5.1: Unique Characteristics of Eukaryotic Cells
-
- Last updated
- Save as PDF
Learning Objectives
- Explain the distinguishing characteristics of eukaryotic cells
- Describe internal and external structures of prokaryotic cells in terms of their physical structure, chemical structure, and function
- Identify and describe structures and organelles unique to eukaryotic cells
- Compare and contrast similar structures found in prokaryotic and eukaryotic cells
Eukaryotic organisms include protozoans, algae, fungi, plants, and animals. Some eukaryotic cells are independent, single-celled microorganisms, whereas others are part of multicellular organisms. The cells of eukaryotic organisms have several distinguishing characteristics. Above all, eukaryotic cells are defined by the presence of a nucleus surrounded by a complex nuclear membrane. Also, eukaryotic cells are characterized by the presence of membrane-bound organelles in the cytoplasm. Organelles such as mitochondria, the endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and peroxisomes are held in place by the cytoskeleton, an internal network that supports transport of intracellular components and helps maintain cell shape (Figure \(\PageIndex{1}\)). The genome of eukaryotic cells is packaged in multiple, rod-shaped chromosomes as opposed to the single, circular-shaped chromosome that characterizes most prokaryotic cells. Table \(\PageIndex{1}\) compares the characteristics of eukaryotic cell structures with those of bacteria and archaea.
| Cell Structure | Prokaryotes | Eukaryotes | |
|---|---|---|---|
| Bacteria | Archaea | ||
| Size | ~0.5–1 μM | ~0.5–1 μM | ~5–20 μM |
| Surface area-to-volume ratio | High | High | Low |
| Nucleus | No | No | Yes |
| Genome characteristics |
|
|
|
| Cell division | Binary fission | Binary fission | Mitosis, meiosis |
| Membrane lipid composition |
|
|
|
| Cell wall composition |
|
|
|
| Motility structures | Rigid spiral flagella composed of flagellin | Rigid spiral flagella composed of archaeal flagellins | Flexible flagella and cilia composed of microtubules |
| Membrane-bound organelles | No | No | Yes |
| Endomembrane system | No | No | Yes (ER, Golgi, lysosomes) |
| Ribosomes | 70S | 70S |
|
Cell Morphologies
Eukaryotic cells display a wide variety of different cell morphologies. Possible shapes include spheroid, ovoid, cuboidal, cylindrical, flat, lenticular, fusiform, discoidal, crescent, ring stellate, and polygonal (Figure \(\PageIndex{2}\)). Some eukaryotic cells are irregular in shape, and some are capable of changing shape. The shape of a particular type of eukaryotic cell may be influenced by factors such as its primary function, the organization of its cytoskeleton, the viscosity of its cytoplasm, the rigidity of its cell membrane or cell wall (if it has one), and the physical pressure exerted on it by the surrounding environment and/or adjoining cells.
Exercise \(\PageIndex{1}\)
Identify two differences between eukaryotic and prokaryotic cell.
Nucleus
Unlike prokaryotic cells, in which DNA is loosely contained in the nucleoid region, eukaryotic cells possess a nucleus, which is surrounded by a complex nuclear membrane that houses the DNA genome (Figure \(\PageIndex{3}\)). By containing the cell’s DNA, the nucleus ultimately controls all activities of the cell and also serves an essential role in reproduction and heredity. Eukaryotic cells typically have their DNA organized into multiple linear chromosomes. The DNA within the nucleus is highly organized and condensed to fit inside the nucleus, which is accomplished by wrapping the DNA around proteins called histones.
Although most eukaryotic cells have only one nucleus, exceptions exist. For example, protozoans of the genus Paramecium typically have two complete nuclei: a small nucleus that is used for reproduction (micronucleus) and a large nucleus that directs cellular metabolism (macronucleus).  Cells whose nuclei divide, but whose cytoplasm does not, are called coenocytes.
The nucleus is bound by a complex nuclear membrane, often called the nuclear envelope, that consists of two distinct lipid bilayers that are contiguous with each other (Figure \(\PageIndex{4}\)). Despite these connections between the inner and outer membranes, each membrane contains unique lipids and proteins on its inner and outer surfaces. The nuclear envelope contains nuclear pores, which are large, rosette-shaped protein complexes that control the movement of materials into and out of the nucleus. The overall shape of the nucleus is determined by the nuclear lamina, a meshwork of intermediate filaments found just inside the nuclear envelope membranes. Outside the nucleus, additional intermediate filaments form a looser mesh and serve to anchor the nucleus in position within the cell.
Nucleolus
The nucleolus is a dense region within the nucleus where ribosomal RNA (rRNA) biosynthesis occurs. In addition, the nucleolus is also the site where assembly of ribosomes begins. Preribosomal complexes are assembled from rRNA and proteins in the nucleolus; they are then transported out to the cytoplasm, where ribosome assembly is completed (Figure \(\PageIndex{5}\)).
Ribosomes
Ribosomes found in eukaryotic organelles such as mitochondria or chloroplasts have 70S ribosomes—the same size as prokaryotic ribosomes. However, nonorganelle-associated ribosomes in eukaryotic cells are 80S ribosomes, composed of a 40S small subunit and a 60S large subunit. In terms of size and composition, this makes them distinct from the ribosomes of prokaryotic cells.
The two types of nonorganelle-associated eukaryotic ribosomes are defined by their location in the cell: free ribosomesand membrane-bound ribosomes. Free ribosomes are found in the cytoplasm and serve to synthesize water-soluble proteins; membrane-bound ribosomes are found attached to the rough endoplasmic reticulum and make proteins for insertion into the cell membrane or proteins destined for export from the cell.
The differences between eukaryotic and prokaryotic ribosomes are clinically relevant because certain antibiotic drugs are designed to target one or the other. For example, cycloheximide targets eukaryotic action, whereas chloramphenicol targets prokaryotic ribosomes. 1 Since human cells are eukaryotic, they generally are not harmed by antibiotics that destroy the prokaryotic ribosomes in bacteria. However, sometimes negative side effects may occur because mitochondria in human cells contain prokaryotic ribosomes.
Endomembrane System
The endomembrane system, unique to eukaryotic cells, is a series of membranous tubules, sacs, and flattened disks that synthesize many cell components and move materials around within the cell (Figure \(\PageIndex{6}\)). Because of their larger cell size, eukaryotic cells require this system to transport materials that cannot be dispersed by diffusion alone. The endomembrane system comprises several organelles and connections between them, including the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles.
Endoplasmic Reticulum
The endoplasmic reticulum (ER) is an interconnected array of tubules and cisternae (flattened sacs) with a single lipid bilayer (Figure \(\PageIndex{7}\)). The spaces inside of the cisternae are called lumen of the ER. There are two types of ER, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). These two different types of ER are sites for the synthesis of distinctly different types of molecules. RER is studded with ribosomes bound on the cytoplasmic side of the membrane. These ribosomes make proteins destined for the plasma membrane (Figure \(\PageIndex{}\)). Following synthesis, these proteins are inserted into the membrane of the RER. Small sacs of the RER containing these newly synthesized proteins then bud off as transport vesicles and move either to the Golgi apparatus for further processing, directly to the plasma membrane, to the membrane of another organelle, or out of the cell. Transport vesicles are single-lipid, bilayer, membranous spheres with hollow interiors that carry molecules. SER does not have ribosomes and, therefore, appears “smooth.” It is involved in biosynthesis of lipids, carbohydrate metabolism, and detoxification of toxic compounds within the cell.
Golgi Apparatus
The Golgi apparatus was discovered within the endomembrane system in 1898 by Italian scientist Camillo Golgi (1843–1926), who developed a novel staining technique that showed stacked membrane structures within the cells of Plasmodium , the causative agent of malaria. The Golgi apparatus is composed of a series of membranous disks called dictyosomes, each having a single lipid bilayer, that are stacked together (Figure \(\PageIndex{8}\)).
Enzymes in the Golgi apparatus modify lipids and proteins transported from the ER to the Golgi, often adding carbohydrate components to them, producing glycolipids, glycoproteins, or proteoglycans. Glycolipids and glycoproteins are often inserted into the plasma membrane and are important for signal recognition by other cells or infectious particles. Different types of cells can be distinguished from one another by the structure and arrangement of the glycolipids and glycoproteins contained in their plasma membranes. These glycolipids and glycoproteins commonly also serve as cell surface receptors.
Transport vesicles leaving the ER fuse with a Golgi apparatus on its receiving, or cis , face. The proteins are processed within the Golgi apparatus, and then additional transport vesicles containing the modified proteins and lipids pinch off from the Golgi apparatus on its outgoing, or trans , face. These outgoing vesicles move to and fuse with the plasma membrane or the membrane of other organelles.
Exocytosis is the process by which secretory vesicles (spherical membranous sacs) release their contents to the cell’s exterior (Figure \(\PageIndex{8}\)). All cells have constitutive secretory pathways in which secretory vesicles transport soluble proteins that are released from the cell continually (constitutively). Certain specialized cells also have regulated secretory pathways, which are used to store soluble proteins in secretory vesicles. Regulated secretion involves substances that are only released in response to certain events or signals. For example, certain cells of the human immune system (e.g., mast cells) secrete histamine in response to the presence of foreign objects or pathogens in the body. Histamine is a compound that triggers various mechanisms used by the immune system to eliminate pathogens.
Lysosomes
In the 1960s, Belgian scientist Christian de Duve (1917–2013) discovered lysosomes, membrane-bound organelles of the endomembrane system that contain digestive enzymes. Certain types of eukaryotic cells use lysosomes to break down various particles, such as food, damaged organelles or cellular debris, microorganisms, or immune complexes. Compartmentalization of the digestive enzymes within the lysosome allows the cell to efficiently digest matter without harming the cytoplasmic components of the cell.
Exercise \(\PageIndex{2}\)
Name the components of the endomembrane system and describe the function of each component.
Peroxisomes
Christian de Duve is also credited with the discovery of peroxisomes, membrane-bound organelles that are not part of the endomembrane system (Figure \(\PageIndex{9}\)). Peroxisomes form independently in the cytoplasm from the synthesis of peroxin proteins by free ribosomes and the incorporation of these peroxin proteins into existing peroxisomes. Growing peroxisomes then divide by a process similar to binary fission.
Peroxisomes were first named for their ability to produce hydrogen peroxide, a highly reactive molecule that helps to break down molecules such as uric acid, amino acids, and fatty acids. Peroxisomes also possess the enzyme catalase, which can degrade hydrogen peroxide. Along with the SER, peroxisomes also play a role in lipid biosynthesis. Like lysosomes, the compartmentalization of these degradative molecules within an organelle helps protect the cytoplasmic contents from unwanted damage.
The peroxisomes of certain organisms are specialized to meet their particular functional needs. For example, glyoxysomes are modified peroxisomes of yeasts and plant cells that perform several metabolic functions, including the production of sugar molecules. Similarly, glycosomes are modified peroxisomes made by certain trypanosomes, the pathogenic protozoans that cause Chagas disease and African sleeping sickness.
Cytoskeleton
Eukaryotic cells have an internal cytoskeleton made of microfilaments, intermediate filaments, and microtubules. This matrix of fibers and tubes provides structural support as well as a network over which materials can be transported within the cell and on which organelles can be anchored (Figure \(\PageIndex{10}\)). For example, the process of exocytosis involves the movement of a vesicle via the cytoskeletal network to the plasma membrane, where it can release its contents.
Microfilaments are composed of two intertwined strands of actin, each composed of actin monomers forming filamentous cables 6 nm in diameter 2 (Figure \(\PageIndex{11}\)). The actin filaments work together with motor proteins, like myosin, to effect muscle contraction in animals or the amoeboid movement of some eukaryotic microbes. In ameboid organisms, actin can be found in two forms: a stiffer, polymerized, gel form and a more fluid, unpolymerized soluble form. Actin in the gel form creates stability in the ectoplasm, the gel-like area of cytoplasm just inside the plasma membrane of ameboid protozoans.
Temporary extensions of the cytoplasmic membrane called pseudopodia (meaning “false feet”) are produced through the forward flow of soluble actin filaments into the pseudopodia, followed by the gel-sol cycling of the actin filaments, resulting in cell motility. Once the cytoplasm extends outward, forming a pseudopodium, the remaining cytoplasm flows up to join the leading edge, thereby creating forward locomotion. Beyond amoeboid movement, microfilaments are also involved in a variety of other processes in eukaryotic cells, including cytoplasmic streaming (the movement or circulation of cytoplasm within the cell), cleavage furrow formation during cell division, and muscle movement in animals (Figure \(\PageIndex{11}\)). These functions are the result of the dynamic nature of microfilaments, which can polymerize and depolymerize relatively easily in response to cellular signals, and their interactions with molecular motors in different types of eukaryotic cells.
Intermediate filaments (Figure \(\PageIndex{12}\)) are a diverse group of cytoskeletal filaments that act as cables within the cell. They are termed “intermediate” because their 10-nm diameter is thicker than that of actin but thinner than that of microtubules. 3 They are composed of several strands of polymerized subunits that, in turn, are made up of a wide variety of monomers. Intermediate filaments tend to be more permanent in the cell and maintain the position of the nucleus. They also form the nuclear lamina (lining or layer) just inside the nuclear envelope. Additionally, intermediate filaments play a role in anchoring cells together in animal tissues. The intermediate filament protein desmin is found in desmosomes, the protein structures that join muscle cells together and help them resist external physical forces. The intermediate filament protein keratin is a structural protein found in hair, skin, and nails.
Microtubules (Figure \(\PageIndex{13}\)) are a third type of cytoskeletal fiber composed of tubulin dimers (α tubulin and β tubulin). These form hollow tubes 23 nm in diameter that are used as girders within the cytoskeleton. 4 Like microfilaments, microtubules are dynamic and have the ability to rapidly assemble and disassemble. Microtubules also work with motor proteins (such as dynein and kinesin) to move organelles and vesicles around within the cytoplasm. Additionally, microtubules are the main components of eukaryotic flagella and cilia, composing both the filament and the basal body components (Figure \(\PageIndex{20}\)).
In addition, microtubules are involved in cell division, forming the mitotic spindle that serves to separate chromosomes during mitosis and meiosis. The mitotic spindle is produced by two centrosomes, which are essentially microtubule-organizing centers, at opposite ends of the cell. Each centrosome is composed of a pair of centrioles positioned at right angles to each other, and each centriole is an array of nine parallel microtubules arranged in triplets (Figure \(\PageIndex{14}\)).
Exercise \(\PageIndex{3}\)
Compare and contrast the three types of cytoskeletal structures described in this section.
Mitochondria
The large, complex organelles in which aerobic cellular respiration occurs in eukaryotic cells are called mitochondria(Figure \(\PageIndex{15}\)). The term “mitochondrion” was first coined by German microbiologist Carl Benda in 1898 and was later connected with the process of respiration by Otto Warburg in 1913. Scientists during the 1960s discovered that mitochondria have their own genome and 70S ribosomes. The mitochondrial genome was found to be bacterial, when it was sequenced in 1976. These findings ultimately supported the endosymbiotic theory proposed by Lynn Margulis, which states that mitochondria originally arose through an endosymbiotic event in which a bacterium capable of aerobic cellular respiration was taken up by phagocytosis into a host cell and remained as a viable intracellular component.
Each mitochondrion has two lipid membranes. The outer membrane is a remnant of the original host cell’s membrane structures. The inner membrane was derived from the bacterial plasma membrane. The electron transport chain for aerobic respiration uses integral proteins embedded in the inner membrane. The mitochondrial matrix, corresponding to the location of the original bacterium’s cytoplasm, is the current location of many metabolic enzymes. It also contains mitochondrial DNA and 70S ribosomes. Invaginations of the inner membrane, called cristae, evolved to increase surface area for the location of biochemical reactions. The folding patterns of the cristae differ among various types of eukaryotic cells and are used to distinguish different eukaryotic organisms from each other.
Chloroplasts
Plant cells and algal cells contain chloroplasts, the organelles in which photosynthesis occurs (Figure \(\PageIndex{16}\)). All chloroplasts have at least three membrane systems: the outer membrane, the inner membrane, and the thylakoid membrane system. Inside the outer and inner membranes is the chloroplast stroma, a gel-like fluid that makes up much of a chloroplast’s volume, and in which the thylakoid system floats. The thylakoid system is a highly dynamic collection of folded membrane sacs. It is where the green photosynthetic pigment chlorophyll is found and the light reactions of photosynthesis occur. In most plant chloroplasts, the thylakoids are arranged in stacks called grana (singular: granum), whereas in some algal chloroplasts, the thylakoids are free floating.
Other organelles similar to mitochondria have arisen in other types of eukaryotes, but their roles differ. Hydrogenosomes are found in some anaerobic eukaryotes and serve as the location of anaerobic hydrogen production. Hydrogenosomes typically lack their own DNA and ribosomes. Kinetoplasts are a variation of the mitochondria found in some eukaryotic pathogens. In these organisms, each cell has a single, long, branched mitochondrion in which kinetoplast DNA, organized as multiple circular pieces of DNA, is found concentrated at one pole of the cell.
Mitochondria-Related Organelles in Protozoan Parasites
Many protozoans, including several protozoan parasites that cause infections in humans, can be identified by their unusual appearance. Distinguishing features may include complex cell morphologies, the presence of unique organelles, or the absence of common organelles. The protozoan parasites Giardia lamblia and Trichomonas vaginalis are two examples.
G. lamblia , a frequent cause of diarrhea in humans and many other animals, is an anaerobic parasite that possesses two nuclei and several flagella. Its Golgi apparatus and endoplasmic reticulum are greatly reduced, and it lacks mitochondria completely. However, it does have organelles known as mitosomes, double-membrane-bound organelles that appear to be severely reduced mitochondria. This has led scientists to believe that G. lamblia’ s ancestors once possessed mitochondria that evolved to become mitosomes. T. vaginalis , which causes the sexually transmitted infection vaginitis, is another protozoan parasite that lacks conventional mitochondria. Instead, it possesses hydrogenosomes, mitochondrial-related, double-membrane-bound organelles that produce molecular hydrogen used in cellular metabolism. Scientists believe that hydrogenosomes, like mitosomes, also evolved from mitochondria. 5
Plasma Membrane
The plasma membrane of eukaryotic cells is similar in structure to the prokaryotic plasma membrane in that it is composed mainly of phospholipids forming a bilayer with embedded peripheral and integral proteins (Figure \(\PageIndex{17}\)). These membrane components move within the plane of the membrane according to the fluid mosaic model. However, unlike the prokaryotic membrane, eukaryotic membranes contain sterols, including cholesterol, that alter membrane fluidity. Additionally, many eukaryotic cells contain some specialized lipids, including sphingolipids, which are thought to play a role in maintaining membrane stability as well as being involved in signal transduction pathways and cell-to-cell communication.
Membrane Transport Mechanisms
The processes of simple diffusion, facilitated diffusion, and active transport are used in both eukaryotic and prokaryotic cells. However, eukaryotic cells also have the unique ability to perform various types of endocytosis, the uptake of matter through plasma membrane invagination and vacuole/vesicle formation (Figure \(\PageIndex{18}\)). A type of endocytosis involving the engulfment of large particles through membrane invagination is called phagocytosis, which means “cell eating.” In phagocytosis, particles (or other cells) are enclosed in a pocket within the membrane, which then pinches off from the membrane to form a vacuole that completely surrounds the particle. Another type of endocytosis is called pinocytosis, which means “cell drinking.” In pinocytosis, small, dissolved materials and liquids are taken into the cell through small vesicles. Saprophytic fungi, for example, obtain their nutrients from dead and decaying matter largely through pinocytosis.
Receptor-mediated endocytosis is a type of endocytosis that is initiated by specific molecules called ligands when they bind to cell surface receptors on the membrane. Receptor-mediated endocytosis is the mechanism that peptide and amine-derived hormones use to enter cells and is also used by various viruses and bacteria for entry into host cells.
The process by which secretory vesicles release their contents to the cell’s exterior is called exocytosis. Vesicles move toward the plasma membrane and then meld with the membrane, ejecting their contents out of the cell. Exocytosis is used by cells to remove waste products and may also be used to release chemical signals that can be taken up by other cells.
Cell Wall
In addition to a plasma membrane, some eukaryotic cells have a cell wall. Cells of fungi, algae, plants, and even some protists have cell walls. Depending upon the type of eukaryotic cell, cell walls can be made of a wide range of materials, including cellulose (fungi and plants); biogenic silica, calcium carbonate, agar, and carrageenan (protists and algae); or chitin (fungi). In general, all cell walls provide structural stability for the cell and protection from environmental stresses such as desiccation, changes in osmotic pressure, and traumatic injury. 6
Extracellular Matrix
Cells of animals and some protozoans do not have cell walls to help maintain shape and provide structural stability. Instead, these types of eukaryotic cells produce an extracellular matrix for this purpose. They secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells (Figure \(\PageIndex{19}\)). Some protein components assemble into a basement membrane to which the remaining extracellular matrix components adhere. Proteoglycans typically form the bulky mass of the extracellular matrix while fibrous proteins, like collagen, provide strength. Both proteoglycans and collagen are attached to fibronectin proteins, which, in turn, are attached to integrin proteins. These integrin proteins interact with transmembrane proteins in the plasma membranes of eukaryotic cells that lack cell walls.
In animal cells, the extracellular matrix allows cells within tissues to withstand external stresses and transmits signals from the outside of the cell to the inside. The amount of extracellular matrix is quite extensive in various types of connective tissues, and variations in the extracellular matrix can give different types of tissues their distinct properties. In addition, a host cell’s extracellular matrix is often the site where microbial pathogens attach themselves to establish infection. For example, Streptococcus pyogenes , the bacterium that causes strep throat and various other infections, binds to fibronectin in the extracellular matrix of the cells lining the oropharynx (upper region of the throat).
Flagella and Cilia
Some eukaryotic cells use flagella for locomotion; however, eukaryotic flagella are structurally distinct from those found in prokaryotic cells. Whereas the prokaryotic flagellum is a stiff, rotating structure, a eukaryotic flagellum is more like a flexible whip composed of nine parallel pairs of microtubules surrounding a central pair of microtubules. This arrangement is referred to as a 9+2 array (Figure \(\PageIndex{20}\)). The parallel microtubules use dynein motor proteins to move relative to each other, causing the flagellum to bend.
Cilia (singular: cilium ) are a similar external structure found in some eukaryotic cells. Unique to eukaryotes, cilia are shorter than flagella and often cover the entire surface of a cell; however, they are structurally similar to flagella (a 9+2 array of microtubules) and use the same mechanism for movement. A structure called a basal body is found at the base of each cilium and flagellum. The basal body, which attaches the cilium or flagellum to the cell, is composed of an array of triplet microtubules similar to that of a centriole but embedded in the plasma membrane. Because of their shorter length, cilia use a rapid, flexible, waving motion. In addition to motility, cilia may have other functions such as sweeping particles past or into cells. For example, ciliated protozoans use the sweeping of cilia to move food particles into their mouthparts, and ciliated cells in the mammalian respiratory tract beat in synchrony to sweep mucus and debris up and out of the lungs (Figure \(\PageIndex{20}\)).
Exercise \(\PageIndex{4}\)
- Explain how the cellular envelope of eukaryotic cells compares to that of prokaryotic cells.
- Explain the difference between eukaryotic and prokaryotic flagella.
Clinical Focus: Resolution
Since amoxicillin has not resolved Barbara’s case of pneumonia, the PA prescribes another antibiotic, azithromycin, which targets bacterial ribosomes rather than peptidoglycan. After taking the azithromycin as directed, Barbara’s symptoms resolve and she finally begins to feel like herself again. Presuming no drug resistance to amoxicillin was involved, and given the effectiveness of azithromycin, the causative agent of Barbara’s pneumonia is most likely Mycoplasma pneumoniae . Even though this bacterium is a prokaryotic cell, it is not inhibited by amoxicillin because it does not have a cell wall and, therefore, does not make peptidoglycan.
Key Concepts and Summary
- Eukaryotic cells are defined by the presence of a nucleus containing the DNA genome and bound by a nuclear membrane (or nuclear envelope ) composed of two lipid bilayers that regulate transport of materials into and out of the nucleus through nuclear pores.
- Eukaryotic cell morphologies vary greatly and may be maintained by various structures, including the cytoskeleton, the cell membrane, and/or the cell wall.
- The nucleolus , located in the nucleus of eukaryotic cells, is the site of ribosomal synthesis and the first stages of ribosome assembly.
- Eukaryotic cells contain 80S ribosomes in the rough endoplasmic reticulum ( membrane bound-ribosomes ) and cytoplasm ( free ribosomes ). They contain 70s ribosomes in mitochondria and chloroplasts.
- Eukaryotic cells have evolved an endomembrane system, containing membrane-bound organelles involved in transport. These include vesicles, the endoplasmic reticulum, and the Golgi apparatus.
- The smooth endoplasmic reticulum plays a role in lipid biosynthesis, carbohydrate metabolism, and detoxification of toxic compounds. The rough endoplasmic reticulum contains membrane-bound 80S ribosomes that synthesize proteins destined for the cell membrane
- The Golgi apparatus processes proteins and lipids, typically through the addition of sugar molecules, producing glycoproteins or glycolipids, components of the plasma membrane that are used in cell-to-cell communication.
- Lysosomes contain digestive enzymes that break down small particles ingested by endocytosis , large particles or cells ingested by phagocytosis , and damaged intracellular components.
- The cytoskeleton , composed of microfilaments , intermediate filaments , and microtubules , provides structural support in eukaryotic cells and serves as a network for transport of intracellular materials.
- Centrosomes are microtubule-organizing centers important in the formation of the mitotic spindle in mitosis.
- Mitochondria are the site of cellular respiration. They have two membranes: an outer membrane and an inner membrane with cristae. The mitochondrial matrix, within the inner membrane, contains the mitochondrial DNA, 70S ribosomes, and metabolic enzymes.
- The plasma membrane of eukaryotic cells is structurally similar to that found in prokaryotic cells, and membrane components move according to the fluid mosaic model. However, eukaryotic membranes contain sterols, which alter membrane fluidity, as well as glycoproteins and glycolipids, which help the cell recognize other cells and infectious particles.
- In addition to active transport and passive transport, eukaryotic cell membranes can take material into the cell via endocytosis , or expel matter from the cell via exocytosis.
- Cells of fungi, algae, plants, and some protists have a cell wall, whereas cells of animals and some protozoans have a sticky extracellular matrix that provides structural support and mediates cellular signaling.
- Eukaryotic flagella are structurally distinct from prokaryotic flagella but serve a similar purpose (locomotion). Cilia are structurally similar to eukaryotic flagella, but shorter; they may be used for locomotion, feeding, or movement of extracellular particles.
Footnotes
- 1 A.E. Barnhill, M.T. Brewer, S.A. Carlson. “Adverse Effects of Antimicrobials via Predictable or Idiosyncratic Inhibition of Host Mitochondrial Components.” Antimicrobial Agents and Chemotherapy 56 no. 8 (2012):4046–4051.
- 2 Fuchs E, Cleveland DW. “A Structural Scaffolding of Intermediate Filaments in Health and Disease.” Science 279 no. 5350 (1998):514–519.
- 3 E. Fuchs, D.W. Cleveland. “A Structural Scaffolding of Intermediate Filaments in Health and Disease.” Science 279 no. 5350 (1998):514–519.
- 4 E. Fuchs, D.W. Cleveland. “A Structural Scaffolding of Intermediate Filaments in Health and Disease.” Science 279 no. 5350 (1998):514–519.
- 5 N. Yarlett, J.H.P. Hackstein. “Hydrogenosomes: One Organelle, Multiple Origins.” BioScience 55 no. 8 (2005):657–658.
- 6 M. Dudzick. “Protists.” OpenStax CNX. November 27, 2013. http://cnx.org/contents/f7048bb6-e46...ef291cf7049c@1


6.10: Introduction to Finding Evidence
What you’ll learn to do: describe ways to find evidence in support of a claim
Once a working thesis statement is in place, your essay has begun to establish a claim — something the project is stating to be true. No matter how elegant the claim itself is, though, it’s only a small piece of the writing task. A claim by itself is powerless to influence a critically-thinking audience, and you should assume that any audience reading your work will be critical thinkers.
In the following pages, we’ll explore the means to locate and apply appropriate evidence to your own writing.
Contributors and Attributions
CC licensed content, Original
- Outcome: Finding Evidence. Provided by : Lumen Learning. License : CC BY: Attribution
- Image of Evidence. Authored by : Kim Louie for Lumen Learning. License : CC BY: Attribution
CC licensed content, Shared previously
- Drug adverts full of unsupported claims. Authored by : vaughanbell. Provided by : Mind Hacks. Located at : https://mindhacks.com/2008/04/18/drug-adverts-full-of-unsupported-claims/ . License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike
- Image of man with test tube. Authored by : Kamil Antosiewicz Monika Powalisz. Located at : https://flic.kr/p/a5x1Bb . License : CC BY: Attribution


|
Alu
|
Gag
|
non-homologous recombination
|
|
anthocyanins
|
genomic complexity
|
Non-LTR transposons
|
|
antibiotic resistance genes
|
heterochromatin
|
protease
|
|
antibodies
|
immune system
|
protein coat
|
|
autonomous transposon
|
immunoglobulin genes
|
prt
|
|
bacterial composite transposons
|
integrase
|
renaturation kinetics
|
|
bacterial IS elements
|
inverted repeats
|
Repetitive DNA
|
|
bacterial Tn elements
|
jumping genes
|
replicative transposition
|
|
bacteriophage
|
L1
|
resolvase
|
|
centromere
|
LINE
|
retrotransposon
|
|
chromatin
|
LTR (long terminal repeats)
|
retrovirus
|
|
chromosomes
|
LTR transposons
|
RNA transposon
|
|
Class I transposon
|
lysis
|
satellite DNA
|
|
Class II transposon
|
lysogeny
|
SINE
|
|
cointegrate
|
lytic pathway of phage
|
spindle fibers
|
|
CoT curves
|
maize AC (activator) gene
|
telomeres
|
|
cut-and-paste transposition
|
maize Ds (dissociator) gene
|
transposase
|
|
density gradient centrifugation
|
mariner
|
triploid endosperm
|
|
direct repeats
|
McClintock
|
Ty
|
|
DNA sequence phylogeny
|
mosaicism
|
viral infection
|
|
exon shuffling
|
Mu phage
|
|
|
fertility (F) plasmids
|
non-autonomous transposon
|
|


2.5: Strict Two-Voice Composition - Composing a Third-Species Counterpoint
In third-species counterpoint, the counterpoint line moves in quarter notes against a cantus firmus in whole notes. This 4:1 rhythmic ratio creates a still greater differentiation between beats than in second species: strong beats (downbeats), moderately strong beats (the third quarter note of each bar), and weak beats (the second and fourth quarter notes of each bar). Third species also introduces the neighbor tone dissonance, and two related figures in which dissonances can participate in leaps.
The counterpoint line
As in first and second species, the counterpoint line should be singable, have a good shape, with a single climax that does not coincide with the climax of the cantus firmus, and primarily stepwise motion (with some small leaps and an occasional large leap for variety). Like second species, a third-species counterpoint should be even more dominated by stepwise motion than in first species, because there are less sticky situations that would require a leap. If the counterpoint must leap, prefer to do so within the bar rather than across the barline. Also like second species, there should usually be one or two secondary climaxes —notes lower than the overall climax that serve as “local” climaxes for portions of the line.
Beginning a third-species counterpoint
Begin a third-species counterpoint above the cantus firmus with do or sol . Begin a third-species counterpoint below the cantus firmus with do . Unisons are permitted for the first and last dyads of the exercise.
A third-species line can begin with four quarter notes in the first bar, or a quarter rest followed by three quarter notes. Regardless of rhythm, the first pitch in the counterpoint should follow the intervallic rules above.
Ending a third-species counterpoint
The final pitch of the counterpoint must always be do , and must be a whole note.
The penultimate note of the counterpoint (the last quarter note of the penultimate bar) should be ti if the cantus is re , and re if the cantus is ti .
Strong beats
Principles for strong beats (downbeats) are generally the same as in second species.
Strong beats are always consonant , and not unisons. Prefer imperfect consonances (thirds and sixths) to perfect consonances (fifths and octaves).
Motion across bar lines (from beat 4 to downbeat) follows the same rules as first species counterpoint.
Progressions from downbeat to downbeat follow principles of second-species counterpoint, with one exception (see below). The following are some examples, but not an exhaustive list:
- No three consecutive bars can begin with the same perfect interval (two in a row are fine).
- No more than three bars in a row should begin with the same imperfect consonance.
- The pitches that begin consecutive downbeats must not make a dissonant melodic interval.
If a downbeat contains a perfect fifth, neither the third or the fourth beat of the previous bar can be a fifth. If a downbeat contains an octave, neither the second, third, or fourth beat of the previous bar can be an octave. Like in second species, the negative effects of parallel fifths and octaves are not mitigated by the addition of a note or two.
Hidden or direct fifths/octaves between successive downbeats are allowed.
Other beats
Beats 2–4 should exhibit a mixture of consonant and dissonant intervals to promote variety. Among consonances, unisons are permitted on weak beats when necessary to make good counterpoint between the lines. Any dissonance must follow the pattern of the dissonant passing tone or the dissonant neighbor tone , explained below. Also explained below are a number of standard patterns for consonant weak beats.
Harmonic dissonances
Generally, dissonances in third species can occur on beat 2, 3, or 4, and should be preceded and followed by stepwise motion (with the exception of the double neighbor and the nota cambiata , explained below). This promotes smoothness, both by keeping the dissonances off of the strongest beat of the bar, and by coupling them with the smoothest melodic motion. If all dissonant notes in the counterpoint follow one of the following models, they should have a pleasing effect. If not, they may sound harsh or unresolved, or will be difficult to sing.
The dissonant passing tone fills in the space of a melodic third via stepwise motion. The notes before and after the passing tone must be consonant with the cantus.
Note that it is possible to have two dissonant passing tones in a row ( P4–d5 or d5–P4 ). As long as these dissonances do not fall on downbeats and the counterpoint moves in stepwise motion in a single direction, there is no negative effect.
The dissonant neighbor tone ornaments a consonant tone by stepping away and stepping back to the original consonance (6–7–6 over the cantus, for example). It is melodically identical to the consonant neighbor tone of second species, with the difference being the harmonic dissonance. Employing it on a weak beat (2 or 4) ensures the greatest smoothness.
The double neighbor occurs when beats 1 and 4 in the counterpoint are the same tone, and beats 2 and 3 include the notes a step higher and a step lower than the original tone. For example, C–D–B–C or C–B–D–C. Both beats 2 and 3 are dissonant, but since both are embellishing the original tone by step, the leap between them does not significantly diminish the smoothness of the line. When using a double neighbor, the direction between beats 3 and 4 should be the same as between beat 4 and the following downbeat. That motion across the barline should also be stepwise. This further maintains smoothness to temper the effect of the dissonances.
The nota cambiata (changing tone) is a five-note figure that outlines a step progression from downbeat to downbeat. It follows one of two patterns:
- down by step – down by third – up by step – up by step
- up by step – up by third – down by step – down by step
The first pattern will result in a step down from downbeat to downbeat, and the second pattern will result in a step up from downbeat to downbeat. For a nota cambiata to be effective, the first, third, and fifth notes must be consonant with the cantus . The second note will be dissonant and will leap to the third tone. However, like the double neighbor, the overall pattern minimizes the negative effect of the leap away from the dissonance. It is surrounded by stepwise motion, the overall progression is a single step, and the dissonant tone and the following downbeat are the same pitch.
Consonances
The counterpoint can move in and out of consonant tones freely by step, as well as by leap from another consonance, with the following considerations:
- All melodic leaps, of course, must be melodic consonances.
- A large leap should be followed by a step in the opposite direction.
- Motion from the fourth beat into the following downbeat should follow the constraints above for motion into strong beats.
Video demonstration
Add trinkets above to have students construct the schemas


3.3: Module 14 Revolving
14
Module 14 Revolving
Wally Baumback
Learning Outcomes
When you have completed this module, you will be able to:
- Describe a centerline object and explain how it is inserted and used in a 2D Sketch.
- Describe how a Base sketch is revolved with and without the use of a centerline to create a solid model.
- Apply the REVOLVE command to create a solid model from a Base sketch.
Revolving
When drawing symmetrical objects it is much easier to create the model by revolving the Base sketch around an axis rather then extruding it. The axis, which can be one of the lines in the sketch or a centerline, must always be located in the centre of the symmetrical model. The sketch can be revolved any angle between 0 and 360 degrees.
In this module, the basic features of the REVOLVE command are taught. The Inventor Advanced book will cover the more advanced features.
The models in Figure 14-1 and 14-2 were created by revolving the same Base sketch around an axis. Take note how the two solid models that were created using the same sketch are quite different. In Figure 14-1, the line on left side of the sketch was used as the axis while in Figure 14-2, it was the centerline that was used as an axis or revolution.
Inventor Command: REVOLVE
The REVOLVE command is used to create a solid model by revolving the Base sketch around an axis.
Shortcut: R
Centerlines
A centerline is a line with its properties set to act as a centerline. In the REVOLVE command, a centerline is automatically recognized as the axis for the revolution. The two methods of drawing a centerline, which is similar to drawing construction a line, are as follows:
Method 1
Draw the line using the LINE command and then select it. While it is selected, click the Centerline icon.
Method 2
Enable the Centerline icon and then draw the line, using the LINE command. The Centerline icon is shown in Figure 14-3. A centerline will display as the centerline linetype.
WORK ALONG: Revolving a Sketch Without using a Centerline
Step 1
Check the default project and if necessary, set it to Inventor Course.
Step 2
Using the NEW command, start a new part file using the template: English-Modules Part (in).ipt .
Step 3
Save the file with the name: Inventor Workalong 14-1 . (Figure Step 3A and 3B)
Step 4
Start a new sketch on the Front or XZ Plane. Project the Center Point onto the sketch.
Step 5
Draw and dimension one-half of the Front view as shown in the figure. Ensure that the sketch is fully constrained (Figure Step 5)
Step 6
In Model mode, enter the REVOLVE command. It will highlight the sketch automatically as the area to revolve. (Figure Step 6)
Step 7
In the Revolve dialogue box, set the Extents to Full and enable the Axis icon. Select the line on the right side of the sketch as the axis. The Full setting means that it will be revolved 360 degrees. (Figure Step 7)
Step 8
After you select the axis, the REVOLVE command will display the Base model as it is revolved. If this is the desired outcome, click OK. (Figure Step 8A and 8B)
Step 9
Start a new sketch on the top plane of the model. (Figure Step 9)
Step 10
Using what you learned in Module 12, draw a construction circle and four construction lines. Insert a dimension for the diameter of the circle. Ensure that the sketch is fully constrained. (Figure Step 10)
Step 11
Using the technique that you learned in Module 12, draw the 4 circles. Dimension one and constrain the additional 3 with an Equal constraint. (Figure Step 11A and 11B)
Step 12
Extrude the four circles to the To Next extents. (Figure Step 12)
Step 13
Start another sketch on the top plane and draw a circle by offsetting the outside diameter. Dimension the circle and extrude it to complete the model. (Figure Step 13)
Step 14
Change the colour to: Aluminum – Polished. (Figure Step 14)
Step 15
Save and close the file.
WORK ALONG: Revolving a Sketch using a Centerline
Step 1
Check the default project and if necessary, set it to Inventor Course.
Step 2
Enter the NEW command to start a new part file using the template: English-Modules Part (in).ipt .
Step 3
Save the file with the name: Inventor Workalong 14-2 . (Figure Step 3)
Step 4
Start a new sketch on the Front or XZ Plane. Draw and dimension a line start it by snapping to the Center Point. Draw it 5 inches in the negative Y direction. This is the length of the model. This is centerline of the solid model. Change the line’s properties to a centerline. (Figure Step 4A and 4B)
Step 5
Draw and dimension one-half of the Front view as shown in the figure. (Figure Step 5A and 5B)
Step 6
Return to Model mode and enter the REVOLVE command. Since a centerline is part of the sketch, the REVOLVE command will automatically use it as the axis to revolve the sketch around. It will display the outcome of the revolution. (Figure Step 6)
Step 7
In a new sketch, add the four smaller circles and extrude them to complete the model.
Step 8
Change the colour to: Aluminum – Polished . (Figure Step 8)
Step 9
Save and close the file.
Drafting Lesson: Cross Sections
When a view of an object requires a clearer description of its interior or it is hard to dimension because of the hidden lines, a cross section view can be drawn in place of the normal multiview. See Figure 32-1
A cross section view, also called a section , is a view of the object as if it were cut along a cutting plane and the two pieces pulled apart exposing the inside of the object. See Figure 32-2 and 32-3.
A cutting plane line is the line along the object where the cut would have been made. See Figure 32-2. The arrows point in the direction that you are looking when drawing the section view. The surfaces of the object that are solid, when cut, are crosshatched.
Key Principles
Key Principles in Module 14
- When drawing symmetrical objects, it is much easier to create the model by revolving the Base sketch around an axis rather then extruding it. The axis, which can be one of the lines in the sketch or a centerline, must always be located in the centre of the symmetrical MODEL.
- A centerline is a line with its properties set to act as a centerline.
Lab Exercise 14-1
Time allowed: 60 minutes.
| Part Name | Project | Units | Template | Color | Material |
| Inventor Lab Lab 14-1 | Inventor Course | Millimeters | Metric-Modules Part (mm).ipt | Copper – Polished | N/A |
Step 1
Project the Center Point onto the Base plane.
Step 2
Note the location of X0Y0Z0. Draw the Base sketch and revolve it create the Base model of the object shown below. Revolve it by using a line in the sketch. Do not draw a centerline. (Figure Step 2A and 2B)
Step 3
Apply all of the necessary geometrical and dimensional constraints to fully constrain all sketches.
Step 4
Apply the colour shown above. (Figure Step 4A and 4B)
Step 5
Add the four small holes on a new sketch and extrude them.
Lab Exercise 14-2
Time allowed: 60 minutes.
| Part Name | Project | Units | Template | Color | Material |
| Inventor Lab Lab 14-2 | Inventor Course | Inches | English-Modules Part (in).ipt | Zinc | N/A |
Step 1
Project the Center Point onto the Base plane.
Step 2
Note the location of X0Y0Z0. Draw the Base sketch and revolve it create the Base model of the object shown below. Revolve it by using a centerline. (Figure Step 2A, 2B, 2C, 2D, and 2E)
Step 3
Apply all of the necessary geometrical and dimensional constraints to fully constrain all sketches.
Step 4
Apply the colour shown above. (Figure Step 4A and 4B)
Step 5
Add the four small holes and the key on new sketches and extrude them.


Skip to main content
-
Alpha decay is more common because an alpha particle happens to be a very stable arrangement of protons and neutrons.
-
The evidence for the big bang theory of the origin of the universe was discussed on p. 356.
-
For two opposing viewpoints, see Tubiana et al., “The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data,” Radiology, 251 (2009) 13 and Little et al., “ Risks Associated with Low Doses and Low Dose Rates of Ionizing Radiation: Why Linearity May Be (Almost) the Best We Can Do,” Radiology, 251 (2009) 6.
-
Baker and Chesser, Env. Toxicology and Chem. 19 (1231) 2000. Similar effects have been seen at the Bikini Atoll, the site of a 1954 hydrogen bomb test. Although some species have disappeared from the area, the coral reef is in many ways healthier than similar reefs elsewhere, because humans have tended to stay away for fear of radiation (Richards et al., Marine Pollution Bulletin 56 (2008) 503).
-
The evidence for the big bang theory of the origin of the universe was discussed in book 3 of this series.


1.21.8: Third Law of Thermodynamics
The Third Law of Thermodynamics states that the entropy and the heat capacity of a perfect crystal vanish in the limit of zero kelvin [1].
When a system is heated, energy is stored in the form of molecular vibrations leading to an increase in entropy. The isochoric heat capacity is related to the differential dependence of energy on temperature at equilibrium.
A more detailed analysis is required if phase changes and inter-component mixing is involved. Here there are additional contributions to the change in entropy accompanying irreversible processes which Gurney describes as the cratic part of the entropy [2]. In a certain sense an isentropic process is ‘a draw between Maxwell’s demon and a natural process’ [3].
Footnotes.
[1] K. S. Pitzer, Thermodynamics, McGraw-Hill, New York, 3rd. edn.,1965.
[2] R. W. Gurney, Ionic Processes in Solution, McGraw-Hill, New York, 1953.
[3] A. B. Pippard, The Elements of Classical Thermodynamics, University Press, Cambridge ,1957, p.99.


8.2E: Exercises - Compound Interest
PROBLEM SET: COMPOUND INTEREST
Do the following compound interest problems involving a lump-sum amount.
|
1) What will the final amount be in 4 years if $8,000 is invested at 9.2% compounded monthly? |
2) How much should be invested at 10.3% compounded quarterly for it to amount to $10,000 in 6 years? |
|
3) Lydia's aunt Rose left her $5,000. Lydia spent $1,000 on her wardrobe and deposited the rest
|
4) Thuy needs $1,850 in eight months for her college tuition. How much money should she deposit lump sum in an account paying 8.2% compounded monthly to achieve that goal? |
|
5) Bank A pays 5% compounded daily, while
|
6) EZ Photo Company needs five copying machines in 2 1/2 years for a total cost of $15,000. How much money should be deposited now to pay for these machines, if the interest rate is 8% compounded semiannually? |
|
7) Jon's grandfather was planning to give him $12,000 in 10 years. Jon has convinced his grandfather to pay him $6,000 now, instead. If Jon invests this $6,000 at 7.5% compounded continuously, how much money will he have in 10 years? |
8) What will be the price of a $20,000 car in 5 years if the inflation rate is 6%? |
COMPOUND INTEREST
Do the following compound interest problems.
|
9) At an interest rate of 8% compounded continuously, how many years will it take to double your money? |
10) If an investment earns 10% compounded continuously, in how many years will it triple? . |
|
11) The City Library ordered a new computer system costing $158,000; it will be delivered in 6 months, and the full amount will be due 30 days after delivery. How much must be deposited today into an account paying 7.5% compounded monthly to have $158,000 in 7 months? |
12) Mr. and Mrs. Tran are expecting a baby girl in a few days. They want to put away money for her college education now. How much money should they deposit in an account paying 10.2% so they will have $100,000 in 18 years to pay for their daughter's educational expenses? |
|
13) Find the effective interest rate for an account paying 7.2% compounded quarterly. |
14) If a bank pays 5.75% compounded monthly, what is the effective interest rate? |
|
15) The population of the African nation of Cameroon was 12 million people in the year 2015; it has been growing at the rate of 2.5% per year. If the population continues to grow that rate,what will the population be in 2030?
|
16) According to the Law of 70, if an amount grows at an annual rate of 1%, then it doubles every seventy years. Suppose a bank pays 5% interest, how long will it take for you to double your money? How about at 15%? |


10.1: Neurons and Glial Cells
Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are the primary type of cell that most anyone associates with the nervous system. They are responsible for the computation and communication that the nervous system provides. They are electrically active and release chemical signals to target cells. Glial cells, or glia, are known to play a supporting role for nervous tissue. Ongoing research pursues an expanded role that glial cells might play in signaling, but neurons are still considered the basis of this function. Neurons are important, but without glial support they would not be able to perform their function.
Neurons
Neurons are the cells considered to be the basis of nervous tissue. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. An important part of the function of neurons is in their structure, or shape. The three- dimensional shape of these cells makes the immense numbers of connections within the nervous system possible.
Glial Cells
Glial cells, or neuroglia or simply glia, are the other type of cell found in nervous tissue. They are considered to be supporting cells, and many functions are directed at helping neurons complete their function for communication. The name glia comes from the Greek word that means “glue,” and was coined by the German pathologist Rudolph Virchow, who wrote in 1856: “This connective substance, which is in the brain, the spinal cord, and the special sense nerves, is a kind of glue (neuroglia) in which the nervous elements are planted.” Today, research into nervous tissue has shown that there are many deeper roles that these cells play. And research may find much more about them in the future.


2.7: The Power Rules for Exponents
Overview
- The Power Rule for Powers
- The Power Rule for Products
- The Power Rule for quotients
The Power Rule for Powers
The following examples suggest a rule for raising a power to a power:
\((a^2)^3 = a^2 \cdot a^2 \cdot a^2\)
Using the product rule we get:
\((a^2)^3 = a^{2+2+2}\)
\((a^2)^3 = a^{3 \cdot 2}\)
\((a^2)^3 = a^6\)
\((x^9)^4 = x^9 \cdot x^9 \cdot x^9 \cdot x^9\)
\((x^9)^4 = x^{9+9+9+9}\)
\((x^9)^4 = x^{4 \cdot 9}\)
\((x^9)^4 = x^{36}\)
If \(x\) is a real number and \(n\) and \(m\) are natural numbers,
\((x^n)^m = x^{n \cdot m}\)
To raise a power to a power, multiply the exponents.
Sample Set A
Simplify each expression using the power rule for powers. All exponents are natural numbers.
\((x^3)^4 = x^{3 \cdot 4} = x^{12}\)
\((y^5)^3 = y^{5 \cdot 3} = y^{15}\)
\((d^{20})^6 = d^{20 \cdot 6} = d^{120}\)
\((x^□)^△ = x^{□△}\)
Although we don’t know exactly what number □△ is, the notation □△ indicates the multiplication.
Practice Set A
Simplify each expression using the power rule for powers.
\((x^5)^4\)
- Answer
-
\(x^{20}\)
\((y^7)^7\)
- Answer
-
\(y^{49}\)
The Power Rule for Products
The following examples suggest a rule for raising a product to a power:
\(
\begin{aligned}
&(a b)^{3}=a b \cdot a b \cdot a b \text { Use the commutative property of multiplication. }\\
&\begin{array}{l}
=a a a b b b \\
=a^{3} b^{3}
\end{array}
\end{aligned}
\)
\(
\begin{aligned}
(x y)^{5} &=x y \cdot x y \cdot x y \cdot x y \cdot x y \\
&=x x x x x \cdot \text { yyyyy } \\
&=x^{5} y^{5}
\end{aligned}
\)
\(
\begin{aligned}
(4 x y \mathrm{z})^{2} &=4 x y z \cdot 4 x y z \\
&=4 \cdot 4 \cdot x x \cdot y y \cdot z z \\
&=16 x^{2} y^{2} z^{2}
\end{aligned}
\)
If \(x\) and \(y\) are real numbers are \(n\) is a natural number,
\((xy)^n = x^ny^n\)
To raise a product to a power, apply the exponent rule to each and every factor
Sample Set B
Make use of either or both the power rule for products and power rule for powers to simplify each expression.
\((ab)^7 = a^7b^7\)
\((axy)^4 = a^4x^4y^4\)
\((3ab)^2 = 3^2a^2b^2 = 9a^2b^2\)
Don't forget to apply the exponent to the 3!
\((2st)^5 = 2^5s^5t^5 = 32s^5t^5\)
\((ab^3)^2 = a^2(b^3)^2 = a^2b^6\)
We used two rules here. First, the power rule for products. Second, the power rule for powers.
\((7a^4b^2c^8)^2 = 7^2(a^4)^2(b^2)^2(c^8)^2 = 49a^8b^4c^{16}\)
If \(6a^3c^7 \not = 0\), then \((6a^3c^7)^0 = 1\). Recall that \(x^0 = 1\) for \(x \not = 0\)
\([2(x+1)^4]^6 = 2^6(x+1)^{24} = 64(x+1)^{24}\)
Practice Set B
Make use of either or both the power rule for products and the power rule for powers to simplify each expression.
\((ax)^4\)
- Answer
-
\(a^4x^4\)
\((3bxy)^2\)
- Answer
-
\(9b^2x^2y^2\)
\([4t(s-5)]^3\)
- Answer
-
\(64t^3(s-5)^3\)
\((9x^3y^5)^2\)
- Answer
-
\(81x^6y^{10}\)
\((1a^5b^8c^3d)^6\)
- Answer
-
\(a^{30}b^{48}c^{18}d^6\)
\([(a+8)(a+5)]^4\)
- Answer
-
\((a+8)^4(a+5)^4\)
\([(12c^4u^3(w-3)^2]^5\)
- Answer
-
\(12^5c^{20}u^{15}(w-3)^{10}\)
\([10t^4y^7j^3d^2v^6n^4g^8(2-k)^{17}]^4\)
- Answer
-
\(10^4t^{16}y^{28}j^{12}d^8v^{24}n^{16}g^{32}(2-k)^{68}\)
\((x^3x^5y^2y^6)^9\)
- Answer
-
\((x^8y^8)^9 = x^{72}y^{72}\)
\((10^6 \cdot 10^{12} \cdot 10^5)^{10}\)
- Answer
-
\(10^{230}\)
The Power Rule for Quotients
The following example suggests a rule for raising a quotient to a power.
\((\dfrac{a}{b})^3 = \dfrac{a}{b} \cdot \dfrac{a}{b} \cdot \dfrac{a}{b} = \dfrac{a \cdot a \cdot a}{b \cdot b \cdot b} = \dfrac{a^3}{b^3}\)
If \(x\) and \(y\) are real numbers and \(n\) is a natural number,
\((\dfrac{x}{y})^n = \dfrac{x^n}{y^n}, y \not = 0\)
To raise a quotient to a power, distribute the exponent to both the numerator and denominator.
Sample Set C
Make use of the power rule for quotients, the power rule for products, the power rule for powers, or a combination of these rules to simplify each expression. All exponents are natural numbers.
\((\dfrac{x}{y})^6 = \dfrac{x^6}{y^6}\)
\((\dfrac{a}{c})^2 = \dfrac{a^2}{c^2}\)
\((\dfrac{2x}{b})^4 = \dfrac{(2x)^4}{b^4} = \dfrac{2^4x^4}{b^4} = \dfrac{16x^4}{b^4}\)
\((\dfrac{a^3}{b^5})^7 = \dfrac{(a^3)^7}{(b^5)^7} = \dfrac{a^21}{b^35}\)
\((\dfrac{3c^4r^2}{2^3g^5})^3 = \dfrac{3^3c^12r^6}{2^9g^{15}} = \dfrac{27c^{12}r^6}{2^9g^{15}} \text {or} \dfrac{27c^{12}r^6}{512g^15}\)
\([\dfrac{(a-2)}{(a+7)}]^4 = \dfrac{(a-2)^4}{(a+7)^4}\)
\([\dfrac{6x(4-x)^4}{2a(y-4)^6}]^2 = \dfrac{6^2x^2(4-x)^8}{2^2a^2(y-4)^{12}} = \dfrac{36x^2(4-x)^8}{4a^2(y-4)^{12}} = \dfrac{9x^2(4-x)^8}{a^2(y-4)^{12}}\)
\(
\left(\dfrac{a^{3} b^{5}}{a^{2} b}\right)^{3}=\left(a^{3-2} b^{5-1}\right)^{3}
\)
We can simplify within the parentheses. We have a rule that tells us to proceed this way
\(
=\left(a b^{4}\right)^{3}
=a^{3} b^{12}
\left(\dfrac{a^{3} b^{5}}{a^{2} b}\right)^{3}=\dfrac{a^{9} b^{15}}{a^{6} b^{3}}=a^{9-6} b^{15-3}=a^{3} b^{12}
\)
We could have actually used the power rule for quotients first.
Distribute the exponent, then simplify using the other rules.
It is probably better, for the sake of consistency, to work inside the parentheses first.
\((\dfrac{a^rb^s}{s^t})^w = \dfrac{a^{rw}b^{sw}}{c^{tw}}\)
Practice Set C
Make use of the power rule for quotients, the power rule for products, the power rule for powers, or a combination of these rules to simplify each expression.
\((\dfrac{a}{c})^5\)
- Answer
-
\(\dfrac{a^5}{c^5}\)
\((\dfrac{2x}{3y})^3\)
- Answer
-
\(\dfrac{8x^3}{27y^3}\)
\((\dfrac{x^2y^4z^7}{a^5b})^9\)
- Answer
-
\(\dfrac{x^{18}y^{36}z^{63}}{a^{45}b^9}\)
\([\dfrac{2a^4(b-1)}{3b^3(c+6)}]^4\)
- Answer
-
\(\dfrac{16a^{16}(b-1)^4}{81b^{12}(c+6)^4}\)
\((\dfrac{8a^3b^2c^6}{4a^2b})^3\)
- Answer
-
\(8a^3b^3c^{18}\)
\([\dfrac{(9+w)^2}{(3+w)^5}]^{10}\)
- Answer
-
\(\dfrac{(9+w)^{20}}{(3+w)^{50}}\)
\([\dfrac{5x^4(y+1)}{5x^4(y+1)}]^6\)
- Answer
-
\(1\), if \(x^4(y+1) \not = 0\)
\((\dfrac{16x^3v^4c^7}{12x^2vc^6})^0\)
- Answer
-
\(1\), if \(x^2vc^6 \not = 0\)
Exercises
Use the power rules for exponents to simplify the following problems. Assume that all bases are nonzero and that all variable exponents are natural numbers.
\((ac)^5\)
- Answer
-
\(a^5c^5\)
\((nm)^7\)
\((2a)^3\)
- Answer
-
\(8a^3\)
\((2a)^5\)
\((3xy)^4\)
- Answer
-
\(81x^4y^4\)
\((2xy)^5\)
\((3ab)^4\)
- Answer
-
\(81a^4b^4\)
\((6mn)^2\)
\((7y^3)^2\)
- Answer
-
\(49y^6\)
\((3m^3)^4\)
\((5x^6)^3\)
\((10a^2b)^2\)
- Answer
-
\(100a^4b^2\)
\((8x^2y^3)^2\)
\((x^2y^3z^5)^4\)
- Answer
-
\(x^8y^{12}z^{20}\)
\((2a^5b^{11})^0\)
\((x^3y^2z^4)^5\)
- Answer
-
\(x^{15}y^{10}z^{20}\)
\((m^6n^2p^5)^5\)
\((a^4b^7c^6d^8)^8\)
- Answer
-
\(a^{32}b^{56}c^{48}d^{64}\)
\((x^2y^3z^9w^7)^3\)
\((9xy^3)^0\)
- Answer
-
\(1\)
\((\dfrac{1}{2}f^2r^6s^5)^4\)
\((\dfrac{1}{8}c^{10}d^8e^4f^9)^2\)
- Answer
-
\(\dfrac{1}{64}c^{20}d^{16}e^{8}f^{18}\)
\((\dfrac{3}{5}a^3b^5c^{10})^3\)
\((xy)^4(x^2y^4)\)
- Answer
-
\(x^6y^8\)
\((2a^2)^4(3a^5)^2\)
\((a^2b^3)^3(a^3b^3)^4\)
- Answer
-
\(a^{18}b^{21}\)
\((h^3k^5)^2(h^2k^4)^3\)
\((x^4y^3z)^4(x^5yz^2)^2\)
- Answer
-
\(x^{26}y^{14}z^8\)
\((ab^3c^2)^5(a^2b^2c)^2\)
\(\dfrac{(6a^2b^8)^2}{(3ab^5)^2}\)
- Answer
-
\(4a^2b^6\)
\(\dfrac{(a^3b^4)^5}{(a^4b^4)^3}\)
\(\dfrac{(x^6y^5)^3}{(x^2y^3)^5}\)
- Answer
-
\(x^8\)
\(\dfrac{(a^8b^{10})^3}{(a^7b^5)^3}\)
\(\dfrac{(m^5n^6p^4)^4}{(m^4n^5p)^4}\)
- Answer
-
\(m^4n^4p^{12}\)
\(\dfrac{(x^8y^3z^2)^5}{(x^6yz)^6}\)
\(\dfrac{(10x^4y^5z^{11})^3}{(xy^2)^4}\)
- Answer
-
\(100x^8y^7z^{33}\)
\(\dfrac{(9a^4b^5)(2b^2c)}{(3a^3b)(6bc)}\)
\(\dfrac{(2x^3y^3)^4(5x^6y^8)^2}{(4x^5y^3)^2}\)
- Answer
-
\(25x^{14}y^{22}\)
\((\dfrac{3x}{5y})^2\)
\((\dfrac{3ab}{4xy})^3\)
- Answer
-
\(\dfrac{27a^3b^3}{64x^3y^3}\)
\((\dfrac{x^2y^2}{2z^3})^5\)
\((\dfrac{3a^2b^3}{c^4})^3\)
- Answer
-
\(\dfrac{27a^6b^9}{c^{12}}\)
\((\dfrac{4^2a^3b^7}{b^5c^4})^2\)
\([\dfrac{x^2(y-1)^3}{(x+6)}]^4\)
- Answer
-
\(\dfrac{x^8(y-1)^{12}}{(x+6)^4}\)
\((x^nt^{2m})^4\)
\(\dfrac{(x^{n+2})^3}{x^{2n}}\)
- Answer
-
\(x^{n+6}\)
\((xy)^△\)
\(\dfrac{4^3a^Δa^□}{4a^∇}\)
\((\dfrac{4x^Δ}{2y^∇})^□\)
- Answer
-
\(\dfrac{2^□x^{Δ□}}{y^{∇□}}\)


13.2.7: Managerial Roles
What Roles Do Managers Take on in Different Organizational Settings?
In carrying out the responsibilities of planning, organizing, leading, and controlling, managers take on many different roles. A role is a set of behavioral expectations, or a set of activities that a person is expected to perform. Managers’ roles fall into three basic categories: informational roles, interpersonal roles, and decisional roles. In an informational role , the manager may act as an information gatherer, an information distributor, or a spokesperson for the company. A manager’s interpersonal roles are based on various interactions with other people. Depending on the situation, a manager may need to act as a figurehead, a company leader, or a liaison. When acting in a decisional role , a manager may have to think like an entrepreneur, make decisions about resource allocation, help resolve conflicts, or negotiate compromises.
Managerial Decision Making
In every function performed, role taken on, and set of skills applied, a manager is a decision-maker. Decision-making means choosing among alternatives. Decision-making occurs in response to the identification of a problem or an opportunity. The decisions managers make fall into two basic categories: programmed and non-programmed. Programmed decisions are made in response to routine situations that occur frequently in a variety of settings throughout an organization. For example, the need to hire new personnel is a common situation for most organizations. Therefore, standard procedures for recruitment and selection are developed and followed in most companies.
Table \(\PageIndex{1}\): The Many Roles Managers Play in an Organization
| Role | Description | Example |
|---|---|---|
| Information Roles | ||
| Monitor |
|
|
| Disseminator |
|
|
| Spokesperson |
|
|
| Interpersonal Roles | ||
| Figurehead |
|
|
| Leader |
|
|
| Liaison |
|
|
| Decisional Roles | ||
| Entrepreneur |
|
|
| Disturbance handler |
|
|
| Resource allocator |
|
|
| Negotiator |
|
|
Infrequent, unforeseen, or very unusual problems and opportunities require non-programmed decisions by managers. Because these situations are unique and complex, the manager rarely has a precedent to follow. The earlier example of the Norfolk Southern employee, who had to decide the best way to salvage a five-mile-long piece of railroad track from the bottom of Lake Pontchartrain, is an example of a non-programmed decision. Likewise, when Hurricane Katrina was forecast to make landfall, Thomas Oreck, then CEO of the vacuum manufacturer that bears his name, had to make a series of non-programmed decisions. Oreck’s corporate headquarters were in New Orleans, and its primary manufacturing facility was in Long Beach, Mississippi. Before the storm hit, Oreck transferred its computer systems and call-center operations to backup locations in Colorado and planned to move headquarters to Long Beach. The storm, however, brutally hit both locations. Oreck executives began searching for lost employees, tracking down generators, assembling temporary housing for workers, and making deals with UPS to begin distributing its product (UPS brought food and water to Oreck from Atlanta and took vacuums back to the company’s distribution center there). All of these decisions were made in the middle of a very challenging crisis environment.
Whether a decision is programmed or non-programmed, managers typically follow five steps in the decision-making process, as illustrated in Figure <IP_ADDRESS>:
- Recognize or define the problem or opportunity. Although it is more common to focus on problems because of their obvious negative effects, managers who do not take advantage of new opportunities may lose competitive advantage to other firms.
- Gather information so as to identify alternative solutions or actions.
- Select one or more alternatives after evaluating the strengths and weaknesses of each possibility.
- Put the chosen alternative into action.
- Gather information to obtain feedback on the effectiveness of the chosen plan.
It can be easy (and dangerous) for managers to get stuck at any stage of the decision-making process. For example, entrepreneurs can become paralyzed evaluating the options. For Gabby Slome, the co-founder of natural pet food maker Ollie, the idea for starting the company came after her rescue dog began having trouble digesting store-bought pet food after living on scraps. Slome decided that the pet food industry, a $30 billion a year business, was ripe for a natural food alternative. She laments, however, that she let perfect be the enemy of the very good by indulging in “analysis paralysis.”
CONCEPT CHECK
- What are the three types of managerial roles?
- Give examples of things managers might do when acting in each of the different types of roles.
- List the five steps in the decision-making process.


1.1: Prelude to Units and Measurement
Galaxies are as immense as atoms are small, yet the same laws of physics describe both, along with all the rest of nature—an indication of the underlying unity in the universe. The laws of physics are surprisingly few, implying an underlying simplicity to nature’s apparent complexity. In this text, you learn about the laws of physics. Galaxies and atoms may seem far removed from your daily life, but as you begin to explore this broad-ranging subject, you may soon come to realize that physics plays a much larger role in your life than you first thought, no matter your life goals or career choice.
Figure \(\PageIndex{1}\):
This image might be showing any number of things. It might be a whirlpool in a tank of water or perhaps a collage of paint and shiny beads done for art class. Without knowing the size of the object in units we all recognize, such as meters or inches, it is difficult to know what we’re looking at. In fact, this image shows the Whirlpool Galaxy (and its companion galaxy), which is about 60,000 light-years in diameter (about 6×1017km across). (credit: S. Beckwith (STScI) Hubble Heritage Team, (STScI/AURA), ESA, NASA)


6.2: Eye and Face Protection
Eye & Face Protection
- Dust, dirt, metal or wood chips entering the eye from activities such as chipping, grinding, sawing, hammering, the use of power tools or even strong wind forces.
- Chemical splashes from corrosive substances, hot liquids, solvents or other hazardous solutions.
- Objects swinging into the eye or face, such as tree limbs, chains, tools or ropes.
- Radiant energy from welding, harmful rays from the use of lasers or other radiant light (as well as heat, glare, sparks, splash and flying particles).
Types of Eye Protection
- Ability to protect against specific workplace hazards.
- Should fit properly and be reasonably comfortable to wear.
- Should provide unrestricted vision and movement.
- Should be durable and cleanable.
- Should allow unrestricted functioning of any other required PPE.


11.12: Checking Out the Theory
Learning Objectives
By the end of this section, you will be able to:
- Explain how the H–R diagram of a star cluster can be related to the cluster’s age and the stages of evolution of its stellar members
- Describe how the main-sequence turnoff of a cluster reveals its age
In the previous section, we indicated that open clusters are younger than globular clusters, and associations are typically even younger. In this section, we will show how we determine the ages of these star clusters. The key observation is that the stars in these different types of clusters are found in different places in the H–R diagram, and we can use their locations in the diagram in combination with theoretical calculations to estimate how long they have lived.
H–R Diagrams of Young Clusters
What does theory predict for the H–R diagram of a cluster whose stars have recently condensed from an interstellar cloud? Remember that at every stage of evolution, massive stars evolve more quickly than their lower-mass counterparts. After a few million years (“recently” for astronomers), the most massive stars should have completed their contraction phase and be on the main sequence, while the less massive ones should be off to the right, still on their way to the main sequence. These ideas are illustrated in Figure \(\PageIndex{1}\), which shows the H–R diagram calculated by R. Kippenhahn and his associates at Munich University for a hypothetical cluster with an age of 3 million years.
There are real star clusters that fit this description. The first to be studied (in about 1950) was NGC 2264, which is still associated with the region of gas and dust from which it was born (Figure \(\PageIndex{2}\)).
The NGC 2264 cluster’s H–R diagram is shown in Figure \(\PageIndex{3}\). The cluster in the middle of the Orion Nebula (shown in Figures \(21.1.3\) and \(21.1.4\) in Section 21.1) is in a similar stage of evolution.
As clusters get older, their H–R diagrams begin to change. After a short time (less than a million years after they reach the main sequence), the most massive stars use up the hydrogen in their cores and evolve off the main sequence to become red giants and supergiants. As more time passes, stars of lower mass begin to leave the main sequence and make their way to the upper right of the H–R diagram.
To see the evolution of a star cluster in a dwarf galaxy, you can watch this brief animation of how its H–R diagram changes.
Figure \(\PageIndex{4}\) is a photograph of NGC 3293, a cluster that is about 10 million years old. The dense clouds of gas and dust are gone. One massive star has evolved to become a red giant and stands out as an especially bright orange member of the cluster.
Figure \(\PageIndex{5}\) shows the H–R diagram of the open cluster M41, which is roughly 100 million years old; by this time, a significant number of stars have moved off to the right and become red giants. Note the gap that appears in this H–R diagram between the stars near the main sequence and the red giants. A gap does not necessarily imply that stars avoid a region of certain temperatures and luminosities. In this case, it simply represents a domain of temperature and luminosity through which stars evolve very quickly. We see a gap for M41 because at this particular moment, we have not caught a star in the process of scurrying across this part of the diagram.
H–R Diagrams of Older Clusters
After 4 billion years have passed, many more stars, including stars that are only a few times more massive than the Sun, have left the main sequence (Figure \(\PageIndex{6}\)). This means that no stars are left near the top of the main sequence; only the low-mass stars near the bottom remain. The older the cluster, the lower the point on the main sequence (and the lower the mass of the stars) where stars begin to move toward the red giant region. The location in the H–R diagram where the stars have begun to leave the main sequence is called the main-sequence turnoff .
The oldest clusters of all are the globular clusters. Figure \(\PageIndex{7}\) shows the H–R diagram of globular cluster 47 Tucanae. Notice that the luminosity and temperature scales are different from those of the other H–R diagrams in this chapter. In Figure \(\PageIndex{6}\), for example, the luminosity scale on the left side of the diagram goes from 0.1 to 100,000 times the Sun’s luminosity. But in Figure \(\PageIndex{7}\), the luminosity scale has been significantly reduced in extent. So many stars in this old cluster have had time to turn off the main sequence that only the very bottom of the main sequence remains.
Check out this brief NASA video with a 3-D visualization of how an H–R diagram is created for the globular cluster Omega Centauri.
Just how old are the different clusters we have been discussing? To get their actual ages (in years), we must compare the appearances of our calculated H–R diagrams of different ages to observed H–R diagrams of real clusters. In practice, astronomers use the position at the top of the main sequence (that is, the luminosity at which stars begin to move off the main sequence to become red giants) as a measure of the age of a cluster (the main-sequence turnoff we discussed previously). For example, we can compare the luminosities of the brightest stars that are still on the main sequence in Figures \(\PageIndex{3}\) and \(\PageIndex{6}\).
Using this method, some associations and open clusters turn out to be as young as 1 million years old, while others are several hundred million years old. Once all of the interstellar matter surrounding a cluster has been used to form stars or has dispersed and moved away from the cluster, star formation ceases, and stars of progressively lower mass move off the main sequence, as shown in Figures \(\PageIndex{3}\), \(\PageIndex{5}\), and \(\PageIndex{6}\).
To our surprise, even the youngest of the globular clusters in our Galaxy are found to be older than the oldest open cluster. All of the globular clusters have main sequences that turn off at a luminosity less than that of the Sun. Star formation in these crowded systems ceased billions of years ago, and no new stars are coming on to the main sequence to replace the ones that have turned off (Figure \(\PageIndex{8}\)).
Indeed, the globular clusters are the oldest structures in our Galaxy (and in other galaxies as well). The youngest have ages of about 11 billion years and some appear to be even older. Since these are the oldest objects we know of, this estimate is one of the best limits we have on the age of the universe itself—it must be at least 11 billion years old. We will return to the fascinating question of determining the age of the entire universe in the chapter on The Big Bang.
Key Concepts and Summary
The H–R diagram of stars in a cluster changes systematically as the cluster grows older. The most massive stars evolve most rapidly. In the youngest clusters and associations, highly luminous blue stars are on the main sequence; the stars with the lowest masses lie to the right of the main sequence and are still contracting toward it. With passing time, stars of progressively lower masses evolve away from (or turn off) the main sequence. In globular clusters, which are all at least 11 billion years old, there are no luminous blue stars at all. Astronomers can use the turnoff point from the main sequence to determine the age of a cluster.
Glossary
- main-sequence turnoff
- location in the H–R diagram where stars begin to leave the main sequence
Contributors and Attributions
-
Andrew Fraknoi (Foothill College), David Morrison (NASA Ames Research Center), Sidney C. Wolff (National Optical Astronomy Observatory) with many contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at https://openstax.org/details/books/astronomy ).


8.3: The State and the Multinational Corporation
-
- Last updated
- Save as PDF
The industrialised state of the twenty-first century is going through significant stages of adaptation and transformation in response to economic globalisation and losing its privileged position in the international system. Not only the rising powers of Brazil, Russia, India and China but also multinational corporations represent a serious challenge to its once dominant role. There is now little expectation that major economies will adopt a light regulation economic policy style along the lines of the once dominant US model. Instead, the notion of the competition state captures best how since the 1990s government actors have created more business-friendly regulatory frameworks actively supporting internationally operating firms in their efforts to generate more growth and employment opportunities. A well-trained domestic workforce becomes, in this context, an important asset to promote a particular territory for the allocation of foreign direct investment.
Despite similar pressures to reduce government expenditure, states have also continued to diverge in the way they provide welfare for different social groups within their societies. It has become popular to privatise public services and leave the task of their delivery to companies rather than the state. As a consequence, the role of the civil servant is now similar to that of a business manager overseeing the spread of markets into new areas such as education, health and security. Yet, in line with the Polanyi-type adjustment process, government agencies and state organisations cannot entirely shed their responsibility for some of the negative effects of radical policies associated with market liberalisation, especially in trade and finance. Economic globalisation creates ‘winners’ and ‘losers’, which leads to the issue of inequality in societies. To win the support of the ‘losers’, governments typically have to offer compensatory measures through income redistribution, retraining programmes or further educational opportunities. The budgetary resources necessary for the funding of such activities brings into perspective taxation as a main attribute of modern forms of government as well as an indicator of state power relative to other actors in the international system. As the international controversy around the tax bills of large multinational corporations like Amazon has shown, there is a general public expectation that multinational corporations should make a fair contribution to the states in which they generate their profit. After all, for their business models to succeed they have to be able to draw on a well-developed infrastructure, an educated workforce and general health care.
Furthermore, through direct tax evasion, or the use of regulatory loopholes, large corporations may gain a decisive advantage over local suppliers operating in the same market sector and offering comparable services. For example, due to different tax laws within member states of the European Union, the video streaming service Netflix International was exempt from UK corporation tax despite having around 4.5 million paying customers in the UK. In line with the letter of the law, it only paid 5 per cent income tax in Luxembourg. Although this is a regional example, multinational companies with global operations can also shift profits to countries where lower taxes apply by transferring royalties between different branches of their business. What emerges is a picture of waning state power with global business actors playing off different tax regimes to their own advantage. Seen from their angle, multinational corporations are merely following the rules of the game as implemented by governments in their national systems. If the rules change, their behaviour will change as well. Indeed, due to public pressures there seems to be evidence of a step change in this issue, at least in Europe where corporations like Google and Starbucks have been reprimanded.
Multinational corporations in their interaction with civil society have sometimes been the target of non-governmental pressure groups and trade unions, which call for boycotts due to breaches of international environmental or labour standards. More frequently, however, liberal approaches have singled out their exceptional capacity to create wealth at a national, as well as international, level. Their cross-border investment activities in home or host states are often assessed positively as they ensure technology and capital transfer, develop managerial skills in diverse country contexts and ensure market access while simultaneously creating new jobs, thus providing a ‘social’ service in lieu of those typically seen as justifying the state and, therefore, excusing them from taxes. In the case of Apple this has taken the form of a global supply chain by which the bulk of its products are designed in the United States, but manufactured elsewhere – predominantly in China – due to lower costs. This is also an indication of the impact technological change in the production process has on the multinational corporation–state relationship. Seen from the Polanyi angle it is no surprise that when Apple’s chief executive officer Steve Jobs was asked by US president Barack Obama why manufacturing could not return to the US, he simply replied, ‘Those jobs aren’t coming back’ (Duhigg and Bradsher 2012). Even the most powerful national politicians find it hard to deal with the social consequences of these technological innovations in the global market.


4.16: Assignment- Hot Topic Infographic
-
-
Last updated
-
-
Save as PDF
-
STEP 1
: Select an interesting, debatable topic from this module that you would like to learn more about. Do some background research, and then find at least two journal articles that provide more insight into that topic. You may also reference information from national organizations that focus on child development (American Academy of Pediatrics, UNICEF, etc.). Here are some topics that have been debated in recent times, although you may choose your own:
-
breastfeeding
-
vaccinations
-
circumcision
-
gender-neutral parenting
-
co-sleeping
STEP 2
: Pick out some interesting facts from your research. Think about some favorite insights, graphs, or charts. Your objective is to create an interesting visual (think: infographic) so that an outside observer could quickly learn at least
three new things
by looking at it. It must include at least two images (pictures, charts, and graphs all count as images) and some text. You can present both sides of the “debate” on your infographic (for example, the pros and cons of circumcision), or you can focus on one side. Include your references in APA format either at the bottom of the visual or on a separate page.
Please do not feel overwhelmed by creating a visual. You can think of it as making a simplified “poster” about the topic. You may design the poster in any medium you desire, including Microsoft Word, PowerPoint, Photoshop, or one of the following programs:
-
Canva
is really easy to use and convenient because it has tons of free shapes and designs for you to use.
-
Infogram
is a fabulous tool if you want to include a chart or graph in your infographic.
-
Easel.ly
has some great pre-designed Infographic options to work with.
OPTIONAL STEP
: Share your creation with the world so that others can benefit from your work! Using either
Flickr
or
Wikimedia Commons
, upload your finished product and publish it so that others can see and use your work. Although not required, it’s recommended to upload and release your work with a
Creative Commons license
.
STEP 3
: Submit your presentation along with a 200-500 word write-up explaining what you learned about the topic from your research and in creating the presentation.
Sample Grading Rubric
|
Criteria
|
Proficient
|
Developing
|
Not Evident
|
Points
|
|
Creates a visual infographic poster on a relevant topic
|
Visual is attractive and interesting.
|
Visual is somewhat attractive and interesting.
|
Visual is not attractive or interesting.
|
__/5
|
|
Includes at least two images and text about the topic
|
Visual includes at least two visuals as well as some text
|
Visual partially includes visuals and text
|
Visual does not include at least two visuals as well as some text
|
__/5
|
|
Presents at least three pieces of information inside the inforgraphic and explains it in the writing.
|
Includes at least three accurate and informative facts about the topic. Also includes a summary paragraph with submission.
|
Partially includes accurate and informative facts about the topic
|
Does not includes at least three accurate and informative facts about the topic
|
__/10
|
|
Includes correct APA citations
|
Provides APA citations either on the image or a separate reference page
|
Provides partial or incorrect APA citations either on the image or a separate reference page
|
Does not provide APA citations
|
__/5
|
|
Total:
|
__/25
|
Contributors and Attributions
CC licensed content, Original
-
Modification, adaptation, and original content.
Authored by
: Jessica Traylor for Lumen Learning.
Provided by
: Lumen Learning.
License
:
CC BY: Attribution
CC licensed content, Shared previously


5: Paid Time Off- Offering Competitive and Creative Benefits
Paid Time Off (PTO)
Often referred to as PTO, paid time off is personal time that employees take to spend out of the office (and not working) while still receiving pay for regular wages. PTO policies can be structured in many different ways depending on a given company’s size, structure, and industry. Consider the following terminology as you work through this module.
Paid Time Off
PTO is the time that employees can take off of work while still getting paid regular wages. This does not include times in which an employee is working remotely or telecommuting . Often, PTO policies combine vacation, sick, and personal days.
Unpaid Time Off
Time off in which an employee is not compensated for the missed days. Types of unpaid time off may include a leave of absence, military leave , unpaid personal time off, vacation beyond paid vacation days, and medical leave .
PTO Banks
A PTO strategy that bundles together multiple PTO types, most commonly sick leave and vacation time, rather than assigning a certain number of days for each type.
PTO Accrual
Time off that an employee has earned over a given amount of time, typically over a certain number of hours, days, weeks, or months worked.
Common reasons to use PTO:
- Holidays
- Floating holidays
- Paid family leave
- Paid sick leave
- Paid bereavement leave
- Jury duty
- Vacation
- Personal appointments
Review the link below for a more thorough listing of types of time off.
Image: Mohamed Hassan. Camping. CC0 Public Domain
Source: "18 Types of Paid Time Off" , Days Plan, July 4, 2016.


Skip to main content
-
What is entrepreneurial opportunity?
-
What are five methods through which an entrepreneur can create new economic opportunities, according to Joseph Schumpeter?
-
What are some factors that might indicate it is a good time to start a business?
-
When should an entrepreneur explore opportunities?
-
What should a potential entrepreneur research before starting a business?
-
What kind of information is available in census data and how might that data be useful?
-
Compare and contrast supply-based opportunities and demand-based opportunities.
-
How can using a PEST analysis contribute to discovering new patterns of trends for recognizing entrepreneurial opportunities?
-
What is a SWOT analysis and how is it useful?
-
What is a unique selling proposition?
-
What is a business model?


26.8: O Captain! My Captain!
Herman Melville’s “Benito Cereno” (1856) is an early representation of American interactions outside the geographical bounds of the nation. Despite being titled after the Spanish captain; the story is written from the limited third-person point of view (POV) of the American Captain Delano. In other words, everything that we know about his situation is limited to his perception of reality. This POV puts readers in an “American” mindset, representing how Americans perceive their encounters with the rest of the world.
Upon boarding the San Dominick, Captain Delano finds Don Cereno’s behavior bizarre. The narrator writes that “[t]he Spaniard’s manner, too, conveyed a sort of sour and gloomy disdain, which he seemed at no pains to disguise. But this the American in charity ascribed to the harassing effects of sickness” (9). Brushing off the strange demeanor of Don Cereno, the “charitable” American does as charitable Americans do by offering to provide aid to the ship and safely get it to shore. Later—after likening Don Cereno to the Spanish Roman Emperor, Charles V., who stepped down after the empire grew too big for him to control—Captain Delano offers him advice on how to manage his ship.
This sense of authority and knowledge that Captain Delano exerts, as well as the POV of the novella, shows how American literature doesn’t necessarily need to be set in America. “America,” in this sense, is an ideology. In the first half of “Benito Cereno,” we see this ideology described as one that is charitable, all-knowing, and perhaps a little too fearless. Furthermore, the beginning half of this story portrays an American mindset that remains “neutral” in the presence of evil. Captain Delano, amused by the relationships between Spanish crew members and African slaves neither supports or rejects slavery. Instead, he makes jokes about buying Babo, offers second-hand advice on how to keep the slaves in order on the ship (oh, the irony once the story is over), and reflects upon his pet-like fondness of Africans. Captain Delano, like so many figures in American literature, is just another well-intentioned white guy.