3.1: Gas Transport
- Explain how oxygen and carbon dioxide are transported in blood or equivalent fluid medium.
The other major activity in the lungs is the process of respiration, the process of gas exchange. The function of respiration is to provide oxygen for use by body cells during cellular respiration and to eliminate carbon dioxide, a waste product of cellular respiration, from the body. In order for the exchange of oxygen and carbon dioxide to occur, both gases must be transported between the external and internal respiration sites. Although carbon dioxide is more soluble than oxygen in blood, both gases require a specialized transport system for the majority of the gas molecules to be moved between the lungs and other tissues.
Oxygen Transport in the Blood
Even though oxygen is transported via the blood, you may recall that oxygen is not very soluble in liquids. A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Erythrocytes contain a metalloprotein, hemoglobin, which serves to bind oxygen molecules to the erythrocyte (Figure 3.1). Heme is the portion of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing Heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product, oxyhemoglobin (\(\ce{Hb–O2}\)), which is formed when oxygen binds to hemoglobin. Oxyhemoglobin is a bright red-colored molecule that contributes to the bright red color of oxygenated blood.
\[\ce{Hb + O2 <=> Hb − O2Hb + O2 <=> Hb − O2}\]
In this formula, Hb represents reduced hemoglobin, that is, hemoglobin that does not have oxygen bound to it. There are multiple factors involved in how readily heme binds to and dissociates from oxygen, which will be discussed in the subsequent sections.
Function of hemoglobin
Hemoglobin is composed of subunits, a protein structure that is referred to as a quaternary structure. Each of the four subunits that make up hemoglobin is arranged in a ring-like fashion, with an iron atom covalently bound to the heme in the center of each subunit. Binding of the first oxygen molecule causes a conformational change in hemoglobin that allows the second molecule of oxygen to bind more readily. As each molecule of oxygen is bound, it further facilitates the binding of the next molecule, until all four heme sites are occupied by oxygen. The opposite occurs as well: After the first oxygen molecule dissociates and is “dropped off” at the tissues, the next oxygen molecule dissociates more readily. When all four heme sites are occupied, the hemoglobin is said to be saturated. When one to three heme sites are occupied, the hemoglobin is said to be partially saturated. Therefore, when considering the blood as a whole, the percent of the available heme units that are bound to oxygen at a given time is called hemoglobin saturation. Hemoglobin saturation of 100 percent means that every heme unit in all of the erythrocytes of the body is bound to oxygen. In a healthy individual with normal hemoglobin levels, hemoglobin saturation generally ranges from 95 percent to 99 percent.
Oxygen dissociation from hemoglobin
Partial pressure is an important aspect of the binding of oxygen to and disassociation from heme. An oxygen-hemoglobin dissociation curve is a graph that describes the relationship of partial pressure to the binding of oxygen to heme and its subsequent dissociation from heme (Figure 3.2). Remember that gases travel from an area of higher partial pressure to an area of lower partial pressure. In addition, the affinity of an oxygen molecule for heme increases as more oxygen molecules are bound. Therefore, in the oxygen-hemoglobin saturation curve, as the partial pressure of oxygen increases, a proportionately greater number of oxygen molecules are bound by heme. Not surprisingly, the oxygen-hemoglobin saturation/dissociation curve also shows that the lower the partial pressure of oxygen, the fewer oxygen molecules are bound to heme. As a result, the partial pressure of oxygen plays a major role in determining the degree of binding of oxygen to heme at the site of the respiratory membrane, as well as the degree of dissociation of oxygen from heme at the site of body tissues.
The mechanisms behind the oxygen-hemoglobin saturation/dissociation curve also serve as automatic control mechanisms that regulate how much oxygen is delivered to different tissues throughout the body. This is important because some tissues have a higher metabolic rate than others. Highly active tissues, such as muscle, rapidly use oxygen to produce ATP, lowering the partial pressure of oxygen in the tissue to about 20 mm Hg. The partial pressure of oxygen inside capillaries is about 100 mm Hg, so the difference between the two becomes quite high, about 80 mm Hg. As a result, a greater number of oxygen molecules dissociate from hemoglobin and enter the tissues. The reverse is true of tissues, such as adipose (body fat), which have lower metabolic rates. Because less oxygen is used by these cells, the partial pressure of oxygen within such tissues remains relatively high, resulting in fewer oxygen molecules dissociating from hemoglobin and entering the tissue interstitial fluid. Although venous blood is said to be deoxygenated, some oxygen is still bound to hemoglobin in its red blood cells. This provides an oxygen reserve that can be used when tissues suddenly demand more oxygen.
Factors other than partial pressure also affect the oxygen-hemoglobin saturation/dissociation curve. For example, a higher temperature promotes hemoglobin and oxygen to dissociate faster, whereas a lower temperature inhibits dissociation (see Figure 3.2b). However, the human body tightly regulates temperature, so this factor may not affect gas exchange throughout the body. The exception to this is in highly active tissues, which may release a larger amount of energy than is given off as heat. As a result, oxygen readily dissociates from hemoglobin, which is a mechanism that helps to provide active tissues with more oxygen.
Certain hormones, such as androgens, epinephrine, thyroid hormones, and growth hormone, can affect the oxygen-hemoglobin saturation/disassociation curve by stimulating the production of a compound called 2,3-bisphosphoglycerate (BPG) by erythrocytes. BPG is a byproduct of glycolysis. Because erythrocytes do not contain mitochondria, glycolysis is the sole method by which these cells produce ATP. BPG promotes the disassociation of oxygen from hemoglobin. Therefore, the greater the concentration of BPG, the more readily oxygen dissociates from hemoglobin, despite its partial pressure.
The pH of the blood is another factor that influences the oxygen-hemoglobin saturation/dissociation curve (see Figure 3.2b). The Bohr effect is a phenomenon that arises from the relationship between pH and oxygen’s affinity for hemoglobin: A lower, more acidic pH promotes oxygen dissociation from hemoglobin. In contrast, a higher, or more basic, pH inhibits oxygen dissociation from hemoglobin. The greater the amount of carbon dioxide in the blood, the more molecules that must be converted, which in turn generates hydrogen ions and thus lowers blood pH. Furthermore, blood pH may become more acidic when certain byproducts of cell metabolism, such as lactic acid, carbonic acid, and carbon dioxide, are released into the bloodstream.
Carbon dioxide transport in the blood
Carbon dioxide is transported by three major mechanisms. The first mechanism of carbon dioxide transport is by blood plasma, as some carbon dioxide molecules dissolve in the blood. The second mechanism is transport in the form of bicarbonate (HCO 3 – ), which also dissolves in plasma. The third mechanism of carbon dioxide transport is similar to the transport of oxygen by erythrocytes (Figure 3.3).
Dissolved carbon dioxide
Although carbon dioxide is not considered to be highly soluble in blood, a small fraction—about 7 to 10 percent—of the carbon dioxide that diffuses into the blood from the tissues dissolves in plasma. The dissolved carbon dioxide then travels in the bloodstream and when the blood reaches the pulmonary capillaries, the dissolved carbon dioxide diffuses across the respiratory membrane into the alveoli, where it is then exhaled during pulmonary ventilation.
Bicarbonate buffer
A large fraction—about 70 percent—of the carbon dioxide molecules that diffuse into the blood is transported to the lungs as bicarbonate. Most bicarbonate is produced in erythrocytes after carbon dioxide diffuses into the capillaries, and subsequently into red blood cells. Carbonic anhydrase (CA) causes carbon dioxide and water to form carbonic acid (H 2 CO 3 ), which dissociates into two ions: bicarbonate (HCO 3 – ) and hydrogen (H + ). The following formula depicts this reaction:
\[\ce{CO2 + H2O CA↔ H2CO3↔H+ + HCO3−CO2 + H2O CA↔ H2CO3↔H+ + HCO3−}\]
Bicarbonate tends to build up in the erythrocytes so that there is a greater concentration of bicarbonate in the erythrocytes than in the surrounding blood plasma. As a result, some of the bicarbonate will leave the erythrocytes and move down its concentration gradient into the plasma in exchange for chloride (Cl – ) ions. This phenomenon is referred to as the chloride shift and occurs because by exchanging one negative ion for another negative ion, neither the electrical charge of the erythrocytes nor that of the blood is altered.
At the pulmonary capillaries, the chemical reaction that produced bicarbonate (shown above) is reversed, and carbon dioxide and water are the products. Much of the bicarbonate in the plasma re-enters the erythrocytes in exchange for chloride ions. Hydrogen ions and bicarbonate ions join to form carbonic acid, which is converted into carbon dioxide and water by carbonic anhydrase. Carbon dioxide diffuses out of the erythrocytes and into the plasma, where it can further diffuse across the respiratory membrane into the alveoli to be exhaled during pulmonary ventilation.
Carbaminohemoglobin
About 20 percent of carbon dioxide is bound by hemoglobin and is transported to the lungs. Carbon dioxide does not bind to iron as oxygen does; instead, carbon dioxide binds amino acid moieties on the globin portions of hemoglobin to form carbaminohemoglobin, which forms when hemoglobin and carbon dioxide bind. When hemoglobin is not transporting oxygen, it tends to have a bluish-purple tone to it, creating the darker maroon color typical of deoxygenated blood. The following formula depicts this reversible reaction:
\[\ce{CO2 + Hb↔HbCO2CO2 + Hb↔HbCO2}\]
Similar to the transport of oxygen by heme, the binding and dissociation of carbon dioxide to and from hemoglobin is dependent on the partial pressure of carbon dioxide. Because carbon dioxide is released from the lungs, blood that leaves the lungs and reaches body tissues has a lower partial pressure of carbon dioxide than is found in the tissues. As a result, carbon dioxide leaves the tissues because of its higher partial pressure, enters the blood, and then moves into red blood cells, binding to hemoglobin. In contrast, in the pulmonary capillaries, the partial pressure of carbon dioxide is high compared to within the alveoli. As a result, carbon dioxide dissociates readily from hemoglobin and diffuses across the respiratory membrane into the air.
In addition to the partial pressure of carbon dioxide, the oxygen saturation of hemoglobin and the partial pressure of oxygen in the blood also influence the affinity of hemoglobin for carbon dioxide. The Haldane effect is a phenomenon that arises from the relationship between the partial pressure of oxygen and the affinity of hemoglobin for carbon dioxide. Hemoglobin that is saturated with oxygen does not readily bind carbon dioxide. However, when oxygen is not bound to heme and the partial pressure of oxygen is low, hemoglobin readily binds to carbon dioxide.
- Watch this to see the transport of oxygen from the lungs to the tissues.
Oxyhemoglobin forms by a chemical reaction between which of the following?
a. hemoglobin and carbon dioxide
b. carbonic anhydrase and carbon dioxide
c. hemoglobin and oxygen
d. carbonic anhydrase and oxygen
Which of the following factors play a role in the oxygen-hemoglobin saturation/dissociation curve?
a. temperature
b. pH
c. BPG
d. All of the above
Which of the following occurs during the chloride shift?
a. Chloride is removed from the erythrocyte.
b. Chloride is exchanged for bicarbonate.
c. Bicarbonate is removed from the erythrocyte.
d. Bicarbonate is removed from the blood
A low partial pressure of oxygen promotes hemoglobin binding to carbon dioxide. This is an example of the ________.
a. Haldane effect
b. Bohr effect
c. Dalton’s law
d. Henry’s law
Why is oxygenated blood bright red, whereas deoxygenated blood tends to be more of a purple color? (think back to the video about oxygen transport)
Describe the relationship between the partial pressure of oxygen and the binding of oxygen to hemoglobin.


1.7: Examples of 2-Dimensional Motion
Circular Motion
Using what we just derived regarding the parallel and perpendicular components of acceleration, we turn now to the special case of an object traveling in a circle. The parallel part of the acceleration obviously always points tangent to the circle, which narrows it down to two directions at any given point on the circle. If the object is speeding up, then of course the tangent points in the direction of motion, and if it is slowing down, the tangent vector points in the direction opposite to the motion. The perpendicular part must be at a right angle to this tangent, which means it must be toward or away from the center of the circle. Unlike the tangent case, however, both directions are not possible. We can see this by considering the average perpendicular acceleration vector over two nearby moments in time:
Figure 1.7.1 – Direction of Centripetal Acceleration
What is the magnitude of this centripetal acceleration ? Well, it depends upon how fast the object is going (the faster it is moving, the more acceleration is required to turn in the same circle), and the radius of the circle (the acceleration is greater when the radius is smaller). Deriving the magnitude is left as an exercise, but the answer comes out to be:
\[ |\overrightarrow a_c | = \dfrac{v^2}{r} \]
Sometimes circular motion is the result of something rotating. For example, a bug on the outer rim of a rotating turntable travels in a circle, and therefore experiences centripetal acceleration. Well, when we deal with rotating objects we often know only the rate of its rotation (say in units of revolutions per minute), and we have to translate into linear motion to know the speed. There is a simple and standard way to do this.
Digression: Radians
If we are talking about rotational motion, we need to discuss how we measure such motion. We clearly don’t measure the speed of a spinning top or turntable in terms of meters per second, but rather how much it turns in a period of time. How does one measure the angle through which something turns? One way is to divide the full circle up into 360 equally-sized pie slices. The magnitude of one of these angles we call a 'degree.' But really this division is arbitrary. So why was 360º selected? Well, given that we often have to deal with slices of pie, we can avoid having to use fractional degrees if we select a number with lots of factors, and 360 certainly fits the bill – it is divisible by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 120, and 180.
But there is no reason at all that divisibility needs to be our only criterion. In fact, we don’t even need to divide the circle into an integral number of pieces. For example, we could divide it into 7.5 pieces and call the size of each piece “1 flibber.” We can even translate between different systems of units: \(1^f\) = 48º.
But there is another criterion that leads to a definition of a measurement of angles that is different from degrees. Suppose we want a simple translation from angle to arclength (the distance traveled along the circular curve subtended by that angle). We know that traveling around an entire circle requires a journey of a distance equal to \(2 \pi\) times the radius of the circle. So going around some fraction of a circle requires a journey equal to that fraction times \(2 \pi r\). So if we divide the circle into an uneven number of pieces such that \(2 \pi\) of these pieces fit into the circle, then in these units you can calculate the arclength by just multiplying the angle measured in those units (called radians ) by the radius of the circle:
If we want to translate between the speed that something is going around the circle to the angular speed at which the slice of the pie is being swept-out by this motion, we need only take a derivative:
This gives us an alternative way of expressing the centripetal acceleration:
\[ | \vec a _ c | = \frac{v^2}{r} = \frac{\left( r \omega \right) ^2}{r} = r \omega^2 \]
A bead is threaded onto a circular hoop of wire which lies in a vertical plane. The bead starts at the bottom of the hoop from rest, and is pushed around the hoop such that it speeds up at a steady rate.
- Analysis
-
The tangential motion of the bead is in one dimension, so we can use the usual kinematics equations to describe its motion along the circle. That is, equations like:
\[x\left(t\right)=x_o+v_o t +\frac{1}{2}at^2\nonumber\]
can be used here, where the displacement \(\Delta x=x-x_o\) is the distance measured around the arc of the circle. So if the bead goes all the way around, then \(\Delta x\) is just the circumference of the circle.
The fact that the bead "speeds up at a steady rate" means that the part of the bead's acceleration in its direction of motion (i.e. tangent to the circle) is a constant. This is not to say that the acceleration of the bead is constant, however. Its motion is changing direction, which means that there is a component of acceleration perpendicular to its velocity (in this case, centripetal). Given that the magnitude of centripetal acceleration depends upon the radius of the circle (which in this case doesn't change) and the speed of the object (which in this case does change), then this component of acceleration is changing in magnitude over time.
We can apply some general mathematics to this case. If we call the constant acceleration tangent to the circle \(a\), then since it starts from rest, the speed of the bead tangent to the circle at any given time is just \(v(t)=at\). If we call the radius of the circle \(R\), then we can write down the centripetal acceleration as a function of time as:
\[a_c=\dfrac{v^2}{R}=\dfrac{a^2}{R}t^2\nonumber\]
Projectile Motion
For circular motion, we have the components of velocity changing in tandem in a specific manner to keep the path circular. Another – actually simpler – form of motion involves only a single fixed coordinate component of velocity changing, while the other components involve no change in velocity. What I am alluding to here is projectile motion , which comes about because the vertical component of motion is subject to constant acceleration (as we discussed when we talked about free-fall), while the horizontal component is unaffected by gravity’s influence. This kind of motion is only one small step from the free-fall we are already familiar with, in that it includes a totally independent horizontal component of motion that incorporates (to the extent that air resistance can be ignored) no acceleration. As simple as this sounds, a couple of examples muddy the waters a bit, and sorting them out is very instructive:
Conceptual Question
A hunter climbs a tree and fires a bullet directly at a monkey that is hanging from a branch of another tree at precisely the same height as the barrel of the hunter’s gun. The instant the bullet leaves the gun, the monkey lets go of the branch. Ignoring air resistance (and the size of the monkey - assume it is very small), what is the fate of the monkey?
- The monkey will be hit by the bullet.
- The bullet will pass beneath the monkey.
- The bullet will fly over the monkey’s head.
- Whether the bullet flies over the monkey’s head or passes beneath it depends upon how fast the bullet is moving when it leaves the barrel of the gun.

- Solution
-
A (and E). The vertical motion of the monkey is independent of the horizontal motion, so in equal time spans, the bullet falls the same distance as the monkey. Since they started at the same level, they remain at the same level at all times, including when the horizontal position of the bullet equals the horizontal position of the monkey.
Conceptual Question
After falling out of the tree the last time he tried to shoot a monkey (his gun misfired), the hunter now decides to shoot a monkey from the ground. He is aiming upward at an angle, and is assuming the monkey will again let go of the branch just as the bullet is on its way. How should the hunter aim this time, if he is to bag his simian prize?
- He should aim right at the monkey.
- He should aim above the monkey.
- He should aim below the monkey.
- Unlike the level-shot case, where he should aim this time does depend upon how fast the bullet is coming out of the gun.
- The jerk should just aim at himself.
- Solution
-
A (and E). If there was no gravity, the bullet would follow a straight line to the monkey. With gravity acting straight down, the amount that the bullet drops below that straight line is the same that an object starting from rest on that straight line falls in an equal time. So the bullet and the monkey remain the same distance from the straight line at all times. When the bullet’s horizontal position equals the monkey’s horizontal position, they will coincide.
The only difference between this example and the previous one is that in the previous case, the line joining the barrel of the gun and the target was horizontal. Still, not everyone may be as convinced in this case as in the previous one, so let's do the math...
Suppose there is no gravity. The path that the bullet takes (\(y\) as a function of \(x\)) can be written down pretty easily. If the point where the bullet exits the barrel is chosen to be the origin, then the straight line to the monkey has a slope equal to the ratio of the vertical and horizontal components of velocity:
\[y=mx+b=\left(\dfrac{v_{oy}}{v_{ox}} \right)x \nonumber \]
Now suppose there is gravity. We have separate horizontal and vertical equations of motion. Again, with the bullet starting at the origin, we have:
\[x=v_{ox}t \\ y=v_{oy}t-\frac{1}{2}gt^2 \nonumber \]
Now solve for \(t\) in the first equation and plug it into the first term of the second equation to get:
\[y=\dfrac{v_{oy}}{v_{ox}}x-\frac{1}{2}gt^2 \nonumber \]
Comparing this with the first equation above, we see that the \(y\) value would follow the same straight line if not for the second term, and the amount that the height of the bullet \(y\) is decreased from that line after a time \(t\) is exactly the same distance that the monkey falls from that line in the same time.
With the number of variables and constants involved in projectile motion problems, there are countless ways to construct problems. There is no substitute for independent thinking and creativity, but the steps given below provide a good starting point for solving these kinds of problems.
- Draw a picture, labeling it as completely as you can, using information you have been given. Then spend some time thinking about what is happening – put yourself into the situation.
Alert
While this is given as a step for projectile problems, this is actually how you should start every physics problem!
- Pick an \(x\), \(y\) origin as well as \(+x\) and \(+y\) directions. Often for projectile problems up is chosen as the positive direction (making the acceleration due to gravity a negative value), but this is by no means required. What is important is that you use the positive direction consistently throughout the constants and variables in the equations.
- Break any initial velocities into components along the \(x\) and \(y\) directions.
- Write down the equations of motion, circling quantities that you know, and underlining the number you are looking for. If you have too many un-circled quantities for the number of equations available, you cannot yet do the algebra, so you’ll need to review the statement of the problem for any values concealed in the language of the problem (if you just scan a problem for numbers without carefully reading it, you will miss these).
- Solve the algebra and reconstitute components back into vectors, if necessary.
- Briefly check to see if the answer makes sense.
Alert
This is actually how you should end every physics problem!
One thing in projectile motion that is a useful tool is known as the range equation. This was of particular use to military firing cannonballs or (farther back in history than that), catapults. This equation relates the distance that a projectile will fly assuming it lands at the same vertical position that it started, given the starting speed of the projectile and the starting angle. Let’s treat finding this equation as if it was a projectile motion problem given to us, and follow the procedure outlined above
A cannonball is fired at an angle \(\theta\) up from the horizontal at a speed of \(v_o\), along level ground. Ignore air resistance in your analysis.
- Analysis
-
The diagram below labels the origin and the + directions. It sure seems like knowing the initial angle and speed (as well as the fact that the ground is level) should be sufficient to determine how far the cannonball travels. We will therefore look for \(R\) (referred to as the "range") in terms of the initial speed \(v_o\) of the projectile and the launch angle \(\theta\), which we treat as known values. The rest of the procedure and algebra is given below.
It is interesting to note that for any given launch speed, there are in general two (complementary) angles that correspond to the same range (except for \(45^o\)). For example, a cannonball fired at \(\theta=50^o\) will land at the same place as a cannonball fired at the same speed at an angle of \(\theta=40^o\).
It is also possible to determine the angle at which the range is maximized for a given velocity. Treating \(v_o\) as a constant and maximizing the function \(R\left(\theta\right)\) gives:
\[0=\dfrac{dR}{d\theta}=2\dfrac{v_o^2}{g}\cos 2\theta\;\;\;\Rightarrow\;\;\;\theta=45^o\nonumber\]
Two warlords aim identical catapults (i.e. they both release rocks at the same speed) at each other, with both of them being at the same altitude. The warlords have made the necessary computations to crush the other, and fire their catapults simultaneously. Amazingly, the two stones do not collide with each other in mid-air, but instead the stone Alexander fired passes well below the stone that Genghis shot.
- Analysis
-
These are two projectiles fired with equal speeds to equal ranges, but using the result from the previous analysis box, we know they must have been fired at complimentary angles. While the ranges are the same, the times are not, since the time for the full flight is twice the time from the apex to the ground, which means that the projectile fired at the lower angle (which will reach a lower peak height) will reach its target first. Because Alexander's stone passes below Genghis's stone, it must have a greater \(x\) component of velocity, which means that when the stones pass by each other, the crossing point must be closer to Genghis than Alexander, and Alexander's stine is on the way down, while Genghi's is still on the way up. It looks something like this:
If we knew something about the times these projectiles take to hit their targets, we could relate the (constant) \(x\)-components of their velocities. Combining this with the knowledge that they have equal total speeds and are fired at complementary angles gives us a lot to work with.


2.5: The modular view of the capability approach
It is time to take stock. What do we already know about the capability approach, and what questions are raised by the analysis so far? The capability approach is an open approach, and depending on its purpose can be developed into a range of capability theories or capabilitarian applications. It is focused on what people can do and be (their capabilities) and on what they are actually achieving in terms of beings and doings (their functionings). However, this still does not answer the question of what kind of framework the capability approach is. Can we give an account of a capability theory that is more enlightening regarding what exactly makes a theory a capabilitarian theory, and what doesn’t?
In this book, I present an account of the capability approach that, on the one hand, makes clear what all capability theories share, yet on the other hand allows us to better understand the many forms that a capability theory or capability account can take — hence to appreciate the diversity within the capability approach more fully. The modular view that I present here is a modified (and, I hope, improved) version of the cartwheel model that I have developed elsewhere (Robeyns 2016b). The modular view shifts the focus a little bit from the question of how to understand the capability approach in general, to the question of how the various capability accounts, applications and theories should be understood and how they should be constructed. After all, students, scholars, policy makers and activists are often not concerned with the capability approach in general, but rather want to know whether it would be a smart idea to use the capability approach to construct a particular capability theory, application or account for the problem or question they are trying to analyse. In order to answer the question of whether, for their purposes, the capability approach is a helpful framework to consider, they need to know what is needed for a capability theory, application or account. The modular view that will follow will give those who want to develop a capability theory, application or analysis a list of properties their theory has to meet, a list of choices that need to be made but in which several options regarding content are possible, and a list of modules that they could take into account, but which will not always be necessary.
Recall that in order to improve readability, I use the term ‘a capability theory’ as a short-hand for ‘a capability account, or capability analysis, or capability application, or capability theory’. A capability theory is constructed based on three different types of module, which (in order to facilitate discussion) will be called the A-module, B-modules and C-modules. The A-module is a single module which is compulsory for all capability theories. The A-module consists of a number of propositions (definitions and claims) which a capability theory should not violate. This is the core of the capability approach, and hence entails those properties that all capability theories share. The B-modules consist of a range of non-optional modules with optional content. That is, if we construct a capability theory, we have to consider the issue that the module addresses, but there are several different options to choose from in considering that particular issue. For example, module B1 concerns the ‘purpose’ of the theory: do we want to make a theory of justice, or a more comprehensive evaluative framework for societal institutions, or do we want to measure poverty or inequality, or design a curriculum, or do we want to use the capability approach to conceptualise ‘social progress’ or ‘efficiency’ or to rethink the role of universities in the twenty-first century? All these purposes are possible within the capability approach. The point of seeing these as B-modules is that one has to be clear about one’s purpose, but there are many different purposes possible. The C-modules are either contingent on a particular choice made in a B-module, or they can be fully optional. For example, one can offer a comprehensive evaluation of a country’s development path, and decide that as part of this evaluation, one wants to include particular accounts of the history and culture of that country, since this may make more comprehensible the reasons why that country has taken this particular development path rather than another. The particular historical account that would be part of one’s capability theory would then be optional. 16
Given this three-fold structure of the modular view of capability theories, let us now investigate what the content of the compulsory module A is, as well as what the options are within the B-modules and C-modules.
16 To say that the insertion of those theories is fully optional is not the same as saying that capability theories that will be developed with different types of additional complementary theories will all be equally good. For example, historians are very likely to think that most theories, even normative theories, have to be historically informed, and hence the relevant historical knowledge will need to be added to a capability theory. But these are matters of dispute that have to be debated, and cannot be settled by narrowing down the definition of a capability theory.


6.1: Putting It Together- Organizational Structures
Back to IBM Credit Corporation
Let’s return to our case study of IBM’s credit arm that we considered at the outset of this module. You’ll recall that credit applications could take six days to several weeks to be processed, during which time sales were being lost to competitors. So what did IBM do?
Two senior managers with the company decided to follow a credit application throughout the entire process. When they did, they were surprised to discover that the actual processing time for each application was only ninety minutes! It quickly became evident that the delays were not a result of the amount of work that needed to be completed. Instead, it was a function of the structure the company had implemented. Each step in the approval process was routed to a different specialist to be completed.
- Step 1: Central office operator receives a finance request from a salesperson and records it on an input form → form is routed to the credit department
- Step 2: Credit specialist reviews the customer and makes a credit decision → result is recorded on the form, which is routed to the business practices department
- Step 3: Business practices approves any customer-requested changes to the standard loan covenants → changes are noted on the form and it is sent to the pricing department
- Step 4: Pricing specialist determines the appropriate rate to charge based on the customer’s credit and specific loan covenants → form moves to the administration department
- Step 5: Administration specialist turns all information recorded on the form into a quote letter → quote letter is routed to the sales specialist for delivery to the customer
Based on what you learned in this module, how would you describe IBM Credit’s organizational structure? Thinking back to Schein’s four key elements of an organization, where do you see opportunities for improvement?
- Common Purpose – Do the specialists understand their role in the overall purpose of the credit arm’s goal to support the sale of IBM computers, software, and equipment?
- Coordinated Effort – Has management coordinated the effort of work in a way that best adds value to the organization?
- Specialization and Division of Labor – Has management broken down the tasks into optimum sizes to allow maximum efficiency?
- Hierarchy of Authority – Is the optimal reporting structure in place?
In the end, the company realized that it had done a poor job of coordinating the efforts of the organization. Although each of the specialists was working hard, the structure did not support the overall goal of maximizing IBM Corp’s sales. In fact, the problem was based on an erroneous assumption that every request that was received was unique and difficult. In reality, the majority of credit requests were straightforward and easy to process. It generally did not require someone with the in-depth knowledge of a specialist. The organization had divided the labor too narrowly.
The company changed its structure, and instead of using specialists, it assigned generalists trained to handle a standard credit request. They would own the request from start to finish and would only engage the help of a specialist if the situation was more complex than they could handle. The result? The new turnaround time was closer to four hours compared with six days or weeks!
This example clearly illustrates the need for managers to carefully analyze their organizational structure to ensure that it is capable of delivering the desired results.
Contributors and Attributions
- Putting It Together: Organizational Structures. Authored by : Jeff Heflin and Lumen Learning. License : CC BY: Attribution
- IBM. Authored by : Michael Cote. Located at : https://www.flickr.com/photos/cote/4709133844/ . License : CC BY: Attribution


6.1: Introduction
Virtually every task performed by living organisms requires energy. Organisms require energy to perform heavy labor and exercise, but humans also use considerable energy while thinking, and even during sleep. Every organism's living cells constantly use energy. Organisms import nutrients and other molecules. They metabolize (break down) and possibly synthesize into new molecules. If necessary, molecules modify, move around the cell and may distribute themselves to the entire organism. For example, the large proteins that make up muscles are actively built from smaller molecules. Complex carbohydrates break down into simple sugars that the cell uses for energy. Just as energy is required to both build and demolish a building, energy is required to synthesize and break down molecules. Additionally, signaling molecules such as hormones and neurotransmitters transport between cells. Cells ingest and break down bacteria and viruses. Cells must also export waste and toxins to stay healthy, and many cells must swim or move surrounding materials via the beating motion of cellular appendages like cilia and flagella.
The cellular processes that we listed above require a steady supply of energy. From where, and in what form, does this energy come? How do living cells obtain energy, and how do they use it? This chapter will discuss different forms of energy and the physical laws that govern energy transfer. This chapter will also describe how cells use energy and replenish it, and how chemical reactions in the cell perform with great efficiency.
Contributors and Attributions
Remixed and/or curated from the following works:
Clark, M. A., Douglas, M., & Choi, J. (2018). 2.3.1 Introduction . In Biology 2e . OpenStax (CC BY 4.0; Access for free at https://openstax.org/books/biology-2e/pages/1-introduction ).


2.2: Psalms
In this chapter you will
- revisit the large collection of song lyrics within the Bible known as the Psalms
- compare their historic liturgical use with their treatment as art music
Whole courses have been taught on the Psalms alone. Whole books can be written just on how one particular psalm has been given different musical treatments. But by the time it was published, it would already be obsolete, as new settings would have appeared in the interim—not that any book on even just one psalm would manage to be comprehensive. We have had the occasion to mention the Psalms repeatedly throughout this book already. They are important among the earliest evidence related to music in the biblical tradition, even though there may be yet older texts and references to music embedded here and there in the Torah. The early chapters of this book highlighted their importance in Jewish liturgy, in Orthodox and Catholic liturgy and monastic practice, and when arranged metrically and thereby turned into hymns in Protestantism. [1] Still more can be said and—more importantly in this context—listened to.
Richard Taruskin writes in The Oxford History of Western Music ,
An important aspect of the monastic regimen was staying up at night, a discipline known as the vigil. To help them keep awake and to assist their meditations, monks would read and recite constantly, chiefly from the Bible, and particularly from the Psalter. The standard practice, eventually turned into a rule, was to recite the Psalter in an endless cycle, somewhat in the manner of a mantra, to distract the mind from physical appetites, to fill the back of the mind with spiritually edifying concepts so as to free the higher levels of consciousness (the intellectus, as it was called) for mystical enlightenment.…
Christian psalmody emphasized not metaphors of wealth and exuberance (the orchestras, dancers, and multiple choirs of the Temple) but metaphors of community and discipline, both symbolized at once by unaccompanied singing in unison. That remained the Gregorian ideal, although the community of worshipers was replaced in the more public repertory of the Mass by the specially trained.…Monophony was thus a choice, not a necessity. It reflects not the primitive origins of music (as the chant’s status as oldest surviving repertory might all too easily suggest) but the actual rejection of earlier practices, both Judaic and pagan, that were far more elaborate and presumably polyphonic. [2]
Composers have set the Psalms for liturgical use as well as simply as expressions of their own musicality. The Milken Archive has examples with commentary from a young Leonard Bernstein (Psalm 148) and from contemporary composer Ofer Ben-Amots (Psalm 81) . You may also wish to listen now to the Psalm settings by Lili Boulanger in chapter 29.
While often the entirety of a psalm has been set to music, sometimes parts are left out. This may be done for any number of reasons, but whatever the motivation, the resulting song and its lyrics deserve to be considered not only as a “setting” of the text but also as a new composition heard both on its own terms and with consideration of what has been omitted. An excellent example is Psalm 137 . Many know it as a reggae or pop song (depending on whether their musical tastes incline them more toward the Melodians , Boney M , or Sublime ). That version understandably omits the mention of dashing Babylonian infants against rocks. The reggae version also has some differences in wording that reflect the Rastafarian context in which the song was written. Other settings, such as Pelham Humfrey’s from the seventeenth century, keep the words, as does Mario Davidovsky’s Biblical Songs , which includes this psalm along with settings of other biblical texts. [3] In this latter instance, it is interesting that the composer chose small portions of other texts yet included the entirety of this psalm, switching to Hebrew in the middle and then back to English again.
Among the Psalms, one finds some of the most accessible and familiar parts of the Bible and some that may seem particularly troubling. Imprecatory psalms—that is, psalms that curse or wish ill upon enemies—can be difficult for some who come to the Bible expecting it to be divine words rather than human ones. When we recognize that the psalmist behind Psalm 137 had lost his or her own children in the Babylonian siege of Jerusalem, we understand the raw emotion expressed in this lament in a new light. It is not merely wishing others harm but a desire for those who caused pain to be made to feel that pain themselves. In some cases, the expression of the desire in this way may lead one to pull back and resist the urge to repay in kind. Complaining is embraced in some traditions as an important aspect of biblical piety, while in others its psychological and spiritual benefits are liable to remain unexplored, at least in formal religious settings.
Sometimes a composer opts to set just a portion of a psalm, perhaps even a small one. Herbert Howells has set Psalm 42:1–3 , Psalm 84:9–10 , and Psalm 118:24 . Issachar Miron’s Psalms of Israel features small portions of several psalms set in the original Hebrew. In these cases, listeners should reflect on how the meaning of the words changes not only through the addition of music but through the omission of words. So too when a composer sets more than one psalm as part of a larger work, the question of what meaning emerges not only from the interplay of music and text but from the juxtaposition of multiple texts deserves reflection. One famous example that you should listen to is Igor Stravinsky’s Symphony of Psalms . Here is a performance by the Chicago Symphony Orchestra, with the Chicago Symphony Chorus and Glen Ellyn Children’s Chorus, conducted by Sir Georg Solti. [4]
In places, Stravinsky sets the words in a way that goes against the grain of the natural rhythms of the text or connectedness of words, allowing his musical goals to predominate. While Stravinsky created a symphony from parts of several psalms , some composers have made a single psalm the focus of a symphony. Both Carlos Riesco and Archibald James Potter have composed works titled Sinfonia “De Profundis.” That is the Latin title of a great many settings of Psalm 130, including those by Lili Boulanger and Arnold Schoenberg mentioned elsewhere in the book (John Rutter’s Requiem also includes a setting of this psalm in English as one of its movements). It might be possible to miss that certain works are settings of psalms or other Scripture—for instance, if one did not translate the Latin title of G. F. Handel’s Dixit Dominus (Psalm 110, “The Lord Said”). Whole projects dedicated to setting and recording the Psalms continue to appear. Individual artists such as Poor Bishop Hooper have set out to write and record a song setting of every psalm. Contemporary composers like Tamás Beischer-Matyó have set multiple psalms . Having set out to create a setting of every psalm, Beischer-Matyó found after several that his compositional interests had shifted in a different direction (although he may one day return to the Psalms and even complete the project at some point). After setting Psalm 1 and Psalm 23 , Beischer-Matyó found when working on Psalm 6 that his entire approach to composition shifted as a result of his engagement with the biblical text and the act of interpreting it musically. [5] In other chapters, we find something similar in the lives of other composers—how the process of setting a particular text was associated with a major change of direction in their musical style as well. [6]
One could spend a lot of time just comparing two relatively recent settings of Psalm 84, such as those by Victoria Bond and the Philippines -based Jesuit group Himig Heswita . Bond’s decision to set this particular psalm was influenced by the way it features prominently in Brahms’s Requiem (which is discussed elsewhere in this book). On her website, Bond describes the way she decided to allow the Hebrew text and a range of possible English translations interact among the voices in her composition. She writes, “Counterpoint forms the basis of my musical language in this setting, it being a traditional technique favored by Baroque composers. Counterpoint was also a useful tool to express the multiplicity of translations, perspectives and moods I wanted to illuminate. The voices unify only during the communal prayer-like settings of the opening text.” [7] Have a listen. [8]
One can also spend extended amounts of time comparing what the same composer has done with two different psalms, such as (in addition to several already mentioned) Cyrillus Kreek’s settings of Psalm 22 and Psalm 137 —both laments with many resonances with and connections to other parts of the Bible. Consider also David Hurd’s settings of Psalm 51 (“Miserere Mei, Deus”) and Psalm 100, which feel very different in keeping with the different moods of the words. [9]
There are interviews with Dr. David Hurd that will introduce you to more of his music as well as aspects of his life and work as a composer, and they are highly recommended.
In this chapter, more than perhaps any other, hopefully it will be clear that your exploration may begin here, with the Psalms and/or with this book, but if it ends here, it will miss a lot that is beautiful and fascinating. To further explore how the Psalms have found expression in a wide variety of styles and genres, have a listen to U2’s song “40,” Dr. Nathan M. Carter’s several Psalm settings, Ian White’s several albums , Steve Reich’s “Tehillim,” Kim Hill’s song “Psalm 1,” Jah Woosh’s reggae setting of Psalm 121 , one of Brazilian gospel artist Diante do Trono’s versions of the Psalms , and any of the many rap versions of the Psalms (which have important characteristics that bring us closer to ancient chanting practices than other musical approaches do). [10] All are contemporary and together illustrate how different the results can be when the words of the Psalms from ancient Israel are conjoined to music of another age, allowing them to be heard and sung in a fresh way. They provide an opportunity to reflect on whether and to what extent these varied songs may allow today’s listener to get a slight inkling of what the Psalms were like for those who first wrote, sang, and heard them thousands of years ago.
For Further Reading
Bailey, Marc. “Psalmic Music in Orthodox Liturgy as Foundation, Movement, and Ministry (Part 1).” Jacob’s Well , Spring–Summer 2000, 21–25. https://web.archive.org/web/20210515224439/https://jacwell.org/Summer_2000/psalmic_music_in_orthodox_liturg.htm.
Bell, John. “The Lost Tradition of Lament.” In Composing Music for Worship , edited by Stephen Darlington and Alan Kreider, 104–16. Norwich, UK: Canterbury Press, 2003.
Brown, William P., ed. The Oxford Handbook of the Psalms . New York: Oxford University Press, 2014.
Holladay, William L. The Psalms through Three Thousand Years : Prayerbook of a Cloud of Witnesses . Minneapolis: Fortress, 1993.
Riesco, Carlos. “Historia de una Sinfonía.” Revista Musical Chilena 39, no. 164 (1985): 80–103.
Smith, Mark S. Psalms: The Divine Journey . New York: Paulist, 1987.
Stern, Max. Psalms and Music: Influences of the Psalms on Western Music . Brooklyn: KTAV, 2013.
Zak, Rose A. “Dialogue and Discourse in Stravinsky’s ‘Symphony of Psalms.’” Criticism 22, no. 4 (1980): 357–75.
Zinar, Ruth. “Stravinsky and His Latin Texts.” College Music Symposium 18, no. 2 (1978): 176–88.
- In addition to the chapter on metrical psalms in this book, see also Janet Wootton’s discussion of Isaac Watts and several other hymnwriters who set and drew on Scripture in her chapter, “The Future of the Hymn,” in Composing Music for Worship , ed. Stephen Darlington and Alan Kreider (Norwich: Canterbury Press, 2003), 117–40 (especially 120–21). ↵
- Richard Taruskin, The Oxford History of Western Music , vol. 1, Music from the Earliest Notations to the Sixteenth Century (New York: Oxford University Press, 2009) http://www.oxfordwesternmusic.com/view/Volume1/actrade-9780195384819-div1-001007.xml . ↵
- Davidovsky has also set parts of the Song of Songs to music in his Shulamit’s Dream and Scenes from Shir ha-Shirim . ↵
- Licensed to YouTube by UMG on behalf of Decca. ↵
- This information comes from a personal conversation with the composer, to whom the author is extremely grateful for his input. ↵
- Arvo Pärt and Arnold Schoenberg provide particularly interesting and important examples. ↵
- Victoria Bond, “Repertoire: How Lovely Is Your Dwelling Place (Psalm 84),” https://www.victoriabond.com/artist.php?view=reper&rid=2776 . Counterpoint is when two melodic lines move independently of one another in music. The Baroque era is explained further in chapter 25 on Bach . ↵
- Shared on YouTube by the composer Victoria Bond, the video is of a performance on November 23, 2014, at the Cathedral Church of Saint John the Divine, featuring the combined choirs of Temple Emanu-El and the Cathedral Church of Saint John the Divine, conducted by Kent Tritle. ↵
- Two recordings follow. The first is a recording of a performance of David Hurd’s “Miserere Mei, Deus” at the Cathedral of the Immaculate Conception in Portland, Oregon. Licensed to YouTube by the Orchard. The second is a recording of Hurd’s “Psalm 100” performed by the Singers, Minnesota Choral Artists. The recording is shared on YouTube by its publisher, E. C. Schirmer. ↵
- On the phenomenon of Brazilian gospel music, see Philip Jenkins’s article “Brazil’s Diverse Música Gospel,” Christian Century , November 12, 2021, https://www.christiancentury.org/article/notes-global-church/brazil-s-explosion-m-sica-gospel . If you feel that microtonal music has been neglected, listen to Mordecai Sandberg’s setting of Psalm 130 . ↵


<IP_ADDRESS>: When to Cite
When to Cite
Tip: Why Cite Sources?
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Citing sources is often described as a straightforward, rule-based practice. But in fact, there are many gray areas around citation, and learning how to apply citation guidelines takes practice and education. If you are confused by it, you are not alone – in fact you might be doing some good thinking. Here are some guidelines to help you navigate citation practices.
Cite when you are directly quoting. This is the easiest rule to understand. If you are stating word-for-word what someone else has already written, you must put quotes around those words and you must give credit to the original author. Not doing so would mean that you are letting your reader believe these words are your own and represent your own effort.
Cite when you are summarizing and paraphrasing. This is a trickier area to understand. First of all, summarizing and paraphrasing are two related practices but they are not the same. Summarizing is when you read a text, consider the main points, and provide a shorter version of what you learned. Paraphrasing is when you restate what the original author said in your own words and in your own tone. Both summarizing and paraphrasing require good writing skills and an accurate understanding of the material you are trying to convey.
Cite when you are citing something that is highly debatable. For example, if you want to claim that the Patriot Act has been an important tool for national security, you should be prepared to give examples of how it has helped and how experts have claimed that it has helped. Many U.S. citizens concerned that it violates privacy rights won’t agree with you, and they will be able to find commentary that the Patriot Act has been more harmful to the nation than helpful. You need to be prepared to show such skeptics that you have experts on your side, too.
Tip: Why Cite Sources?
This section covers how and when to cite sources. For a discussion of why to cite sources, see Ethical Use of Sources.
Don’t cite when what you are saying is your own insight. As you learned in The Purpose of Academic Argument, research involves forming opinions and insights around what you learn. You may be citing several sources that have helped you learn, but at some point you must integrate your own opinion, conclusion, or insight into the work. The fact that you are not citing it helps the reader understand that this portion of the work is your unique contribution developed through your own research efforts.
Don’t cite when you are stating common knowledge. What is common knowledge is sometimes difficult to discern. In general, quick facts like historical dates or events are not cited because they are common knowledge.
Examples of information that would not need to be cited include:
Some quick facts, such as statistics, are trickier. For example, the number of gun-related deaths per year probably should be cited, because there are a lot of ways this number could be determined (does the number include murder only, or suicides and accidents, as well?) and there might be different numbers provided by different organizations, each with an agenda about gun laws.
A guideline that can help with deciding whether or not to cite facts is to determine whether the same data is repeated in multiple sources. If it is not, it is best to cite.
The other thing that makes this determination difficult might be that what seems new and insightful to you might be common knowledge to an expert in the field. You have to use your best judgment, and probably err on the side of over-citing, as you are learning to do academic research. You can seek the advice of your instructor, a writing tutor, or a librarian. Knowing what is and is not common knowledge is a practiced skill that gets easier with time and with your own increased knowledge.
You’ve likely been told at some point that you can’t cite Wikipedia, or any encyclopedia for that matter, in your scholarly work.
The reason is that such entries are meant to prepare you to do research, not be evidence of your having done it. Wikipedia entries, which are tertiary sources, are already a summary of what is known about the topic. Someone else has already done the labor of synthesizing lots of information into a concise and quick way of learning about the topic.
So while Wikipedia is a great shortcut for getting context, background, and a quick lesson on topics that might not be familiar to you, don’t quote, paraphrase, or summarize from it. Just use it to educate yourself.


7.1.1: Factors Affecting Enzyme Activity
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Learning Objectives
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Define or describe the following:
- metabolism
- catabolic reaction
- anabolic reaction
- enzyme
- substrate
- apoenzyme
- haloenzyme
- cofactor (coenzyme)
- State how enzymes are able to speed up the rate of chemical reactions.
- Briefly describe a generalized enzyme-substrate reaction, state the function of an enzyme's active site, and describe how an enzyme is able to speed up chemical reactions.
- State four characteristics of enzymes.
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State how the following affect the rate of an enzyme reaction.
- enzyme concentration
- substrate concentration
- temperature
- pH
- salt concentration
- State how chemicals such as chlorine, iodine, iodophores, mercurials, and ethylene oxide inhibit or kill bacteria.
- State how high temperature and low temperature exert their effect on bacteria.
To live, grow, and reproduce, microorganisms undergo a variety of chemical changes. They alter nutrients so they can enter the cell and they change them once they enter in order to synthesize cell parts and obtain energy. Metabolism refers to all of the organized chemical reactions in a cell. Reactions in which chemical compounds are broken down are called catabolic reactions while reactions in which chemical compounds are synthesized are termed anabolic reactions. All of these reactions are under the control of enzymes.
Enzymes are substances present in the cell in small amounts that function to speed up or catalyze chemical reactions. On the surface of the enzyme is usually a small crevice that functions as an active site or catalytic site to which one or two specific substrates are able to bind. (Anything that an enzyme normally combines with is called a substrate.) The binding of the substrate to the enzyme causes the flexible enzyme to change its shape slightly through a process called induced fit to form a tempore intermediate called an enzyme-substrate complex (Figure \(\PageIndex{1}\)).
Enzymes speed up the rate of chemical reactions because they lower the energy of activation, the energy that must be supplied in order for molecules to react with one another (Figure \(\PageIndex{2}\)). Enzymes lower the energy of activation by forming an enzyme-substrate complex allowing products of the enzyme reaction to be formed and released (Figure \(\PageIndex{3}\)).
Many enzymes require a nonprotein cofactor to assist them in their reaction. In this case, the protein portion of the enzyme, called an apoenzyme, combines with the cofactor to form the whole enzyme or haloenzyme (Figure \(\PageIndex{3}\)). Some cofactors are ions such as Ca ++ , Mg ++ , and K + ; other cofactors are organic molecules called coenzymes which serve as carriers for chemical groups or electrons. NAD + , NADP + , FAD, and coenzyme A (CoA) are examples of coenzymes.
Characteristics of Enzymes
Chemically, enzymes are generally globular proteins. (Some RNA molecules called ribozymes can also be enzymes. These are usually found in the nuclear region of cells and catalyze the splitting of RNA molecules). Enzymes are catalysts that breakdown or synthesize more complex chemical compounds. They allow chemical reactions to occur fast enough to support life. Enzymes speed up the rate of chemical reactions because they lower the energy of activation, the energy that must be supplied in order for molecules to react with one another. Anything that an enzyme normally combines with is called a substrate. Enzymes are very efficient. An enzyme generally can typically catalyze between 1 and 10,000 molecules of substrate per second. Enzymes are only present in small amounts in the cell since they are not altered during their reactions. and they are highly specific for their substrate. Generally there is one specific enzyme for each specific chemical reaction.
Enzyme Activity
Enzyme activity is affected by a number of factors including:
- The concentration of enzyme : Assuming a sufficient concentration of substrate is available, increasing enzyme concentration will increase the enzyme reaction rate.
- The concentration of substrate : At a constant enzyme concentration and at lower concentrations of substrates, the substrate concentration is the limiting factor. As the substrate concentration increases, the enzyme reaction rate increases. However, at very high substrate concentrations, the enzymes become saturated with substrate and a higher concentration of substrate does not increase the reaction rate.
- The temperature : Each enzyme has an optimum temperature at which it works best. A higher temperature generally results in an increase in enzyme activity. As the temperature increases, molecular motion increases resulting in more molecular collisions. If, however, the temperature rises above a certain point, the heat will denature the enzyme, causing it to lose its three-dimensional functional shape by denaturing its hydrogen bonds. Cold temperature, on the other hand, slows down enzyme activity by decreasing molecular motion.
- The pH : Each enzyme has an optimal pH that helps maintain its three-dimensional shape. Changes in pH may denature enzymes by altering the enzyme's charge. This alters the ionic bonds of the enzyme that contribute to its functional shape.
- The salt concentration : Each enzyme has an optimal salt concentration. Changes in the salt concentration may also denature enzymes.
Some relationships between bacterial enzymes and the use of disinfectants and extremes of temperature to control bacteria.
- Many disinfectants, such as chlorine, iodine, iodophores, mercurials, silver nitrate, formaldehyde, and ethylene oxide, inactivate bacterial enzymes and thus block metabolism.
- High temperatures, such as autoclaving, boiling, and pasteurization, denature proteins and enzymes.
- Cold temperatures, such as refrigeration and freezing, slow down or stop enzyme reactions.
Summary
- Enzymes are substances present in the cell in small amounts that function to speed up or catalyze chemical reactions so they occur fast enough to support life.
- On the surface of the enzyme is typically a small crevice that functions as an active site or catalytic site to which one or two specific substrates are able to bind.
- Anything that an enzyme normally combines with is called a substrate.
- The binding of the substrate to the enzyme causes the flexible enzyme to change its shape slightly through a process called induced fit to form a temporary intermediate called an enzyme-substrate complex.
- Enzymes speed up the rate of chemical reactions because they lower the energy of activation, the energy that must be supplied in order for molecules to react with one another.
- Many enzymes require a nonprotein cofactor to assist them in their reaction. In this case, the protein portion of the enzyme, called an apoenzyme, combines with the cofactor to form the whole enzyme or haloenzyme.
- Some cofactors are ions such as Ca ++ , Mg ++ , and K + ; other cofactors are organic molecules called coenzymes which serve as carriers for chemical groups or electrons. NAD + , NADP + , FAD, and coenzyme A (CoA) are examples of coenzymes.
- Chemically, enzymes are generally globular proteins. Some RNA molecules called ribozymes can also be enzymes, usually functioning to cleave RNA molecules.
- Enzymes are only present in small amounts in the cell since they are not altered during their reactions and are highly specific for their substrate.
- Enzyme activity is affected by a number of factors including the concentration of the enzyme, the concentration of the substrate, the temperature, the pH, and the salt concentration.


Regardless of setting, there is value in practicing effective management principles. This course teaches students how to think as managers and actively manage organizations and teams using effective practices around planning, decision making, organizational structure, culture, leadership, motivation, and communication. The course begins by addressing foundational management principles, including primary functions of managers, types of management, and types of strategy, and develops toward addressing more complex topics such as ethics, control, and global business management.
This course was created in collaboration with John Bruton, Ph.D., retired professor of management/department chair, Cal State Northridge; Linda Bruton, retired from McGraw Hill; Jeff Heflin, director of finance at Asurion; Talia Lambarki, MBA; Lisa Jo Rudy, educational writer and consultant; Aaron Spencer, curriculum developer; David J. Thompson, Ph.D., professor at Ohio State University; Robert Carroll, professor at Montgomery College; and Nina Burokas, professor at Mendocino College and Saddleback College.
Course Improvements
This new edition of Waymaker Principles of Management includes new practice questions on each page, giving students more opportunities to practice their learning.
About Lumen
Lumen Learning’s mission is to make great learning opportunities available to all students, regardless of socioeconomic background.
We do this by using open educational resources (OER) to create well-designed and low-cost course materials that replace expensive textbooks. Because learning is about more than affordability and access, we also apply learning science insights and efficacy research to develop learning activities that are engineered to improve subject mastery, course completion and retention.
If you’d like to connect with us to learn more about adopting this course, please Contact Us .
You can also make an appointment for OER Office Hours to connect virtually with a live Lumen expert about any question you may have.


Phillips, D.J. (2019). The 110 techniques of communication and public speaking. Ted.
https://youtu.be/K0pxo-dS9Hc
Diep, K. (2019). I hired a speech therapist to fix my boring voice. Buzzfeed Video.
https://youtu.be/nLDRQYeYQJg
One of the most famous examples of speech coaching is Margaret Thatcher, who worked to strengthen the authority in her voice.
Margaret Thatcher voice before/after. (2011).
https://youtu.be/28_0gXLKLbk
Standard YouTube License.
Valentine, C. (2018). The visual and verbal methods: A key secret to making your points stick.
https://youtu.be/8rQfcEIC5fA
The Distilled Man. How to stop saying “um”, “like,” and “You Know.”
https://www.youtube.com/watch?v=W995352_kkw
Garcia, Amaya, L. (2021). Why do we like, hesitate when we um speak?
https://youtu.be/FsMWbVrjucg
Every frame a painting. (2014). Martin Scorsese-The art of silence.
https://www.youtube.com/watch?v=NUrTRjEXjSM&t=290s


2.5: Sigma Notation and Calculating the Arithmetic Mean
Formula for Population Mean
\[{\mu}=\frac{1}{N} \sum_{i=1}^{N} x_{i}\nonumber\]
Formula for Sample Mean
\[\overline{x}=\frac{1}{n} \sum_{i=1}^{n} x_{i}\nonumber\]
Here are the formulas for a population mean and the sample mean. The Greek letter \(\mu\) is the symbol for the population mean and \(\overline{x}\) is the symbol for the sample mean. Both formulas have a mathematical symbol that tells us how to make the calculations. It is called Sigma notation because the symbol is the Greek capital letter sigma: \(\Sigma\). Like all mathematical symbols it tells us what to do: just as the plus sign tells us to add and the \(x\) tells us to multiply. These are called mathematical operators. The \(\Sigma\) symbol tells us to add a specific list of numbers.
Let’s say we have a sample of animals from the local animal shelter and we are interested in their average age. If we list each value, or observation, in a column, you can give each one an index number. The first number will be number 1 and the second number 2 and so on.
| Animal | Age |
| 1 | 9 |
| 2 | 1 |
| 3 | 8.5 |
| 4 | 10.5 |
| 5 | 10 |
| 6 | 8.5 |
| 7 | 12 |
| 8 | 8 |
| 9 | 1 |
| 10 | 9.5 |
Each observation represents a particular animal in the sample. Purr is animal number one and is a 9 year old cat, Toto is animal number 2 and is a 1 year old puppy and so on.
To calculate the mean we are told by the formula to add up all these numbers, ages in this case, and then divide the sum by 10, the total number of animals in the sample.
Animal number one, the cat Purr, is designated as \(X_1\), animal number 2, Toto, is designated as \(X_2\) and so on through Dundee who is animal number 10 and is designated as \(X_{10}\).
The i in the formula tells us which of the observations to add together. In this case it is \(X_1\) through \(X_{10}\) which is all of them. We know which ones to add by the indexing notation, the \(i = 1\) and the \(n\) or capital \(N\) for the population. For this example the indexing notation would be \(i = 1\) and because it is a sample we use a small \(n\) on the top of the \(\Sigma\) which would be 10.
The standard deviation - which you'll learn about later in this chapter - requires the same mathematical operator.
The sum of the ages is found to be 78 and dividing by 10 gives us the sample mean age as 7.8 years.


5.2: Rotational Inertia
Rotational Kinetic Energy and Rotational Inertia
While our first approach to studying dynamics for linear motion was Newton's laws (forces cause accelerations), we will find it easier to examine rotational dynamics from a standpoint of energy first. Consider an object that is rotating around a stationary center of mass. Does such an object possess kinetic energy? We might be inclined to say that it does, but with the center of mass not moving, its momentum is zero, which would make the quantity \(\frac{p^2}{2m}\) also equal to zero.
Rigid objects are collections of multiple particles, and when they are rotating, all those particles (except those right at the pivot point) are moving, which means they all have kinetic energy. At any given moment, there are particles moving in opposite directions, and if the center of mass of the object is stationary, these opposite momenta (which are vectors) cancel, Their kinetic energies, on the other hand, are not vectors, and are all positive numbers, so they can never cancel out.
In some sense, the particles comprising a rotating object can be thought of as contributing to the "internal" energy of the object as we discussed back in Section 3.2 . But doing this runs contrary to the main reason for the introduction of the mechanical/internal energy idea, which was to separate the kinetic energy of the system that we can clearly see from the kinetic energy that is concealed from us inside the confines of the system. We can clearly see rotational motion of an object, so we choose to include rotational kinetic energy in the category of "mechanical energy."
Okay, so a rotating object does possess kinetic energy. Our task now is to express that kinetic energy in terms of the rotation variables we have already defined, but all we know about kinetic energy is the linear version. In the figure below we consider the motion of a single particle within a rigid rotating object.


11.1: Introduction to Sexuality Through the Lifespan
After completing this module, students will have working knowledge of:
- Sexuality in Children
- Sexuality in Teens
- Sexuality in Mid-Adulthood
- Sexuality in Older Adults
Introduction
Our sexuality remains an important part of our overall wellness through our lifespan. However, our sexuality across the lifespan is not static, but rather dynamic and continually evolves as we go through our life cycle. In this chapter, we will look at human sexuality as a developmental process through various life stages and examine some of the biopsychosocial factors that contribute to the changes in sexual development.
Author caveat: much of the research on sexual development is gendered and we are reporting on this research while acknowledging taking a new critical view of gendering in this field is a direction we hope to see more of in future research. As this book is not a static document we hope to update and invite those who use this text to modify as new research surfaces.


7.6: Intelligence Testing - The What, the Why, and the Who
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Measuring Intelligence: Standardization and the Intelligence Quotient
The goal of most intelligence tests is to measure “g”, the general intelligence factor. Good intelligence tests are reliable , meaning that they are consistent over time, and also demonstrate validity , meaning that they actually measure intelligence rather than something else. Because intelligence is such an important part of individual differences, psychologists have invested substantial effort in creating and improving measures of intelligence, and these tests are now considered the most accurate of all psychological tests.
Intelligence changes with age. A 3-year-old who could accurately multiply 183 by 39 would certainly be intelligent, but a 25-year-old who could not do so would be seen as unintelligent. Thus understanding intelligence requires that we know the norms or standards in a given population of people at a given age. The standardization of a test involves giving it to a large number of people at different ages and computing the average score on the test at each age level.
Once the standardization has been accomplished, we have a picture of the average abilities of people at different ages and can calculate a person’s mental age , which is the age at which a person is performing intellectually. If we compare the mental age of a person to the person’s chronological age, the result is the Intelligence Quotient (IQ) , a measure of intelligence that is adjusted for age. A simple way to calculate IQ is by using the following formula:
IQ = mental age ÷ chronological age × 100.
 Most modern intelligence tests are based on the relative position of a person’s score among people of the same age, rather than on the basis of this formula, but the idea of intelligence “ratio” or “quotient” provides a good description of the score’s meaning.
The Flynn Effect
It is important that intelligence tests be standardized on a regular basis, because the overall level of intelligence in a population may change over time. The Flynn effect refers to the observation that scores on intelligence tests worldwide have increased substantially over the past decades (Flynn, 1999). Although the increase varies somewhat from country to country, the average increase is about 3 IQ points every 10 years. There are many explanations for the Flynn effect, including better nutrition, increased access to information, and more familiarity with multiple-choice tests (Neisser, 1998). But whether people are actually getting smarter is debatable (Neisser,1997). 33
The Value of IQ Testing
The value of IQ testing is most evident in educational or clinical settings. Children who seem to be experiencing learning difficulties or severe behavioral problems can be tested to ascertain whether the child’s difficulties can be partly attributed to an IQ score that is significantly different from the mean for her age group. Without IQ testing—or another measure of intelligence—children and adults needing extra support might not be identified effectively. People also use IQ testing results to seek disability benefits from the Social Security Administration.
While IQ tests have sometimes been used as arguments in support of insidious purposes, such as the eugenics movement , which was the science of improving a human population by controlled breeding to increase desirable heritable characteristics. However, the value of this test is important to help those in need.34
Intelligence Tests and Those Who Created Them
Alfred Binet & Théodore Simon - Stanford- Binet Intelligence Test
From 1904- 1905 the French psychologist Alfred Binet (1857–1914) and his colleague Théodore Simon (1872–1961) began working on behalf of the French government to develop a measure that would identify children who would not be successful with the regular school curriculum. The goal was to help teachers better educate these students (Aiken, 1994).
Binet and Simon developed what most psychologists today regard as the first intelligence test, which consisted of a wide variety of questions that included the ability to name objects, define words, draw pictures, complete sentences, compare items, and construct sentences. Binet and Simon (Binet, Simon, & Town, 1915; Siegler, 1992) believed that the questions they asked the children all assessed the basic abilities to understand, reason, and make judgments.
Soon after Binet and Simon introduced their test, the American psychologist Lewis Terman at Stanford University (1877–1956) developed an American version of Binet’s test that became known as the Stanford- Binet Intelligence Test . The Stanford-Binet is a measure of general intelligence made up of a wide variety of tasks including vocabulary, memory for pictures, naming of familiar objects, repeating sentences, and following commands.36
David Wechsler- Wechsler-Bellevue Intelligence Scale
In 1939, David Wechsler, a psychologist who spent part of his career working with World War I veterans, developed a new IQ test in the United States. Wechsler combined several subtests from other intelligence tests used between 1880 and World War I. These subtests tapped into a variety of verbal and nonverbal skills, because Wechsler believed that intelligence encompassed “the global capacity of a person to act purposefully, to think rationally, and to deal effectively with his environment” (Wechsler, 1958, p. 7). He named the test the Wechsler-Bellevue Intelligence Scale (Wechsler, 1981). This combination of subtests became one of the most extensively used intelligence tests in the history of psychology.
Today, there are three intelligence tests credited to Wechsler, the Wechsler Adult Intelligence Scale-fourth edition (WAIS-IV), the Wechsler Intelligence Scale for Children (WISC-V), and the Wechsler Preschool and Primary Scale of Intelligence—Revised (WPPSI-III) (Wechsler, 2002). These tests are used widely in schools and communities throughout the United States, and they are periodically normed and standardized as a means of recalibration.
Bias of IQ Testing
Intelligence tests and psychological definitions of intelligence have been heavily criticized since the 1970s for being biased in favor of Anglo-American, middle-class respondents and for being inadequate tools for measuring non-academic types of intelligence or talent. Intelligence changes with experience, and intelligence quotients or scores do not reflect that ability to change. What is considered smart varies culturally as well, and most intelligence tests do not take this variation into account. For example, in the West, being smart is associated with being quick. A person who answers a question the fastest is seen as the smartest, but in some cultures being smart is associated with considering an idea thoroughly before giving an answer. A well- thought out, contemplative answer is the best answer.38
A Spectrum of Intellectual Development
The results of studies assessing the measurement of intelligence show that IQ is distributed in the population in the form of a Normal Distribution (or bell curve) , which is the pattern of scores usually observed in a variable that clusters around its average. In a normal distribution, the bulk of the scores fall toward the middle, with many fewer scores falling at the extremes. The normal distribution of intelligence shows that on IQ tests, as well as on most other measures, the majority of people cluster around the average (in this case, where IQ = 100), and fewer are either very smart or very dull (see below).
Distribution of IQ Scores in the General Population
This means that about 2% of people score above an IQ of 130, often considered the threshold for giftedness, and about the same percentage score below an IQ of 70, often being considered the threshold for an intellectual disability.
Intellectual Disabilities
One end of the distribution of intelligence scores is defined by people with very low IQ. Intellectual disability (or intellectual developmental disorder ) is assessed based on cognitive capacity (IQ) and adaptive functioning. The severity of the disability is based on adaptive functioning, or how well the person handles everyday life tasks. About 1% of the United States population, most of them males, fulfill the criteria for intellectual developmental disorder, but some children who are given this diagnosis lose the classification as they get older and better learn to function in society. A particular vulnerability of people with low IQ is that they may be taken advantage of by others, and this is an important aspect of the definition of intellectual developmental disorder (Greenspan, Loughlin, & Black, 2001).
One example of an intellectual developmental disorder is Down syndrome , a chromosomal disorder caused by the presence of all or part of an extra 21st chromosome. The incidence of Down syndrome is estimated at approximately 1 per 700 births, and the prevalence increases as the mother’s age increases (CDC, 2014a). People with Down syndrome typically exhibit a distinctive pattern of physical features, including a flat nose, upwardly slanted eye, a protruding tongue, and a short neck.
Fortunately, societal attitudes toward individuals with intellectual disabilities have changed over the past decades. We no longer use terms such as “retarded,” “moron,” “idiot,” or “imbecile” to describe people with intellectual differences, although these were the official psychological terms used to describe degrees of what was referred to as mental retardation in the past. Laws such as the Americans with Disabilities Act (ADA) have made it illegal to discriminate on the basis of mental and physical disability.
The normal distribution of IQ scores in the general population shows that most people have about average intelligence, while very few have extremely high or extremely low intelligence.41
Giftedness
Being gifted refers to children who have an IQ of 130 or higher (Lally & Valentine-French, 2015). Having an extremely high IQ is clearly less of a problem than having an extremely low IQ but there may also be challenges to being particularly smart. It is often assumed that school children who are labeled as “gifted” may have adjustment problems that make it more difficult for them to create and maintain social relationships.
As you might expect based on our discussion of intelligence, there are also different types and areas of intelligence and giftedness. Some children are particularly good at math or science, some at automobile repair or carpentry, some at music or art, some at sports or leadership, and so on. There is a lively debate among scholars about whether it is appropriate or beneficial to label some children as “gifted and talented” in school and to provide them with accelerated special classes and other programs that are not available to everyone. Although doing so may help the gifted kids (Colangelo & Assouline, 2009), it also may isolate them from their peers and make such provisions unavailable to those who are not classified as “gifted.” Testing for high IQ or for disabilities needs to be critically looked at so that the good that these tests were created for are not used for undesirable purposes.43
How do we know so much about what children learn in schools? In the next section we’ll look at the different types of tests and what the schools are testing.
Testing in Schools
Children's academic performance is often measured with the use of standardized tests. Those tests include, but are not limited to Achievement and Aptitude tests.
Achievement tests are used to measure what a child has already learned. Achievement tests are often used as measures of teaching effectiveness within a school setting and as a method to make schools that receive tax dollars (such as public schools, charter schools, and private schools that receive vouchers) accountable to the government for their performance.
Aptitude tests are designed to measure a student’s ability to learn or to determine if a person has potential in a particular program. These are often used at the beginning of a course of study or as part of college entrance requirements. The Scholastic Aptitude Test (SAT) and Preliminary Scholastic Aptitude Test (PSAT) are perhaps the most familiar aptitude tests to students in grades 6 and above. Learning test taking skills and preparing for SATs has become part of the training that some students in these grades receive as part of their pre-college preparation. Other aptitude tests include the MCAT (Medical College Admission Test), the LSAT (Law School Admission Test), and the GRE (Graduate Record Examination). Intelligence tests are also a form of aptitude test, which designed to measure a person’s ability to learn.45
What Happened to No Child Left Behind?
In 2001, President Bush signed into effect Public Law 107-110, better known as the No Child Left Behind Act mandating that schools administer achievement tests to students and publish those results so that parents have an idea of their children's performance. Additionally, the government would have information on the gaps in educational achievement between children from various social class, racial, and ethnic groups.
Schools that showed significant gaps in these levels of performance were mandated to work toward narrowing these gaps. Educators criticized the policy for focusing too much on testing as the only indication of student performance. Target goals were considered unrealistic and set by the federal government rather than individual states. Because these requirements became increasingly unworkable for schools, changes to the law were requested.
On December 12, 2015 President Obama signed into law the Every Student Succeeds Act (ESSA). This law is state-driven and focuses on expanding educational opportunities and improving student outcomes, including in the areas of high school graduation, drop-out rates, and college attendance.48
Contributors and Attributions
33. Introduction to Psychology - Measures of Intelligence references Psychology by OpenStax CNX , licensed under CC BY 4.0 (modified by Dawn Rymond)
34. Introduction to Psychology - Measures of Intelligence references Psychology by OpenStax CNX , licensed under CC BY 4.0 (modified by Dawn Rymond)
36. Introduction to Psychology - Measures of Intelligence references Psychology by OpenStax CNX , licensed under CC BY 4.0
38. Sociology: Brief Edition – Agents of Socialization by Steven E. Barkan is licensed under CC BY-NC-SA 3.0
Introduction to Psychology - Measures of Intelligence references Psychology by OpenStax CNX , licensed under CC BY 4.0
41. Introduction to Psychology - Measures of Intelligence references Psychology by OpenStax CNX , licensed under CC BY 4.0
43. Lifespan Development: A Psychological Perspective by Martha Lally and Suzanne Valentine-French is licensed under CC BY-NC-SA 3.0
45. Sociology: Brief Edition – Agents of Socialization by Steven E. Barkan is licensed under CC BY-NC-SA 3.0
48. Lifespan Development: A Psychological Perspective by Martha Lally and Suzanne Valentine-French is licensed under CC BY-NC-SA 3.0


9.5: Using Sources Creatively
Using Sources Creatively
Heather Logan
(printable version here)
When writing papers that require the use of outside source material, it is often tempting to cite only direct quotations from your sources. If, however, this is the only method of citation you choose, your paper will become nothing more than a series of quotations linked together by a few connecting words. Your paper will seem to be a collection of others’ thoughts and will contain little thinking on your part.
To avoid falling into this trap, follow a few simple pointers:
- Avoid using long quotations merely as space-fillers . While this is an attractive option when faced with a ten-page paper, the overuse of long quotations gives the reader the impression you cannot think for yourself.
- Don’t use only direct quotations . Try using paraphrases in addition to your direct quotations. To the reader, the effective use of paraphrases indicates that you took the time to think about the meaning behind the quote’s words. (For further assistance see our materials on “Using Paraphrases.”)
- When introducing direct quotations, try to use a variety of verbs in your signal phrases . Don’t always rely on stock verbs such as “states” or “says.” Think for a little while about the purpose of your quotation and then choose a context-appropriate verb.
Also, when using direct quotations try qualifying them in a novel or interesting manner. Depending on the system of documentation you’re using, the signal phrases don’t always have to introduce the quotation.
For example, instead of saying:
“None of them knew the color of the sky” is the opening line of Stephen Crane’s short story, “The Open Boat” (339). This implies the idea that “all sense of certainty” in the lives of these men is gone (Wolford 18).
Try saying:
“None of them knew the color of the sky,” the opening line of Stephen Crane’s, “The Open Boat,” implies that “all sense of certainty” in the lives of these men is gone (Crane 339; Wolford 18).
The combination of these two sentences into one is something different. It shows thought on the writer’s part in how to combine direct quotations in an interesting manner.
Contributors and Attributions
- Using Sources Creatively. Authored by : Heather Logan. Provided by : University of Richmond Writing Center. Located at : writing2.richmond.edu/writing/wweb/creatsrc.html. License : CC BY-NC-ND: Attribution-NonCommercial-NoDerivatives


9.4: Chapter 9 Key Terms
- Analysis of Variance
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also referred to as ANOVA, is a method of testing whether or not the means of three or more populations are equal. The method is applicable if:
- all populations of interest are normally distributed.
- the populations have equal standard deviations.
- samples (not necessarily of the same size) are randomly and independently selected from each population.
The test statistic for analysis of variance is the \(F\)-ratio.
- Between-Groups Variance
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an estimate of the average variance among sample means (i.e., from the different groups) across all of the groups.
- One-Way ANOVA
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an analysis of variance with one independent (grouping) variable.
- Within-Groups Variance
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an estimate of the average of the sample variances (i.e., within the different groups) across all of the groups.


2.3: Job Order Costing for a Service Company
Job order costing is also used for service businesses where the service and costs are unique to each customer, such as those of an attorney, accountant, physician, or event planner. Each customer, client, or patient is a separate job or project. Clients, customers, and patients incur direct costs, direct labor and applied overhead costs. And while there are no materials related to inventory for a service business, there may be expenditures associated directly with a particular project, such as travel or supplies.
2.3.1 Comprehensive Example of Job Order Costing Transactions for a Service Company
Creative Compton, Inc. is an advertising agency that designs web sites and promotional materials for medium-sized businesses. For each client project, Creative Compton accumulates the direct labor costs of its professional designersat an hourly rate of $140. The company allocates overhead costs to jobs at a rate of 35% of total direct labor cost incurred. Creative Compton, Inc. earns a 60% profit on each job.
Journalize the journal entries for the direct labor, the overhead, the sale of the project, and the reconciliation of actual to estimated overhead.
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Job 4 incurs 20 hours of professional direct labor time (20 hours x $140 per hour).
Account Debit Credit Development Costs
2,800
▲ Development Costs is an asset account
Wages Payable
2,800
▲ Wages Payable is a liability account that is increasing
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The company pays cash for the following costs that are directly related to Job 4: travel, $340; supplies, $60; and domain name filing fees, $120.
Account
Debit
Credit
Development Costs
520
▲ Development Costs is an asset account that is increasing
Cash
520
▼ Cash is an asset account that is decreasing
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Estimated overhead costs incurred for Job 4 are $980. ($2,800 direct wages cost x 35%)
Account
Debit
Credit
Development Costs
980
▲ Development Costs is an asset account that is increasing
Overhead
980
▼ Overhead is an expense account that is decreasing
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A customer is invoiced for the completed Job 4.
 The first is to record the project’s selling price to the customer. The second is to reduce the development costs incurred and expense them off to Cost of Services .
Cost of the project: $2,800 direct labor + $520 direct costs + $980 overhead costs = $4,300
Selling price of the project: $4,300 costs x 1.6 to include the markup = $6,880
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Actual overhead for Job 4 is ultimately determined to be $960.
Account
Debit
Credit
Too much factory overhead was applied in transaction #3
Overhead
20
▲ Overhead is an expense account that is increasing that is increasing
Cost of Service
20
▼ Cost of Services is an expense account decreasing
In transaction #3 , recorded previously, $980 of overhead was applied to Development Costs based on an estimate of 35% of direct labor. The difference between applied factory overhead and estimated factory overhead is $20 ($980 estimated - $960 actual). Since too much had been applied, $20 now needs to be backed out by debiting the Overhead account. Cost of Services is used as the credit account rather than Development Costs in reconciling the Overhead account.


2.23: Synthesis of Biological Macromolecules - Types of Biological Macromolecules
- Identify the four major classes of biological macromolecules
Nutrients are the molecules that living organisms require for survival and growth but that animals and plants cannot synthesize themselves. Animals obtain nutrients by consuming food, while plants pull nutrients from soil.
Many critical nutrients are biological macromolecules. The term “macromolecule” was first coined in the 1920s by Nobel laureate Hermann Staudinger. Staudinger was the first to propose that many large biological molecules are built by covalently linking smaller biological molecules together.
Monomers and Polymers
Biological macromolecules play a critical role in cell structure and function. Most (but not all) biological macromolecules are polymers, which are any molecules constructed by linking together many smaller molecules, called monomers. Typically all the monomers in a polymer tend to be the same, or at least very similar to each other, linked over and over again to build up the larger macromolecule. These simple monomers can be linked in many different combinations to produce complex biological polymers, just as a few types of Lego blocks can build anything from a house to a car.
Examples of these monomers and polymers can be found in the sugar you might put in your coffee or tea. Regular table sugar is the disaccharide sucrose (a polymer), which is composed of the monosaccharides fructose and glucose (which are monomers). If we were to string many carbohydrate monomers together we could make a polysaccharide like starch. The prefixes “mono-” (one), “di-” (two),and “poly-” (many) will tell you how many of the monomers have been joined together in a molecule.
Biological macromolecules all contain carbon in ring or chain form, which means they are classified as organic molecules. They usually also contain hydrogen and oxygen, as well as nitrogen and additional minor elements.
Four Classes of Biological Macromolecules
There are four major classes of biological macromolecules:
- carbohydrates
- lipids
- proteins
- nucleic acids
Each of these types of macromolecules performs a wide array of important functions within the cell; a cell cannot perform its role within the body without many different types of these crucial molecules. In combination, these biological macromolecules make up the majority of a cell’s dry mass. (Water molecules make up the majority of a cell’s total mass.) All the molecules both inside and outside of cells are situated in a water-based (i.e., aqueous) environment, and all the reactions of biological systems are occurring in that same environment.
Carbohydrates, proteins, and nucleic acids are built from small molecular units that are connected to each other by strong covalent bonds. The small molecular units are called monomers (mono means one, or single), and they are linked together into long chains called polymers (poly means many, or multiple). Each different type of macromolecule, except lipids, is built from a different set of monomers that resemble each other in composition and size. Lipids are not polymers, because they are not built from monomers (units with similar composition).
Key Points
- Biological macromolecules are important cellular components and perform a wide array of functions necessary for the survival and growth of living organisms.
- The four major classes of biological macromolecules are carbohydrates, lipids, proteins, and nucleic acids.
Key Terms
- polymer : A relatively large molecule consisting of a chain or network of many identical or similar monomers chemically bonded to each other.
- monomer : A relatively small molecule that can form covalent bonds with other molecules of this type to form a polymer.