solid and liquid at equilibrium, the reciprocal process of melting and freezing occur at equal rates, and the quantities of solid and liquid therefore remain constant. The temperature at which the solid and liquid phases of a given substance are in equilibrium is called the melting point of the solid or the freezing point of the liquid. Use of one term or the other is normally dictated by the direction of the phase transition being considered, for example, solid to liquid (melting) or liquid to solid (freezing).
The enthalpy of fusion and the melting point of a crystalline solid depend on the strength of the attractive forces between the units present in the crystal. Molecules with weak attractive forces form crystals with low melting points. Crystals consisting of particles with stronger attractive forces melt at higher temperatures.
The amount of heat required to change one mole of a substance from the solid state to the liquid state is the enthalpy of fusion, \(ΔH_{fus}\) of the substance. The enthalpy of fusion of ice is 6.0 kJ/mol at 0 °C. Fusion (melting) is an endothermic process:
\[\ce{H2O}_{(s)} \rightarrow \ce{H2O}_{(l)} \;\; ΔH_\ce{fus}=\mathrm{6.01\; kJ/mol} \label{10.4.9}\]
The reciprocal process, freezing, is an exothermic process whose enthalpy change is −6.0 kJ/mol at 0 °C:
\[\ce{H_2O}_{(l)} \rightarrow \ce{H_2O}_{(s)}\;\; ΔH_\ce{frz}=−ΔH_\ce{fus}=−6.01\;\mathrm{kJ/mol} \label{10.4.10}\]
Selected molar enthalpies of fusion are tabulated in Table \(\PageIndex{1}\). Solids like ice which have strong intermolecular forces have much higher values than those like CH 4 with weak ones. Note that the enthalpies of fusion and vaporization change with temperature.
| Substance | Formula |
ΔH(fusion)
/ kJ mol 1 |
Melting Point / K | ΔH(vaporization) / kJ mol -1 | Boiling Point / K |
(ΔH
v
/T
b
)
/ JK -1 mol -1 |
|---|---|---|---|---|---|---|
| Neon | Ne | 0.33 | 24 | 1.80 | 27 | 67 |
| Oxygen | O 2 | 0.44 | 54 | 6.82 | 90.2 | 76 |
| Methane | CH 4 | 0.94 | 90.7 | 8.18 | 112 | 73 |
| Ethane | C 2 H 6 | 2.85 | 90.0 | 14.72 | 184 | 80 |
| Chlorine | Cl 2 | 6.40 | 172.2 | 20.41 | 239 | 85 |
| Carbon tetrachloride | CCl 4 | 2.67 | 250.0 | 30.00 | 350 | 86 |
| Water* | H 2 O |
6.00678 at 0°C, 101kPa
6.354 at 81.6 °C, 2.50 MPa |
273.1 |
40.657 at 100 °C,
45.051 at 0 °C, 46.567 at -33 °C |
373.1 | 109 |
| n -Nonane | C 9 H 20 | 19.3 | 353 | 40.5 | 491 | 82 |
| Mercury | Hg | 2.30 | 234 | 58.6 | 630 | 91 |
| Sodium | Na | 2.60 | 371 | 98 | 1158 | 85 |
| Aluminum | Al | 10.9 | 933 | 284 | 2600 | 109 |
| Lead | Pb | 4.77 | 601 | 178 | 2022 | 88 |
*www1.lsbu.ac.uk/water/data.html
Contributors and Attributions
-
Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at<EMAIL_ADDRESS>).


Problem Set 1. Profit Maximization for the Monopolist of Monopolistically Competitive Firm
Exercise \(\PageIndex{1}\)
Given the following:
The inverse demand is P = 100-2Q.
Marginal cost is 20.
Average variable cost is 20.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 20 units.
The price is 60 dollars.
Profits above FC are 800 dollars.
Exercise \(\PageIndex{2}\)
Given the following:
The inverse demand is P = 200-2.5Q.
Marginal cost is 20.
Average variable cost is 20.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 36 units.
The price is 110 dollars.
Profits above FC are 3240 dollars.
Exercise \(\PageIndex{3}\)
Given the following:
The inverse demand is P = 300-3Q.
Marginal cost is 30.
Average variable cost is 30.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 45 units.
The price is 165 dollars.
Profits above FC are 6075 dollars.
Exercise \(\PageIndex{4}\)
Given the following:
The inverse demand is P = 400-4Q.
Marginal cost is 40.
Average variable cost is 40.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 45 units.
The price is 220 dollars.
Profits above FC are 8100 dollars.
Exercise \(\PageIndex{5}\)
Given the following:
The inverse demand is P = 460-5Q.
Marginal cost is 50.
Average variable cost is 50.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 41 units.
The price is 255 dollars.
Profits above FC are 8405 dollars.
Exercise \(\PageIndex{6}\)
Given the following:
The inverse demand is P = 200-3Q.
Marginal cost is 20.
Average variable cost is 20.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 30 units.
The price is 110 dollars.
Profits above FC are 2700 dollars.
Exercise \(\PageIndex{7}\)
Given the following:
The inverse demand is P = 288-3Q.
Marginal cost is 30.
Average variable cost is 30.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 43 units.
The price is 159 dollars.
Profits above FC are 5547 dollars.
Exercise \(\PageIndex{8}\)
Given the following:
The inverse demand is P = 300-2.5Q.
Marginal cost is 30.
Average variable cost is 30.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 54 units.
The price is 165 dollars.
Profits above FC are 7290 dollars.
Exercise \(\PageIndex{9}\)
Given the following:
The inverse demand is P = 400-4Q.
Marginal cost is 80.
Average variable cost is 80.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 40 units.
The price is 240 dollars.
Profits above FC are 6400 dollars.
Exercise \(\PageIndex{10}\)
Given the following:
The inverse demand is P = 456-4.5Q.
Marginal cost is 42.
Average variable cost is 42.
Assume a profit maximizing monopolist or monopolistically competitive firm.
Find the quantity, price and profits above fixed costs (FC).
-
Answer
-
The quantity is 46 units.
The price is 249 dollars.
Profits above FC are 9522 dollars.
Problem Set 2. Two-Firm Cournot Duopoly
Exercise \(\PageIndex{1}\)
Given the following:
The inverse demand is P = 200-2Qa-2Qb.
Marginal cost for each firm is 20.
Average variable cost for each firm is 20.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 30 units.
The market price is 80 dollars.
Each firm's profits above FC are 1800 dollars.
Exercise \(\PageIndex{2}\)
Given the following:
The inverse demand is P = 200-2.5Qa-2.5Qb.
Marginal cost for each firm is 20.
Average variable cost for each firm is 20.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 24 units.
The market price is 80 dollars.
Each firm's profits above FC are 1440 dollars.
Exercise \(\PageIndex{3}\)
Given the following:
The inverse demand is P = 250-5Qa-5Qb.
Marginal cost for each firm is 25.
Average variable cost for each firm is 25.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 15 units.
The market price is 100 dollars.
Each firm's profits above FC are 1125 dollars.
Exercise \(\PageIndex{4}\)
Given the following:
The inverse demand is P = 300-4Qa-4Qb.
Marginal cost for each firm is 36.
Average variable cost for each firm is 36.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 22 units.
The market price is 124 dollars.
Each firm's profits above FC are 1936 dollars.
Exercise \(\PageIndex{5}\)
Given the following:
The inverse demand is P = 400-5Qa-5Qb.
Marginal cost for each firm is 40.
Average variable cost for each firm is 40.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 24 units.
The market price is 160 dollars.
Each firm's profits above FC are 2880 dollars.
Exercise \(\PageIndex{6}\)
Given the following:
The inverse demand is P = 500-4Qa-4Qb.
Marginal cost for each firm is 80.
Average variable cost for each firm is 80.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
-
Answer
-
Each firm's quantity is 35 units.
The market price is 220 dollars.
Each firm's profits above FC are 4900 dollars.
Exercise \(\PageIndex{7}\)
Given the following:
The inverse demand is P = 300-3Qa-3Qb.
Marginal cost for each firm is 30.
Average variable cost for each firm is 30.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
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Answer
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Each firm's quantity is 30 units.
The market price is 120 dollars.
Each firm's profits above FC are 2700 dollars.
Exercise \(\PageIndex{8}\)
Given the following:
The inverse demand is P = 300-2.5Qa-2.5Qb.
Marginal cost for each firm is 30.
Average variable cost for each firm is 30.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
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Answer
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Each firm's quantity is 36 units.
The market price is 120 dollars.
Each firm's profits above FC are 3240 dollars.
Exercise \(\PageIndex{9}\)
Given the following:
The inverse demand is P = 500-4Qa-4Qb.
Marginal cost for each firm is 80.
Average variable cost for each firm is 80.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
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Answer
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Each firm's quantity is 35 units.
The market price is 220 dollars.
Each firm's profits above FC are 4900 dollars.
Exercise \(\PageIndex{10}\)
Given the following:
The inverse demand is P = 420-4.5Qa-4.5Qb.
Marginal cost for each firm is 42.
Average variable cost for each firm is 42.
Qa and Qb are quantities Firms A and B place on the market, respectively.
Find the Cournot Nash equilibrium quantity for each firm.
Calculate the market price at this equilibrium.
Calculate the resulting profits above fixed costs (FC) for each firm.
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Answer
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Each firm's quantity is 28 units.
The market price is 168 dollars.
Each firm's profits above FC are 3528 dollars.
Problem Set 3. Find the Monopolist’s or Monopolistically Competitive Firm’s Price
Exercise \(\PageIndex{1}\)
Given the following:
The elasticity of demand facing the firm is -1.5.
The firm's marginal cost is 8.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 24.
Exercise \(\PageIndex{2}\)
Given the following:
The elasticity of demand facing the firm is -2.5.
The firm's marginal cost is 30.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 50.
Exercise \(\PageIndex{3}\)
Given the following:
The elasticity of demand facing the firm is -2.
The firm's marginal cost is 30.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 60.
Exercise \(\PageIndex{4}\)
Given the following:
The elasticity of demand facing the firm is -3.
The firm's marginal cost is 20.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 30.
Exercise \(\PageIndex{5}\)
Given the following:
The elasticity of demand facing the firm is -2.
The firm's marginal cost is 20.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 40.
Exercise \(\PageIndex{6}\)
Given the following:
The elasticity of demand facing the firm is -1.5.
The firm's marginal cost is 20.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 60.
Exercise \(\PageIndex{7}\)
Given the following:
The elasticity of demand facing the firm is -2.5.
The firm's marginal cost is 12.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 20.
Exercise \(\PageIndex{8}\)
Given the following:
The elasticity of demand facing the firm is -2.
The firm's marginal cost is 20.
What price maximizes this firm's profits?
-
Answer
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The profit maximizing price is 40.
Exercise \(\PageIndex{9}\)
Given the following:
The elasticity of demand facing the firm is -3.
The firm's marginal cost is 40.
What price maximizes this firm's profits?
-
Answer
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The profit maximizing price is 60.
Exercise \(\PageIndex{10}\)
Given the following:
The elasticity of demand facing the firm is -2.
The firm's marginal cost is 40.
What price maximizes this firm's profits?
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Answer
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The profit maximizing price is 80.
Problem Set 4. Multiple Choice
Exercise \(\PageIndex{1}\)
-
An industry with many sellers with differentiated products is classified as
a) A monopoly
b) An oligopoly
c) Monopolistically competitive
d) Perfectly competitive
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Answer
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c
Exercise \(\PageIndex{2}\)
-
The folk theorem is of primary interest in understanding competition in an industry that is
a) A monopoly
b) An oligopoly
c) Monopolistically competitive
d) Perfectly competitive
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Answer
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b
Exercise \(\PageIndex{3}\)
-
An industry where firms are price takers is
a) A monopoly
b) A monopsony
c) Monopolistically competitive
d) Perfectly competitive
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Answer
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d
Exercise \(\PageIndex{4}\)
-
An industry where firms face an infinitely negative own-price elasticity is
a) A monopoly
b) A monopsony
c) Monopolistically competitive
d) Perfectly competitive
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Answer
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d
Exercise \(\PageIndex{5}\)
-
In the Cournot model, competitors compete by choosing
a) Prices
b) Quantities
c) Contracting methods
d) Management styles
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Answer
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b
Exercise \(\PageIndex{6}\)
-
In the Bertrand model, competitors compete by choosing
a) Prices
b) Quantities
c) Contracting methods
d) Management styles
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Answer
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a
Exercise \(\PageIndex{7}\)
-
The Cournot or Bertrand Nash equilibrium is
a) Analogous to the prisoner’s dilemma outcome because there is a feasible outcome that is better for the firms involved.
b) Modeled using a hedonic pricing model
c) Similar to 1st degree price discrimination
d) Similar to 3rd degree price discrimination
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Answer
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a
Exercise \(\PageIndex{8}\)
-
Which is true of a price taking firm?
a) It can sell all that it wants at the going price.
b) Its actions have a negligible impact on the market price.
c) It will maximize profits by producing where price is equal to marginal cost.
d) All of the above.
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Answer
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d
Exercise \(\PageIndex{9}\)
-
A profit maximizing firm will set price = marginal cost (p = MC) in which market structure?
a) Perfect competition
b) Monopolistic competition
c) Oligopoly
d) Monopoly
e) All of the above
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Answer
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a
Exercise \(\PageIndex{10}\)
-
A profit maximizing firm will set marginal revenue = marginal cost (MR = MC) in which market structure?
a) Perfect competition
b) Monopolistic competition
c) Oligopoly
d) Monopoly
e) All of the above
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Answer
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e
Exercise \(\PageIndex{11}\)
-
In which market structure are strategic interactions among firms of primary interest?
a) Perfect competition
b) Monopolistic competition
c) Oligopoly
d) Monopoly
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Answer
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c
Exercise \(\PageIndex{12}\)
-
Which best describes a tit-for-tat response?
a) The firm always prices lower than the competitor
b) The firm always prices a bit higher than the competitor to protect its margin
c) The firm cuts (raises) its price in response to a cut (raise) in price by its competitor
d) The firm chooses its Nash equilibrium price
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Answer
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c
Exercise \(\PageIndex{13}\)
-
A firm that advertises, “We will match any competitors price”
a) Could be warning its competitors that it follows a tit-for-tat pricing strategy
b) Must have low costs
c) Is more worried about market share than profits
d) All of the above
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Answer
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a
Exercise \(\PageIndex{14}\)
-
Which factor makes it more likely that firms will be able to tacitly cooperate on a price above the Bertrand price?
a) Discount rates are high
b) It takes a long time for firms to respond to a price change by a competitor
c) Firm’s know that the competitive interaction will last for only three periods
d) Discount rates are low
e) There are major differences among firms in terms of costs and quality
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Answer
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d
Exercise \(\PageIndex{15}\)
-
Which best describes a Nash equilibrium?
a) Tacit coordination on the monopoly price
b) A situation where MR < P
c) A situation where each agent is choosing its best strategy given the strategies of all other agents.
d) Cases where price is above the break-even point
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Answer
-
c


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14: Sustainability - Ethics, Culture, and History
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Page 14.1: The Human Dimensions of Sustainability- History, Culture, Ethics
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Once we begin talking about sustainability, it’s hard to stop. That’s because sustainability is truly the science of everything, from technical strategies for repowering our homes and cars, to the ecological study of biodiversity in forests and oceans, to how we think and act as human beings.
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Page 14.2: It’s Not Easy Being Green- Anti-Environmental Discourse, Behavior, and Ideology
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The consensus view among scientists and professional elites in the early twenty-first century, as it has been among environmental activists for a much longer time, is that our globalized industrial world system is on an unsustainable path. Inherent in this view is a stern judgment of the recent past: we have not adapted well, as a species, to the fruits of our own brilliant technological accomplishments, in particular, to the harnessing of fossil fuels to power transport and industry.
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Page 14.3: The Industrialization of Nature- A Modern History (1500 to the present)
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It is a measure of our powers of normalization that we in the developed world take the existence of cheap energy, clean water, abundant food, and international travel so much for granted, when they are such recent endowments for humanity, and even now are at the disposal of considerably less than half the global population.
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Page 14.4: Case Study- Agriculture and the Global Bee Colony Collapse
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Two thousand years ago, at the height of the Roman Empire, the poet Virgil wrote lovingly about the practice of beekeeping, of cultivating the “aerial honey and ambrosial dews” he called “gifts of heaven” (Georgics IV: 1-2). Bees represent a gift to humanity even greater that Virgil knew.
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Page 14.5: Sustainability Ethics
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The 1987 United Nations Brundtland definition of sustainability embodies an intergenerational contract: to provide for our present needs, while not compromising the ability of future generations to meet their needs. It’s a modest enough proposal on the face of it, but it challenges our current expectations of the intergenerational contract: we expect each new generation to be better off than their parents.


13.3: DNA Structure and Sequencing
- Describe the structure of DNA
- Explain the Sanger method of DNA sequencing
- Discuss the similarities and differences between eukaryotic and prokaryotic DNA
The building blocks of DNA are nucleotides. The important components of the nucleotide are a nitrogenous base, deoxyribose (5-carbon sugar), and a phosphate group (Figure \(\PageIndex{1}\)). The nucleotide is named depending on the nitrogenous base. The nitrogenous base can be a purine such as adenine (A) and guanine (G), or a pyrimidine such as cytosine (C) and thymine (T).
The nucleotides combine with each other by covalent bonds known as phosphodiester bonds or linkages. The purines have a double ring structure with a six-membered ring fused to a five-membered ring. Pyrimidines are smaller in size; they have a single six-membered ring structure. The carbon atoms of the five-carbon sugar are numbered 1', 2', 3', 4', and 5' (1' is read as “one prime”). The phosphate residue is attached to the hydroxyl group of the 5' carbon of one sugar of one nucleotide and the hydroxyl group of the 3' carbon of the sugar of the next nucleotide, thereby forming a 5'-3' phosphodiester bond.
In the 1950s, Francis Crick and James Watson worked together to determine the structure of DNA at the University of Cambridge, England. Other scientists like Linus Pauling and Maurice Wilkins were also actively exploring this field. Pauling had discovered the secondary structure of proteins using X-ray crystallography. In Wilkins’ lab, researcher Rosalind Franklin was using X-ray diffraction methods to understand the structure of DNA. Watson and Crick were able to piece together the puzzle of the DNA molecule on the basis of Franklin's data because Crick had also studied X-ray diffraction (Figure \(\PageIndex{2}\)). In 1962, James Watson, Francis Crick, and Maurice Wilkins were awarded the Nobel Prize in Medicine. Unfortunately, by then Franklin had died, and Nobel prizes are not awarded posthumously.
Watson and Crick proposed that DNA is made up of two strands that are twisted around each other to form a right-handed helix. Base pairing takes place between a purine and pyrimidine; namely, A pairs with T and G pairs with C. Adenine and thymine are complementary base pairs, and cytosine and guanine are also complementary base pairs. The base pairs are stabilized by hydrogen bonds; adenine and thymine form two hydrogen bonds and cytosine and guanine form three hydrogen bonds. The two strands are anti-parallel in nature; that is, the 3' end of one strand faces the 5' end of the other strand. The sugar and phosphate of the nucleotides form the backbone of the structure, whereas the nitrogenous bases are stacked inside. Each base pair is separated from the other base pair by a distance of 0.34 nm, and each turn of the helix measures 3.4 nm. Therefore, ten base pairs are present per turn of the helix. The diameter of the DNA double helix is 2 nm, and it is uniform throughout. Only the pairing between a purine and pyrimidine can explain the uniform diameter. The twisting of the two strands around each other results in the formation of uniformly spaced major and minor grooves (Figure \(\PageIndex{3}\)).
DNA Sequencing Techniques
Until the 1990s, the sequencing of DNA (reading the sequence of DNA) was a relatively expensive and long process. Using radiolabeled nucleotides also compounded the problem through safety concerns. With currently available technology and automated machines, the process is cheap, safer, and can be completed in a matter of hours. Fred Sanger developed the sequencing method used for the human genome sequencing project, which is widely used today (Figure \(\PageIndex{4}\)).
Interactive Link
Visit this site to watch a video explaining the DNA sequence reading technique that resulted from Sanger’s work.
The method is known as the dideoxy chain termination method. The sequencing method is based on the use of chain terminators, the dideoxynucleotides (ddNTPs). The dideoxynucleotides, or ddNTPSs, differ from the deoxynucleotides by the lack of a free 3' OH group on the five-carbon sugar. If a ddNTP is added to a growing a DNA strand, the chain is not extended any further because the free 3' OH group needed to add another nucleotide is not available. By using a predetermined ratio of deoxyribonucleotides to dideoxynucleotides, it is possible to generate DNA fragments of different sizes.
The DNA sample to be sequenced is denatured or separated into two strands by heating it to high temperatures. The DNA is divided into four tubes in which a primer, DNA polymerase, and all four nucleotides (A, T, G, and C) are added. In addition to each of the four tubes, limited quantities of one of the four dideoxynucleotides are added to each tube respectively. The tubes are labeled as A, T, G, and C according to the ddNTP added. For detection purposes, each of the four dideoxynucleotides carries a different fluorescent label. Chain elongation continues until a fluorescent dideoxy nucleotide is incorporated, after which no further elongation takes place. After the reaction is over, electrophoresis is performed. Even a difference in length of a single base can be detected. The sequence is read from a laser scanner. For his work on DNA sequencing, Sanger received a Nobel Prize in chemistry in 1980.
Gel electrophoresis is a technique used to separate DNA fragments of different sizes. Usually the gel is made of a chemical called agarose. Agarose powder is added to a buffer and heated. After cooling, the gel solution is poured into a casting tray. Once the gel has solidified, the DNA is loaded on the gel and electric current is applied. The DNA has a net negative charge and moves from the negative electrode toward the positive electrode. The electric current is applied for sufficient time to let the DNA separate according to size; the smallest fragments will be farthest from the well (where the DNA was loaded), and the heavier molecular weight fragments will be closest to the well. Once the DNA is separated, the gel is stained with a DNA-specific dye for viewing it (Figure \(\PageIndex{5}\)).
The first draft sequence of the Neanderthal genome was recently published by Richard E. Green et al. in 2010. 1 Neanderthals are the closest ancestors of present-day humans. They were known to have lived in Europe and Western Asia before they disappeared from fossil records approximately 30,000 years ago. Green’s team studied almost 40,000-year-old fossil remains that were selected from sites across the world. Extremely sophisticated means of sample preparation and DNA sequencing were employed because of the fragile nature of the bones and heavy microbial contamination. In their study, the scientists were able to sequence some four billion base pairs. The Neanderthal sequence was compared with that of present-day humans from across the world. After comparing the sequences, the researchers found that the Neanderthal genome had 2 to 3 percent greater similarity to people living outside Africa than to people in Africa. While current theories have suggested that all present-day humans can be traced to a small ancestral population in Africa, the data from the Neanderthal genome may contradict this view. Green and his colleagues also discovered DNA segments among people in Europe and Asia that are more similar to Neanderthal sequences than to other contemporary human sequences. Another interesting observation was that Neanderthals are as closely related to people from Papua New Guinea as to those from China or France. This is surprising because Neanderthal fossil remains have been located only in Europe and West Asia. Most likely, genetic exchange took place between Neanderthals and modern humans as modern humans emerged out of Africa, before the divergence of Europeans, East Asians, and Papua New Guineans.
Several genes seem to have undergone changes from Neanderthals during the evolution of present-day humans. These genes are involved in cranial structure, metabolism, skin morphology, and cognitive development. One of the genes that is of particular interest is RUNX2, which is different in modern day humans and Neanderthals. This gene is responsible for the prominent frontal bone, bell-shaped rib cage, and dental differences seen in Neanderthals. It is speculated that an evolutionary change in RUNX2 was important in the origin of modern-day humans, and this affected the cranium and the upper body.
Interactive Link
Watch Svante Pääbo’s talk explaining the Neanderthal genome research at the 2011 annual TED (Technology, Entertainment, Design) conference.
DNA Packaging in Cells
When comparing prokaryotic cells to eukaryotic cells, prokaryotes are much simpler than eukaryotes in many of their features (Figure \(\PageIndex{6}\)). Most prokaryotes contain a single, circular chromosome that is found in an area of the cytoplasm called the nucleoid.
The size of the genome in one of the most well-studied prokaryotes, E.coli, is 4.6 million base pairs (approximately 1.1 mm, if cut and stretched out). So how does this fit inside a small bacterial cell? The DNA is twisted by what is known as supercoiling. Supercoiling means that DNA is either under-wound (less than one turn of the helix per 10 base pairs) or over-wound (more than 1 turn per 10 base pairs) from its normal relaxed state. Some proteins are known to be involved in the supercoiling; other proteins and enzymes such as DNA gyrase help in maintaining the supercoiled structure.
Eukaryotes, whose chromosomes each consist of a linear DNA molecule, employ a different type of packing strategy to fit their DNA inside the nucleus (FIgure \(\PageIndex{7}\)). At the most basic level, DNA is wrapped around proteins known as histones to form structures called nucleosomes. The histones are evolutionarily conserved proteins that are rich in basic amino acids and form an octamer. The DNA (which is negatively charged because of the phosphate groups) is wrapped tightly around the histone core. This nucleosome is linked to the next one with the help of a linker DNA. This is also known as the “beads on a string” structure. This is further compacted into a 30 nm fiber, which is the diameter of the structure. At the metaphase stage, the chromosomes are at their most compact, are approximately 700 nm in width, and are found in association with scaffold proteins.
In interphase, eukaryotic chromosomes have two distinct regions that can be distinguished by staining. The tightly packaged region is known as heterochromatin, and the less dense region is known as euchromatin. Heterochromatin usually contains genes that are not expressed, and is found in the regions of the centromere and telomeres. The euchromatin usually contains genes that are transcribed, with DNA packaged around nucleosomes but not further compacted.
Summary
The currently accepted model of the double-helix structure of DNA was proposed by Watson and Crick. Some of the salient features are that the two strands that make up the double helix are complementary and anti-parallel in nature. Deoxyribose sugars and phosphates form the backbone of the structure, and the nitrogenous bases are stacked inside. The diameter of the double helix, 2 nm, is uniform throughout. A purine always pairs with a pyrimidine; A pairs with T, and G pairs with C. One turn of the helix has ten base pairs. During cell division, each daughter cell receives a copy of the DNA by a process known as DNA replication. Prokaryotes are much simpler than eukaryotes in many of their features. Most prokaryotes contain a single, circular chromosome. In general, eukaryotic chromosomes contain a linear DNA molecule packaged into nucleosomes, and have two distinct regions that can be distinguished by staining, reflecting different states of packaging and compaction.
Review Questions
DNA double helix does not have which of the following?
- antiparallel configuration
- complementary base pairing
- major and minor grooves
- uracil
- Answer
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Answer: D
In eukaryotes, what is the DNA wrapped around?
- single-stranded binding proteins
- sliding clamp
- polymerase
- histones
- Answer
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Answer: D
Free Response
Provide a brief summary of the Sanger sequencing method.
- Answer
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Answer: The template DNA strand is mixed with a DNA polymerase, a primer, the 4 deoxynucleotides, and a limiting concentration of 4 dideoxynucleotides. DNA polymerase synthesizes a strand complementary to the template. Incorporation of ddNTPs at different locations results in DNA fragments that have terminated at every possible base in the template. These fragments are separated by gel electrophoresis and visualized by a laser detector to determine the sequence of bases.
Describe the structure and complementary base pairing of DNA.
- Answer
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Answer: DNA has two strands in anti-parallel orientation. The sugar-phosphate linkages form a backbone on the outside, and the bases are paired on the inside: A with T, and G with C, like rungs on a spiral ladder.
Art Connections
Figure \(\PageIndex{6}\): In eukaryotic cells, DNA and RNA synthesis occur in a separate compartment from protein synthesis. In prokaryotic cells, both processes occur together. What advantages might there be to separating the processes? What advantages might there be to having them occur together?
- Answer
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Answer: Compartmentalization enables a eukaryotic cell to divide processes into discrete steps so it can build more complex protein and RNA products. But there is an advantage to having a single compartment as well: RNA and protein synthesis occurs much more quickly in a prokaryotic cell.
Footnotes
- 1 Richard E. Green et al., “A Draft Sequence of the Neandertal Genome,” Science 328 (2010): 710-22.
Glossary
- electrophoresis
- technique used to separate DNA fragments according to size
Contributors and Attributions
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Connie Rye (East Mississippi Community College), Robert Wise (University of Wisconsin, Oshkosh), Vladimir Jurukovski (Suffolk County Community College), Jean DeSaix (University of North Carolina at Chapel Hill), Jung Choi (Georgia Institute of Technology), Yael Avissar (Rhode Island College) among other contributing authors. Original content by OpenStax (CC BY 4.0; Download for free at<EMAIL_ADDRESS>).


45.2A: Exponential Population Growth
- Describe exponential growth of a population size
Exponential growth
In his theory of natural selection, Charles Darwin was greatly influenced by the English clergyman Thomas Malthus. Malthus published a book in 1798 stating that populations with unlimited natural resources grow very rapidly, after which population growth decreases as resources become depleted. This accelerating pattern of increasing population size is called exponential growth.
The best example of exponential growth is seen in bacteria. Bacteria are prokaryotes that reproduce by prokaryotic fission. This division takes about an hour for many bacterial species. If 1000 bacteria are placed in a large flask with an unlimited supply of nutrients (so the nutrients will not become depleted), after an hour there will be one round of division (with each organism dividing once), resulting in 2000 organisms. In another hour, each of the 2000 organisms will double, producing 4000; after the third hour, there should be 8000 bacteria in the flask; and so on. The important concept of exponential growth is that the population growth rate, the number of organisms added in each reproductive generation, is accelerating; that is, it is increasing at a greater and greater rate. After 1 day and 24 of these cycles, the population would have increased from 1000 to more than 16 billion. When the population size, N, is plotted over time, a J-shaped growth curve is produced.
The bacteria example is not representative of the real world where resources are limited. Furthermore, some bacteria will die during the experiment and, thus, not reproduce, lowering the growth rate. Therefore, when calculating the growth rate of a population, the death rate (D; the number organisms that die during a particular time interval) is subtracted from the birth rate (B; the number organisms that are born during that interval). This is shown in the following formula:
\[\dfrac{ΔN}{ΔT} =B− \dfrac{\Delta N}{\Delta T} =B−D\]
where \(ΔN\) = change in number, \(ΔT\) = change in time, \(B\) = birth rate, and \(D\) = death rate. The birth rate is usually expressed on a per capita (for each individual) basis. Thus, B (birth rate) = bN (the per capita birth rate “b” multiplied by the number of individuals “N”) and D (death rate) = dN (the per capita death rate “d” multiplied by the number of individuals “N”). Additionally, ecologists are interested in the population at a particular point in time: an infinitely small time interval. For this reason, the terminology of differential calculus is used to obtain the “instantaneous” growth rate, replacing the change in number and time with an instant-specific measurement of number and time.
\[\dfrac{dN}{dT}=BN DN=(BD)NdN/dT=BN DN=(BD)N\]
Notice that the “d” associated with the first term refers to the derivative (as the term is used in calculus) and is different from the death rate, also called “d.” The difference between birth and death rates is further simplified by substituting the term “r” (intrinsic rate of increase) for the relationship between birth and death rates:
\[\dfrac{dN}{dT}=rN \dfrac{dN}{dT}=rN\]
The value “r” can be positive, meaning the population is increasing in size; negative, meaning the population is decreasing in size; or zero, where the population’s size is unchanging, a condition known as zero population growth. A further refinement of the formula recognizes that different species have inherent differences in their intrinsic rate of increase (often thought of as the potential for reproduction), even under ideal conditions. Obviously, a bacterium can reproduce more rapidly and have a higher intrinsic rate of growth than a human. The maximal growth rate for a species is its biotic potential, or r max , thus changing the equation to:
\[\dfrac{dN}{dT}=r_{max}N\]
Key Points
- To get an accurate growth rate of a population, the number that died in the time period (death rate) must be removed from the number born during the same time period (birth rate).
- When the birth rate and death rate are expressed in a per capita manner, they must be multiplied by the population to determine the number of births and deaths.
- Ecologists are usually interested in the changes in a population at either a particular point in time or over a small time interval.
- The intrinsic rate of increase is the difference between birth and death rates; it can be positive, indicating a growing population; negative, indicating a shrinking population; or zero, indicting no change in the population.
- Different species have a different intrinsic rate of increase which, when under ideal conditions, represents the biotic potential or maximal growth rate for a species.
Key Terms
- fission : the process by which a bacterium splits to form two daughter cells
- per capita : per person or individual


5.20: Discussion- Analyzing Social Responsibility
Instructions
Write a two-part post for the Discussion on this topic. Each part should be 1–2 paragraphs in length.
Part 1: Current Status
It is no longer acceptable for businesses to disregard issues related to ethics and social responsibility. Conduct research and briefly describe what your organization is doing now with regard to corporate social responsibility and pursuing sustainable business practices.
Think broadly about what to consider: philanthropy, energy conservation, sustainable supply chains, reducing carbon footprint, fair trade, community service, volunteerism, etc.
Part 2: Recommendations
Based on your understanding of the organization’s goals, what recommendations do you have for how to create a more ethical, socially responsible, and/or sustainable business? What practices do you recommend the organization pursue?
Part 3: Respond to Classmates’ Posts
After you have created your own post, look over the discussion posts of your classmates and respond to at least two of them.
Grading Rubric for Discussion Posts
The following grading rubric may be used consistently for evaluating all discussion posts.
Discussion Grading Rubric
| Criteria | Response Quality: Not Evident | Response Quality: Developing | Response Quality: Exemplary | Point Value Possible |
|---|---|---|---|---|
| Submit your initial response | No post made – 0 pts | Post is either late or off-topic – 2 pts | Post is made on time and is focused on the prompt – 5 pts | Point value possible – 5 pts |
| Respond to at least two peers’ presentations | No response to peers – 0 pts | Responded to only one peer – 2 pts | Responded to two peers – 5 pts | Point value possible –5 pts |
Total Points Possible for Discussion Assignment: 10pts.
Contributors and Attributions
- Discussion: Analyzing Social Responsibility. Provided by : Lumen Learning. License : CC BY: Attribution


18: Multimodal and Online Writing- Creative Interaction between Text and Image
Figure \(18.1\) Multimodal text incorporates many different types of communication, making it visually and aurally compelling as well as highly accessible for audiences. (credit: “Computer Internet Tools Gadgets Edited 2020” by www.mechanicalcaveman.com/flickr, CC BY 2.0)
Chapter Outline
Introduction
Chances are you already have a great deal of experience with multimodal composition—that is, writing or creating content by combining different types of communication. Much of your experience may come from digital spaces, perhaps even from platforms such as social media that you don’t associate with academics. According to literature examining adolescent and young adult literacy skills, young adults incorporate a great deal of multimodal communication—which includes sound, images, movement, and text—into their everyday lives to express themselves and connect with others. Social media has no doubt hastened the spread of multimodal communication, and its prevalence in the world is unprecedented. Perhaps you have never believed that your experience with digital and multimodal writing connects to academic composition, but indeed it does. Just as technology has changed how people interact with the world, multimodal composition has altered how they create content. In this chapter, you will learn how to combine your experience in creating and using multimodal composition with established writing practices, particularly those used in argumentative writing, to generate connected content that creates meaning.
Multimodal composition begins where any other composition does: with the rhetorical situation , or the circumstance of communication in which one person (the composer) uses communication to influence the perspective of another (the audience). All multimodal compositions are created for a specific time and place and a particular audience who views the world in an explicit and culturally influenced way. As a writer, you make choices based on the rhetorical situation: context, audience, purpose, genre, and culture. You consider the strengths and weaknesses of all the possible means and tools available for reaching your rhetorical goals. By identifying the audience, determining what you need to tell the audience, and analyzing the best way to do that (including which types of media to use), you are empowered to create an effective and targeted composition.
In many ways, multimodal composition opens a range of possibilities by offering you any number of tools to make meaning, rather than limiting you to text alone. For example, a sportswriter might rely heavily on visuals to engage readers and demonstrate a runner’s prowess, or they might create infographics to relay statistics about the athlete or the meet itself.
Figure \(18.2\) Composers often use images to engage readers and relate details that are difficult to express with words alone. (credit: “ISST 2014 Munich” by R. Boed/flickr, CC BY 2.0)
Websites require a balance of text, images, and careful formatting to present information in ways that are easy to digest and not overwhelming for the reader. In fact, the most difficult part of this type of creation may be choosing among the available tools to create meaning effectively without doing too much or too little. In some ways, the flexibility of websites can make it hard to know where to get started—or where to end.
This chapter presents a blog post by Alexandra Dapolito Dunn, formerly of the Environmental Protection Agency. Studying this article and the components of multimodal writing that Dunn chooses to use will help you understand how different platforms and rhetorical needs require different elements of text, media, and modes. Later in the chapter, you will learn how to address a range of audiences through your own textual and digital compositions.


5.2: Changes in Chromosome Structure
Learning Objectives
- Distinguish between the 4 types of chromosomal rearrangements and their effects on gene dosage and meiosis.
If the chromosome is altered, but still retains the three critical features of a chromosome (centromeres, telomeres, and origin of replication), it will continue to be inherited during subsequent cell divisions, however the daughter cell may not retain all the genes. For example, if a segment of the chromosome has been lost, the cell may be missing some genes. The causes and consequences of chromosome structural abnormalities are described here. They all involve breaks in the chromosomal DNA backbone.
Cause #1: Incorrect Repair of Double Strand DNA Breaks During Interphase
A chromosome is a very long but very thin molecule. In the phosphodiester backbone there are only two covalent bonds holding each base pair to the next. If one of these covalent bonds is broken the chromosome will still remain intact, although a DNA ligase will be needed to repair the nick. Problems arise when both strands are broken at or near the same location. This double strand break will cleave the chromosome into two independent pieces. Because these events do occur in cells, there is a repair system called the non-homologous end joining (NHEJ) system to fix them. Proteins bind to each broken end of the DNA and reattach them with new covalent bonds. This system is not perfect and sometimes leads to chromosome rearrangements (see next section).
The NHEJ system proteins only function if required. If the chromosomes within an interphase nucleus are all intact, the system is not active. The telomeres at the natural ends of chromosomes prevent the NHEJ system from attempting to join the normal ends of chromosomes together. If there is one double-strand break, the two broken ends can be recognized and joined. However, if there are two (or more) double-strand breaks at the same time there will be four broken ends in total. The NHEJ system proteins recognize the breaks but do not have the ability to identify exactly which ends should be joined to restore the original chromosome. Thus, NHEJ may join the ends together correctly, but if they do not the result is a chromosome rearrangement .
The Four Types of Chromosome Rearrangements
Errors during the repair of multiple double-strand breaks can cause four types of chromosome rearrangements. The type of chromosome rearrangement is dependent upon where the two breaks were originally and how they are rejoined. First double-strand DNA break occurs in one site; a second DNA break occurs and the NHEJ proteins mend the damage incorrectly by joining the ends.
There are four major types of rearrangements:
Cause #2: Incorrect Crossovers During Meiosis
Meiotic crossovers occur at the beginning of meiosis for two reasons. They help hold the homologous chromosomes together until separation occurs during anaphase I. They also allow recombination to occur between linked genes. The event itself takes place during prophase I when a double strand break on one piece of DNA is joined with a double strand break on another piece of DNA and the ends are put together. Most of the time the breaks are on non-sister chromatids and most of the time the breaks are at the same relative locations.
Problems occur when the wrong pieces of DNA are matched up along the chromosomes during crossover events. This can happen if the same or similar DNA sequence is found at multiple sites on the chromosomes. For example, if there are two Alu transposable elements on a chromosome. When the homologous chromosomes pair during prophase I the wrong Alu sequences might line up. A crossover may occur in this region. If so, when the chromosomes separate during anaphase I one of the chromatids will have a duplication and one will have a deletion. Ultimately, of the four cells produced by this meiosis, two will be normal, one will have a chromosome with extra genes, and one will have a chromosome missing some genes. Errors of this type can also cause inversions and translocations.
Consequence #1: Abnormal pairing at Meiosis
DNA forms loops to achieve pairing when chromosomes are rearranged
Homologous regions of chromosomes pair at meiosis I (prophase I). With rearranged chromosomes this can lead to visible abnormalities and segregation abnormalities.
Deletion chromosomes will pair up with a normal homolog along the shared regions and at the missing segment, the normal homolog will loop out (nothing to pair with) to form a deletion loop. This feature can be used to locate the deletion cytologically. The deleted region is also pseudo-dominant , in that the cell no longer has two copies of the genes in this region, therefore mutant recessive alleles may produce a phenotypic change.
When an inversion chromosome is paired up in meiosis there is an inversion loop formed. If there is a crossover within the loop then abnormal products will result and abnormal, unbalanced gametes will be produced. For example, a crossover event within the loop of a par a centric inversion will lead to a dicentric product that will break into deletion products and produce unbalanced gametes. Similarly, with a per i centric inversion , a crossover event leads to duplicate/deletion products that are unbalanced.
Video explanation: Crossing over in inversions
Translocated chromosomes pair with more than one homologous chromosome
For translocations , a consequence for the two chromosomes involved is that when they pair at meiosis both replicated chromosome pairs will be together. During meiosis I, homologous chromosomes separate. The four chromosomes can segregate in different ways, depending on which centromeres are pulled to each pole during anaphase. This set of paired, replicated chromosomes can segregate as Alternate (balanced) where both non-translocated (N1 and N2) chromosomes go to one pole and both translocated chromosomes go to the other pole. A gamete that contains the two translocated (T1 and T2) chromosome still contains one full copy of both chromosomes. However, the chromosomes may segregate as Adjacent-1 (unbalanced) where a cells gets one normal and one translocation chromosome; each gamete will contain extra copies of some genes and lack copies of other genes. Each of these possibilities occur with approximately equal frequency and thus about half the gametes will be unbalanced.
Consequence #2: Decreased Viability
All of the chromosome rearrangements shown above produce functional chromosomes. Each has one centromere, two telomeres, and thousands of origins of replication. Because inversions and translocations do not change the number of genes in a cell or organism they are said to be balanced rearrangements. Unless one of the breakpoints occurred in the middle of a gene the cells will not be affected. On the other hand, deletions and duplications are unbalanced rearrangements. The larger they are (more genes involved) the more disruption they cause to the proper functioning of the cell or organism.
Note about gene dosage
Having too much or too little gene activity for a large number of genes can disrupt the cellular metabolism to generate a phenotype or reduce viability.
Consequence #3: Decreased Fertility
Recall that during meiosis I homologous chromosomes pair up. If a cell has a chromosome with a rearrangement this chromosome will have to pair with its normal homolog.
Cells heterozygous for balanced rearrangements actually have more difficulties in prophase I. There are different ways they might pair during prophase I, but if a crossover occurs in the inverted region the result will be unbalanced gametes. Embryos made with unbalanced gametes rarely survive. The consequence is that the heterozygous organism will have reduced fertility .
Figure \(\PageIndex{8}\): Meiosis in a cell heterozygous for the chromosomes shown in Figure 9.11. Note that of the four gametes one has a deletion of the A gene and a duplication of the D gene while another gamete has a duplication of A and a deletion of D. (Original-Harrington-CC:AN)
Note that an organism homozygous for this inversion chromosome will not be affected in this way because no loops are formed. The chromosomes can pair along their entire length and crossovers will not produce any unbalanced gametes. This is a general property of inversions and translocations. In heterozygotes there are problems during meiosis, that result in a lot many unbalanced gametes and an overall reduction in fertility. In homozygotes the rearranged chromosomes pair with one another just fine and there is no effect on fertility.
Consequence #4: Cancer
Some chromosome rearrangements have breakpoints within genes leading to the creation of hybrid genes – the first part of one gene with the last part of another. If the hybrid gene inappropriately promotes cell replication, the cell can become cancerous. One example of such a translocation t(9:22) is the cause of chronic myelogenous leukemia (CML). Association of this translocation in cancer was first suggested in a brief letter 1960 (Nowell and Hungerford, Science 132:1497). The translocation creates a fusion gene with the BCR gene promoter and 5' region and the ABL 3' end. When transcribed and translated, this fusion protein is a constitutively active kinase.
Consequence #5: Evolution
Those chromosome changes that duplicate genes are important for evolution. If an organism has an extra copy of important genes, one gene can be retained for their original function while others can mutate and potentially acquire new functions. For example, multiple copies of the globin genes are found in mammals and have unique functions.
Chromosome rearrangements that decrease fertility are also important for the origin of new species. If a rearrangement becomes common in a small isolated population, that population has 100% fertility if they mate within their group, but a reduced fertility if they mate with members of the larger population. As rearrangements accumulate the small population will become more and more reproductively isolated. When members are incapable of forming viable, fertile offspring with the original population the group will have become a new species.
Contributors and Attributions
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Dr. Todd Nickle and Isabelle Barrette-Ng (Mount Royal University) The content on this page is licensed under CC SA 3.0 licensing guidelines.


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agnosticism
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the belief that God or the divine is unknowable and therefore skepticism is appropriate.
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animism
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a worldview in which there is believed to be spiritual agency in all things, including natural elements such as rocks and trees.
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atheism
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the lack of belief in a god or gods.
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binary opposition
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two opposing concepts, commonly found in institutions such as kinship and in myth.
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communitas
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a cohort of individuals participating in a rite of passage who share a strong sense of equality and social bonding among themselves.
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deity
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a god, usually named, with individual personalities and interests.
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divination
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a practice or test to discern knowledge about a certain event or situation.
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doctrine
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a set of formal and usually rigid principles or teachings of a religious organization.
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earth-diver myths
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creation myths in which a creator deity sends an agent, usually an animal, into deep waters to find mud that the deity will use to create dry land and humans.
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exorcism
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the removal of an adverse supernatural spirit from a person.
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goddesses
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female deities.
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gods
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deities; often, specifically male deities.
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hierophany
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the manifestation of the sacred or divine.
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law of contagion
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the belief that things that have once been in contact with each other remain connected always; a theory of magic.
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law of similarity
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the belief that things that are alike exert a force on each other; a theory of magic.
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liminality
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a state in which an individual is viewed as being in a transition from one social stage to another.
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magic
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a supposed system of natural law, the practice of which causes a transformation to occur.
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mana
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an impersonal force that can adhere to people or animate and inanimate objects to make them sacred
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metaphor
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a symbol that is not naturally connected to what it represents.
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metonym
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a symbol in which a part stands for the whole.
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monotheistic religion
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a religion that centers on a single named god or goddess.
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multivocal
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describes symbols that have more than one meaning.
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myth
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a well-known story that teaches primary principles, beliefs, and values outside of chronological time.
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mythemes
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the stripped-down minimal and portable units that form the structure of a myth.
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none
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a person with no religious affiliation.
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pilgrimage
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a sacred journey to a shrine or other holy place.
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place
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a location that has sociocultural meaning attached to it.
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polytheistic religion
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a religion that centers on a group of gods and/or goddesses, each devoted to a specific action or behavior.
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priests
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full-time religious leaders who manage and administer at a high level within the religious bureaucracy.
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primary messages
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the meaning of a myth, which can be applied universally.
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prophet
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an individual associated with religious change who calls for a renewal of beliefs or a restructuring of the status quo. A prophet’s leadership is usually temporary or indirect.
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proselytization
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a recruitment practice in which members actively seek converts to the group.
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religion
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a shared system of beliefs and practices that are highly regarded in society. Most often, religion is focused on the interaction of natural and supernatural phenomena.
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rite of affliction
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a ritual invoked to seek some sort of redress, remedy, or compensation for an individual by means of supernatural intervention.
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rite of intensification
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a ritual performed by a religious group to affirm, strengthen, and maintain bonds of solidarity.
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rite of passage
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a ritual in which an individual or group marks a social transformation.
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rituals
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performative acts by which people carry out religious beliefs, both public and private; also called rites.
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secular religion
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a system of beliefs held by a society that elevates social ideas, qualities, or commodities to a metaphysical, semidivine status.
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shaman
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a part-time religious figure who works to connect with deities on behalf of others.
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shamanism
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a practice of healing and divination that involves soul travel to connect natural and supernatural realms in nonlinear time.
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sorcery
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a practice involving the use of material elements to cause a change in circumstances to another person.
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space
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an unmarked physical field; a place with no specific cultural meaning.
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spirit
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supernatural being associated with specific activities, such as an earth spirit or guardian spirit (or angel).
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spirituality
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a loose structure of beliefs and feelings about relationships between the natural and supernatural worlds.
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state religion
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a formal religious institution with full-time administrators, a set doctrine of beliefs and regulations, and a policy of seeking growth by conversion of new practitioners.
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structuralism
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a theory and method focused on identifying patterns in culture; also includes mythic analysis.
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superstition
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a belief or practice that is believed to have no credible evidence for its efficacy.
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symbol
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something that stands arbitrarily for something else and has no natural connection to its referent.
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syncretism
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an integration or use of more than one religious system.
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witchcraft
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a practice involving the use of intangible means to cause a change in circumstances to another person.
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worldview
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a specific outlook or orientation that an individual or group of individuals holds on the nature of the world.