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What type of temperatures increase the likelihood of fires? | lower | freezing | reduced | higher | |
Fertilizer runoff can create what type of zones in the ocean? | hot zones | fresh zones | barren zones | dead zones | Fertilizer runoff can create dead zones in the ocean. |
What kind of electricity can you generate with the energy found in flowing water? | transient power | wind energy | electrical power | hydroelectric power | The mechanical energy of rapidly flowing water can turn a turbine and generate electricity. Electricity produced in this way is called hydroelectric power. The water may flow over a waterfall or through a dam. You can see a picture of a dam in the Figure below . A drawback of dams is that they flood land upstream from the dam and reduce water flow downstream from the dam, and this can destroy ecosystems. At the following URL, you can learn more about hydroelectric power and see an animation of a hydroelectric power plant. |
At the time of birth, bones of the brain case are separated by what wide areas of fibrous connective tissue, which later become sutures? | sporozoans | fluctuations | cerebellum | fontanelles | 7.5 Embryonic Development of the Axial Skeleton Formation of the axial skeleton begins during early embryonic development with the appearance of the rod-like notochord along the dorsal length of the early embryo. Repeating, paired blocks of tissue called somites then appear along either side of notochord. As the somites grow, they split into parts, one of which is called a sclerotome. This consists of mesenchyme, the embryonic tissue that will become the bones, cartilages, and connective tissues of the body. Mesenchyme in the head region will produce the bones of the skull via two different mechanisms. The bones of the brain case arise via intramembranous ossification in which embryonic mesenchyme tissue converts directly into bone. At the time of birth, these bones are separated by fontanelles, wide areas of fibrous connective tissue. As the bones grow, the fontanelles are reduced to sutures, which allow for continued growth of the skull throughout childhood. In contrast, the cranial base and facial bones are produced by the process of endochondral ossification, in which mesenchyme tissue initially produces a hyaline cartilage model of the future bone. The cartilage model allows for growth of the bone and is gradually converted into bone over a period of many years. The vertebrae, ribs, and sternum also develop via endochondral ossification. Mesenchyme accumulates around the notochord and produces hyaline cartilage models of the vertebrae. The notochord largely disappears, but remnants of the notochord contribute to formation of the intervertebral discs. In the thorax region, a portion of the vertebral cartilage model splits off to form the ribs. These then become attached anteriorly to the developing cartilage model of the sternum. Growth of the cartilage models for the vertebrae, ribs, and sternum allow for enlargement of the thoracic cage during childhood and adolescence. The cartilage models gradually undergo ossification and are converted into bone. |
What are inorganic compounds that take the form of discrete molecules called? | functional compounds | magnetic compounds | ionic compounds | molecular compounds | Molecular compounds are inorganic compounds that take the form of discrete molecules . Examples include such familiar substance as water (H 2 O) and carbon dioxide (CO 2 ). These compounds are very different from ionic compounds like sodium chloride (NaCl). Ionic compounds are formed when metal atoms lose one or more of their electrons to nonmetal atoms. The resulting cations and anions are electrostatically attracted to each other. |
The other ammonium ions are changed into nitrogen gas by what? | accompanying bacteria | fluctuations bacteria | fungi | denitrifying bacteria | The other ammonium ions are changed into nitrogen gas by denitrifying bacteria. |
What is typical weather for chicago in winter? | ice and humidity | rain and wind | dry and windy | cold & snow | Cold and snow are typical for Chicago in the winter. |
What works by providing a lower energy pathway from reactants to products? | magnetism | thermodynamics | hormones | catalyst | A catalyst works by providing a lower energy pathway from reactants to products. The use of a catalyst involves intermediate reactions which have lower activation complexes than the original reaction. On a simplified reaction energy diagram, this can be thought of as lowering the activation energy for a given transformation. If the activation energy of a reaction is decreased, more collisions will have enough energy to overcome this lower barrier, so the reactant-to-product transformation will occur more frequently. As a result, the overall reaction rate will be higher than for an identical reaction with a larger activation energy barrier. |
What is the smallest part of a compound? | nucleus | electron | dna | molecule | A compound is a substance that consists of two or more elements. A compound has a unique composition that is always the same. The smallest particle of a compound is called a molecule. |
What layer of skin is located right beneath the epidermis? | humus | cusps | scars | dermis | The dermis is the lower layer of the skin, located directly beneath the epidermis (see Figure below ). It is made of tough connective tissue and attached to the epidermis by collagen fibers. The dermis contains blood vessels and nerve endings. Because of the nerve endings, skin can feel touch, pressure, heat, cold, and pain. The dermis also contains hair follicles and two types of glands. |
Some terrestrial species breathe through their skin and oral cavity because they lack what? | mouth | windpipe | nose | lungs | |
What is the main type of cell in the nervous system called? | axon | sensory | conduction | neuron | Nervous Tissues Nervous tissues are made of cells specialized to receive and transmit electrical impulses from specific areas of the body and to send them to specific locations in the body. The main cell of the nervous system is the neuron, illustrated in Figure. |
Many ionic compounds occur as hydrates, compounds that contain specific ratios of loosely bound water molecules, called waters of hydration. waters of hydration can often be removed simply by doing this? | melting | cooling | observing | heating | Hydrates Many ionic compounds occur as hydrates, compounds that contain specific ratios of loosely bound water molecules, called waters of hydration. Waters of hydration can often be removed simply by heating. For example, calcium dihydrogen phosphate can form a solid that contains one molecule of water per Ca(H2PO4)2 unit and is used as a leavening agent in the food industry to cause baked goods to rise. The empirical formula for the solid is Ca(H 2PO4)2·H2O. In contrast, copper sulfate usually forms a blue solid that contains five waters of hydration per formula unit, with the empirical formula CuSO 4·5H2O. When heated, all five water molecules are lost, giving a white solid with the empirical formula CuSO 4 (Figure 2.9 "Loss of Water from a Hydrate with Heating"). |
When blood vessels in the head dilate, what kind of severe headache can occur? | tension headache | malignant | chronic headache | migraine | A migraine is a more severe type of headache. It occurs when blood vessels in the head dilate, or expand. This may be triggered by certain foods, bright lights, weather changes, or other factors. People with migraines may also have nausea or other symptoms. Fortunately, migraines can often be relieved with prescription drugs. |
Acne and different types of cancer can affect what large organ? | brain | liver | lungs | skin | Common skin problems include acne and skin cancer. |
Prokaryotic cells can only regulate gene expression by controlling the amount of what? | RNA processing | folding | translation | transcription | Evolution of Gene Regulation Prokaryotic cells can only regulate gene expression by controlling the amount of transcription. As eukaryotic cells evolved, the complexity of the control of gene expression increased. For example, with the evolution of eukaryotic cells came compartmentalization of important cellular components and cellular processes. A nuclear region that contains the DNA was formed. Transcription and translation were physically separated into two different cellular compartments. It therefore became possible to control gene expression by regulating transcription in the nucleus, and also by controlling the RNA levels and protein translation present outside the nucleus. Some cellular processes arose from the need of the organism to defend itself. Cellular processes such as gene silencing developed to protect the cell from viral or parasitic infections. If the cell could quickly shut off gene expression for a short period of time, it would be able to survive an infection when other organisms could not. Therefore, the organism evolved a new process that helped it survive, and it was able to pass this new development to offspring. |
Where do oceans absorb gases from? | sunlight | stratosphere | wind | atmosphere | Oceans are an important part of the water cycle. They absorb gases from the atmosphere. They evaporate and supply water vapor to the atmosphere. |
Engaging in relatively simple behaviors helps maintain a nearly constant body temperature for organisms classified as what? | endotherms | photophores | placoderms | ectotherms | |
Meningitis is an infection of the membranes that cover the brain and what else? | liver | umbilical cord | notochord | spinal cord | Meningitis is an infection of the membranes that cover the brain and spinal cord. If you have meningitis, you are likely to have a fever and a headache. Another telltale symptom is a stiff neck. Meningitis can be caused by viruses or bacteria. Viral meningitis often clears up on its own after a few days. Bacterial meningitis is much more serious ( Figure below ). It may cause brain damage and death. People with bacterial meningitis need emergency medical treatment. They are usually given antibiotics to kill the bacteria. |
What use enzymes to break down foreign matter and dead cells? | lymphocytes | lipids | hormones | lysosomes | Lysosomes, which use enzymes to break down foreign matter and dead cells. |
What is indicated by the ratio of the output force to the input force in a machine? | man hours | momentum | magnetic force | mechanical advantage | The mechanical advantage of a machine is the factor by which the machine changes the input force. It equals the ratio of the output force to the input force. A wheel and axle may either increase or decrease the input force, depending on whether the input force is applied to the axle or the wheel. |
Glucocorticoids and mineralocorticoids are the two main types of what in humans? | hormones | carotenoids | metabolites | corticosteroids | |
What keeps the earth orbiting the sun? | weak nuclear force | strong nuclear force | magnetic force | gravity | Earth and Moon orbit each other. This Earth-Moon system orbits the Sun in a regular path ( Figure below ). Gravity is the force of attraction between all objects. Gravity keeps the Earth and Moon in their orbits. Earth’s gravity pulls the Moon toward Earth’s center. Without gravity, the Moon would continue moving in a straight line off into space. |
How do bees communicate to tell other bees where food is located? | high pitch noise | wing flapping | mating dance | waggle dance | Animals may communicate by sight with gestures, body postures, or facial expressions. Look at the cat in Figure below . There’s no mistaking the meaning of its arched back, standing hair, and exposed fangs. It’s clearly saying “stay away, or else!” Bees communicate with a waggle dance. They use it to tell other bees where food is located. |
Along with nerve tissue, what kind of tissue are lecithins and cephalins important constituents of? | skin tissue | heart tissue | lung tissue | brain tissue | (a) Amino alcohols are commonly found in phosphoglycerides, which are evident in its structural formula (b). There are two common types of phosphoglycerides. Phosphoglycerides containing ethanolamine as the amino alcohol are called phosphatidylethanolamines orcephalins. Cephalins are found in brain tissue and nerves and also have a role in blood clotting. Phosphoglycerides containing choline as the amino alcohol unit are called phosphatidylcholines or lecithins. Lecithins occur in all living organisms. Like cephalins, they are important constituents of nerve and brain tissue. Egg yolks are especially rich in lecithins. Commercial-grade lecithins isolated from soybeans are widely used in foods as emulsifying agents. An emulsifying agent is used to stabilize an emulsion—a dispersion of two liquids that do not normally mix, such as oil and water. Many foods are emulsions. Milk is an emulsion of butterfat in water. The emulsifying agent in milk is a protein called casein. Mayonnaise is an emulsion of salad oil in water, stabilized by lecithins present in egg yolk. Saylor URL: http://www. saylor. org/books. |
Metal detectors used for airport security work on which principle? | conductivity | electricity | inertia | inductance | One common application of inductance is used in traffic lights that can tell when vehicles are waiting at the intersection. An electrical circuit with an inductor is placed in the road under the place a waiting car will stop over. The body of the car increases the inductance and the circuit changes sending a signal to the traffic lights to change colors. Similarly, metal detectors used for airport security employ the same technique. A coil or inductor in the metal detector frame acts as both a transmitter and a receiver. The pulsed signal in the transmitter coil induces a signal in the receiver. The self-inductance of the circuit is affected by any metal object in the path. Such detectors can be adjusted for sensitivity and also can indicate the approximate location of metal found on a person. (But they will not be able to detect any plastic explosive such as that found on the “underwear bomber. ”) See Figure 23.43. |
Methanogens in their gut enable what process in cows? | regeneration | absorption | excretion | digestion | Cows are able to digest grass with the help of the methanogens in their gut. |
The skeleton of lampreys is made of what? | chitin | ligament | collagen | cartilage | |
How do amphibians reproduce? | they don't | asexually | biologically | sexually | Amphibians reproduce sexually. Fertilization may take place inside or outside the body. Amphibians are oviparous. Embryos develop in eggs outside the mother’s body. |
What are scientists called who study the weather and give forecasts? | botanists | climatologists | geologists | meteorologists | People often complain when the weather forecast is wrong. Weather forecasts today, however, are much more accurate than they were just 20 years ago. Scientists who study and forecast the weather are called meteorologists. How do they predict the weather?. |
Autocrine signaling takes place within the same what? | organ | tissue type | proteins | cell | Other Types of Chemical Signaling In endocrine signaling, hormones secreted into the extracellular fluid diffuse into the blood or lymph, and can then travel great distances throughout the body. In contrast, autocrine signaling takes place within the same cell. An autocrine (auto= “self”) is a chemical that elicits a response in the same cell that secreted it. Interleukin-1, or IL-1, is a signaling molecule that plays an important role in inflammatory response. The cells that secrete IL-1 have receptors on their cell surface that bind these molecules, resulting in autocrine signaling. Local intercellular communication is the province of the paracrine, also called a paracrine factor, which is a chemical that induces a response in neighboring cells. Although paracrines may enter the bloodstream, their concentration is generally too low to elicit a response from distant tissues. A familiar example to those with asthma is histamine, a paracrine that is released by immune cells in the bronchial tree. Histamine causes the smooth muscle cells of the bronchi to constrict, narrowing the airways. Another example is the neurotransmitters of the nervous system, which act only locally within the synaptic cleft. |
Both dna and rna are what type of acids? | fatty acids | proteins acids | synthesize acids | nucleic acids | DNA and RNA are nucleic acids. DNA stores genetic information. RNA helps build proteins. Proteins, in turn, determine the structure and function of all your cells. Proteins consist of chains of amino acids. A protein’s structure and function depends on the sequence of its amino acids. Instructions for this sequence are encoded in DNA. |
What kind of a resource is soil, for human purposes? | emanates resource | renewable resource | guarana resource | nonrenewable resource | Although renewable, soil takes a very long time to form—up to hundreds of millions of years. So, for human purposes, soil is a nonrenewable resource. It is also constantly depleted of nutrients through careless use, and eroded by wind and water. For example, misuse of soil caused a huge amount of it to simply blow away in the 1930s during the Dust Bowl (see Figure below ). Soil must be used wisely to preserve it for the future. Conservation practices include contour plowing and terracing. Both reduce soil erosion. Soil also must be protected from toxic wastes. |
A natural resource that is consumed or used up faster than it can be made by nature is termed what? | fossil fuel | renewable | energy-inefficient | non-renewable | A nonrenewable resource is a natural resource that is consumed or used up faster than it can be made by nature. Two main types of nonrenewable resources are fossil fuels and nuclear power. Fossil fuels , such as petroleum, coal, and natural gas, formed from plant and animal remains over periods from 50 to 350 million years ago. They took millions of years to form. Humans have been consuming fossil fuels for less than 200 years, yet remaining reserves of oil can supply our needs only until around the year 2055. Natural gas can only supply us until around 2085. Coal will last longer, until around the year 2250. That is why it is so important to develop alternate forms of energy, especially for our cars. Today, electric cars are becoming more and more common. What would happen if we ran out of gasoline? Alternative use of energy, especially in transportation, must become a standard feature of all cars and trucks and planes by the middle of the century. |
An electrical motor changes electrical energy into what? | thermal energy | chemical energy | solar energy | mechanical energy | Electrical motors change electrical energy into mechanical energy. The motor consists of an electrical circuit with part of the wires inside a magnetic field. This can be seen below. Positive charges move through the circuit in the direction of the light purple arrows. When the charges move up through the part of the coil that is right next to the north pole, the right hand rule tells us that the wire suffers the force, F , pushing the wire in the direction of the blue arrow, toward the back of the sketch. On the other side of the coil, where the charges are moving down through the field, the right hand rule shows the force would push this side of the coil toward the front. These two forces are working together, rotating the coil in the direction of the circular red arrow. |
What is name for a piece of collagen-rich skin formed after the process of wound healing that differs from normal skin? | size | tissue | Sore | scar | Scars and Keloids Most cuts or wounds, with the exception of ones that only scratch the surface (the epidermis), lead to scar formation. A scar is collagen-rich skin formed after the process of wound healing that differs from normal skin. Scarring occurs in cases in which there is repair of skin damage, but the skin fails to regenerate the original skin structure. Fibroblasts generate scar tissue in the form of collagen, and the bulk of repair is due to the basket-weave pattern generated by collagen fibers and does not result in regeneration of the typical cellular structure of skin. Instead, the tissue is fibrous in nature and does not allow for the regeneration of accessory structures, such as hair follicles, sweat glands, or sebaceous glands. Sometimes, there is an overproduction of scar tissue, because the process of collagen formation does not stop when the wound is healed; this results in the formation of a raised or hypertrophic scar called a keloid. In contrast, scars that result from acne and chickenpox have a sunken appearance and are called atrophic scars. Scarring of skin after wound healing is a natural process and does not need to be treated further. Application of mineral oil and lotions may reduce the formation of scar tissue. However, modern cosmetic procedures, such as dermabrasion, laser treatments, and filler injections have been invented as remedies for severe scarring. All of these procedures try to reorganize the structure of the epidermis and underlying collagen tissue to make it look more natural. |
Young eutherians complete their embryonic development within what? | spores | pollen grains | ovaries | uterus | |
Nuclear reactors use fission reactions to vaporize water, producing steam to drive a turbine and generate what? | fuel | light | oil | electricity | Nuclear reactors use fission reactions to vaporize water. The resulting steam is used to drive a turbine, which generates electricity. |
What type of air do plants take in and use? | carbon | oxygen | liquid dioxide | carbon dioxide | |
How long can a large star be on the main sequence stage? | 60.11 million years | 3 million years | 200.4 million years | 10 million years | Large stars burn through their supply of hydrogen very quickly. These stars “live fast and die young!” A very large star may only be on the main sequence for 10 million years. A very small star could remain on the main sequence for tens to hundreds of billions of years—far longer than the current age of our Universe. |
What do you call the pattern of lines formed when light passes through a prism to separate it into the different frequencies of light it contains? | light emission spectrum | prismatic rainbow | kaleidoscope effect | atomic emission spectrum | Scientists studied the distinctive pink color of the gas discharge created by hydrogen gas. When a narrow beam of this light was viewed through a prism, the light was separated into four lines of very specific wavelengths (and frequencies since and are inversely related). An atomic emission spectrum is the pattern of lines formed when light passes through a prism to separate it into the different frequencies of light it contains. The Figure below shows the atomic emission spectrum of hydrogen. |
What is the term for a watertight seal between two adjacent animal cells? | placental barrier | cell membrane | cell wall | tight junction | A tight junction is a watertight seal between two adjacent animal cells (Figure 3.17b). Proteins hold the cells tightly against each other. This tight adhesion prevents materials from leaking between the cells. Tight junctions are typically found in the epithelial tissue that lines internal organs and cavities, and composes most of the skin. For example, the tight junctions of the epithelial cells lining the urinary bladder prevent urine from leaking into the extracellular space. Also found only in animal cells are desmosomes, which act like spot welds between adjacent epithelial cells (Figure 3.17c). They keep cells together in a sheet-like formation in organs and tissues that stretch, like the skin, heart, and muscles. Gap junctions in animal cells are like plasmodesmata in plant cells in that they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate (Figure 3.17d). Structurally, however, gap junctions and plasmodesmata differ. |
What is at the surface of a cell, arranged in similar bilayer? | pigments | fats | eukaryotes | phospholipids | |
Vitamins are organic compounds that are essential in very small amounts for the maintenance of normal what? | calcium | respiration | pigments | metabolism | Vitamins are organic compounds that are essential in very small (trace) amounts for the maintenance of normal metabolism. They generally cannot be synthesized at adequate levels by the body and must be obtained from the diet. The absence or shortage of a vitamin may result in a vitamin-deficiency disease. In the first half of the 20th century, a major focus of biochemistry was the identification, isolation, and characterization of vitamins. Despite accumulating evidence that people needed more than just carbohydrates, fats, and proteins in their diets for normal growth and health, it was not until the early 1900s that research established the need for trace nutrients in the diet. Because organisms differ in their synthetic abilities, a substance that is a vitamin for one species may not be so for another. Over the past 100 years, scientists have identified and isolated 13 vitamins required in the human diet and have divided them into two broad categories: the fat-soluble vitamins, which include vitamins A, D, E, and K, and the water-soluble vitamins, which are the B complex vitamins and vitamin C. All fatsoluble vitamins contain a high proportion of hydrocarbon structural components. There are one or two oxygen atoms present, but the compounds as a whole are nonpolar. In contrast, water-soluble vitamins contain large numbers of electronegative oxygen and nitrogen atoms, which can engage in hydrogen bonding with water. Most water-soluble vitamins act as coenzymes or are required for the synthesis of coenzymes. The fatsoluble vitamins are important for a variety of physiological functions. The key vitamins and their functions are found in Table 18.8 "Fat-Soluble Vitamins and Physiological Functions" and Table 18.9 "Water-Soluble Vitamins and Physiological Functions". Table 18.8 Fat-Soluble Vitamins and Physiological Functions Vitamin. |
In eukaryotic cells, what divides before the cell itself divides? | protons | electrons | cell wall | nucleus | In eukaryotic cells, the nucleus divides before the cell itself divides. The process in which the nucleus divides is called mitosis. Before mitosis occurs, a cell’s DNA is replicated. This is necessary so that each daughter cell will have a complete copy of the genetic material from the parent cell. How is the replicated DNA sorted and separated so that each daughter cell gets a complete set of the genetic material? To understand how this happens, you need to know more about chromosomes. |
The joint that lies between the radius and the ulna is what kind of joint? | shaft joint | hinge joint | socket joint | pivot joint | Pivot Joint. The joint at which the radius and ulna meet is a pivot joint. Movement at this joint allows you to flip your palm over without moving your elbow joint. |
Because it damages hair cells, what is the most cause of hearing loss in adults? | water in the ears | bacteria | ear wax | exposure to noise | Most adults experience at least some hearing loss as they get older. The most common cause is exposure to loud sounds, which damage hair cells. The louder a sound is, the less exposure is needed for damage to occur. Even a single brief exposure to a sound louder than 115 decibels can cause hearing loss. Figure below shows the relationship between loudness, exposure time, and hearing loss. |
What is regulated to ensure that the correct proteins are made? | Fat expression | acids expression | variation expression | gene expression | Gene expression is regulated to ensure that the correct proteins are made when and where they are needed. Regulation may occur at any point in the expression of a gene, from the start of transcription to the processing of a protein after translation. The focus in this lesson is the regulation of transcription. |
What mirrors diverge light rays and, thus, have a negative focal length? | diffraction | curved | concave | convex | behind the mirror. Convex mirrors diverge light rays and, thus, have a negative focal length. |
During what stage are chromosomes condensed enough to be seen under a microscope? | epistasis | cytokinesis | meiosis | mitosis | |
What is an odorless white solid that is harmless unless consumed in large quantities? | oxygen chloride | Hydrogen | carbon chloride | sodium chloride | A: Sodium chloride is an odorless white solid that is harmless unless consumed in large quantities. In fact, it is a necessary component of the human diet. |
Melting, sublimation, and evaporation absorb what from their surroundings? | cold | vibration | moisture | heat | Melting, sublimation, and evaporation absorb heat from their surroundings. Freezing, deposition, and condensation release heat. |
What is the series of changes in the reproductive system of a mature female that happens monthly? | pregnancy | urinary cycle | fetal cycle | menstrual cycle | The menstrual cycle is a series of changes in the reproductive system of mature females that repeats every month. While the egg and follicle are developing in the ovary, tissues are building up inside the uterus , the reproductive organ where the baby would develop. The uterus develops a thick lining covered in tiny blood vessels. This prepares the uterus to receive an egg that could develop into a child (a fertilized egg). The occurs during the first part of the cycle. |
What is the average number of individuals per unit of area or volume called? | population count | crowdedness | population structure | population density | Population size is the number of individuals in a population. Population density is the average number of individuals per unit of area or volume. The pattern of spacing of individuals in a population may be affected by characteristics of a species or its environment. |
What types of living beings have water vascular systems and unique tube feet? | Ducks | diatoms | mollusks | echinoderms | Echinoderms have a unique water vascular system with tube feet. This allows slow but powerful movement. |
Which two gases make up the bulk of earth's atmosphere? | nitrogen and argon | carbon and oxygen | phosphorus and oxygen | nitrogen and oxygen | A: Air in the atmosphere is a gaseous solution. It is a mixture that contains mainly nitrogen and oxygen gases, with very small amounts of several other gases. The circle graph in the Figure below shows the composition of air. Because air is a solution, it is homogeneous. In other words, no matter where you go, the air always contains the same proportion of gases that are shown in the graph. |
What is the decayed remains of living organisms called? | oil | plateaus | fossils | humus | Humus is the decayed remains of living organisms. Humus makes soil fertile. |
The motor thus acts as a generator whenever its coil does what? | oscillates | stops | revolves | rotates | 23.6 Back Emf It has been noted that motors and generators are very similar. Generators convert mechanical energy into electrical energy, whereas motors convert electrical energy into mechanical energy. Furthermore, motors and generators have the same construction. When the coil of a motor is turned, magnetic flux changes, and an emf (consistent with Faraday’s law of induction) is induced. The motor thus acts as a generator whenever its coil rotates. This will happen whether the shaft is turned by an external input, like a belt drive, or by the action of the motor itself. That is, when a motor is doing work and its shaft is turning, an emf is generated. Lenz’s law tells us the emf opposes any change, so that the input emf that powers the motor will be opposed by the motor’s self-generated emf, called the back emf of the motor. (See Figure 23.25. |
Norovirus causes the inflammation of the stomach and what else? | lungs | muscles | liver | intestines | Common foodborne viruses include norovirus and hepatitis A virus. Norovirus, which causes inflammation of the stomach and intestines, has been a recent issue on cruise ships, infecting hundreds of passengers and crew on certain voyages. Hepatitis A causes inflammation of the liver, which is treated with rest and diet changes. Parasites are tiny organisms that live inside another organism. Giardia is a parasite spread through water contaminated with the stools of people or animals who are infected. Food preparers who are infected with parasites can also contaminate food if they do not thoroughly wash their hands after using the bathroom and before handling food. Trichinella is a type of roundworm parasite. People may be infected with this parasite by consuming raw or undercooked pork or wild game. |
What forms when tectonic plates move above a hot spot? | volcanic setting | earthquake chain | volcanic system | volcanic chain | As the tectonic plates move above a hot spot, they form a chain of volcanoes. The islands of Hawaii formed over a hot spot in the middle of the Pacific plate. The Hawaii hot spot has been active for tens of millions of years. The volcanoes of the Hawaiian Islands formed at this hot spot. Older volcanoes that formed at the hot spot have eroded below sea level. These are called the Emperor Seamounts. |
What is the multicellular diploid stage called? | lymphocyte | blastocyte | sporangium | sporophyte | |
Myopia is commonly called what? | scoliosis | farsightedness | blindness | nearsightedness | Myopia is commonly called nearsightedness. People with myopia can see nearby objects clearly, but distant objects appear blurry. Myopia occurs when images focus in front of the retina because the eyeball is too long. This vision problem can be corrected with concave lenses, which curve inward. The lenses focus images correctly on the retina. |
The prostate gland secretes a fluid that mixes with sperm to help form what? | urine | testosterone | hormone | semen | The prostate gland secretes a fluid that mixes with sperm to help form semen. The prostate gland is located beneath the bladder. Semen is a "milky" liquid that carries sperm through the urethra and out of the body. In addition to sperm cells, semen contains sugars (fructose) which provide energy to the sperm cells, and enzymes and other substances which help the sperm survive. |
About 95 percent of lipids are absorbed in what organ of the digestive system? | large intestine | kidneys | stomach | small intestine | Lipid Absorption About 95 percent of lipids are absorbed in the small intestine. Bile salts not only speed up lipid digestion, they are also essential to the absorption of the end products of lipid digestion. Short-chain fatty acids are relatively water soluble and can enter the absorptive cells (enterocytes) directly. Despite being hydrophobic, the small size of short-chain fatty acids enables them to be absorbed by enterocytes via simple diffusion, and then take the same path as monosaccharides and amino acids into the blood capillary of a villus. The large and hydrophobic long-chain fatty acids and monoacylglycerides are not so easily suspended in the watery intestinal chyme. However, bile salts and lecithin resolve this issue by enclosing them in a micelle, which is a tiny sphere with polar (hydrophilic) ends facing the watery environment and hydrophobic tails turned to the interior, creating a receptive environment for the long-chain fatty acids. The core also includes cholesterol and fat-soluble vitamins. Without micelles, lipids would sit on the surface of chyme and never come in contact with the absorptive surfaces of the epithelial cells. Micelles can easily squeeze between microvilli and get very near the luminal cell surface. At this point, lipid substances exit the micelle and are absorbed via simple diffusion. The free fatty acids and monoacylglycerides that enter the epithelial cells are reincorporated into triglycerides. The triglycerides are mixed with phospholipids and cholesterol, and surrounded with a protein coat. This new complex, called a chylomicron, is a water-soluble lipoprotein. After being processed by the Golgi apparatus, chylomicrons are released from the cell (Figure 23.33). Too big to pass through the basement membranes of blood capillaries, chylomicrons instead enter the large pores of lacteals. The lacteals come together to form the lymphatic vessels. The chylomicrons are transported in the lymphatic vessels and empty through the thoracic duct into the subclavian vein of the circulatory system. Once in the bloodstream, the enzyme lipoprotein lipase breaks down the triglycerides of the chylomicrons into free fatty acids and glycerol. These breakdown products then pass through capillary walls to be used for energy by cells or stored in adipose tissue as fat. Liver cells combine the remaining chylomicron remnants with proteins, forming lipoproteins that transport cholesterol in the blood. |
What type of work called occurs when a system pushes back the surroundings against a restraining pressure? | retention work | shape work | contrast work | expansion work | A type of work called expansion work (or pressure-volume work) occurs when a system pushes back the surroundings against a restraining pressure, or when the surroundings compress the system. An example of this occurs during the operation of an internal combustion engine. The reaction of gasoline and oxygen is exothermic. Some of this energy is given off as heat, and some does work pushing the piston in the cylinder. The substances involved in the reaction are the system, and the engine and the rest of the universe are the surroundings. The system loses energy by both heating and doing work on the surroundings, and its internal energy decreases. (The engine is able to keep the car moving because this process is repeated many times per second while the engine is running. ) We will consider how to determine the amount of work involved in a chemical or physical change in the chapter on thermodynamics. |
In some parts of the world, too much of the sun's harmful uv radiation gets through because of a hole in what layer? | thermosphere | mesosphere | troposphere | ozone | Punta Arenas, Chile is the world's most southern city. At such a high latitude, winters are exceedingly cold and dark. Unlike the children pictured above, the children in Punta Arenas must stay inside to avoid the cold. Of course, they look forward to spring when they can go out to play. But some years, it is too dangerous for the children to go outside. The ozone hole has moved north. Too much of the Sun's harmful UV radiation gets through. |
What type of animal eats both plants and animals? | herbivores | insectivores | carnivores | omnivores | |
What is the term for the muscular duct through which sperm are propelled? | the västerås deferens | the glarus deferens | the glans deferens | the vas deferens | |
What is the most common cause of cancer? | technology mutations | poor diet | smoking | cell mutations | Most cancers are caused by mutations. Mutations are random errors in genes. Mutations that lead to cancer usually occur in genes that control the cell cycle. Because of the mutations, abnormal cells are allowed to divide. |
The testes produce what hormone? | estrogen | dopamine | insulin | testosterone | The gonads secrete sex hormones. The male gonads are called testes . They secrete the male sex hormone testosterone. The female gonads are called ovaries . They secrete the female sex hormone estrogen. Sex hormones are involved in the changes of puberty. They also control the production of gametes by the gonads. |
Capillaries are narrow-diameter tubes that can fit red blood cells through in single file and are the sites for the exchange of what? | components | proteins | fluids | nutrients | Arterioles diverge into capillary beds. Capillary beds contain a large number (10 to 100) of capillaries that branch among the cells and tissues of the body. Capillaries are narrow-diameter tubes that can fit red blood cells through in single file and are the sites for the exchange of nutrients, waste, and oxygen with tissues at the cellular level. Fluid also crosses into the interstitial space from the capillaries. The capillaries converge again into venules that connect to minor veins that finally connect to major veins that take blood high in carbon dioxide back to the heart. Veins are blood vessels that bring blood back to the heart. The major veins drain blood from the same organs and limbs that the major arteries supply. Fluid is also brought back to the heart via the lymphatic system. |
Pieces of the cell break off and form a new cell in what type of reproduction that produces genetically identical organisms? | Fusion | Meiosis | Mitosis | fragmentation | Like bacteria, reproduction in archaea is asexual. Archaea can reproduce through binary fission , where a parent cell divides into two genetically identical daughter cells. Archaea can also reproduce asexually through budding and fragmentation, where pieces of the cell break off and form a new cell, also producing genetically identical organisms. |
How do most reptiles produce? | asexually | occasionally | biologically | sexually | Most reptiles reproduce sexually and have internal fertilization. Males have one or two penises that pass sperm from their cloaca to the cloaca of a female. Fertilization occurs within the cloaca, and fertilized eggs leave the female’s body through the opening in the cloaca. In a minority of species, the eggs are retained inside the female’s body until they hatch. Then the offspring leave the mother’s body through the cloaca opening. |
The minimum amount necessary for self-sustained fission of a given nuclide is called what? | its activation energy | its half-life | its molar mass | its critical mass | Not every neutron produced by fission induces fission. Some neutrons escape the fissionable material, while others interact with a nucleus without making it fission. We can enhance the number of fissions produced by neutrons by having a large amount of fissionable material. The minimum amount necessary for self-sustained fission of a given nuclide is called its critical mass. |
What are genes that are close together on the same chromosome called? | stored genes | mutated genes | infected genes | linked genes | Linked genes are genes that are close together on the same chromosome. Linked genes are inherited together. |
What do neutral atoms have the same number of? | Measure and electrons | toxins and protons | gases and protons | electrons and protons | Summary Each atom of an element contains the same number of protons, which is theatomic number (Z). Neutral atoms have the same number of electrons and protons. Atoms of an element that contain different numbers of neutrons are calledisotopes. Each isotope of a given element has the same atomic number but a different mass number (A), which is the sum of the numbers of protons and neutrons. The relative masses of atoms are reported using the atomic mass unit(amu), which is defined as one-twelfth of the mass of one atom of carbon-12, with 6 protons, 6 neutrons, and 6 electrons. The atomic mass of an element is the weighted average of the masses of the naturally occurring isotopes. When one or more electrons are added to or removed from an atom or molecule, a charged particle called an ion is produced, whose charge is indicated by a superscript after the symbol. |
Omnivores are animals that eat both plant- and? | biofuel | recycled food | liquid diets | animal-derived food | Omnivores are animals that eat both plant- and animal-derived food. In Latin, omnivore means to eat everything. Humans, bears (shown in Figure 34.4a), and chickens are example of vertebrate omnivores; invertebrate omnivores include cockroaches and crayfish (shown in Figure 34.4b). |
Bacterial dna is contained in a large, circular strand; this single chromosome is located in a region of the cell called what? | nucleic acid | polypeptide | amino acid | the nucleoid | DNA. By contrast though, bacterial DNA is contained in a large, circular strand. This single chromosome is located in a region of the cell called the nucleoid . The nucleoid is not an organelle, but a region within the cytoplasm. Many bacteria also have additional small rings of DNA known as plasmids . |
Which primate group generally lives alone? | human | chimpanzee | gorilla | orangutan | Yes! This is the Hubbard Glacier in Alaska. As the glacier meets the relatively warm seawater, it calves. Pieces of the glacier break off and fall into the water. These icebergs may be as large as a ten-story building. |
Carbon and what are the second and third most abundant elements in your body? | calcium | helium | mercury | hydrogen | 2.4 | Inorganic Compounds Essential to Human Functioning By the end of this section, you will be able to: • Compare and contrast inorganic and organic compounds • Identify the properties of water that make it essential to life • Explain the role of salts in body functioning • Distinguish between acids and bases, and explain their role in pH • Discuss the role of buffers in helping the body maintain pH homeostasis The concepts you have learned so far in this chapter govern all forms of matter, and would work as a foundation for geology as well as biology. This section of the chapter narrows the focus to the chemistry of human life; that is, the compounds important for the body’s structure and function. In general, these compounds are either inorganic or organic. • An inorganic compound is a substance that does not contain both carbon and hydrogen. A great many inorganic compounds do contain hydrogen atoms, such as water (H2O) and the hydrochloric acid (HCl) produced by your stomach. In contrast, only a handful of inorganic compounds contain carbon atoms. Carbon dioxide (CO2) is one of the few examples. • An organic compound, then, is a substance that contains both carbon and hydrogen. Organic compounds are synthesized via covalent bonds within living organisms, including the human body. Recall that carbon and hydrogen are the second and third most abundant elements in your body. You will soon discover how these two elements combine in the foods you eat, in the compounds that make up your body structure, and in the chemicals that fuel your functioning. The following section examines the three groups of inorganic compounds essential to life: water, salts, acids, and bases. Organic compounds are covered later in the chapter. |
Glucagon and insulin are produced in what organ? | thyroid | hypothalamus | thymus | pancreas | |
Anagen, catagen and telogen are phases in the growth of what, which involves the root and follicle? | bone | brain | teeth | hair | Hair Growth Hair grows and is eventually shed and replaced by new hair. This occurs in three phases. The first is the anagen phase, during which cells divide rapidly at the root of the hair, pushing the hair shaft up and out. The length of this phase is measured in years, typically from 2 to 7 years. The catagen phase lasts only 2 to 3 weeks, and marks a transition from the hair follicle’s active growth. Finally, during the telogen phase, the hair follicle is at rest and no new growth occurs. At the end of this phase, which lasts about 2 to 4 months, another anagen phase begins. The basal cells in the hair matrix then produce a new hair follicle, which pushes the old hair out as the growth cycle repeats itself. Hair typically grows at the rate of 0.3 mm per day during the anagen phase. On average, 50 hairs are lost and replaced per day. Hair loss occurs if there is more hair shed than what is replaced and can happen due to hormonal or dietary changes. Hair loss can also result from the aging process, or the influence of hormones. |
What is the scientific term for the dropping of leaves, fruits, and flowers, which led to the naming of an acid thought to play a role in the process? | ablation | ascorbition | affixation | abscission | Abscisic acid is misnamed because it was once believed to play a role in abscission (the dropping of leaves, fruits, and flowers), but we now know abscission is caused by ethylene. The actual role of abscisic acid is to close the stomata, the tiny openings in leaves that allow substances to enter and leave, and to maintain dormancy. When a plant is stressed due to lack of water, abscisic acid tells the stomata to close. This prevents water loss through the stomata. |
Sudden changes in geologic and climatic conditions can spur what process? | symbiosis | generation | cloning | evolution | When geologic and climatic conditions are changing, evolution may occur more quickly. Thus, long periods of little change may be interrupted by bursts of rapid change. This model of the timing of evolution is called punctuated equilibrium . It is better supported by the fossil record than is gradualism. This model suggests that niches left open by sudden geologic and climatic changes may be rapidly filled by bursts of evolution. |
What is the fluid that carries sperm through the urethra and out of the body, and provides it with nutrients? | yeast | blood | bacteria | semen | Semen is the fluid that carries sperm through the urethra and out of the body. In addition to sperm, it contains secretions from the glands. The secretions control pH and provide sperm with nutrients for energy. |
In what unit is frequency measured in? | gram | mole | centimeter | hertz | The frequency , , is the number of cycles an object or wave goes through in 1 second. Frequency is measured in Hertz (Hz). 1 Hz = 1 cycle per sec. |
Mixtures of materials called alloys contain at least one of what type of material? | steel | coal | liquid | metal | Alloys are mixtures of materials, at least one of which is a metal. |
The challenge of techniques used for proteomic analyses is the difficulty in detecting small quantities of what? | particles | bacteria | acids | proteins | The challenge of techniques used for proteomic analyses is the difficulty in detecting small quantities of proteins. Although mass spectrometry is good for detecting small amounts of proteins, variations in protein expression in diseased states can be difficult to discern. Proteins are naturally unstable molecules, which makes proteomic analysis much more difficult than genomic analysis. |
What type of gas is delivered to homes to use for cooking and heating? | nuetralized gas | fluid gas | compounded gas | natural gas | Natural gas is delivered to homes, where it is used for cooking and heating. Natural gas is also a major energy source for powering turbines to make electricity. Natural gas releases most of its energy as heat when it burns. The power plant is able to use this heat, either in the form of hot gases or steam, to spin turbines. The spinning turbines turn generators, and the generators create electricity. |
Chewing a bite of bread mixes it with what and facilitates its chemical breakdown? | interstitial fluid | chyme | calcium | saliva | Exergonic c. Decomposition d. Catabolic, exergonic, and decomposition 18. Which of the following combinations of atoms is most likely to result in a chemical reaction? a. hydrogen and hydrogen b. hydrogen and helium c. helium and helium d. neon and helium 19. Chewing a bite of bread mixes it with saliva and facilitates its chemical breakdown. This is most likely due to the fact that ________. the inside of the mouth maintains a very high temperature b. chewing stores potential energy c. chewing facilitates synthesis reactions d. saliva contains enzymes 20. CH4 is methane. This compound is ________. |
What is occurring at an alarming rate as a result of global climate change and the constant melting point of ice? | glacial formation | glacial movement | glacial hardening | glacier melt | Because of global climate change, temperatures all over Earth are rising. However, the melting points of Earth’s substances, including ice, are constant. The result? Glaciers are melting at an alarming rate. Melting glaciers cause rising sea levels and the risk of dangerous river flooding on land. You can learn more about these effects of melting at this URL: http://video. nationalgeographic. com/video/player/environment/global-warming-environment/glacier-melt. html . |
What triggers the fight-or-flight response? | endorphine | respiration | amphetamine | epinephrine | |
What is the term for the force applied to a wheel and axle? | output force | velocity force | momentum | input force | In a wheel and axle, force may be applied either to the wheel or to the axle. This force is called the input force. A wheel and axle does not change the direction of the input force. However, the force put out by the machine, called the output force, is either greater than the input force or else applied over a greater distance. |
Magnetic resonance imaging devices use what to cool the superconducting magnets? | fluorocarbons | antifreeze | dry ice | liquid nitrogen | Magnetic resonance imaging (NMR) devices use liquid nitrogen to cool the superconducting magnets. Nitrogen is a gas at room temperature and liquefies at -195.8°C. Its neighbor on the periodic table (oxygen) boils at -182.95°C. The interactions between nitrogen molecules (N 2 ) are weaker, so the boiling point is lower. Interactions between non-polar molecules depend on the degree of electron fluctuation within the molecule. |
Water moving up the plane and evaporating from the leaves is a process known as what? | evaporation | propagation | sublimation | transpiration | Water also moves through the living organisms in an ecosystem. Plants soak up large amounts of water through their roots. The water then moves up the plant and evaporates from the leaves in a process called transpiration . The process of transpiration, like evaporation, returns water back into the atmosphere. |
How many bones fuse together to form the cranium? | 8 | 6 | 3 | 8 | Fixed joints do not allow any bone movement. Many of the joints in your skull are fixed ( Figure below ). There are eight bones that fuse together to form the cranium. The joints between these bones do not allow movement, which helps protect the brain. |
What is the amount of moisture in the atmosphere? | heat | static | mixture | humidity | |
What heisenberg principle imposes ultimate limits on what is knowable in science? | certainty principle | impossibility principle | vacuum principle | uncertainty principle | The value of ħ is not large, so the uncertainty in the position or momentum of a macroscopic object like a baseball is too insignificant to observe. However, the mass of a microscopic object such as an electron is small enough that the uncertainty can be large and significant. It should be noted that Heisenberg’s uncertainty principle is not just limited to uncertainties in position and momentum, but it also links other dynamical variables. For example, when an atom absorbs a photon and makes a transition from one energy state to another, the uncertainty in the energy and the uncertainty in the time required for the transition are similarly related, as ΔE Δt ≥ ℏ . As will be discussed later, even the vector components of angular 2 momentum cannot all be specified exactly simultaneously. Heisenberg’s principle imposes ultimate limits on what is knowable in science. The uncertainty principle can be shown to be a consequence of wave–particle duality, which lies at the heart of what distinguishes modern quantum theory from classical mechanics. Recall that the equations of motion obtained from classical mechanics are trajectories where, at any given instant in time, both the position and the momentum of a particle can be determined exactly. Heisenberg’s uncertainty principle implies that such a view is untenable in the microscopic domain and that there are fundamental limitations governing the motion of quantum particles. This does not mean that microscopic particles do not move in trajectories, it is just that measurements of trajectories are limited in their precision. In the realm of quantum mechanics, measurements introduce changes into the system that is being observed. |
Narrowing of the arterioles causes an increase of what upstream in the arteries? | red blood cells | white blood cells | heart beat | blood pressure | |
What are double sugars called? | silicates | monosaccharides | sodiums | disaccharides |
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