4.2: Building a Resume
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Building a resume is an important task as you join any professional community, teaching or otherwise. A resume is a quick and professional introduction to you and your skills. It allows potential employers and collaborators get to know you. A resume should tell a good story. A teaching resume should tell a good story about your professional education and experiences that shape your stance as a qualified educator. It is important to begin shaping your professional teaching resume early in your teacher preparation program. You may then continue adding to and revising the resume as you gain valuable professional experiences by completing and documenting field experience opportunities in the program.
Discussion Questions
What are the conventions of a teaching resume?
In what ways do resumes tell a story?
What makes an educational resume different than other professions?
Sample Resume
BEA A. TEACHER
Local Street Address,
City, State Zip
Permanent Street Address, City, State Zip phone
number • email
OBJECTIVE
To obtain a teaching position at the elementary level in the Oneonta City School District
EDUCATION
Bachelor of Science, Early Childhood/Childhood Education (B-6), Concentration in Biology Month Year
State University of New York (SUNY), College at Oneonta, Oneonta, NY NCATE Accredited
Advanced Regents Diploma Month Year
Burnt Hills-Ballston Lake Senior High School , Burnt Hills, NY
RELATED EXPERIENCE
Teacher , School Name , City, State Month Year – Month Year
- Work with 25 students, K-12, and all ability levels
- Instruction in reading, writing, math, and study skills
- Effectively manage average classroom of 20 students
- Met with parents regarding student classroom behavior
Student Teacher – Kindergarten, School Name, City, State Month Year – Month Year
- Used centers for math, science, social studies, health, and writing
- Implemented a positive discipline plan and phonics instruction with small groups
- Developed thematic unit on plants/gardening around major instructional goals
Student Teacher – Fourth Grade , School Name, City, State Month Year – Month Year
- Created and implemented literature units on density
- Developed and taught writing unit on “why” stories
- Used teacher’s manuals as guideline for teaching math and science
- Modified lesson plans to meet students’ needs required for 504/IEP plans
- Adapted units for time, money, geometry, and weather
Program Assistant, School/Organization Name , City, State Month Year – Month Year
- After school program sponsored by XYZ Central School
- Supervised and managed groups of 15-20 children grades K-5
FIELD EXPERIENCE
Observation/Participation – 200 Hours Year – Year
- Kindergarten Participation, Unadilla Valley Central School, New Berlin, NY
- Pre-Kindergarten, Head Start/Early Head Start Day Care, Oneonta, NY
- Fourth Grade , Commack Road Elementary School, Islip, NY
- First Grade, Wing Elementary School, Islip, NY
OTHER EXPERIENCE
Support Staff, Company Name , City, State Month Year – Month Year
- Various clerical responsibilities, including developed proficiency in all Microsoft Office products
Sales Clerk, Department Store, City, State Month Year – Month Year
- Provided exceptional customer service to approximately 40 individuals each day
- Utilized creativity to design two store displays each month
- Responsible for additional duties in manager’s absence
VOLUNTEER EXPERIENCE
St. Vincent Elementary School, St. Vincent, NY Month Year – Month Year
- Coordinated after school program for 25 children, ages 5 to 8
- Maintained a safe and conducive learning environment
ACTIVITIES
Leadership Institute, SUNY Oneonta, Oneonta, NY Month Year – Month Year
Elementary Education Club, SUNY Oneonta, Oneonta, NY Month Year – Month Year
Professional Memberships
Professional Education Council, SUNY Oneonta, Oneonta, NY Month Year – Month Year
Association for Teachers, SUNY Oneonta, Oneonta, NY Month Year – Month Year
Skills
Foreign Language: Spanish Fluency
Computer Programs: MS Word, Excel, PowerPoint, Access Classroom Technology: ELMO, SmartBoard
MM 08/17
Figure 1. Sample Resume Adapted from Template (All Business Templates, 2017)
Many resources exist on the campus of SUNY Oneonta to assist you in building your resume. The Career Development Center (2019) is available to provide guidance concerning the necessary components and steps for building your resume.
The document is provided by the Career Development Center, specifically for students who are beginning to build their professional resume.
Career Development Center
110 Netzer Admin. Building
(607) 436 -2534
10 Steps to Building A Solid Resume
Students often ask: what should I be doing now to prepare to write my resume when the time comes? Here are some steps that you can take today to make sure that yours will be a resume that will gain the attention of potential future employers:
- Establish solid relationships with professors and employers . Don’t be afraid to talk to your professors. They can provide a wealth of information and assistance as you determine your career path. You can also learn a great deal from work supervisors, even in part-time and summer jobs. Some day you will be asking these people to write or give a verbal reference for you; the better they know you, the more qualified they will feel to speak about your skills and abilities.
- Set career goals. As soon as you are ready to do so, it is better to start off in a direction, even if you may need to alter that direction later on. Do some research– talk to professors, advisors, career counselors, professionals in fields of interest, etc.– and then weigh the information you have collected. The suggestions in the remainder of this article will help you as you evaluate your plans and goals.
- Join clubs and participate in activities related to your career goals. There are many clubs and organizations on your campus; some relate to academic majors, others to interest areas. Participating in any of these groups can help you to gain insight into a particular field or investigate your interests and skills. Working with fellow students, faculty advisors, and others you encounter can also provide extremely valuable experience in building teamwork and communication skills, both of which are vital to almost any career you may pursue.
- Be selective about part-time and summer employment. While any job can provide valuable experience, employers are often looking for someone who can demonstrate as many of the necessary skills as possible for their available position. The more relevant experience you have, the better prepared you are for a position in your chosen field. You can also use part-time and summer jobs to “test drive” a career choice you are considering.
- Volunteer with an organization or agency where you can gain skills related to your career goals. Volunteering is another a great way to meet people, gain skills, and find out if a certain career is really a good “fit” for you. There are many wonderful opportunities for volunteering in most communities; showing that you had the initiative to take advantage of this type of experience can be very impressive to future employers. This step is especially important for those students who are limited in their choices of summer and part-time jobs.
- Do an internship . What better way to familiarize yourself with the inner workings of a prospective career field than to do an internship with a company or organization in that field? For many internships, academic credit is obtained through the student’s major department. Contact your academic advisor for more information and, if encouraged to locate your own internship, you can contact your college career center for further assistance.
- Get good grades . In almost any career you can imagine, employers are looking for the best and brightest graduates to fill their company’s openings. Whether you plan to be a teacher, an accountant, a stockbroker, or a psychologist, the better you have performed in your past “job” (as a student), the better your prospective employers can expect you to perform for them. And if you plan to attend graduate school, a high GPA may be an entrance requirement.
- Determine skills and abilities needed to succeed in your career and take every possible opportunity to strengthen them. Flexibility? Communication? Computer literacy? Initiative? What are the skills you will need to succeed on the job? Look at job descriptions, talk to employers, professors, and those currently employed in your field of choice to find out what you will need to do to succeed in your chosen career. Skills do not magically appear your first day on the job (or during your interview!) but take time and effort to build. Start now with your “job” as a student and practice, practice, practice! Be on time for class, initiate questions or discussions, gain computer skills, and make sure that all work you submit shows your best possible effort.
- Start planning early . As you can see from steps #1 – 8 above, planning and preparing for a career is not something that can be done well during the last semester of your senior year. You can write your resume during that time, but if you want some good, quality information to put on it, the earlier you start, the better off you’ll be.
- Visit your college career center . For the most current information about almost any career field you can imagine, your college career center is the first place you should check. If you need any assistance at all in determining what your career path might be, staff members will be willing to take the time to answer your questions. And when you are ready to write your resume, many career centers offer workshops, written materials, and/or a resume critiquing service to help ensure that your resume is the best possible tool for marketing your skills to employers.
ADDITIONAL RESOURCE
Northland University (2019) has created an excellent guide to creating a resume. This guide is geared toward new educators who wish to build their resumes in order to highlight experience during their programs. This guide is available at https://my.northland.edu/wp-content/uploads/sites/2/2015/07/Education-Majors-Resume-Guide.pdf
Contributors and Attributions
- Foundations of Education. Authored by : SUNY Oneonta Education Department. License : CC BY: Attribution


21.3: Introduction to Transmission Lines
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A transmission line is a structure intended to transport electromagnetic signals or power.
A rudimentary transmission line is simply a pair of wires with one wire serving as a datum (i.e., a reference; e.g., “ground”) and the other wire bearing an electrical potential that is defined relative to that datum. Transmission lines having random geometry, such as the test leads shown in Figure \(\PageIndex{1}\), are useful only at very low frequencies and when loss, reactance, and immunity to electromagnetic interference (EMI) are not a concern.
Figure \(\PageIndex{1}\): These leads used to connect test equipment to circuits in a laboratory are a very rudimentary form of transmission line, suitable only for very low frequencies. (Public Domain; Dmitry G)However, many circuits and systems operate at frequencies where the length or cross-sectional dimensions of the transmission line may be a significant fraction of a wavelength. In this case, the transmission line is no longer “transparent” to the circuits at either end. Furthermore, loss, reactance, and EMI are significant problems in many applications. These concerns motivate the use of particular types of transmission lines, and make it necessary to understand how to properly connect the transmission line to the rest of the system.
In electromagnetics, the term “transmission line” refers to a structure which is intended to support a guided wave . A guided wave is an electromagnetic wave that is contained within or bound to the line, and which does not radiate away from the line. This condition is normally met if the length and cross-sectional dimensions of the transmission line are small relative to a wavelength – say \(\lambda/100\) (i.e., 1% of the wavelength). For example, two randomly-arranged wires might serve well enough to carry a signal at \(f=10\) MHz over a length \(l=3\) cm, since \(l\) is only 0.1% of the wavelength \(\lambda=c/f=30\) m. However, if \(l\) is increased to \(3\) m, or if \(f\) is increased to 1 GHz, then \(l\) is now 10% of the wavelength. In this case, one should consider using a transmission line that forms a proper guided wave.
Preventing unintended radiation is not the only concern. Once we have established a guided wave on a transmission line, it is important that power applied to the transmission line be delivered to the circuit or device at the other end and not reflected back into the source. For the random wire \(f=10\) MHz, \(l=3\) cm example above, there is little need for concern, since we expect a phase shift of roughly \(0.001\cdot 360^{\circ} = 0.36^{\circ}\) over the length of the transmission line, which is about \(0.72^{\circ}\) for a round trip. So, to a good approximation, the entire transmission line is at the same electrical potential and thus transparent to the source and destination. However, if \(l\) is increased to \(3\) m, or if \(f\) is increased to 1 GHz, then the associated round-trip phase shift becomes \(72^{\circ}\). In this case, a reflected signal traveling in the opposite direction will add to create a total electrical potential, which varies in both magnitude and phase with position along the line. Thus, the impedance looking toward the destination via the transmission line will be different than the impedance looking toward the destination directly (Section 3.15 gives the details). The modified impedance will depend on the cross-sectional geometry, materials, and length of the line.
Cross-sectional geometry and materials also determine the loss and EMI immunity of the transmission line.
Summarizing:
Transmission lines are designed to support guided waves with controlled impedance, low loss, and a degree of immunity from EMI.


10.2: Aerobic Exercise
Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means "relating to, involving, or requiring free oxygen", and refers to the use of oxygen to adequately meet energy demands during exercise. Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time. When practiced in this way, examples of cardiovascular/aerobic exercise are medium to long distance running/jogging, swimming, cycling, and walking, according to the first extensive research on aerobic exercise, conducted in the 1960s on over 5,000 U.S. Air Force personnel by Dr. Kenneth H. Cooper.
Kenneth Cooper was the first person to introduce the concept of aerobic exercise. In the 1960s, Cooper started research into preventive medicine. He became intrigued by the belief that exercise can preserve one's health. In 1970 he created his own institute (the Cooper Institute) for non-profit research and education devoted to preventive medicine. He sparked millions into becoming active and is now known as the "father of aerobics".
Aerobic versus anaerobic exercise
Aerobic exercise and fitness can be contrasted with anaerobic exercise, of which strength training and short-distance running are the most salient examples. The two types of exercise differ by the duration and intensity of muscular contractions involved, as well as by how energy is generated within the muscle. Anaerobic exercise becomes necessary when the heart and lungs can not keep up with the Oxygen demands of the muscle.
New research on the endocrine functions of contracting muscles has shown that both aerobic and anaerobic exercise promote the secretion of myokines, which are beneficial hormones, with attendant benefits including: growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases. Myokine secretion in turn is dependent on the amount of muscle contracted, and the duration and intensity of contraction. As such, both types of exercise (aerobic and anaerobic) produce quite a number of health benefits.
In almost all conditions, anaerobic exercise is accompanied by aerobic exercises because the less efficient anaerobic metabolism must supplement the aerobic system due to energy demands that exceed the aerobic system's capacity. What is generally called aerobic exercise might be better termed "solely aerobic", because it is designed to be low-intensity enough not to generate lactate (or lactic acid), so that all carbohydrate is aerobically turned into energy.
Initially during increased exertion, muscle glycogen is broken down to produce glucose, which undergoes glycolysis producing pyruvate which then reacts with oxygen (Krebs cycle, Chemiosmosis) to produce carbon dioxide and water and releases energy. If there is a shortage of oxygen (anaerobic exercise, explosive movements), carbohydrate is consumed more rapidly because the pyruvate ferments into lactate. If the intensity of the exercise exceeds the rate with which the cardiovascular system can supply muscles with oxygen, it results in buildup of lactate and quickly makes it impossible to continue the exercise. Unpleasant effects of lactate buildup initially include the burning sensation in the muscles, and may eventually include nausea and even vomiting if the exercise is continued without allowing lactate to clear from the bloodstream.
As glycogen levels in the muscle begin to fall, glucose is released into the bloodstream by the liver, and fat metabolism is increased so that it can fuel the aerobic pathways. Aerobic exercise may be fueled by glycogen reserves, fat reserves, or a combination of both, depending on the intensity. Prolonged moderate-level aerobic exercise at 65% VO 2 max (the heart rate of 150 bpm for a 30-year-old human) results in the maximum contribution of fat to the total energy expenditure. At this level, fat may contribute 40% to 60% of total, depending on the duration of the exercise. Vigorous exercise above 75% VO 2 max (160 bpm) primarily burns glycogen.
Major muscles in a rested, untrained human typically contain enough energy for about 2 hours of vigorous exercise. Exhaustion of glycogen is a major cause of what marathon runners call "hitting the wall". Training, lower intensity levels, and carbohydrate loading may allow postponement of the onset of exhaustion beyond 4 hours.
Aerobic exercise comprises innumerable forms. In general, it is performed at a moderate level of intensity over a relatively long period of time. For example, running a long distance at a moderate pace is an aerobic exercise, but sprinting is not. Playing singles tennis, with near-continuous motion, is generally considered aerobic activity, while golf or two person team tennis, with brief bursts of activity punctuated by more frequent breaks, may not be predominantly aerobic. Some sports are thus inherently "aerobic", while other aerobic exercises, such as fartlek training or aerobic dance classes, are designed specifically to improve aerobic capacity and fitness. It is most common for aerobic exercises to involve the leg muscles, primarily or exclusively. There are some exceptions. For example, rowing to distances of 2,000 m or more is an aerobic sport that exercises several major muscle groups, including those of the legs, abdominals, chest, and arms. Common kettlebell exercises combine aerobic and anaerobic aspects.
Among the recognized health benefits of doing regular aerobic exercise are:
- Strengthening the muscles involved in respiration, to facilitate the flow of air in and out of the lungs
- Strengthening and enlarging the heart muscle, to improve its pumping efficiency and reduce the resting heart rate, known as aerobic conditioning
- Improving circulation efficiency and reducing blood pressure
- Increasing the total number of red blood cells in the body, facilitating transport of oxygen
- Improved mental health, including reducing stress and lowering the incidence of depression, as well as increased cognitive capacity.
- Reducing the risk for diabetes. One meta-analysis has shown, from multiple conducted studies, that aerobic exercise does help lower Hb A 1C levels for type 2 diabetics.
As a result, aerobic exercise can reduce the risk of death due to cardiovascular problems. In addition, high-impact aerobic activities (such as jogging or using a skipping rope) can stimulate bone growth, as well as reduce the risk of osteoporosis for both men and women. In addition to the health benefits of aerobic exercise, there are numerous performance benefits:
- Increased storage of energy molecules such as fats and carbohydrates within the muscles, allowing for increased endurance
- Neovascularization of the muscle sarcomeres to increase blood flow through the muscles
- Increasing speed at which aerobic metabolism is activated within muscles, allowing a greater portion of energy for intense exercise to be generated aerobically
- Improving the ability of muscles to use fats during exercise, preserving intramuscular glycogen
- Enhancing the speed at which muscles recover from high intensity exercise
- Neurobiological effects: improvements in brain structural connections and increased gray matter density, new neuron growth, improved cognitive function (cognitive control and various forms of memory), and improvement or maintenance of mental health
Some drawbacks of aerobic exercise include:
- Overuse injuries because of repetitive, high-impact exercise such as distance running.
- Is not an effective approach to building muscle.
- Only effective for fat loss when used consistently.
Both the health benefits and the performance benefits, or "training effect", require a minimum duration and frequency of exercise. Most authorities suggest at least twenty minutes performed at least three times per week.
Aerobic Capacity
Aerobic capacity describes the functional capacity of the cardiorespiratory system, (the heart, lungs and blood vessels). Aerobic capacity refers to the maximum amount of oxygen consumed by the body during intense exercises, in a given time frame. It is a function both of cardiorespiratory performance and the maximum ability to remove and utilize oxygen from circulating blood. To measure maximal aerobic capacity, an exercise physiologist or physician will perform a VO 2 max test, in which a subject will undergo progressively more strenuous exercise on a treadmill, from an easy walk through to exhaustion. The individual is typically connected to a respirometer to measure oxygen consumption, and the speed is increased incrementally over a fixed duration of time. The higher the measured cardiorespiratory endurance level, the more oxygen has been transported to and used by exercising muscles, and the higher the level of intensity at which the individual can exercise. More simply put, the higher the aerobic capacity, the higher the level of aerobic fitness. The Cooper and multi-stage fitness tests can also be used to assess functional aerobic capacity for particular jobs or activities.
The degree to which aerobic capacity can be improved by exercise varies very widely in the human population: while the average response to training is an approximately 17% increase in VO 2 max, in any population there are "high responders" who may as much as double their capacity, and "low responders" who will see little or no benefit from training. Studies indicate that approximately 10% of otherwise healthy individuals cannot improve their aerobic capacity with exercise at all. The degree of an individual's responsiveness is highly heritable, suggesting that this trait is genetically determined.
| Indoor | Outdoor |
|---|---|
|
Stair climbing Indoor rower Stairmaster Stationary bicycle Treadmill |
Walking Cycling Running Cross-country skiing Cross-country running Nordic walking Inline skating Rowing |
Alternatives
Higher intensity exercise, such as High-intensity interval training (HIIT), increases the resting metabolic rate (RMR) in the 24 hours following high intensity exercise, ultimately burning more calories than lower intensity exercise; low intensity exercise burns more calories during the exercise, due to the increased duration, but fewer afterwards.
Aerobic exercise has long been a popular approach to achieving weight loss and physical fitness, often taking a commercial form.
- In the 1970s Judi Sheppard Missett helped create the market for commercial aerobics with her Jazzercise program
- In the 1980s Richard Simmons hosted an aerobic exercise show on television, and also released a series of exercise videos
- In the 1990s Billy Blanks's Tae Bo helped popularize cardio-boxing workouts that incorporated martial arts movements
Contributors and Attributions
- Wikipedia


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Review of Key Points:
-
A wide variety of theoretical perspectives influence how psychologists view personality, including psychodynamic factors, learning/cognitive factors, biological factors, inherent drives, and sociocultural influences.
-
An important trend in psychology today is the emphasis on positive psychology, and the potential for the field of psychology to contribute in positive ways to society.
-
A wide variety of personality tests have been developed, both objective and projective tests. Since it often proves difficult to establish the reliability and validity of some personality tests, a clinical interview is an essential step in forming an opinion regarding someone’s personality (especially if there is a question of mental illness).
-
Critical thinking is purposeful, reasoned, goal-directed thinking aimed at evaluating claims that are made as being true.


9: Carbonyl Condensation Reactions
When you have completed Chapter 9, you should be able to
- fulfill all of the detailed objectives listed under each individual section.
- design multi‑step syntheses in which the reactions introduced in this unit are used in conjunction with any of the reactions described in previous units.
- solve road‑map problems that require a knowledge of carbonyl condensation reactions.
- define, and use in context, any of the key terms introduced.
In this chapter, we consider the fourth and final general type of reaction that carbonyl compounds undergo—the carbonyl condensation reaction. Carbonyl condensation reactions take place between two carbonyl‑containing reactants, one of which must possess an alpha‑hydrogen atom. The first step of the reaction involves the removal of an alpha‑hydrogen atom by a base. In the second step, the enolate anion that results from this removal attacks the carbonyl‑carbon of the second reacting molecule. In the final step of the reaction, a proton is transferred to the tetrahedral intermediate formed in the second step, although in some cases the product that results may subsequently be dehydrated.
-
- 9.7: Intramolecular Aldol Reactions
- Molecules which contain two carbonyl functionalities have the possibility of forming a ring through an intramolecular aldol reaction. The term “Intramolecular” means “within the same molecule.” In this case, it means that the enolate donor and the electrophilic acceptor of an aldol reaction are contained in the same molecule such as dialdehydes, keto aldehydes, or diketones. In these cases, the small distance between the donor and acceptor leads to faster reaction rates.
-
- 9.11: Conjugate Carbonyl Additions - The Michael Reaction
- Certain nucleophiles undergo conjugate addition with the alkene of an α, β-unsaturated carbonyl compounds rather than undergo direct nucleophilic addition with the carbonyl. During conjugate addition, a nucleophile adds to the electrophilic β-alkene carbon to from a C-Nuc bond. If the starting materials contains an ester the corresponding alkoxide is used as the base in the reaction. Otherwise a hydroxide base, such as sodium or potassium hydroxide, is commonly used.


13.5: The Prostate
The prostate gland is part of sexual anatomy, and produces the fluid that nourishes and helps to transport semen. The prostate normally doubles in size during puberty. At approximately age 25, it gradually begins to enlarge again. This enlargement does not usually cause problems; however, abnormal growth of the prostate, or benign prostatic hyperplasia (BPH), can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, such as a frequent and intense urge to urinate, a weak stream, and a sensation that the bladder has not emptied completely. By age 60, approximately 40 percent of men have some degree of BPH. By age 80, the number of affected individuals has jumped to as many as 80 percent. Treatments for BPH attempt to relieve the pressure on the urethra so that urine can flow more normally. Mild to moderate symptoms are treated with medication, whereas severe enlargement of the prostate is treated by surgery, in which a portion of the prostate tissue is removed.
The prostate gland can be a source of great sexual pleasure, and a direct route to orgasm and ejaculation. During arousal, the prostate gland swells and this is when prostate stimulation can feel most pleasurable. One can stimulate one’s own prostate or a partner can do it, by inserting a finger in the anus and stroking towards the front of the body. Prostate massage is sometimes referred to as “milking the prostate” when it results in ejaculation or fluid coming out of the penis. When heterosexual couples do prostate massage and stimulation, it is sometimes referred to as pegging. The Ultimate Guide to Prostate Pleasure is a great resource for more information on how to safely enjoy sexual pleasure with prostate play.
Sometimes, surgery is recommended in order to treat prostate cancer. Removal of part or most of the prostate can cause the inability to achieve an erection. Working with a pelvic floor physical therapist prior to and after surgery can sometimes prevent this. Before having a prostate surgery, it can be helpful to speak to a healthcare provider regarding how it might affect erections.


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HGTC BIO 225: Microbiology Lab Manual
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6.4: Preview
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- Cindy Stephens, Gina Peterson, Sharon Eyrich, & Jennifer Paris
- College of the Canyons via College of the Canyons
As discussed in chapter 2, the field of early care and education relies on developmental and learning theories to guide our practices. Not only do theories help us to better understand a child’s social, emotional, cognitive, and physical needs, theories help us to see each child as a unique learner and can also help us to set appropriate expectations. With the information we uncover by watching and listening to children, we can provide developmentally appropriate learning opportunities so they can thrive. In this chapter, we will examine how observation techniques are used to connect theory principles to practical applications. In other words, we will explore how teachers can incorporate observation, documentation, and assessment into their daily routines in order to effectively work with children and their families.
In the field of early care and education, the pursuit of high-quality care is a top priority. Throughout the day, preschool teachers have numerous tasks and responsibilities. In addition to providing a safe and nurturing environment, teachers must plan effective curriculum, assess development, decorate the classroom, stock the shelves with age-appropriate materials, and they must develop respectful relationships with children and their families. So you might be wondering, what does this all have to do with observation, documentation, and assessment? To effectively support a child’s development and to help them thrive, preschool teachers are expected to be accountable and intentional with every interaction and experience. Let’s take a closer look and examine how teachers utilize observation, documentation, and assessment to maintain a high-quality learning environment.
Pause to Reflect
How would you define observation? Compare your definition to the one below.
According to Gordon and Browne (2016) “Observing is more than ordinary supervision. It takes energy and concentration to become an accurate observer.” [36] It also takes time and practice to learn how to distinguish the difference between trivial details and detailed data. Once teachers master objective observation techniques and they can recognize their own biases , they are ready to conduct purposeful observations and support children’s play, learning, growth, and development.


10.1: Theories of Adolescent Socioemotional Development
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Learning Objectives
By the end of this section, you will be able to:
- Discuss theories about the role of adolescence in the lifespan
- Describe adolescence’s central challenge: the search for identity
- Identify the developmental tasks and milestones of the adolescent period
Seventeen-year-old Armaan rushes downstairs with a basket full of his laundry. He loads the washer and readies his change of clothes and water bottle for after-school marching band practice. That evening, after a three-hour practice, Armaan grabs a veggie burger with friends. Back home, he takes a quick shower and starts studying for a big history test. Before he goes to bed, he texts with friends as he unloads the dishwasher. It’s only Monday, but he’s excitedly anticipating watching the high school football game on Friday night and sleeping in on Saturday.
This brief window into the life of an older adolescent leads to some big-picture questions about this period of the lifespan, including what its central developmental tasks are and how psychologists mark progression through them. Adolescence is a time of profound and often rapid change in multiple dimensions, including identity exploration and achievement, and emotional development. These changes necessitate sensitive and accommodating responses from individuals who care for teens, as well as from societal institutions like schools and governments that serve them.
What Is Adolescence?
Human development is a series of transitions, particularly so in adolescence, which can bring sudden and dramatic changes like the onset of puberty , changes in voice, and growth in height. Adolescence is a time many societies set aside for children to transition to adult stature, status, roles, and capabilities. In other countries, children may quickly transition to adult responsibilities without being afforded the time and space to adjust to this immense developmental shift.
For instance, in several Asian and African cultures, adolescents tend to have strong family obligations and responsibilities, emphasizing group harmony and family loyalty. Older adolescents in Cambodia and rural Vietnam assume caretaking tasks and the family supporter’s role (Yi, 2015). Teenage girls may face stricter gender roles and fewer opportunities than boys. Early marriage and childbearing are common in Bangladesh (Uddin, 2021) and Nigeria (Musa et al., 2021). In WEIRD nations like the United States and Canada, many families consider finishing high school a marker of adulthood, and eighteen-year-old graduates may begin to work full time and start their own households or may enter further schooling or a trade. Adolescence focuses on preparation for adulthood, such as through extended formal education, and it precludes adult status and its markers such as driving and beginning to participate in the workforce (Figure 10.2).
The smoothness of the adolescent transition in countries such as the United States and Canada also varies by family composition, cultural beliefs and backgrounds, available opportunities, and socioeconomic status (SES). Adolescents from single-parent families, for example, often help with household tasks like caring for younger siblings and may even contribute to household finances. Teens who grow up in farming families or families that own a bodega or other business may begin to help run the family business and then continue to do so, if they also enjoy that industry. Teens who show interest in an academic education beyond high school may spend after-school and summer hours in academic enrichment activities. Still other teens who show interests in craft or trade industries may pursue hobbies such as sewing, electrical work, or woodworking to begin identifying potential occupational options. As these examples show, it is difficult to characterize adolescence in many countries as solely continuous or discontinuous in nature.
To understand the complexities of the adolescent transition, consider the developmental tasks associated with it. These are the biologically, psychologically, and socially relevant challenges of adolescence (Havighurst, 1948; 1972). They include achieving the cognitive development crucial for decision-making, acquiring impulse control and reasoning, developing a sense of self and personal identity, and building friendships while navigating social dynamics to gain a sense of belonging and acceptance. In addition to the biological and physical changes of puberty discussed in Chapter 9 Physical and Cognitive Development in Adolescence (Ages 12 to 18), adolescents also face several psychological and social developmental tasks (Table 10.1). To the extent that they make individual progress on these tasks, adolescents gradually mature into adulthood.
| Psychological | Social |
|---|---|
|
|
Many societies and cultures use explicit markers to recognize progress toward adult status. Anthropologists call such a marker a rite of passage . Table 10.2 and Figure 10.3 show some examples (Alcorta & Sosis, 2020). Parents, teens, and society alike put much attention and energy into some of these. Notice that no single marker signifies adult status in all areas of life.
| Marker (Rite) | Age of Adult Status (Years) |
|---|---|
| Participating in bar/bat Mitzvah (Jewish religion) | 12–13 |
| Participating in quinceañera/o (many Latine cultures) | 15 |
| Driving | 15–17 depending on the state |
| Attending “R” rated movie without caregiver | 17 |
| Graduating from high school | 17–19 |
| Voting | 18 |
| Consenting to sexual activity | 16–18 (depending upon U.S. state) |
| Drinking, purchasing alcohol | 21 |
| Renting a car | 25 |
| Procuring own health insurance | 26 (Affordable Care Act, United States) |
Psychosocial Theory of Development: Identity versus Role Confusion
To a developmental psychologist, a teenager’s social struggles and ever-evolving choices illustrate the work of adolescence: actively exploring interests, abilities, strengths, weaknesses, peer relations, and work and community roles. Collectively, these make up the most important psychosocial development task: the formation of identity.
Identity, also known as ego identity, is an individual’s complete sense of who they are, including their traits, capabilities, interests, values, and social roles. The building of identity is a lifelong process, but it takes on critical importance in adolescence because of both the sheer number of changes experienced and the sense that life is reaching a point at which our decisions and choices could have lifelong consequences (Branje et al., 2021; Crain, 1992). Forming a coherent identity takes time, and adolescence accommodates this key developmental task. Erik Erikson ’s contribution to identity is sometimes thought to be one of his greatest insights, perhaps in part due to his own experience as an immigrant with a varied cultural heritage. Erikson moved across multiple countries in his youth, experienced multiple name changes, identified as multi racial, and studied identity in multiple cultural and historic contexts (Miller, 2011).
Erikson’s fifth psychosocial stage, identity versus role confusion , involves forming a stable and whole identity by first exploring various roles and identities. This stage typically occurs from ages twelve to eighteen years and is distinctive as a stage when individuals try out a variety of roles and personas in a journey to discover their individual identity. Developing an identity leads to strength and stability of identity. Failing to develop an identity results in role confusion, sometimes called diffusion , which leads to feeling fragmented or lost (Orenstein & Lewis, 2022). A strong sense of identity helps teenagers reject negative self-evaluations that don't match their inner and outer experiences, reducing anxiety. As they explore their identity, adolescents consider their past experiences, societal expectations, and personal aspirations to establish their values and discover who they are.
A recent study looked at identity development and depressive symptoms in Belgian adolescents between the ages of twelve to twenty-five years. They found young people generally develop a stronger sense of identity and experience less role confusion, though this can vary at different stages. A strong sense of identity is linked to fewer depressive symptoms, while role confusion is linked to more depressive symptoms throughout adolescence (Bogaerts et al., 2021).
It Depends: Should We Take the Teen Movie Genre Seriously?
Film critics and social commentators may dismiss the latest movies about teenage experiences and the coming-of-age process, but they often become huge popular successes, and for good reason. Not only are they highly entertaining, filled with young stars and amusing plots, but they are tailor-made for a teenage audience that likes to see their own experiences represented, and perhaps to see whether the adult filmmakers truly understand them. Some popular examples of the teenage movie genre include Perks of Being a Wallflower (2012), Spider Man: Homecoming (2017), Spider-Man: Into the Spider-Verse (2018), The Breakfast Club (1985), Eighth Grade (2018), Mean Girls (2004, 2023), Juno (2007), and To All the Boys I’ve Loved Before (2018).
Almost without exception, these films take place in and around a U.S. high school, and they frequently introduce the audience to various cliques and larger social groups within the school’s social ecosystem. For example, in The Breakfast Club , a student lists cliques like “brains” and “jocks.” Mean Girls starts with a character pointing out different social groups. Each clique and crowd offers teenagers a way to select and try on parts of their possible identity, while some crowds are socially selected for them. Eighth Grade shows the life of a middle school-high school student, Kayla (Elsie Fisher), navigating anxiety-inducing social situations, social media overload, typical parent-child communication struggles, questions about sexuality, and her personal and public identity. These films highlight a central adolescent experience—exploring and achieving a complete sense of self. They reflect adolescents' experiences, sometimes playfully naming groups and often depicting characters moving through identities and roles to complete a quest. Adults are sometimes peripheral or absent.
Other adolescent themes frequently depicted in movies include inspiration, social comparison, coping, identification and idealization, and strong social relationships that bring joy, gratitude, and loss (Greenwood & Long, 2015). These themes speak to the youth culture that thrives in high schools, where the most important focus seems to be on social status and peer relations. All else pales in importance, even the whole point of school—academics. While sociocultural context and individual personality traits govern the way teens interpret these films and behave in school and out, by responding to these movies with enthusiasm, adolescent audiences tell us they are valid perspectives on their real-life experience.
Recall that in Erikson’s theory, development is motivated and fueled by psychosocial crises or challenges. The relatively rapid changes in the physical bodies of adolescents guarantee that others in the social environment will begin reacting differently when around them. For example, the deep voice, tall stature, and facial hair of a fifteen-year-old male might lead others to expectations of mature thinking and behavior, even as he still struggles with some immature thought processes and lack of adult levels of brain development and self-regulation. Interactions between the developing individual and those in their social environment propel developmental progress. The adolescent is motivated to make sense of their changing place in the world and thus begin the process of identity exploration.
Identity Statuses
James Marcia built on Erikson’s work by focusing on how best to describe the developing adolescent’s identity status at any point in time (Marcia, 1966; 1980). Marcia emphasized two key questions in determining the identity status of an individual: “Is there evidence of identity exploration?” and “Is the individual currently committed to an identity?” The answers, yes or no, establish the adolescent as being in identity achievement, moratorium, foreclosure, or identity diffusion (Figure 10.4). Those who reach identity achievement often arrive after much exploration, while those in moratorium are still exploring different roles without making firm decisions (Kroger et al. 2010). These statuses also take into account various aspects of an individual’s identity, including their occupation, sexuality, beliefs, and values. Often, adolescents move through these identity statuses before settling on successful identity achievement.
In identity moratorium , individuals are actively exploring various identities but not declaring an identity to be fully formed, instead experiencing an "identity crisis." Meeus (2023) noted that adolescents spend much of their time in identity moratorium, where identity is a work in progress. Although the term makes this sound negative, the moratorium provides the psychological space and motivation to explore. A newfound ability to imagine possible selves , various identities they may work toward in the future, motivates adolescents to start on the path toward achieving an identity. For example, people often describe college as a great period of moratorium wherein you explore various academic interests and potential paths while meeting a wider range of people.
In identity diffusion , which most closely aligns with Erikson’s role confusion, individuals have low commitment and often feel lost; they do not actively seek an identity. Marcia (1980) described them as lacking a clear sense of where they will fit into society as an adult and at risk of role confusion. This might be an acceptable identity status in early adolescence, but society’s expectation is that all individuals will use these years to explore and pursue interests, abilities, and roles. By exploring roles and interests, adolescents move toward identity achievement , the realization and commitment to a coherent understanding of themselves and their relationship with society. This is the pivotal psychosocial achievement of adolescence, and it provides adolescents with an initial sense of direction, purpose, and a starting point in the world at large as they enter adulthood.
In Marcia’s concept of identity foreclosure , the developing teen shows an early commitment to an identity, claiming they know who they are and what they stand for, even if there is no evidence they did any exploratory work to reach that conclusion. For example, teens in early and even mid-adolescence will sometimes state their political values—such as by taking a particular stance on climate or immigration or foreign policy—but these values typically match those of their parents, and the adolescent cannot elaborate on any specifics. Identity foreclosure may serve a developmental purpose by giving the young adolescent a starting point for later exploration—after all, the world is complex and having an initial set of answers to help make sense of it can be comforting. The key is for the adolescent to eventually begin actively exploring their values and interests, with the goal of backing their own belief system with experience and/or thoughtful consideration. While an adolescent might align with their parents on a value or identity, such as sharing the same religious identity, an adolescent who has identity achievement will be able to fully explain how they arrived at that identity on their own.
While identity achievement often occurs during adolescence or early adulthood, it is not uncommon for it to take many years beyond adolescence for individuals to fully settle into identity achievement. After all, in the decades beyond adolescence we are often learning and growing across several aspects of our identity, potentially shifting in our occupations, family and friendship roles, and moral beliefs or personal values. Achieving identity in adolescence represents a pivotal step in identity , rather than a permanent, unchangeable status.
Link to Learning
This short Pew Research Center article explores survey data on the similarities between teens’ and their parents’ religious and political views.
References
Alcorta, C. S., & Sosis, R. (2020). Adolescent religious rites of passage: An anthropological perspective. In S. Hupp and J. Jewell (Eds.), The encyclopedia of child and adolescent development (pp. 1–12). doi.org/10.1002/9781119171492.wecad326
Bogaerts, A., Claes, L., Buelens, T., Verschueren, M., Palmeroni, N., Bastiaens, T., & Luyckx, K. (2021). Identity synthesis and confusion in early to late adolescents: Age trends, gender differences, and associations with depressive symptoms. Journal of Adolescence, 87 , 106–116. psycnet.apa.org/doi/10.1016/...ce.2021.01.006
Branje, S., De Moor, E. L., Spitzer, J., & Becht, A. I. (2021). Dynamics of identity development in adolescence: A decade in review. Journal of Research on Adolescence, 31 (4), 908–927. doi.org/10.1111/jora.12678
Crain, W. C. (1992). Theories of development: Concepts and applications (3rd ed.). Prentice-Hall, Inc. psycnet.apa.org/record/1992-98367-000
Greenwood, D., & Long, C. R. (2015). When movies matter: Emerging adults recall memorable movies. Journal of Adolescent Research, 30 (5), 625–650. doi.org/10.1177/0743558414561296
Havighurst, R. (1972). Developmental tasks and education . D. McKay Company. psycnet.apa.org/record/1950-00529-000
Havighurst, R. J. (1948). Developmental tasks and education. The University of Chicago Press. psycnet.apa.org/record/1950-00529-000
Kroger, J., Martinussen, M., & Marcia, J. E. (2010). Identity status change during adolescence and young adulthood: A meta-analysis. Journal of adolescence, 33 (5), 683–698. doi.org/10.1016/j.adolescence.2009.11.002
Marcia, J. E. (1966). Development and validation of ego-identity status. Journal of Personality and Social Psychology, 3 (5), 551–558. psycnet.apa.org/doi/10.1037/h0023281
Marcia, J. E. (1980). Identity in adolescence. Handbook of adolescent psychology, 9 (11), 159–187. scholar.google.com/citations...J:u-x6o8ySG0sC
McIntosh, N., Helms, P. J., & Smyth, R. L. (Eds.). (2003). Forfar & Arneil's textbook of pediatrics (6th ed.). Churchill Livingstone. https://archive.org/details/forfararneilstex6edunse
Meeus, W. (2023). Fifty years of longitudinal research into identity development in adolescence and early adulthood: An overview. APA handbook of adolescent and young adult development, 139–157. psycnet.apa.org/doi/10.1037/0000298-009
Miller, P. H. (2011). Theories of developmental psychology (5th ed.). Worth Publishers.
Musa, S. S., Odey, G. O., Musa, M. K., Alhaj, S. M., Sunday, B. A., Muhammad, S. M., & Lucero-Prisno, D. E. (2021). Early marriage and teenage pregnancy: The unspoken consequences of COVID-19 pandemic in Nigeria. Public Health in Practice, 2, 100152. https://doi.org/10.1016/j.puhip.2021.100152
Orenstein, G. A., & Lewis, L. (2022). Eriksons stages of psychosocial development . In StatPearls [Internet]. StatPearls Publishing. www.ncbi.nlm.nih.gov/books/NBK556096/
Uddin, M. E. (2021). Teenage marriage and high school dropout among poor girls: A narrative review for family pathways in Bangladesh. Journal of Research in Social Sciences and Language, 1 (1), 55–76. https://doi.org/10.20375/0000-000D-FF92-F
Yi, C. C. (2015). Adolescents and transition to adulthood in Asia. In S. R. Quah, Routledge handbook of families in Asia (pp. 191–210). Routledge. doi.org/10.4324/9781315881706


5.18: The Beta Prime Distribution
Basic Theory
The beta prime distribution is the distribution of the odds ratio associated with a random variable with the beta distribution . Since variables with beta distributions are often used to model random probabilities and proportions, the corresponding odds ratios occur naturally as well.
Definition
Suppose that \( U \) has the beta distribution with shape parameters \( a, \, b \in (0, \infty) \). Random variable \( X = U \big/ (1 - U) \) has the beta prime distribution with shape parameters \( a \) and \( b \).
The special case \( a = b = 1 \) is known as the standard beta prime distribution . Since \( U \) has a continuous distribution on the interval \( (0, 1) \), random variable \( X \) has a continuous distribution on the interval \( (0, \infty) \).
Distribution Functions
Suppose that \( X \) has the beta prime distribution with shape parameters \( a, \, b \in (0, \infty) \), and as usual, let \( B \) denote the beta function.
\( X \) has probability density function \( f \) given by \[ f(x) = \frac{1}{B(a, b)} \frac{x^{a - 1}}{(1 + x)^{a + b}}, \quad x \in (0, \infty) \]
Proof
First, recall that the beta PDF \( g \) with parameters \( a \) and \( b \) is \[ g(u) = u^{a-1} (1 - u)^{b-1}, \quad u \in (0, 1) \] The transformation \( x = u \big/ (1 - u) \) maps \( (0, 1) \) onto \( (0, \infty) \) and is increasing. The inverse transformation is \( u = x \big/ (x + 1) \), and \( 1 - u = 1 \big/ (x + 1) \) and \( du / dx = 1 \big/ (x + 1)^2 \). Thus, by the change of variables formula, \[ f(x) = g(u) \frac{du}{dx} = \frac{1}{B(a, b)} \left(\frac{x}{x+1}\right)^{a-1} \left(\frac{1}{x + 1}\right)^{b-1} \frac{1}{(x + 1)^2} = \frac{1}{B(a, b)} \frac{x^{a-1}}{(x + 1)^{a + b}}, \quad x \in (0, \infty) \]
If \( a \ge 1 \), the probability density function is defined at \( x = 0 \), so in this case, it's customary add this endpoint to the domain. In particular, for the standard beta prime distribution, \[ f(x) = \frac{1}{(1 + x)^2}, \quad x \in [0, \infty) \] Qualitatively, the first order properties of the probability density function \( f \) depend only on \( a \), and in particular on whether \( a \) is less than, equal to, or greater than 1.
The probability density function \( f \) satisfies the following properties:
- If \( 0 \lt a \lt 1 \), \( f \) is decreasing with \( f(x) \to \infty \) as \( x \downarrow 0 \).
- If \( a = 1 \), \( f \) is decreasing with mode at \( x = 0 \).
- If \( a \gt 1 \), \( f \) increases and then decreases with mode at \( x = (a - 1) \big/ (b + 1) \).
Proof
These properties follow from standard calculus. The first derivative of \( f \) is \[ f^\prime(x) = \frac{1}{B(a, b)} \frac{x^{a-2}}{(1 + x)^{a + b + 1}} [(a - 1) - x(b + 1)], \quad x \in (0, \infty) \]
Qualitatively, the second order properties of \( f \) also depend only on \( a \), with transitions at \( a = 1 \) and \( a = 2 \).
For \( a \gt 1 \), define \begin{align} x_1 & = \frac{(a - 1)(b + 2) - \sqrt{(a - 1)(b + 2)(a + b)}}{(b + 1)(b + 2)} \\ x_2 & = \frac{(a - 1)(b + 2) + \sqrt{(a - 1)(b + 2)(a + b)}}{(b + 1)(b + 2)} \end{align} The probability density function \( f \) satisfies the following properties:
- If \( 0 \lt a \le 1 \), \( f \) is concave upward.
- If \( 1 \lt a \le 2 \), \( f \) is concave downward and then upward, with inflection point at \( x_2 \).
- If \( a \gt 2 \), \( f \) is concave upward, then downward, then upward again, with inflection points at \( x_1 \) and \( x_2 \).
Proof
These results follow from standard calculus. The second derivative of \( f \) is \[ f^{\prime\prime}(x) = \frac{1}{B(a, b)} \frac{x^{a-3}}{(1 + x)^{a + b + 2}}\left[(a - 1)(a - 2) - 2 (a - 1)(b + 2) x + (b + 1)(b + 2)x^2\right], \quad x \in (0, \infty) \]
Open the Special Distribution Simulator and select the beta prime distribution. Vary the parameters and note the shape of the probability density function. For selected values of the parameters, run the simulation 1000 times and compare the empirical density function to the probability density function.
Because of the definition of the beta prime variable, the distribution function of \( X \) has a simple expression in terms of the beta distribution function with the same parameters, which in turn is the regularized incomplete beta function. So let \( G \) denote the distribution function of the beta distribution with parameters \( a, \, b \in (0, \infty) \), and recall that \[ G(x) = \frac{B(x; a, b)}{B(a, b)}, \quad x \in (0, 1) \]
\( X \) has distribution function \( F \) given by \[ F(x) = G\left(\frac{x}{x + 1}\right), \quad x \in [0, \infty) \]
Proof
As noted in the proof of the formula for the PDF , \( x = u \big/ (1 - u) \) is strictly increasing with inverse \( u = x \big/ (x + 1) \). Hence \[ F(x) = \P(X \le x) = \P\left(\frac{U}{U - 1} \le x\right) = \P\left(U \le \frac{x}{x + 1}\right) = G\left(\frac{x}{x + 1}\right), \quad x \in [0, \infty)\]
Similarly, the quantile function of \( X \) has a simple expression in terms of the beta quantile function \( G^{-1} \) with the same parameters.
\( X \) has quantile function \( F^{-1} \) given by \[ F^{-1}(p) = \frac{G^{-1}(p)}{1 - G^{-1}(p)}, \quad p \in [0, 1) \]
Proof
This follows from the result for the CDF by solving \( p = F(x) = G\left(\frac{x}{x+1}\right) \) for \( x \) in terms of \( p \).
Open the Special Distribution Calculator and choose the beta prime distribution. Vary the parameters and note the shape of the distribution function. For selected values of the parameters, find the median and the first and third quartiles.
For certain values of the parameters, the distribution and quantile functions have simple, closed form expressions.
If \( a \in (0, \infty) \) and \( b = 1 \) then
- \( F(x) = \left(\frac{x}{x + 1}\right)^a \) for \( x \in [0, \infty) \)
- \( F^{-1}(p) = \frac{p^{1/a}}{1 - p^{1/a}} \) for \( p \in [0, 1) \)
Proof
For \( a \gt 0 \) and \( b = 1 \), \( G(u) = u^a \) for \( u \in [0, 1] \) and \( G^{-1}(p) = p^{1/a} \) for \( p \in [0, 1] \)
If \( a = 1 \) and \( b \in (0, \infty) \) then
- \( F(x) = 1 - \left(\frac{1}{x + 1}\right)^b \) for \( x \in [0, \infty) \)
- \( F^{-1}(p) = \frac{1 - (1 - p)^{1/b}}{(1 - p)^{1/b}} \) for \( p \in [0, 1) \)
Proof
For \( a = 1 \) and \( b \gt 0 \), \( G(u) = 1 - (1 - u)^b \) for \( u \in [0, 1] \) and \( G^{-1}(p) = 1 - (1 - p)^{1/b} \) for \( p \in [0, 1] \).
If \( a = b = \frac{1}{2} \) then
- \( F(x) = \frac{2}{\pi} \arcsin\left(\sqrt{\frac{x}{x + 1}}\right) \) for \( x \in [0, \infty) \)
- \( F^{-1}(p) = \frac{\sin^2\left(\frac{\pi}{2} p\right)}{1 - \sin^2\left(\frac{\pi}{2} p\right)} \) for \( p \in [0, 1) \)
Proof
For \( a = b = \frac{1}{2} \), \( G(u) = \frac{2}{\pi} \arcsin\left(\sqrt{u}\right) \) for \( u \in (0, 1) \) and \( G^{-1}(p) = \sin^2\left(\frac{\pi}{2} p\right) \) for \( p \in [0, 1] \)
When \( a = b = \frac{1}{2} \), \( X \) is the odds ratio for a variable with the standard arcsine distribution.
Moments
As before, \( X \) denotes a random variable with the beta prime distribution, with parameters \( a, \, b \in (0, \infty) \). The moments of \( X \) have a simple expression in terms of the beta function.
If \( t \in (-a, b) \) then \[ \E\left(X^t\right) = \frac{B(a + t, b - t)}{B(a, b)} \] If \(t \in (-\infty, -a] \cup [b, \infty)\) then \( \E(X^t) = \infty \).
Proof
Once again, let \( g \) denote the beta PDF with parameters \( a \) and \( b \). With the transformation \( x = u \big/ (1 - u) \), as in the proof PDF formula , we have \( f(x) dx = g(u) du \). Hence \[ \int_0^\infty x^t f(x) dx = \int_0^1 \left(\frac{u}{1 - u}\right)^t g(u) du = \frac{1}{B(a, b)} \int_0^1 u^{a + t - 1} (1 - u)^{b - t - 1} du \] If \( t \le -a \) the improper integral diverges to \( \infty \) at 0. If \( t \ge b \) the improper integral diverges to \( \infty \) at 1. If \( -a \lt t \lt b \) the integral is \( B(a + t, b - t) \) by definition of the beta function.
Of course, we are usually most interested in the integer moments of \( X \). Recall that for \( x \in \R \) and \( n \in \N \), the rising power of \( x \) of order \( n \) is \( x^{[n]} = x (x + 1) \cdots (x + n - 1) \).
Suppose that \( n \in \N \). If \( n \lt b \) Then \[ \E\left(X^n\right) = \prod_{k=1}^n \frac{a + k - 1}{b - k} \] If \( n \ge b \) then \( \E\left(X^n\right) = \infty \).
Proof
From the general moment result , \[ \E(X^n) = \frac{B(a + n, b - n)}{B(a, b)} = \frac{\Gamma(a + n) \Gamma(a - n)}{\Gamma(a + b)} \frac{\Gamma(a + b)}{\Gamma(a) \Gamma(b)} = \frac{\Gamma(a + n)}{\Gamma(a)} \frac{\Gamma(b - n)}{\Gamma(b)} = \frac{a^{[n]}}{(b - n)^{[n]}} \] by a basic property of the gamma function.
As a corollary, we have the mean and variance.
If \( b \gt 1 \) then \[ \E(X) = \frac{a}{b - 1} \]
If \( b \gt 2 \) then \[ \var(X) = \frac{a (a + b - 1)}{(b - 1)^2 (b - 2)} \]
Proof
This follows from the general moment result above and the computational formula \( \var(X) = \E\left(X^2\right) = [\E(X)]^2 \).
Open the Special Distribution Simulator and select the beta prime distribution. Vary the parameters and note the size and location of the mean\(\pm\)standard deviation bar. For selected values of the parameters, run the simulation 1000 times and compare the empirical mean and standard deviation to the distribution mean and standard deviation.
Finally, the general moment result leads to the skewness and kurtosis of \( X \).
If \( b \gt 3 \) then \[ \skw(X) = \frac{2 (2 a + b - 1)}{b - 3} \sqrt{\frac{b - 2}{a (a + b - 1)}}\]
Proof
This follows from the usual computational formula for skewness in terms of the moments \( \E(X^n) \) for \( n \in \{1, 2, 3\} \) and the general moment result above.
In particular, the distibution is positively skewed for all \( a \gt 0 \) and \( b \gt 3 \).
If \( b \gt 4 \) then \[ \kur(X) = \frac{3 a^3 b^2 + 69 a^3 b - 30 a^3 + 6 a^2 b^3 +12 a^2 b^2 -78 a^2 b +60 a^2 + 3 a b^4 + 9 a b^3 - 69 a b^2 + 99 a b - 42 a + 6 b^4 - 30 b^3 + 54 b^2- 42 b + 12}{(a + b - 1)(b - 3)(b - 4)} \]
Proof
This follows from the usual computational formula for kurtosis in terms of the moments \( \E(X^n) \) for \( n \in \{1, 2, 3, 4\} \) and the general moment result above.
Related Distributions
The most important connection is the one between the beta prime distribution and the beta distribution given in the definition . We repeat this for emphasis.
Suppose that \( a, \, b \in (0, \infty) \).
- If \( U \) has the beta distribution with parameters \( a \) and \( b \), then \( X = U \big/ (1 - U) \) has the beta prime distribution with parameters \( a \) and \( b \).
- If \( X \) has the beta prime distribution with parameters \( a \) and \( b \), then \( U = X \big/ (X + 1) \) has the beta distribution with parameters \( a \) and \( b \).
The beta prime family is closed under the reciprocal transformation.
If \( X \) has the beta prime distribution with parameters \( a, \, b \in (0, \infty) \) then \( 1 / X \) has the beta prime distribution with parameters \( b \) and \( a \).
Proof
A direct proof using the change of variables formula is possible, of course, but a better proof uses a corresponding property of the beta distribution. By definition, we can take \( X = U \big/ (1 - U) \) where \( U \) has the beta distribution with parameters \( a \) and \( b \). But then \( 1/X = (1 - U) \big/ U \), and \( 1 - U \) has the beta distribution with parameters \( b \) and \( a \). By another application of the definition, \( 1/X \) has the beta prime distribution with parameters \( b \) and \( a \).
The beta prime distribution is closely related to the \( F \) distribution by a simple scale transformation.
Connections with the \( F \) distributions.
- If \( X \) has the beta prime distribution with parameters \( a, \, b \in (0, \infty) \) then \( Y = \frac{b}{a} X \) has the \( F \) distribution with \( 2 a \) degrees of the freedom in the numerator and \( 2 b \) degrees of freedom in the denominator.
- If \( Y \) has the \( F \) distribution with \( n \in (0, \infty) \) degrees of freedom in the numerator and \( d \in (0, \infty) \) degrees of freedom in the denominator, then \( X = \frac{n}{d} Y \) has the beta prime distribution with parameters \( n/2 \) and \( d/2 \).
Proof
Let \( f \) denote the PDF of \( X \) and \( g \) the PDF of \( Y \).
- By the change of variables formula, \[ g(y) = \frac{a}{b} f\left(\frac{a}{b} y\right), \quad x \in (0, \infty) \] Substituting into the beta prime PDF shows that \( Y \) has the appropriate \( F \) distribution.
- Again using the change of variables formula, \[ f(x) = \frac{d}{n} g\left(\frac{d}{n} x\right), \quad x \in (0, \infty) \] Substituting into the \( F \) PDF shows that \( X \) has the appropriate beta prime PDF.
The beta prime is the distribution of the ratio of independent variables with standard gamma distributions. (Recall that standard here means that the scale parameter is 1.)
Suppose that \( Y \) and \( Z \) are independent and have standard gamma distributions with shape parameters \( a \in (0, \infty) \) and \( b \in (0, \infty) \), respectively. Then \( X = Y / Z \) has the beta prime distribution with parameters \( a \) and \( b \).
Proof
Of course, a direct proof can be constructed, but a better approach is to use the previous result. Thus suppose that \( Y \) and \( Z \) are as stated in the theorem. Then \( 2 Y \) and \( 2 Z \) are independent chi-square variables with \( 2 a \) and \( 2 b \) degrees of freedom, respectively. Hence \[ W = \frac{Y / 2a}{Z / 2b} \] has the \( F \) distribution with \( 2 a \) degrees of freedom in the numerator and \( 2 b \) degrees of freedom in the denominator. By the previous result, \[ X = \frac{2 a}{2 b} W = \frac{Y}{Z} \] has the beta prime distribution with parameters \( a \) and \( b \).
The standard beta prime distribution is the same as the standard log-logistic distribution.
Proof
The PDF of the standard beta prime distribution is \( f(x) = 1 \big/ (1 + x)^2 \) for \( x \in [0, \infty) \), which is the same as the PDF of the standard log-logistic distribution.
Finally, the beta prime distribution is a member of the general exponential family of distributions.
Suppose that \( X \) has the beta prime distribution with parameters \( a, \, b \in (0, \infty) \). Then \( X \) has a two-parameter general exponential distribution with natural parameters \( a - 1 \) and \( -(a + b) \) and natural statistics \( \ln(X) \) and \( \ln(1 + X) \).
Proof
This follows from the definition of the general exponential family, since the PDF can be written in the form \[ f(x) = \frac{1}{B(a, b)} \exp[(a - 1) \ln(x) - (a + b) \ln(1 + x)], \quad x \in (0, \infty) \]


8.14D: Nonthermophilic Crenarchaeota
- Discuss the characteristics of nonthermophilic crenarchaeota, specifically Halococcus, that allow it to survive in extreme environments
Crenarchaeota can be extreme halophiles, and include organisms living in highly salty environments (for example, halococcus).
Halococcus is a genus of extremely halophilic archaea, meaning that they require high salt levels, sometimes as high as 32% NaCl, for optimal growth. Halophiles are found mainly in inland bodies of water with high salinity, where their pigments (from a protein called rhodopsinprotein) tint the sediment bright colors. Rhodopsin protein and other proteins serve to protect Halococcus from the extreme salinities of the environment. Some Halococcus may be located in highly salted soil or foods. Because they can function under such high-salt conditions, Halococcus and similar halophilic organisms have been utilized economically in the food industry and even in skin-care production. Halococcus’ genome has not been sequenced yet, although studies of its 16s rDNA have demonstrated its placement on the phylogenetic tree. Due to the organisms’ potential longevity, Halococcus may be a good candidate for exploring taxonomic similarities to life found in outer space.
Halococcus is able to survive in its high-saline habitat by preventing the dehydration of its cytoplasm. To do this they use a solute, which is either found in their cell structure or is drawn from the external environment. Special chlorine pumps allow the organisms to retain chloride to maintain osmotic balance with the salinity of their habitat. The cells are cocci, 0.6-1.5 micrometres long, with sulfated polysaccharide walls. The cells are organtrophic, using amino acids, organic acids, or carbohydrates for energy. In some cases they are also able to photosynthesize.
Key Points
- Halococcus is a genus of extreme halophilic archaea.
- Halophiles are found mainly in inland bodies of water with high salinity, where their pigments (from a protein called rhodopsinprotein) tint the sediment bright colors.
- Halococcus and similar halophilic organisms have been utilized economically in the food industry and even in skin-care production.
- Halococcus is able to survive in its high-saline habitat by preventing the dehydration of its cytoplasm using a solute which is either found in their cell structure or is drawn from the external environment.
Key Terms
- halophile : An organism that lives and thrives in an environment of high salinity, often requiring such an environment; a form of extremophile.


10.9: Physical Activity and Fitness
Both maintaining consistent physical activity and having a high level of physical fitness are protective against the chronic diseases which are the primary causes of death. Physical activity refers to the total amount of movement you get throughout the day. Fitness is referring to the conditioning of your body: the capacity of your heart, lungs, and muscles to perform high intensity work. The two are indelibly intertwined of course, since it takes a minimum level of fitness to be physically active, and those who have a high level of fitness tend to do more physical activity. Yet what is interesting is that each is independently protective against cardiovascular disease, diabetes, and some cancers - regardless of body weight, or age, or sex (which are usually also risk factors). In other words, being active and fit is important for health in every body (Foreman, 2020).
The CDC recommends that adults get a minimum of 150 minutes of moderate physical activity or 75 minutes of vigorous physical activity (or some combination of both) per week, including muscle strengthening exercises on at least 2 days of the week. But that’s just the bare minimum. Doubling that amount - 300 minutes of moderate or 150 minutes of vigorous physical activity - can provide substantially greater health benefits. In this way, physical activity and exercise have a dose-response relationship with better health: some is good, and more is better. Children and adolescents are encouraged to do at least 60 minutes per day of moderate to vigorous physical activity, some of which should include muscle and bone strengthening exercises on at least 3 days per week (U.S. Department of Health and Human Services, 2018). There isn’t anything magical that happens between the ages of 17 and 18 that immediately decreases the need for physical activity - shifting from the recommendations for children and teens to those of adults. However, it should be noted that as kids grow they may shift from unstructured play to organized sports and/or exercise. Perhaps the changes in recommendations are more a reflection of societal demands (education, work, etc.) that change how we engage with physical activity (van Sluijs et al., 2021). Of course, there is also an upper limit where frequent, high intensity exercise provides no further benefits for health and longevity - or could even be dangerous. But this excessive amount is typically only the stuff of avid endurance athletes, or a concern when a sedentary person drastically increases their PE all of a sudden (Foreman, 2020).
Most Americans certainly do not get enough physical activity. In 2018, only 54% of adults reported achieving the CDC recommended minimum for minutes of physical activity per week, only 27.6% performed at least 2 days per week of muscle strengthening exercises, and only 24% got both (DNPAO, NCCDPHP, CDC, 2024). According to data from the Behavioral Risk Factor Surveillance System (BRFSS) over the years 2017-2020, over 25% of adults reported getting NO physical activity outside of their work (CDC, 2024d). Adolescence is a time where physical activity tends to decline - we go from energetic, playful children to much more sedentary teens and young adults. This decline in physical activity is sharper for teen girls than boys, likely due in part to the drop off of PE requirements during the last two years of high school combined with gender-skewed participation in organized sports. Nearly 80% of adolescents across the globe do not get enough physical activity, and in high income countries like the U.S., these trends also disproportionately affect teens in lower socioeconomic tiers (van Sluijs et al., 2021).
“Fitness” is traditionally classified as cardiorespiratory fitness (CRF), as measured by a maximal, submaximal, or field test. These tests either directly or indirectly measure the maximum capacity of the human body to use oxygen for physical work, so they essentially measure aerobic (endurance) capacity. Of course there are other measures of fitness including muscular strength, endurance, flexibility, and balance - all of which also have been shown to have protective health benefits. The majority of the research over the last several decades however has been done on CRF and its inverse association with chronic diseases, and particularly risk factors for cardiovascular disease. Poor CRF is considered a stronger risk factor for all-cause mortality than obesity, hypertension, smoking, high cholesterol, or diabetes (Foreman, 2020). And improving CRF and physical activity levels decreases risks for all-cause mortality regardless of weight status. So for folks who have excess body fat, if they also have a moderate to high level of fitness, they are in better health than those with normal weight and low fitness levels (Gaesser & Angadi, 2021).
Getting an accurate picture of the average CRF in Americans is tricky though. While some studies have been able to collect accurate measurements on large groups of people, the less fit are often left out of these measurements because performing a validated CRF treadmill test on them is too risky. Thus, several studies that attempt to take cross-sectional measurements of CRF tend to recruit people who are already physically active or fit, and their subjects tend to be predominantly white, with relatively high incomes and educational attainment. Even with these limitations to the research, it is still apparent that on average, CRF declines with age, and higher CRF is associated with more leisure-time physical activity and lower body mass. CRF also tends to be disproportionately lower in women of color than other demographic groups (Wang et al., 2010).
Physical activity has other benefits besides chronic disease prevention, including supporting mental health. Being active can reduce both acute (immediate) and long-term symptoms of depression and anxiety. Adolescents who are active on at least 5 days per week and those who play sports tend to have a lower risk for depressive symptoms. By contrast, using a computer - a very sedentary behavior - for more than 3 hours per night increases risks for depression (C. H. Wang & Peiper, 2022). Physical activity can support quality, efficient sleep, which also supports mental and emotional health. When it comes to brain gains, most of the evidence for the acute and long-term cognitive benefits of physical activity has been found in children, yet there is growing evidence for the association of CRF with academic achievement in young adulthood (Åberg et al., 2009). Lifelong physical activity is certainly protective against dementia and improving cognition in older adulthood (U.S. Department of Health and Human Services, 2018). In fact, physical activity and exercise combat most of the markers of aging - including muscle loss (sarcopenia), bone loss (osteoporosis), and reductions in physical functioning. There’s likely no other behavior quite as powerful for longevity and quality of life as being physically active (Foreman, 2020).
The other side of the physical activity coin is time spent not moving - or sedentary time. Research from 2019 suggests that American adults may spend an average of 9.5 hours per day sedentary (Matthews et al., 2021). A follow up in 2022 suggested that the COVID-19 pandemic didn’t really change time spent sedentary for most people. Although some folks started working from home and saving time on their commute, that only seemed to translate to more leisure physical activity time for men, not so much for women. Much of that saved commute time was simply spent in sedentary leisure activities. Families with children who had to complete remote schooling tended to decrease their physical activity throughout that time (Matthews et al., 2022). Recent research suggests that long bouts of sedentary time and/or the accumulation of prolonged sedentary hours is leading to chronic diseases and conditions, including CVD, diabetes, some cancers, muscle weakness, low back pain, depression, and more (Foreman, 2020). Even those adults who reach the recommended minimum physical activity may not be able to undo all of the health hazards of sitting for the rest of the day. Per a meta-analysis of sedentary studies and risk of all-cause mortality, it takes about 60-75 minutes of hard exercise to offset the risks of sitting for more than 8 hours each day (Ekelund et al., 2016). In other words, not only do people need to move more for their health, they also need to sit less.


6.2: Fermentation
Learning Objectives
- Define fermentation and explain why it does not require oxygen
- Describe the fermentation pathways and their end products and give examples of microorganisms that use these pathways
- Compare and contrast fermentation and respiration
There are two mechanisms by which chemoheterotrophs can generate ATP: respiration and fermentation. Although respiration relies on the generation of a proton gradient and ATP synthesis by oxidative phosphorylation, ATP synthesis in fermentation is entirely through substrate-level phosphorylation in metabolic pathways . In general, the amount of ATP produced through fermentation is less than respiration, but there are situations where fermentation is necessary or preferable. Many prokaryotes, such as E. coli, are facultative, meaning that should the environmental conditions change to provide an appropriate inorganic final electron acceptor for respiration, organisms containing all the genes required to do so will switch to respiration because respiration allows for much greater ATP production. Whereas lack of an appropriate inorganic final electron acceptor is environmentally dependent, some organisms lack the ability to respire altogether. Many prokaryotes, including members of the clinically important genera Streptococcus and Clostridium , rely entirely on fermentation for ATP generation.
If respiration does not occur, NADH must be reoxidized to NAD + for reuse as an electron carrier for glycolysis and other catabolic pathways to continue. Some living systems use a metabolite produced through the cell's metabolite (such as pyruvate) as a final electron acceptor through a process called fermentation. Because all the NADH produced must be reoxidized to NAD+, the net NADH of any fermentation pathway must be zero (0). Considering that the purpose of fermentation is to generate ATP, there must also be a net gain of ATP in these metabolic pathways.
Fermentation does not involve an electron transport chain and does not directly produce any additional ATP beyond that produced during glycolysis by substrate-level phosphorylation. Organisms carrying out fermentation typically produce a maximum of two ATP molecules per glucose during glycolysis. Table \(\PageIndex{1}\) compares the final electron acceptors and methods of ATP synthesis in aerobic respiration, anaerobic respiration, and fermentation. Note that the number of ATP molecules shown for glycolysis assumes the Embden-Meyerhof-Parnas pathway. The number of ATP molecules made by substrate-level phosphorylation (SLP) versus oxidative phosphorylation (OP) are indicated.
| Type of Metabolism | Example | Final Electron Acceptor | Pathways Involved in ATP Synthesis (Type of Phosphorylation) | Maximum Yield of ATP Molecules |
|---|---|---|---|---|
| Aerobic respiration | Pseudomonas aeruginosa | O2 |
EMP glycolysis (SLP) Krebs cycle (SLP) Electron transport and chemiosmosis (OP): |
2 2 34 |
| Total | 38 | |||
| Anaerobic respiration | Paracoccus denitrificans |
NO3−,SO−24,Fe+3 other inorganics |
EMP glycolysis (SLP) Krebs cycle (SLP) Electron transport and chemiosmosis (OP): |
2 2 1–32 |
| Total | 5 – 36 | |||
| Fermentation | Candida albicans |
Organics (usually pyruvate) |
EMP glycolysis (SLP) Fermentation |
2 0 |
| Total | 2 |
Drag the slider to compare what is happening during respiration compared to fermentation. (Sorry I can't make it smaller!)
In all bacterial fermentations, at least one of the waste products produced is an organic acid. This feature of bacterial fermentations is frequently exploited in metabolic tests used to identify bacteria. For example, E. coli can ferment lactose, forming gas, whereas some of its close Gram-negative relatives cannot. The ability to ferment the sugar alcohol sorbitol is used to identify the pathogenic enterohemorrhagic O157:H7 strain of E. coli because, unlike other E. coli strains, it is unable to ferment sorbitol. Last, mannitol fermentation differentiates the mannitol-fermenting Staphylococcus aureus from other non–mannitol-fermenting staphylococci.
The simplest fermentation, which is used by some bacteria, like those in yogurt and other soured food products, and by animals in muscles during oxygen depletion, is homolactic or lactic acid fermentation (Figure \(\PageIndex{1}\). In homolactic fermentation the electrons on NADH produced during glycolysis are reoxidized to NAD+ by donating their electrons to the end product of glycolysis, pyruvate. The resulting waste product is lactate (lactic acid).
Bacteria of several Gram-positive genera, including Lactobacillus , Leuconostoc , and Streptococcus , are collectively known as the lactic acid bacteria (LAB), and various strains are important in food production. During yogurt and cheese production, the highly acidic environment generated by lactic acid fermentation denatures proteins contained in milk, causing it to solidify. When lactic acid is the only fermentation product, the process is said to be homolactic fermentation; such is the case for Lactobacillus delbrueckii and S. thermophiles used in yogurt production. However, many bacteria perform heterolactic fermentation, producing a mixture of lactic acid, ethanol and/or acetic acid, and CO 2 as a result, because of their use of the branched pentose phosphate pathway instead of the EMP pathway for glycolysis. One important heterolactic fermenter is Leuconostoc mesenteroides , which is used for souring vegetables like cucumbers and cabbage, producing pickles and sauerkraut, respectively.
Lactic acid bacteria are also important medically. The production of low pH environments within the body inhibits the establishment and growth of pathogens in these areas. For example, the vaginal microbiota is composed largely of lactic acid bacteria, but when these bacteria are reduced, yeast can proliferate, causing a yeast infection. Additionally, lactic acid bacteria are important in maintaining the health of the gastrointestinal tract and, as such, are the primary component of probiotics.
Another familiar fermentation process is alcohol fermentation by yeast, which produces ethanol. The ethanol fermentation reaction is shown in Figure \(\PageIndex{2}\). You may notice that unlike bacterial fermentations this fungal (eukaryotic) fermentation does not produce an acid as a waste product. The ethanol fermentation of pyruvate by the yeast Saccharomyces cerevisiae is used in the production of alcoholic beverages and also makes bread products rise due to CO 2 production. Outside of the food industry, ethanol fermentation of plant products is important in biofuel production.
Beyond lactic acid fermentation and alcohol fermentation, many other fermentation methods occur in microbes, all for the purpose of ensuring an adequate supply of NAD + for glycolysis (Table \(\PageIndex{2}\)). Without these pathways, glycolysis would not occur and no ATP would be harvested from the breakdown of glucose. It should be noted that most forms of fermentation besides homolactic fermentation produce gas, commonly CO 2 and/or hydrogen gas. Many of these different types of fermentation pathways are also used in food production and each results in the production of different organic acids, contributing to the unique flavor of a particular fermented food product. The propionic acid produced during propionic acid fermentation contributes to the distinctive flavor of Swiss cheese, for example.
Several fermentation products are important commercially outside of the food industry. For example, chemical solvents such as acetone and butanol are produced during acetone-butanol-ethanol fermentation. Complex organic pharmaceutical compounds used in antibiotics (e.g., penicillin), vaccines, and vitamins are produced through mixed acid fermentation.
In addition to fermentation ability, fermentation products are used in the laboratory to differentiate various bacteria for diagnostic purposes. For example, enteric bacteria are known for their ability to perform mixed acid fermentation, reducing the pH, which can be detected using a pH indicator. Similarly, the bacterial production of acetoin during butanediol fermentation can also be detected. Gas production from fermentation can also be seen in an inverted Durham tube that traps produced gas in a broth culture.
| Pathway | End Products | Example Microbes | Commercial Products |
|---|---|---|---|
| Acetone-butanol-ethanol | Acetone, butanol, ethanol, CO 2 | Clostridium acetobutylicum | Commercial solvents, gasoline alternative |
| Alcohol | Ethanol, CO 2 | Candida, Saccharomyces | Beer, bread |
| Butanediol | Formic and lactic acid; ethanol; acetoin; 2,3 butanediol; CO 2 ; hydrogen gas | Klebsiella, Enterobacter | Chardonnay wine |
| Butyric acid | Butyric acid, CO 2 , hydrogen gas | Clostridium butyricum | Butter |
| Lactic acid | Lactic acid | Streptococcus, Lactobacillus | Sauerkraut, yogurt, cheese |
| Mixed acid | Acetic, formic, lactic, and succinic acids; ethanol, CO 2 , hydrogen gas | Escherichia, Shigella | Vinegar, cosmetics, pharmaceuticals |
| Propionic acid | Acetic acid, propionic acid, CO 2 | Propionibacterium, Bifidobacterium | Swiss cheese |
Exercise \(\PageIndex{1}\)
When would a metabolically versatile microbe perform fermentation rather than respiration?
IDENTIFYING BACTERIA BY USING API TEST PANELS
Identification of a microbial isolate is essential for the proper diagnosis and appropriate treatment of patients. Scientists have developed techniques that identify bacteria according to their biochemical characteristics. Typically, they either examine the use of specific carbon sources as substrates for fermentation or other metabolic reactions, or they identify fermentation products or specific enzymes present in reactions. In the past, microbiologists have used individual test tubes and plates to conduct biochemical testing. However, scientists, especially those in clinical laboratories, now more frequently use plastic, disposable, multitest panels that contain a number of miniature reaction tubes, each typically including a specific substrate and pH indicator. After inoculation of the test panel with a small sample of the microbe in question and incubation, scientists can compare the results to a database that includes the expected results for specific biochemical reactions for known microbes, thus enabling rapid identification of a sample microbe. These test panels have allowed scientists to reduce costs while improving efficiency and reproducibility by performing a larger number of tests simultaneously.
Many commercial, miniaturized biochemical test panels cover a number of clinically important groups of bacteria and yeasts. One of the earliest and most popular test panels is the Analytical Profile Index (API) panel invented in the 1970s. Once some basic laboratory characterization of a given strain has been performed, such as determining the strain’s Gram morphology, an appropriate test strip that contains 10 to 20 different biochemical tests for differentiating strains within that microbial group can be used. Currently, the various API strips can be used to quickly and easily identify more than 600 species of bacteria, both aerobic and anaerobic, and approximately 100 different types of yeasts. Based on the colors of the reactions when metabolic end products are present, due to the presence of pH indicators, a metabolic profile is created from the results (Figure \(\PageIndex{2}\)). Microbiologists can then compare the sample’s profile to the database to identify the specific microbe.
Key Concepts and Summary
- Fermentation uses an organic molecule as a final electron acceptor to regenerate NAD + from NADH so that glycolysis can continue.
- Fermentation does not involve an electron transport system, and no ATP is made by the fermentation process directly. Fermenters make very little ATP—only two ATP molecules per glucose molecule during glycolysis.
- Microbial fermentation processes have been used for the production of foods and pharmaceuticals, and for the identification of microbes.
- During lactic acid fermentation, pyruvate accepts electrons from NADH and is reduced to lactic acid. Microbes performing homolactic fermentation produce only lactic acid as the fermentation product; microbes performing heterolactic fermentation produce a mixture of lactic acid, ethanol and/or acetic acid, and CO 2 .
- Lactic acid production by the normal microbiota prevents growth of pathogens in certain body regions and is important for the health of the gastrointestinal tract.
- During ethanol fermentation, pyruvate is first decarboxylated (releasing CO 2 ) to acetaldehyde, which then accepts electrons from NADH, reducing acetaldehyde to ethanol. Ethanol fermentation is used for the production of alcoholic beverages, for making bread products rise, and for biofuel production.
- Fermentation products of pathways (e.g., propionic acid fermentation) provide distinctive flavors to food products. Fermentation is used to produce chemical solvents (acetone-butanol-ethanol fermentation) and pharmaceuticals (mixed acid fermentation).
- Specific types of microbes may be distinguished by their fermentation pathways and products. Microbes may also be differentiated according to the substrates they are able to ferment.
Contributors and Attributions
-
Nina Parker, (Shenandoah University), Mark Schneegurt (Wichita State University), Anh-Hue Thi Tu (Georgia Southwestern State University), Philip Lister (Central New Mexico Community College), and Brian M. Forster (Saint Joseph’s University) with many contributing authors. Original content via Openstax (CC BY 4.0; Access for free at https://openstax.org/books/microbiology/pages/1-introduction )


1.1.3: Activity- Solutions and Liquid Mixtures
The concept of activity was introduced by Lewis[1] in descriptions of the properties of liquid mixtures and solutions. By way of illustration we consider the chemical potential of chemical substance \(j\), \(\mu_{j}(\text { system })\) present in a solution at fixed pressure \(p\) and temperature \(T\). By definition,
\[\mu_{j}(\text { system })=\mu_{j}(\text { ref })+R \, T \, \ln \left(a_{j}\right) \nonumber \]
While we can never know either \(\mu_{j}(\text { system })\) or \(\mu_{j}(\text { ref })\), the difference is related to the activity \(a_{j}\), a dimensionless function of the composition of the system. We as observers of the system are required to define the reference state where the chemical potential of chemical substance \(j\) can be clearly defined. Nevertheless the terms \(\mu_{j}(\text { system })\), \(\mu_{j}(\text { ref })\) and \(a_{j}\) in equation (a) are based on somewhat abstract concepts. The link with practical chemistry is made through the differential of equation (a) with respect to pressure at constant temperature.
\[\text { Then, } \mathrm{V}_{\mathrm{j}}(\text { system })=\mathrm{V}_{\mathrm{j}}(\text { ref })+\mathrm{R} \, \mathrm{T} \,\left[\partial \ln \left(\mathrm{a}_{\mathrm{j}}\right) / \partial \mathrm{p}\right]_{\mathrm{T}} \nonumber \]
\(\mathrm{V}_{\mathrm{j}}(\text { system })\) and \(\mathrm{V}_{\mathrm{j}}(\text { ref })\) are, respectively, the partial molar volumes of chemical substance \(j\) in the system and in a convenient reference state. The term \(\mathrm{R} \, \mathrm{T} \,\left[\partial \ln \left(\mathrm{a}_{\mathrm{j}}\right) / \partial \mathrm{p}\right]_{\mathrm{T}}\) contrasts the role of intermolecular interactions in the two states. Four applications of the concept of activity make the point.
For the binary liquid mixture, ethanol + water at defined temperature and pressure, the activity of, for example, water (substance 1) \(a_{1}\) is given by the product, \(x_{1} \, f_{1}\) where \(f_{1}\) is the (rational) activity coefficient and \(x_{1}\) is the mole fraction of water.
\[a_{1}=x_{1} \, f_{1} \nonumber \]
The activity of urea (chemical substance \(j\)) in an aqueous solution is related to the product of activity coefficient \(\gamma_{i}\) and molality \(m_{j}\) using the reference molality \(m^{0}\), namely \(1 \mathrm{ mol kg}^{–1}\).
\[a_{j}=\left(m_{j} / m^{0}\right) \, \gamma_{j} \nonumber \]
If the concentration of urea in the solution equals \(c_{j} \mathrm{ mol dm}^{-3}\), then the activity \(a_{j}\) is given by equation (e) where \(c_{r}\) is the reference concentration \(c_{r}\), \(1 \mathrm{ mol dm}^{–3}\), and \(y_{j}\) is the solute activity coefficient.
\[a_{j}=\left(c_{j} / c_{r}\right) \, y_{j} \nonumber \]
If \(x_{j}\) is the mole fraction of urea and \(\mathrm{f}_{\mathrm{j}}^{*}\) is the asymmetric activity coefficient, the activity of urea is given by equation (d).
\[a_{j}=x_{j} \, f_{j}^{*} \nonumber \]
Equations (d) to (f) describe the same property, namely activity \(a_{j}\) of solute \(j\) in a given solution.
Footnotes
[1] G. N. Lewis, Proc. Am. Acad. Arts Sci.,1907,43,259.


2.3: The Balance Sheet
The Balance Sheet presents a static, unchanging, still-photograph of a company’s financial position at a moment in time, i.e., “as of” a certain date, often December 31st. In theory, any of the figures on the balance sheet would be different, either larger or smaller, on the very first day following (or before) the statement date. The Balance Sheet is usually issued every quarter, i.e., every three months. A very simple balance sheet will look something like the following (with the numbers filled in). Take note that any actual Balance Sheet you may examine may differ from this simple example.
XYZ C orp. Balance Sheet as of 12.31.X X
All Asset accounts are “debit balance” accounts. That means that when the account increases (decreases), the amount is recorded on the debit (credit) side of the firm’s ledger. Liability and Equity Accounts are “credit balance” accounts. We make these entries into the bookkeeper’s ledger’s “T-Accounts” (see immediately below). This mechanistic framework is fundamental to “double-entry book-keeping.”
Let’s repeat this: Asset accounts are “debit balance” (debit = “Dr”) accounts, whereas liability and owners’ (or shareholders’) equity are “credit balance” (credit = “Cr”) accounts. Increases (decreases) in asset accounts are characterized by debit (credit) entries; increases (decreases) in liability and equity accounts are characterized by credit (debit) entries.
In “double-entry” bookkeeping, for every debit entry there must be a credit entry. Debits must equal credits, and the balance sheet must balance: Total Assets = Total Liabilities + Equity. This is the basic accounting equation.
Basic accounting equation : The following equations must, by definition, be true:
A = L + E (Assets = Liabilities plus Equity)
A – L = E (Assets minus Liabilities = Equity)
There are also contra-asset accounts (such as accumulated depreciation and allowance for uncollectible accounts receivables), which are “credit balance” (credit = Cr) accounts. These contra-accounts effectively reduce the (net) asset accounts and are credit entries.
The phrase “current,” as in “current assets,” has to do with the life of the asset – or liability. According to the accountant,any asset (or liability), which is consumed (or paid) within an accounting period (i.e., one year), is current. Any asset – or liability – that has a life exceeding one year is “long-term.” Thus, inventory is placed “above the line,” under current assets. So too is the case with accounts payable. Property is long-term, for example. More on this next….