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An electromagnetic wave begins with what movement by an electrically charged particle? | momentum | acceleration | diffusion | vibration | An electromagnetic wave begins when an electrically charged particle vibrates. This causes a vibrating electric field, which in turn creates a vibrating magnetic field. The two vibrating fields together form an electromagnetic wave. |
What are the sharp projections that specialized cells grow called? | antlers | ossicles | cilia | spicules | Some of the specialized cells grow short, sharp projections called spicules. Spicules make up the sponge’s internal skeleton, or endoskeleton. The endoskeleton helps to support and protect the sponge. |
What is formed when water vapor in the air condenses into tiny droplets? | hail | smoke | rain | fog | Rock bands often use special stage effects, like the fake fog in this picture. Real fog forms when water vapor in the air condenses into tiny droplets of water. The fake fog shown here formed when solid carbon dioxide changed directly to carbon dioxide gas. |
The main components of the circulatory system are the heart, blood vessels, and what else? | brain | lungs | nerves | blood | The circulatory system can be compared to a system of interconnected, one-way roads that range from superhighways to back alleys. Like a network of roads, the job of the circulatory system is to allow the transport of materials from one place to another. As described in Figure below , the materials carried by the circulatory system include hormones, oxygen, cellular wastes, and nutrients from digested food. Transport of all these materials is necessary to maintain homeostasis of the body. The main components of the circulatory system are the heart, blood vessels, and blood. |
From what do tubeworms found deep in the galapagos rift get their energy from? | chemosynthetic viruses | chemosynthetic plants | chemosynthetic fish | chemosynthetic bacteria | Tubeworms deep in the Galapagos Rift get their energy from chemosynthetic bacteria. Tubeworms have no mouth, eyes or stomach. Their survival depends on a symbiotic relationship with the billions of bacteria that live inside them. These bacteria convert the chemicals that shoot out of the hydrothermal vents into food for the worm. |
What is water falling from the sky called? | acid | snow | temperature | precipitation | |
Coal, oil and natural gas are types of what formed from the remains of once living organisms? | crop fuels | living fossils | fossil compounds | fossil fuels | Coal, oil and natural gas are all fossil fuels formed from the remains of once living organisms. |
In a hot water heater, burning fuel causes the water to get hot because combustion is what type of reaction? | biochemical | endothermic | geothermal | exothermic | A: A hot water heater increases the temperature of water in most homes. Many hot water heaters burn a fuel such as natural gas. The burning fuel causes the water to get hot because combustion is an exothermic reaction. |
What is a force that opposes motion? | thrust | tension | momentum | friction | Friction is a force that opposes motion. Any two objects in contact have what is called a mutual coefficient of friction. To find the force of friction between them, we multiply the normal force by this coefficient. Like the forces above, it arises due to electromagnetic interactions of atoms in two objects. There are actually two coefficients of friction: static and kinetic. Static friction will oppose initial motion of two objects relative to each other. Once the objects are moving, however, kinetic friction will oppose their continuing motion. Kinetic friction is lower than static friction, so it is easier to keep an object in motion than to set it in motion. There are some things about friction that are not very intuitive:. |
What is another term for a hand lens? | traversing glass | projecting glass | seeing glass | magnifying glass | An example of a lens is a hand lens, also called a magnifying glass. This type of lens makes objects look bigger than they really are. How do you think this happens?. |
The anterior half of the foot is formed by the five what type of bones? | conidia bones | malignancy bones | conidia bones | metatarsal bones | Metatarsal Bones The anterior half of the foot is formed by the five metatarsal bones, which are located between the tarsal bones of the posterior foot and the phalanges of the toes (see Figure 8.19). These elongated bones are numbered 1–5, starting with the medial side of the foot. The first metatarsal bone is shorter and thicker than the others. The second metatarsal is the longest. The base of the metatarsal bone is the proximal end of each metatarsal bone. These articulate with the cuboid or cuneiform bones. The base of the fifth metatarsal has a large, lateral expansion that provides for muscle attachments. This expanded base of the fifth metatarsal can be felt as a bony bump at the midpoint along the lateral border of the foot. The expanded distal end of each metatarsal is the head of the metatarsal bone. Each metatarsal bone articulates with the proximal phalanx of a toe to form a metatarsophalangeal joint. The heads of the metatarsal bones also rest on the ground and form the ball (anterior end) of the foot. |
What adjective describes the movements that propel the feces during elimination? | hyperplastic | convulsive | enzymatic | peristaltic | The rectum (Figure 16.6) stores feces until defecation. The feces are propelled using peristaltic movements during elimination. The anus is an opening at the far-end of the digestive tract and is the exit point for the waste material. Two sphincters regulate the exit of feces, the inner sphincter is involuntary and the outer sphincter is voluntary. Accessory Organs The organs discussed above are the organs of the digestive tract through which food passes. Accessory organs add secretions and enzymes that break down food into nutrients. Accessory organs include the salivary glands, the liver, the pancreas, and the gall bladder. The secretions of the liver, pancreas, and gallbladder are regulated by hormones in response to food consumption. The liver is the largest internal organ in humans and it plays an important role in digestion of fats and detoxifying blood. The liver produces bile, a digestive juice that is required for the breakdown of fats in the duodenum. The liver also processes the absorbed vitamins and fatty acids and synthesizes many plasma proteins. The gallbladder is a small organ that aids the liver by storing bile and concentrating bile salts. The pancreas secretes bicarbonate that neutralizes the acidic chyme and a variety of enzymes for the digestion of protein and carbohydrates. |
What is transferred in an acid-base reaction | calcium ion | bonding ion | friendly ion | hydrogen ion | Acid-base reactions involve a transfer of a hydrogen ion instead of an electron. Acid-base reactions, like the one below, are also not redox reactions. |
What is the largest planet in our solar system? | earth | uranus | mars | jupiter | Jupiter is the largest planet in our solar system. Jupiter is named for the king of the gods in Roman mythology. The Romans named the largest planet for their most important god. They followed the tradition of the Greeks, who had similarly named the planet Zeus. The Romans built a temple to Jupiter on the hill. |
What does the ubiquitous generator use to generate currents? | gravity | inertia | water | magnetism | The hint of symmetry between electricity and magnetism found in the preceding chapter will be elaborated upon in this chapter. Specifically, we know that a current creates a magnetic field. If nature is symmetric here, then perhaps a magnetic field can create a current. The Hall effect is a voltage caused by a magnetic force. That voltage could drive a current. Historically, it was very shortly after Oersted discovered currents cause magnetic fields that other scientists asked the following question: Can magnetic fields cause currents? The answer was soon found by experiment to be yes. In 1831, some 12 years after Oersted’s discovery, the English scientist Michael Faraday (1791–1862) and the American scientist Joseph Henry (1797–1878) independently demonstrated that magnetic fields can produce currents. The basic process of generating emfs (electromotive force) and, hence, currents with magnetic fields is known as induction; this process is also called magnetic induction to distinguish it from charging by induction, which utilizes the Coulomb force. Today, currents induced by magnetic fields are essential to our technological society. The ubiquitous generator—found in automobiles, on bicycles, in nuclear power plants, and so on—uses magnetism to generate current. Other devices that use magnetism to induce currents include pickup coils in electric guitars, transformers of every size, certain microphones, airport security gates, and damping mechanisms on sensitive chemical balances. Not so familiar perhaps, but important nevertheless, is that the behavior of AC circuits depends strongly on the effect of magnetic fields on currents. |
What prevents soil erosion on a hillside that is being farmed? | no-till farming | slash-and-burn | irrigation | terracing | Although the hillside is interesting, that's not why this was done. Terracing prevents soil erosion on a hillside that is being farmed. Many techniques can be utilized to reduce soil erosion. |
What do the external female reproductive structures are collectively referred to? | endometrium | cervix | Clitoris | vulva | The external female reproductive structures are referred to collectively as the vulva . They include the labia (singular, labium ), which are the “lips” of the vulva. The labia protect the vagina and urethra, both of which have openings in the vulva. |
What is another name for collar cells? | clutches | enzymes | sporozoans | choanocytes | Morphology of Sponges The morphology of the simplest sponges takes the shape of a cylinder with a large central cavity, the spongocoel, occupying the inside of the cylinder. Water can enter into the spongocoel from numerous pores in the body wall. Water entering the spongocoel is extruded via a large common opening called the osculum. However, sponges exhibit a range of diversity in body forms, including variations in the size of the spongocoel, the number of osculi, and where the cells that filter food from the water are located. While sponges (excluding the hexactinellids) do not exhibit tissue-layer organization, they do have different cell types that perform distinct functions. Pinacocytes, which are epithelial-like cells, form the outermost layer of sponges and enclose a jelly-like substance called mesohyl. Mesohyl is an extracellular matrix consisting of a collagen-like gel with suspended cells that perform various functions. The gel-like consistency of mesohyl acts like an endoskeleton and maintains the tubular morphology of sponges. In addition to the osculum, sponges have multiple pores called ostia on their bodies that allow water to enter the sponge. In some sponges, ostia are formed by porocytes, single tube-shaped cells that act as valves to regulate the flow of water into the spongocoel. In other sponges, ostia are formed by folds in the body wall of the sponge. Choanocytes (“collar cells”) are present at various locations, depending on the type of sponge, but they always line the inner portions of some space through which water flows (the spongocoel in simple sponges, canals within the body wall in more complex sponges, and chambers scattered throughout the body in the most complex sponges). Whereas pinacocytes line the outside of the sponge, choanocytes tend to line certain inner portions of the sponge body that surround the mesohyl. The structure of a choanocyte is critical to its function, which is to generate a water current through the sponge and to trap and ingest food particles by phagocytosis. Note the similarity in appearance between the sponge choanocyte and choanoflagellates (Protista). This similarity suggests that sponges and choanoflagellates are closely related and likely share a recent common ancestry. The cell body is embedded in mesohyl and contains all organelles required for normal cell function, but protruding into the “open space” inside of the sponge is a mesh-like collar composed of microvilli with a single flagellum in the center of the column. The cumulative effect of the flagella from all choanocytes aids the movement of water through the sponge: drawing water into the sponge through the numerous ostia, into the spaces lined by choanocytes, and eventually out through the osculum (or osculi). In the meantime, food particles, including waterborne bacteria and algae, are trapped by the sieve-like collar of the choanocytes, slide down into the body of the cell, are ingested by phagocytosis, and become encased in a food vacuole. Lastly, choanocytes will differentiate into sperm for sexual reproduction, where they will become dislodged from the mesohyl and leave the sponge with expelled water through the osculum. |
What involuntary muscle is found only in the heart? | digestive muscle | physiological muscle | respiratory muscle | cardiac muscle | Cardiac muscle is also an involuntary muscle, found only in the heart. The cardiac muscle fibers all contract together, generating enough force to push blood throughout the body. What would happen if this muscle was under conscious or voluntary control?. |
Most sedimentary rocks form from what? | erosion | volcanic activity | glaciers | sediments | Most sedimentary rocks form from sediments. The sediments must be packed together to form a rock. Sedimentary rocks also form as minerals precipitate from saline water. Sedimentary rock formation is described in the next concept. |
What system serves as the relay between the cns and the internal organs? | limbic nervous system | cellular nervous system | central nervous system | autonomic nervous system | The autonomic nervous system serves as the relay between the CNS and the internal organs. It controls the lungs, the heart, smooth muscle, and exocrine and endocrine glands. The autonomic nervous system controls these organs largely without conscious control; it can continuously monitor the conditions of these different systems and implement changes as needed. Signaling to the target tissue usually involves two synapses: a preganglionic neuron (originating in the CNS) synapses to a neuron in a ganglion that, in turn, synapses on the target organ, as illustrated in Figure 35.26. There are two divisions of the autonomic nervous system that often have opposing effects: the sympathetic nervous system and the parasympathetic nervous system. Sympathetic Nervous System The sympathetic nervous system is responsible for the “fight or flight” response that occurs when an animal encounters a dangerous situation. One way to remember this is to think of the surprise a person feels when encountering a snake (“snake” and “sympathetic” both begin with “s”). Examples of functions controlled by the sympathetic nervous system include an accelerated heart rate and inhibited digestion. These functions help prepare an organism’s body for the physical strain required to escape a potentially dangerous situation or to fend off a predator. |
When pumping blood, the hearts of animals with very long necks must overcome what force? | friction | erosion | evolution | gravity | |
The seasonal movements of animals from one area to another is referred to as? | echolocation | mitigation | hybernation | migration | Migration refers to seasonal movements of animals from one area to another. Migrants typically travel long distances, and travel the same paths each seasonal cycle. Usually, the migrants move to another area in order to find food or mates. Many birds, fish, and insects migrate. Mammals such as whales and caribou migrate as well. Figure below shows the migration route of a bird called a godwit. Another example of a behavior with a yearly cycle is hibernation. Hibernation is a state in which an animal’s body processes are slower than usual, and its body temperature falls. An animal uses less energy than usual during hibernation. This helps the animal survive during a time of year when food is scarce. Hibernation may last for weeks or months. Animals that hibernate include species of bats, squirrels, and snakes. Most people think that bears hibernate. In fact, bears do not go into true hibernation. In the winter, they go into a deep sleep. However, their body processes do not slow down very much. Their body temperature also remains about the same as usual. Bears can be awakened easily from their winter sleep. |
Falling onto what joint can fracture the distal humerus? | Foot | thumb | knee | elbow | Figure 8.11 Fractures of the Humerus and Radius Falls or direct blows can result in fractures of the surgical neck or shaft of the humerus. Falls onto the elbow can fracture the distal humerus. A Colles fracture of the distal radius is the most common forearm fracture. |
What term is used to describe the energy reserve carbohydrate of animals? | sucrose | lactose | fructose | glycogen | Glycogen Glycogen is the energy reserve carbohydrate of animals. Practically all mammalian cells contain some stored carbohydrates in the form of glycogen, but it is especially abundant in the liver (4%–8% by weight of tissue) and in skeletal muscle cells (0.5%–1.0%). Like starch in plants, glycogen is found as granules in liver and muscle cells. When fasting, Saylor URL: http://www. saylor. org/books. |
What is used to measure current through a resistor? | microscopes | thermometers | spectrographs | ammeters | Ammeters measure the current through a resistor. |
When struck, how are the rigid crystals of ionic compounds likely to react? | grow | shrink | bend | break | The rigid crystals of ionic compounds are brittle. They are more likely to break than bend when struck. As a result, ionic crystals tend to shatter easily. Try striking salt crystals with a hammer and you’ll find that they readily break into smaller pieces. You can learn more about the properties of ionic compounds by watching the video at this URL:. |
What type of matter transmits light without scattering it? | reflective | opaque | smooth | transparent | Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. You can see clearly through transparent objects, such as the top panes of the window below , because just about all of the light that strikes them passes through to the other side. |
What is the term for the unconscious movements controlled by the somatic nervous system? | tremors | senses | mechanisms | reflexes | The somatic nervous system also controls some unconscious movements, called reflexes. A reflex is a very rapid motor response that is not directed by the brain. In a reflex, nerve impulses travel to and from the spinal cord in a reflex arc , like the one in Figure below . In this example, the person jerks his hand away from the flame without any conscious thought. It happens unconsciously because the nerve impulses bypass the brain. |
What organism captures light energy and converts it to chemical energy inside its cell? | insects | autotrophs | plants | phototrophs | Because glaciers move, they have characteristic features like crevasses and bergshrunds. |
By applying salt to an icy road, the melting point of the ice is what? | increased | concentrated | compounded | decreased | Colligative properties have practical applications, such as the salting of roads in cold-weather climates. By applying salt to an icy road, the melting point of the ice is decreased, and the ice will melt more quickly, making driving safer. Sodium chloride (NaCl) and either calcium chloride (CaCl 2 ) or magnesium chloride (MgCl 2 ) are used most frequently, either alone or in a mixture. Sodium chloride is the least expensive option, but is less effective because it only dissociates into two ions instead of three. |
How many pairs of chromosomes do human have ? | 19 pairs | 12 pairs | 31 pairs | 23 pairs | Human Genome, Chromosomes, and Genes. Each chromosome of the human genome contains many genes as well as noncoding intergenic (between genes) regions. Each pair of chromosomes is shown here in a different color. Notice that there are 23 pairs of chromosomes. |
Where do polychaetes live? | lakes | the tundra | great plains | ocean floor | Polychaetes live on the ocean floor. They may be sedentary filter feeders, active predators, or scavengers. Active species crawl along the ocean floor in search of food. |
What term describes a gene or sequence on a chromosome that co-segregates (shows genetic linkage) with a specific trait? | autosomal | nucleic acid chain | analogous effect | genetic marker | 17.2 | Mapping Genomes By the end of this section, you will be able to: • Define genomics • Describe genetic and physical maps • Describe genomic mapping methods Genomics is the study of entire genomes, including the complete set of genes, their nucleotide sequence and organization, and their interactions within a species and with other species. Genome mapping is the process of finding the locations of genes on each chromosome. The maps created by genome mapping are comparable to the maps that we use to navigate streets. A genetic map is an illustration that lists genes and their location on a chromosome. Genetic maps provide the big picture (similar to a map of interstate highways) and use genetic markers (similar to landmarks). A genetic marker is a gene or sequence on a chromosome that co-segregates (shows genetic linkage) with a specific trait. Early geneticists called this linkage analysis. Physical maps present the intimate details of smaller regions of the chromosomes (similar to a detailed road map). A physical map is a representation of the physical distance, in nucleotides, between genes or genetic markers. Both genetic linkage maps and physical maps are required to build a complete picture of the genome. Having a complete map of the genome makes it easier for researchers to study individual genes. Human genome maps help researchers in their efforts to identify human disease-causing genes related to illnesses like cancer, heart disease, and cystic fibrosis. Genome mapping can be used in a variety of other applications, such as using live microbes to clean up pollutants or even prevent pollution. Research involving plant genome mapping may lead to producing higher crop yields or developing plants that better adapt to climate change. |
What type of blood vessels carry blood away from the heart? | Viens | Heart | tubes | arteries | Arteries are muscular blood vessels that carry blood away from the heart. They have thick walls that can withstand the pressure of blood being pumped by the heart. Arteries generally carry oxygen-rich blood. The largest artery is the aorta, which receives blood directly from the heart. |
How many millions of years ago did pangaea begin breaking apart? | 500 | 600 | 400 | 250 | Pangaea has been breaking apart since about 250 million years ago. Divergent plate boundaries formed within the continents to cause them to rift apart. The continents are still moving apart. The Pacific is shrinking as the Atlantic is growing. The Appalachians ( Figure below ) are now on a passive margin. The mighty mountains have weathered and eroded to what they are today. |
Continental drift also promotes what speciation? | macroevolution | obligate | mutualistic | allopatric | |
Which kind of mutations have the most dramatic effect on proteins? | cancerous mutations | arbitrary mutations | sight mutations | nonsense mutations | These mutations may result in a protein with the same function, with altered function, or with no function. Silent mutations , as they code for the same amino acid, will have no altered effect on the protein. Missense mutations may have a minor effect or a dramatic effect on the protein. Nonsense mutations usually have the most dramatic effet. Depending on the position of the premature stop codon, nonsense mutations may result in an unstable mRNA that cannot be translated, or in a truncated mRNA and a much "smaller" protein without any significant activity. |
When skunks are in danger what do they give off? | sweet odor | warning howls | ejected quills | foul smell | |
What kind of reproduction produces genetically identical organisms or clones? | Sexual | Prophase I | Meiosis | asexual | Introduction Animal reproduction is necessary for the survival of a species. In the animal kingdom, there are innumerable ways that species reproduce. Asexual reproduction produces genetically identical organisms (clones), whereas in sexual reproduction, the genetic material of two individuals combines to produce offspring that are genetically different from their parents. During sexual reproduction the male gamete (sperm) may be placed inside the female’s body for internal fertilization, or the sperm and eggs may be released into the environment for external fertilization. Seahorses, like the one shown in Figure. |
Oceans help control global warming by absorbing what? | methane | hydrogen | ozone | carbon dioxide | Ocean water also absorbs gases from the atmosphere. The most important are oxygen and carbon dioxide. Oxygen is needed by living things in the oceans. Much of the carbon dioxide sinks to the bottom of the seas. Carbon dioxide is a major cause of global warming. By absorbing carbon dioxide, the oceans help control global warming. At least as long as the carbon dioxide stays in the seas. |
A phase diagram plots temperature and what else? | movement | friction | power | pressure | Both temperature and pressure have an effect on the phase in which a given substance exists. A plot of temperature vs. pressure that indicates the states of matter present at each point is known as a phase diagram . Figure below shows the phase diagram for water. |
What kind of hormones are derived from cholesterol? | synthesis | germs | Antibiotic | steroid | 17.2 Hormones Hormones are derived from amino acids or lipids. Amine hormones originate from the amino acids tryptophan or tyrosine. Larger amino acid hormones include peptides and protein hormones. Steroid hormones are derived from cholesterol. Steroid hormones and thyroid hormone are lipid soluble. All other amino acid–derived hormones are water soluble. Hydrophobic hormones are able to diffuse through the membrane and interact with an intracellular receptor. In contrast, hydrophilic hormones must interact with cell membrane receptors. These are typically associated with a G protein, which becomes activated when the hormone binds the receptor. This initiates a signaling cascade that involves a second messenger, such as cyclic adenosine monophosphate (cAMP). Second messenger systems greatly amplify the hormone signal, creating a broader, more efficient, and faster response. Hormones are released upon stimulation that is of either chemical or neural origin. Regulation of hormone release is primarily achieved through negative feedback. Various stimuli may cause the release of hormones, but there are three major types. Humoral stimuli are changes in ion or nutrient levels in the blood. Hormonal stimuli are changes in hormone levels that initiate or inhibit the secretion of another hormone. Finally, a neural stimulus occurs when a nerve impulse prompts the secretion or inhibition of a hormone. |
Eukaryotic cell division involves mitosis and what? | spermatogenesis | meiosis | electrolysis | cytokinesis | Eukaryotic cell division involves mitosis and cytokinesis. |
Why do sodium and chloride ions attract each other? | like attracts like | sulfides attract | magnetism | opposites attract | Sodium and chloride ions have equal but opposite charges. Opposites attract, so sodium and chloride ions attract each other. They cling together in a strong ionic bond. You can see this in row 2 of Figure above . Brackets separate the ions in the diagram to show that the ions in the compound do not share electrons. You can see animations of sodium chloride forming at these URLs:. |
What layer of soil, essential for farming, has the highest proportion of organic material? | subsoil | bedrock | humus | topsoil | Topsoil has the highest proportion of organic material. Topsoil is essential for farming. |
What are the organized instructions within dna for making proteins called? | replicants | clones | genomes | genes | The DNA of a chromosome is encoded with genetic instructions for making proteins. These instructions are organized into units called genes . Most genes contain the instructions for a single protein. There may be hundreds or even thousands of genes on a single chromosome. |
Macrophages, which can swallow and destroy old and dying cells, bacteria, or viruses, are large types of what cells? | dendritic cells | red blood cells | white brain cells | white blood cells | Macrophages are large WBCs that can also swallow and destroy old and dying cells, bacteria, or viruses. Below, a macrophage is attacking and swallowing two particles, possibly disease-causing pathogens ( Figure below ). Macrophages also release chemical messages that cause the number of WBCs to increase. |
What is the distance between the nuclei of two identical atoms bonded together called? | sleep radius | cycle radius | bond radius | atomic radius | Atomic radius is determined as the distance between the nuclei of two identical atoms bonded together. |
What is the term for water that contains one or more dissolved substances? | evaporation solution | dilute solution | sediment solution | aqueous solution | We want to focus on solutions where the solvent is water. An aqueous solution is water that contains one or more dissolved substances. The dissolved substances in an aqueous solution may be solids, gases, or other liquids. Some examples are listed in the Table above . Other examples include vinegar (acetic acid in water), alcoholic beverages (ethanol in water), and liquid cough medicines (various drugs in water). |
Gall bladder removal surgery does not seriously affect digestion because ______ is still being produced. | plasma | saliva | blood | bile | Note Surgical removal is often advised for a gallbladder that becomes infected, inflamed, or perforated. This surgery does not seriously affect digestion because bile is still produced. |
The hepatitis virus attacks only cells of what organ? | brain | lungs | kidney | liver | How Viruses Infect Specific Organs Specific glycoprotein molecules exposed on the surface of the cell membranes of host cells are exploited by many viruses to infect specific organs. For example, HIV is able to penetrate the plasma membranes of specific kinds of white blood cells called T-helper cells and monocytes, as well as some cells of the central nervous system. The hepatitis virus attacks only liver cells. These viruses are able to invade these cells, because the cells have binding sites on their surfaces that the viruses have exploited with equally specific glycoproteins in their coats. (Figure 3.19). The cell is tricked by the mimicry of the virus coat molecules, and the virus is able to enter the cell. Other recognition sites on the virus’s surface interact with the human immune system, prompting the body to produce antibodies. Antibodies are made in response to the antigens (or proteins associated with invasive pathogens). These same sites serve as places for antibodies to attach, and either destroy or inhibit the activity of the virus. Unfortunately, these sites on HIV are encoded by genes that change quickly, making the production of an effective vaccine against the virus very difficult. The virus population within an infected individual quickly evolves through mutation into different populations, or variants, distinguished by differences in these recognition sites. This rapid change of viral surface markers decreases the effectiveness of the person’s immune system in attacking the virus, because the antibodies will not recognize the new variations of the surface patterns. |
A rusty bike has been left outside in damp weather too many times, so the iron in the metal parts have? | decayed | melted | eroded | rusted | Look at this rusty bike. It has been left outside in damp weather too many times, so the iron in the metal parts has rusted. Iron rusts when it combines with oxygen in the air. Iron rusting is an example of a chemical reaction. In a chemical reaction, substances change into entirely different substances. For example, the iron in the bike and the oxygen in the air have changed into rust. |
What two layers is the skin made of? | Blood and dermis | respiration and dermis | layers and dermis | epidermis and dermis | Skin is made up of two layers, the epidermis on top and the dermis below. The tissue below the dermis is called the hypodermis, but it is not part of the skin. |
What are the three major types of blood vessels? | sculptures , veins , capillaries | arteries , pups , capillaries | arteries, capilaries, tubes | arteries, veins, capillaries | Blood vessels form a network throughout the body to transport blood to all the body cells. There are three major types of blood vessels: arteries, veins, and capillaries. All three are shown in Figure below and described below. |
What is the name of the protective layer of gases that surrounds the earth and blocks harmful rays from the sun? | the coma | the corona | the protector | the atmosphere | The atmosphere protects living things from the Sun’s most harmful rays. Gases reflect or absorb the strongest rays of sunlight. Figure below models this role of the atmosphere. |
What are colonies of cells stuck to a surface called? | membranes | membranes | cellular coating | biofilms | Prokaryotic cells are extremely small and have a variety of shapes. Most have flagella and a cell wall. They have several other cell structures as well. Their DNA exists as large and small loops. Some prokaryotes form biofilms, which are colonies of cells stuck to a surface. |
Trichomoniasis is cause by what type of pathogen? | worm | virus | bacteria | protozoa | STIs may be caused by several different types of pathogens, including protozoa, insects, bacteria, and viruses. For example: Protozoa cause an STI called trichomoniasis. The pathogen infects the vagina in females and the urethra in males, causing symptoms such as burning and itching. Trichomoniasis is common in young people. Pubic lice, like the one in Figure below , are insect parasites that are transmitted sexually. They suck the blood of their host and irritate the skin in the pubic area. |
An increase in what, across the periodic table, explains why elements go from metals to metalloids and then to nonmetals? | protons | neutrons | temperature | electrons | The increase in electrons across the periodic table explains why elements go from metals to metalloids and then to nonmetals from left to right across the table. Look at period 2 in Figure below as an example. Lithium (Li) is a metal, boron (B) a metalloid, and fluorine (F) and neon (Ne) are nonmetals. The inner energy level is full for all four elements. This level has just one orbital and can hold a maximum of two electrons. The outer energy level is a different story. This level has four orbitals and can hold a maximum of eight electrons. Lithium has just one electron in this level, boron has three, fluorine has seven, and neon has eight. |
How many pairs of chromosomes are in the human genome? | 13 | 21 | 24 | 23 | The human genome has 23 pairs of chromosomes located in the nucleus of somatic cells. Each chromosome is composed of genes and other DNA wound around histones (proteins) into a tightly coiled molecule. |
What measure is resorted to by people who wish to screen out genetic abnormalities in the fetus? | stem cell therapy | contraceptive use | in vitro fertilization | prenatal testing | A genetic disorder that is caused by a mutation can be inherited. Therefore, people with a genetic disorder in their family may be concerned about having children with the disorder. Professionals known as genetic counselors can help them understand the risks of their children being affected. If they decide to have children, they may be advised to have prenatal (“before birth”) testing to see if the fetus has any genetic abnormalities. One method of prenatal testing is amniocentesis . In this procedure, a few fetal cells are extracted from the fluid surrounding the fetus, and the fetal chromosomes are examined. |
Who built the first telescope? | copernicus | newton | brahe | galileo | Humans have been making and using magnifying lenses for thousands of years. The first telescope was built by Galileo in 1608. His telescope used two lenses to make distant objects appear both nearer and larger. |
Water can be boiled to kill giardia and most other what? | germs | parasites | bacteria | pathogens | Different pathogens spread in different ways. Some pathogens spread through food. They cause food borne illnesses, which are discussed in a previous concept. Some pathogens spread through water. Giardia lamblia is one example. Water can be boiled to kill Giardia and most other pathogens. |
What do you call mixtures of ash and water that travel down river valleys? | mud slides | debris | pollutants | lahars | Lahars are mixtures of ash and water that travel down river valleys. On Mount St. Helens, the eruption melted glaciers. The water mixed with ash from the eruption and created tremendous lahars. The lahars raced down valleys and knocked out many bridges. |
Why do homonuclear diatomic molecules have zero dipole moment? | at homeostasis | no electrical attraction | no activation energy | no difference in electronegativity | A whole molecule may also have a separation of charge, depending on its molecular structure and the polarity of each of its bonds. If such a charge separation exists, the molecule is said to be a polar molecule (or dipole); otherwise the molecule is said to be nonpolar. The dipole moment measures the extent of net charge separation in the molecule as a whole. We determine the dipole moment by adding the bond moments in three-dimensional space, taking into account the molecular structure. For diatomic molecules, there is only one bond, so its bond dipole moment determines the molecular polarity. Homonuclear diatomic molecules such as Br2 and N2 have no difference in electronegativity, so their dipole moment is zero. For heteronuclear molecules such as CO, there is a small dipole moment. For HF, there is a larger dipole moment because there is a larger difference in electronegativity. When a molecule contains more than one bond, the geometry must be taken into account. If the bonds in a molecule are arranged such that their bond moments cancel (vector sum equals zero), then the molecule is nonpolar. This is the situation in CO2 (Figure 7.27). Each of the bonds is polar, but the molecule as a whole is nonpolar. From the Lewis structure, and using VSEPR theory, we determine that the CO2 molecule is linear with polar C=O bonds on opposite sides of the carbon atom. The bond moments cancel because they are pointed in opposite directions. In the case of the water molecule (Figure 7.27), the Lewis structure again shows that there are two bonds to a central atom, and the electronegativity difference again shows that each of these bonds has a nonzero bond moment. In this case, however,. |
The types of white blood cells that arrive at an inflamed site depend on the nature of what? | blood type | genes | skin color | injury or infection | capillaries cause swelling of the area, which in turn causes pain. Various kinds of white blood cells are attracted to the area of inflammation. The types of white blood cells that arrive at an inflamed site depend on the nature of the injury or infecting pathogen. For example, a neutrophil is an early arriving white blood cell that engulfs and digests pathogens. Neutrophils are the most abundant white blood cells of the immune system (Figure 17.9). Macrophages follow neutrophils and take over the phagocytosis function and are involved in the resolution of an inflamed site, cleaning up cell debris and pathogens. |
In what season are temperature inversions more common? | summer | spring | autumn | winter | Sometimes air doesn’t mix in the troposphere. This happens when air is cooler close to the ground than it is above. The cool air is dense, so it stays near the ground. This is called a temperature inversion ( Figure below ). An inversion can trap air pollution near the surface. Temperature inversions are more common in the winter. Can you explain why?. |
Are thunderstorms more likely where the ground temperatures are extremely high or extremely low? | extremely low | somewhat low | somewhat high | extremely high | Thunderstorms grow where ground temperatures are extremely high. |
What type of diseases in humans are caused by protozoa? | diarrhea | protozoa diseases | dysentery | protist diseases | Scientists are searching for ways to create controlled nuclear fusion reactions in order to produce safe nuclear power. Fusion involves only harmless, plentiful elements but requires extremely high temperatures. |
Shark teeth likely evolved from the jagged scales that cover their skin, called what? | pinworm scales | heterotroph scales | hook scales | placoid scales | Chondrichthyes: Cartilaginous Fishes The clade Chondrichthyes is diverse, consisting of sharks (Figure 29.11), rays, and skates, together with sawfishes and a few dozen species of fishes called chimaeras, or “ghost” sharks. ” Chondrichthyes are jawed fishes that possess paired fins and a skeleton made of cartilage. This clade arose approximately 370 million years ago in the early or middle Devonian. They are thought to be descended from the placoderms, which had skeletons made of bone; thus, the cartilaginous skeleton of Chondrichthyes is a later development. Parts of shark skeleton are strengthened by granules of calcium carbonate, but this is not the same as bone. Most cartilaginous fishes live in marine habitats, with a few species living in fresh water for a part or all of their lives. Most sharks are carnivores that feed on live prey, either swallowing it whole or using their jaws and teeth to tear it into smaller pieces. Shark teeth likely evolved from the jagged scales that cover their skin, called placoid scales. Some species of sharks and rays are suspension feeders that feed on plankton. |
In the human ear, sound waves cause the stapes to press against what? | Idea Window | yellow window | shaped window | oval window | Figure 36.14 In the human ear, sound waves cause the stapes to press against the oval window. Vibrations travel up the fluid-filled interior of the cochlea. The basilar membrane that lines the cochlea gets continuously thinner toward the apex of the cochlea. Different thicknesses of membrane vibrate in response to different frequencies of sound. Sound waves then exit through the round window. In the cross section of the cochlea (top right figure), note that in addition to the upper canal and lower canal, the cochlea also has a middle canal. The organ of Corti (bottom image) is the site of sound transduction. Movement of stereocilia on hair cells results in an action potential that travels along the auditory nerve. |
What is the term for proportion of amount of product actually produced in a chemical reaction versus predicted amount ? | percent impact | calculus yield | decrease yield | percent yield | Chemical reactions in the real world don’t always go exactly as planned on paper. In the course of an experiment, many things will contribute to the formation of less product than would be predicted. Besides spills and other experimental errors, there are usually losses due to an incomplete reaction, undesirable side reactions, etc. Chemists need a measurement that indicates how successful a reaction has been. This measurement is called the percent yield. |
What creates wet and dry zones at different latitudes? | horse latitudes | jet stream | trade winds | global air currents | Temperature falls from the equator to the poles. Global air currents create wet and dry zones at different latitudes. They also create global winds. |
What term is used to describe the total spread of values in a sample? | scale | variety | axis | range | Many samples have a lot of variation in measurements. Variation can be described with a statistic called the range. The range is the total spread of values in a sample. It is calculated by subtracting the smallest value from the largest value. |
Fermentation—of grains to produce beer, and of fruits to produce wine—is an ancient art that humans in most cultures have practiced for how long? | decades | years | eons | millennia | Fermentation—of grains to produce beer, and of fruits to produce wine—is an ancient art that humans in most cultures have practiced for millennia. Wild yeasts are acquired from the environment and used to ferment sugars into CO2 and ethyl alcohol under anaerobic conditions. It is now possible to purchase isolated strains of wild yeasts from different wine-making regions. Louis Pasteur was instrumental in developing a reliable strain of brewer’s yeast, Saccharomyces cerevisiae, for the French brewing industry in the late 1850s. This was one of the first examples of biotechnology patenting. Many secondary metabolites of fungi are of great commercial importance. Antibiotics are naturally produced by fungi to kill or inhibit the growth of bacteria, limiting their competition in the natural environment. Important antibiotics, such as penicillin and the cephalosporins, are isolated from fungi. Valuable drugs isolated from fungi include the immunosuppressant drug cyclosporine (which reduces the risk of rejection after organ transplant), the precursors of steroid hormones, and ergot alkaloids used to stop bleeding. Psilocybin is a compound found in fungi such as Psilocybe semilanceata and Gymnopilus junonius, which have been used for their hallucinogenic properties by various cultures for thousands of years. As simple eukaryotic organisms, fungi are important model research organisms. Many advances in modern genetics were achieved by the use of the red bread mold Neurospora crassa. Additionally, many important genes originally discovered in S. cerevisiae served as a starting point in discovering analogous human genes. As a eukaryotic organism, the yeast cell produces and modifies proteins in a manner similar to human cells, as opposed to the bacterium Escherichia coli, which lacks the internal membrane structures and enzymes to tag proteins for export. This makes yeast a much better organism for use in recombinant DNA technology experiments. Like bacteria, yeasts grow easily in culture, have a short generation time, and are amenable to genetic modification. |
In which direction does water travel? | uphill | backwards | northwest | downhill | After a heavy rain, you may find puddles of water standing in low spots. The same principle explains why water collects in ponds and lakes. Water travels downhill, so a depression in the ground fills with standing water. A pond is a small body of standing water. A lake is a large body of standing water. Most lakes have freshwater, but a few are salty. The Great Salt Lake in Utah is an example of a saltwater lake. |
The largest population size that can be supported in an area without harming the environment is referred to as what? | population density | population shift | containing capacity | carrying capacity | At what population size does growth start to slow in the logistic model of growth? That depends on the population’s carrying capacity (see Figure above ). The carrying capacity (K) is the largest population size that can be supported in an area without harming the environment. Population growth hits a ceiling at that size in the logistic growth model. |
What are the smallest particles of elements that maintain their unique properties? | electrons | protons | molecules | atoms | A: The discovery of particles smaller than atoms doesn’t mean that we should scrap the entire theory. Atoms are still known to be the smallest particles of elements that have the properties of the elements. Also, it is atoms—not particles of atoms—that combine in fixed proportions in compounds. Instead of throwing out Dalton’s theory, scientists have refined and expanded on it. |
Where does the christmas tree worm live? | rainforests | northeast coral reefs | Atlantic shoreline | tropical coral reefs | It is actually the Yellow Christmas tree worm. These animals are colorful, and can be red, orange, yellow, blue, and white. The Christmas tree worm lives on tropical coral reefs throughout the world. The Christmas tree worm's plumes are used for feeding and respiration. These worms use their plumes to catch plankton and other small particles passing in the water. Cilia then pass the food to the worm's mouth. |
What are biomes that occur where a river, a source of fresh water, meets the ocean called? | rapids | waterways | sediments | estuaries | Estuaries: Where the Ocean Meets Fresh Water Estuaries are biomes that occur where a river, a source of fresh water, meets the ocean. Therefore, both fresh water and salt water are found in the same vicinity; mixing results in a diluted (brackish) salt water. Estuaries form protected areas where many of the offspring of crustaceans, mollusks, and fish begin their lives. Salinity is an important factor that influences the organisms and the adaptations of the organisms found in estuaries. The salinity of estuaries varies and is based on the rate of flow of its freshwater sources. Once or twice a day, high tides bring salt water into the estuary. Low tides occurring at the same frequency reverse the current of salt water (Figure 20.30). |
What continuously monitors and repairs its genetic material? | proteins | ova | nucleolus | cells | |
What are the large segments of the earth’s crust that ordinarily move very slowly? | distinct plates | ocean plates | lava plates | tectonic plates | Tectonic plates are large segments of the Earth’s crust that move slowly. Suppose that one such plate has an average speed of 4.0 cm/year. (a) What distance does it move in 1 s at this speed? (b) What is its speed in kilometers per million years? 10. (a) Refer to Table 1.3 to determine the average distance between the Earth and the Sun. Then calculate the average speed of the Earth in its orbit in kilometers per second. (b) What is this in meters per second?. |
Which process causes rocks at the earth's surface to change form? | eroding | bleaching | remodeling | weathering | Weathering changes solid rock into sediments. Sediments are different sizes of rock particles. Boulders are sediments; so is gravel. At the other end, silt and clay are also sediments. Weathering causes rocks at the Earth’s surface to change form. The new minerals that form are stable at the Earth’s surface. |
Chemical reactions always involve energy. when methane burns, for example, it releases energy in the form of what? | heat and movement | movement and light | light and sound | heat and light | Chemical reactions always involve energy. When methane burns, for example, it releases energy in the form of heat and light. Other chemical reactions absorb energy rather than release it. |
Alzheimers disease is associated with memory loss in what group of people? | immigrants | juveniles | prehistoric | elderly | One useful application of PET scanning is in the diagnosis of Alzheimer’s disease. This debilitating condition associated with memory loss primarily occurs in elderly individuals. A protein known as beta-amyloid gradually forms deposits, or plaques, in the brain. Severe memory loss and impaired movement appear to be direct results of the plaque growth. |
What global cycle takes place on, above, and below earth’s surface? | water wheel | aqua cycle | water flow | water cycle | Water on Earth is billions of years old. However, individual water molecules keep moving through the water cycle. The water cycle is a global cycle. It takes place on, above, and below Earth’s surface, as shown in Figure below . |
Why are two different minerals considered different though they have the same chemical composition? | different rods structures | different linear structures | different molecular structures | different crystal structures | Sometimes two different minerals have the same chemical composition. But they are different minerals because they have different crystal structures. Diamonds are very valuable as gemstones because they are very pretty and very hard. Graphite is the “lead” in pencils. It's not hard at all! Amazingly, both are made just of carbon. Compare the diamond with the pencil lead ( Figure below ). Why are they so different? The carbon atoms in graphite bond to form layers. The bonds between each layer are weak. The carbon sheets can just slip past each other. The carbon atoms in diamonds bond together in all three directions. This strong network makes diamonds very hard. |
What type of mapping is critical for identifying the location of genes that cause genetic diseases? | chemical mapping | interaction mapping | diagnostic mapping | linkage mapping | Determining recombination frequencies between genes located on the same chromosome allows a linkage map to be developed. Linkage mapping is critical for identifying the location of genes that cause genetic diseases. |
When menstrual periods become less frequent and finally cease; this is called? | metabolic | climax | hormonal imbalance | menopause | Which of the following statements about the menstrual cycle is false? a. Progesterone levels rise during the luteal phase of the ovarian cycle and the secretory phase of the uterine cycle. Menstruation occurs just after LH and FSH levels peak. Menstruation occurs after progesterone levels drop. Estrogen levels rise before ovulation, while progesterone levels rise after. Menopause As women approach their mid-40s to mid-50s, their ovaries begin to lose their sensitivity to FSH and LH. Menstrual periods become less frequent and finally cease; this is menopause. There are still eggs and potential follicles on the ovaries, but without the stimulation of FSH and LH, they will not produce a viable egg to be released. The outcome of this is the inability to have children. The side effects of menopause include hot flashes, heavy sweating (especially at night), headaches, some hair loss, muscle pain, vaginal dryness, insomnia, depression, weight gain, and mood swings. Estrogen is involved in calcium metabolism and, without it, blood levels of calcium decrease. To replenish the blood, calcium is lost from bone which may decrease the bone density and lead to osteoporosis. Supplementation of estrogen in the form of hormone replacement therapy (HRT) can prevent bone loss, but the therapy can have negative side effects. While HRT is thought to give some protection from colon cancer, osteoporosis, heart disease, macular degeneration, and possibly depression, its negative side effects include increased risk of: stroke or heart attack, blood clots, breast cancer, ovarian cancer, endometrial cancer, gall bladder disease, and possibly dementia. |
What blood protein carries oxygen from the lungs to cells throughout the body? | dopamine | plasma | platelets | hemoglobin | The blood protein hemoglobin binds with oxygen and carries it from the lungs to cells throughout the body. Heme is a small molecule containing iron that is part of the larger hemoglobin molecule. Oxygen binds to the iron in heme. |
What is the most abundant element in the universe? | fluoride | oxygen | helium | hydrogen | Summary By far the most abundant element in the universe is hydrogen. The fusion of hydrogen nuclei to form helium nuclei is the major process that fuels young stars such as the sun. Elements heavier than helium are formed from hydrogen and helium in the interiors of stars. Successive fusion reactions of helium nuclei at higher temperatures create elements with even numbers of protons and neutrons up to magnesium and then up to calcium. Eventually, the elements up to iron-56 and nickel-58 are formed by exchange processes at even higher temperatures. Heavier elements can only be made by a process that involves multiple neutron-capture events, which can occur only during the explosion of a supernova. |
The product of a system’s mass multiplied by its velocity is called what? | horizontal momentum | variation momentum | magnetic momentum | linear momentum | 8.1 Linear Momentum and Force Linear Momentum The scientific definition of linear momentum is consistent with most people’s intuitive understanding of momentum: a large, fastmoving object has greater momentum than a smaller, slower object. Linear momentum is defined as the product of a system’s mass multiplied by its velocity. In symbols, linear momentum is expressed as. |
In response to changing environmental conditions, prokaryotic populations can undergo what process in short periods of time? | fusion | extinction | reproduction | evolution | |
What term means the time in which half of the original number of radioactive nuclei in a sample decay? | partial-life | reduced life | quarter-life | half-life | Half-Life Why use a term like half-life rather than lifetime? The answer can be found by examining Figure 31.21, which shows how the number of radioactive nuclei in a sample decreases with time. The time in which half of the original number of nuclei decay is defined as the half-life, t 1 / 2 . Half of the remaining nuclei decay in the next half-life. Further, half of that amount decays in the following half-life. Therefore, the number of radioactive nuclei decreases from. |
What is a shortage of water that causes the soil to dry from the surface down called? | flood | overflowage | tidal wave | drought | |
What are are segmented invertebrates in phylum annelida called? | corals | flatworms | fungi | annelids | Annelids are segmented invertebrates in Phylum Annelida. They include earthworms, polychaete worms, and leeches. Annelids have a coelom and several organ systems. Their body segments may have a variety of different structures such as tentacles or suckers. Annelids may be predators, parasites, filter feeders, or decomposers. |
What is the connection between the two hemispheres of the brain called? | cranial septum | cerebral cortex | spinal cord | corpus callosum | Left Brain, Right Brain Popular media often refer to right-brained and left-brained people, as if the brain were two independent halves that work differently for different people. This is a popular misinterpretation of an important neurological phenomenon. As an extreme measure to deal with a debilitating condition, the corpus callosum may be sectioned to overcome intractable epilepsy. When the connections between the two cerebral hemispheres are cut, interesting effects can be observed. If a person with an intact corpus callosum is asked to put their hands in their pockets and describe what is there on the basis of what their hands feel, they might say that they have keys in their right pocket and loose change in the left. They may even be able to count the coins in their pocket and say if they can afford to buy a candy bar from the vending machine. If a person with a sectioned corpus callosum is given the same instructions, they will do something quite peculiar. They will only put their right hand in their pocket and say they have keys there. They will not even move their left hand, much less report that there is loose change in the left pocket. The reason for this is that the language functions of the cerebral cortex are localized to the left hemisphere in 95 percent of the population. Additionally, the left hemisphere is connected to the right side of the body through the corticospinal tract and the ascending tracts of the spinal cord. Motor commands from the precentral gyrus control the opposite side of the body, whereas sensory information processed by the postcentral gyrus is received from the opposite side of the body. For a verbal command to initiate movement of the right arm and hand, the left side of the brain needs to be connected by the corpus callosum. Language is processed in the left side of the brain and directly influences the left brain and right arm motor functions, but is sent to influence the right brain and left arm motor functions through the corpus callosum. Likewise, the left-handed sensory perception of what is in the left pocket travels across the corpus callosum from the right brain, so no verbal report on those contents would be possible if the hand happened to be in the pocket. |
Banging on a drum is an example of which type of energy? | potential | solar. | molecular | mechanical | |
What do microbes use to make food? | plants | nitrogen | sunlight | chemicals | Microbes use chemicals to make food. The chemicals pour out of a crack on the ocean floor at a mid-ocean ridge. What consumers live in this ecosystem?. |
Space telescopes avoid such problems completely since they orbit outside the what? | earth's crust | ozone layer | galaxy | atmosphere | Telescopes on Earth all have one big problem: Incoming light must pass through the atmosphere. This blocks some wavelengths of radiation. Also, motion in the atmosphere distorts light. You see this when you see stars twinkling in the night sky. Many observatories are built on high mountains. There is less air above the telescope, so there is less interference from the atmosphere. Space telescopes avoid such problems completely since they orbit outside the atmosphere. |
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