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Enzymes are a type of what, and as such, they are not reactants in the reactions they control? | neurotransmitter | hormone | metabolite | catalyst | Like other catalysts, enzymes are not reactants in the reactions they control. They help the reactants interact but are not used up in the reactions. Instead, they may be used over and over again. Unlike other catalysts, enzymes are usually highly specific for particular chemical reactions. They generally catalyze only one or a few types of reactions. |
The entire volume of what is filtered through the kidneys about 300 times per day? | saliva | gastric juice | urine | blood | 25.5 Physiology of Urine Formation The entire volume of the blood is filtered through the kidneys about 300 times per day, and 99 percent of the water filtered is recovered. The GFR is influenced by hydrostatic pressure and colloid osmotic pressure. Under normal circumstances, hydrostatic pressure is significantly greater and filtration occurs. The hydrostatic pressure of the glomerulus depends on systemic blood pressure, autoregulatory mechanisms, sympathetic nervous activity, and paracrine hormones. The kidney can function normally under a wide range of blood pressures due to the autoregulatory nature of smooth muscle. |
The elements in group 2 are called what? | noble gases | halogens | metal alloys | alkaline earth metals | The elements in Group 2 (beryllium, magnesium, calcium, strontium, barium, and radium) are called the alkaline earth metals (see Figure below ). These elements have two valence electrons, both of which reside in the outermost s sublevel. The general electron configuration of all alkaline earth metals is n s 2 . The alkaline earth metals are still too reactive to exist in nature as free elements, but they are less reactive than the alkali metals. They tend to be harder, stronger, and denser than the alkali metals, and they also form numerous compounds with nonmetals. |
What term decribes the amount of time required for half of the original material to decay in an isotope? | life cycle | radioactive isotope | Geiger count | half-life | 11.6 End-of-Chapter Material Chapter Summary To ensure that you understand the material in this chapter, you should review the meanings of the bold terms in the following summary and ask yourself how they relate to the topics in the chapter. Some atoms have unstable nuclei that emit particles and high-energy electromagnetic radiation to form new elements that are more stable. This emission of particles and electromagnetic radiation is called radioactivity. There are three main types of spontaneous radioactive emission: alpha particles, which are equivalent to helium nuclei; beta particles, which are electrons; and gamma radiation, which is highenergy electromagnetic radiation. Another type of radioactive process is spontaneous fission, in which large nuclei spontaneously break apart into smaller nuclei and, often, neutrons. In all forms of radioactivity, new elements are formed from the radioactive reactants. Radioactive isotopes decay at different rates. The rate of an isotope’s decay is expressed as a half-life, which is the amount of time required for half of the original material to decay. The length of its half-life is a characteristic of the particular isotope and can range from less than microseconds to billions of years. Amounts of radioactivity are measured in several different ways. A becquerel is equal to one radioactive decay per second. A curie represents 3.7 × 1010 decays per second. Other units describe the amount of energy absorbed by body tissues. One rad is equivalent to 0.01 joule of energy absorbed per gram of tissue. Different tissues react differently to different types of radioactivity. The rem unit takes into account not only the energy absorbed by the tissues, but also includes a numerical multiplication factor to Saylor URL: http://www. saylor. org/books. |
What occurs when water lost by transpiration is not replaced by absorbtion from room? | perspiration | rotting | shedding | wilting | |
Molds, pollen, and pet dander are examples of air pollution with what type of source? | chemical | ecological | physical | biological | Biological sources of air pollution include molds, pollen, and pet dander. |
Neurons are classified based on the direction in which they carry what? | neurotransmitters | metabolism impulses | energy | nerve impulses | Neurons are classified based on the direction in which they carry nerve impulses. |
What is the process of making an observation in terms of a numerical scale and recording the value? | graduation | ambient | respiration | measurement | Measurement is the process of making an observation in terms of a numerical scale and recording the value. |
What makes monotremes different than other mammals? | they reproduce asexually | they lack backbones | they spawn | they lay eggs | 29.6 Mammals Mammals in general are vertebrates that possess hair and mammary glands. The mammalian integument includes various secretory glands, including sebaceous glands, eccrine glands, apocrine glands, and mammary glands. Mammals are synapsids, meaning that they have a single opening in the skull. A key characteristic of synapsids is endothermy rather than the ectothermy seen in other vertebrates. Mammals probably evolved from therapsids in the late Triassic period, as the earliest known mammal fossils are from the early Jurassic period. There are three groups of mammals living today: monotremes, marsupials, and eutherians. Monotremes are unique among mammals as they lay eggs, rather than giving birth to young. Eutherian mammals are sometimes called placental mammals, because all species possess a complex placenta that connects a fetus to the mother, allowing for gas, fluid, and nutrient exchange. |
The strength of bases is measured on what scale? | pneumatic scale | acid test | litmus test | ph scale | The strength of bases is measured on a scale called the pH scale, which ranges from 0 to 14. On this scale, a pH value of 7 indicates a neutral solution, and a pH value greater than 7 indicates a basic solution. The higher the pH value is, the stronger the base. The strongest bases, such as drain cleaner, have a pH value close to 14. |
What type of isomers contain the same number of atoms of each kind but differ in which atoms are bonded to one another? | constitutional isomers | different isomers | unique isomers | structural isomers | Isomers that contain the same number of atoms of each kind but differ in which atoms are bonded to one another are called structural isomers. Isobutane and n-butane are examples of structural isomers. One kind of isomerism consists of two compounds that have the same empirical formula but differ in the number of formula units present in the molecular formula. An example in coordination compounds is two compounds with the empirical formula Pt(NH 3)2Cl2. One is a simple square planar platinum(II) complex, Pt(NH3)2Cl2, and the other is an ionic compound that contains the [Pt(NH 3)4]2+ cation and the [PtCl4]2− anion, [Pt(NH3)4][PtCl4]. As you might expect, these compounds have very different physical and chemical properties. One arrangement of the Cl− and NH3 ligands around the platinum ion in the former gives the anticancer drug cisplatin, whereas the other arrangement has no known biomedical applications. |
What is the gas that gives rotten eggs and sewage their distinctive smell? | hydrogen peroxide | calcium sulfide | methane | hydrogen sulfide | Prokaryotes have a wide range of metabolisms, and this determines where they live. They live in a particular habitat because they are able to “eat” whatever is around them. For example, there are bacteria and archaea that break down hydrogen sulfide to produce ATP. Hydrogen sulfide is the gas that gives rotten eggs and sewage their distinctive smell. It is poisonous to animals, but some prokaryotes depend on it for life. |
What two values does a blood pressure reading include? | cholesterol and systolic | biotic and abiotic | high and low | systolic and diastolic | Blood pressures are expressed in millimeters of mercury. What would be the blood pressure in atmospheres if a patient’s systolic blood pressure is 120 mmHg and the diastolic blood pressure is 82 mmHg? (In medicine, such a blood pressure would be reported as “120/82,” spoken as “one hundred twenty over eighty-two. |
In humans, what period lasts from the ninth week of development until birth? | development period | third trimester | plasma period | fetal period | 28.3 Fetal Development The fetal period lasts from the ninth week of development until birth. During this period, male and female gonads differentiate. The fetal circulatory system becomes much more specialized and efficient than its embryonic counterpart. It includes three shunts—the ductus venosus, the foramen ovale, and the ductus arteriosus—that enable it to bypass the semifunctional liver and pulmonary circuit until after childbirth. The brain continues to grow and its structures differentiate. Facial features develop, the body elongates, and the skeleton ossifies. In the womb, the developing fetus moves, blinks, practices sucking, and circulates amniotic fluid. The fetus grows from an embryo measuring approximately 3.3 cm (1.3 in) and weighing 7 g (0.25 oz) to an infant measuring approximately 51 cm (20 in) and weighing an average of approximately 3.4 kg (7.5 lbs). Embryonic organ structures that were primitive and nonfunctional develop to the point that the newborn can survive in the outside world. |
Where are protons found in the atom? | outside the nucleus | within electrons | in the orbital | in the nucleus | Rutherford proposed a new atomic model that described the atom as comprised of a positively charged nucleus surrounded by negatively charged electrons. In this model, most of the atom was thought to be empty space. *Protons are positively charged and have a relatively large mass compared to electrons. Protons can be found in the nucleus of the atom. |
What is produced when haploid gametes fuse in sexual reproduction? | isolated zygote | deformity | cell cluster | diploid zygote | Fertilization of an egg cell by a sperm cell. In sexual reproduction, haploid gametes fuse to produce a diploid zygote. |
What are the two different types of vascular tissues called? | epidermis and dermis | acid and base | biotic and abiotic | xylem and phloem | The vascular tissues for which these plants are named are specialized to transport fluid. They consist of long, narrow cells arranged end-to-end, forming tubes. There are two different types of vascular tissues, called xylem and phloem. Both are shown in Figure below . |
During which stage of development do all the major organs begin to form? | transgenic | third trimester | nascent | embryonic | After cells differentiate, all the major organs begin to form during the remaining weeks of embryonic development. A few of the developments that occur in the embryo during weeks 4 through 8 are listed in Figure below . As the embryo develops, it also grows in size. By the eighth week of development, the embryo is about 30 millimeters (just over 1 inch) in length. It may also have begun to move. |
At the anode, liquid chloride ions are oxidized to what? | Heavy Gas | elemental gas | nitrogen gas | chlorine gas | In a Down’s cell, the liquid sodium ions are reduced at the cathode to liquid sodium metal. At the anode, liquid chloride ions are oxidized to chlorine gas. The reactions and cell potentials are shown below. |
A diploid cell contains two sets of what? | atoms | ribosomes | neutrons | chromosomes | The surface of Venus is shrouded by thick clouds. Radar images show a complex surface. There are volcanoes and craters like those found on other planets and moons. The surface is not nearly as complex as the surface of Earth. |
On what basis are lipoproteins classified? | weight | diameter | mass | density | Other lipoproteins also transport lipids throughout the body, but different types of lipoproteins tend to serve different functions. We will discuss some of these differences in the section below on cholesterol and heart disease. Lipoproteins are often classified into five different groups based on their densities. In increasing order of density, these groups include chylomicrons, very-low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). |
The two ovaries are small, oval organs on either side of what part of the body? | pancreas | lungs | heart | uterus | The two ovaries are small, oval organs on either side of the uterus. Each ovary contains thousands of eggs, with about 1-2 million immature eggs present at birth and 40,000 immature eggs present at puberty, as most of the eggs die off. The eggs do not fully develop until a female has gone through puberty. About once a month, on average one egg completes development and is released by the ovary. The ovaries also secrete estrogen , the main female sex hormone. |
Gas exchange during respiration occurs primarily through what? | activation | vaporization | secretion | diffusion | Basic Principles of Gas Exchange Gas exchange during respiration occurs primarily through diffusion. Diffusion is a process in which transport is driven by a concentration gradient. Gas molecules move from a region of high concentration to a region of low concentration. Blood that is low in oxygen concentration and high in carbon dioxide concentration undergoes gas exchange with air in the lungs. The air in the lungs has a higher concentration of oxygen than that of oxygen-depleted blood and a lower concentration of carbon dioxide. This concentration gradient allows for gas exchange during respiration. Partial pressure is a measure of the concentration of the individual components in a mixture of gases. The total pressure exerted by the mixture is the sum of the partial pressures of the components in the mixture. The rate of diffusion of a gas is proportional to its partial pressure within the total gas mixture. This concept is discussed further in detail below. |
Enzymes in the stomach and small intestine break down proteins into what components? | lactic acids | atoms | antioxidants | amino acids | Figure 24.17 Digestive Enzymes and Hormones Enzymes in the stomach and small intestine break down proteins into amino acids. HCl in the stomach aids in proteolysis, and hormones secreted by intestinal cells direct the digestive processes. |
Organisms incapable of photosynthesis that must therefore obtain energy and carbon from food by consuming other organisms are called what? | chemoautotrophs | photoautotrophs | autotrophs | heterotrophs | Heterotrophs are organisms incapable of photosynthesis that must therefore obtain energy and carbon from food by consuming other organisms. The Greek roots of the word heterotroph mean “other” (hetero) “feeder” (troph), meaning that their food comes from other organisms. Even if the food organism is another animal, this food traces its origins back to autotrophs and the process of photosynthesis. Humans are heterotrophs, as are all animals. Heterotrophs depend on autotrophs, either directly or indirectly. Deer and wolves are heterotrophs. A deer obtains energy by eating plants. A wolf eating a deer obtains energy that originally came from the plants eaten by that deer. The energy in the plant came from photosynthesis, and therefore it is the only autotroph in this example (Figure 5.3). Using this reasoning, all food eaten by humans also links back to autotrophs that carry out photosynthesis. |
What allows theories to be widely accepted? | theory | hypothesis | observation | evidence | The term theory is used differently in science than it is used in everyday language. A scientific theory is a broad explanation that is widely accepted because it is supported by a great deal of evidence. Because it is so well supported, a scientific theory has a very good chance of being a correct explanation for events in nature. Because it is a broad explanation, it can explain many observations and pieces of evidence. In other words, it can help connect and make sense of many phenomena in the natural world. |
Elements that specifically are noted to have properties of both metals and nonmetals are known as what? | alkali metals | compund metals | alloys | metalloids | Metalloids are elements that have properties of both metals and nonmetals. Some can conduct electricity but only at certain temperatures. They may be shiny but brittle. All metalloids are solids at room temperature. |
What is the measure of change in velocity of a moving object? | kinetic energy | transmission | vibration | acceleration | Acceleration is a measure of the change in velocity of a moving object. It shows how quickly velocity changes. Acceleration may reflect a change in speed, a change in direction, or both. Because acceleration includes both a size (speed) and direction, it is a vector. |
What celestial events are the source of elements heavier than iron? | Space | neutrons | galaxies | supernovas | Figure 32.21 Supernovas are the source of elements heavier than iron. Energy released powers nucleosynthesis. Spectroscopic analysis of the ring of material ejected by Supernova 1987A observable in the southern hemisphere, shows evidence of heavy elements. The study of this supernova also provided indications that neutrinos might have mass. (credit: NASA, ESA, and P. Challis). |
Algae are similar to plants in that they both produce their food through what process? | hydrolysis | mitosis | cell division | photosynthesis | Why are algae considered plant-like? The main reason is that they contain chloroplasts and produce food through photosynthesis. However, they lack many other structures of true plants. For example, algae do not have roots, stems, or leaves. Some algae also differ from plants in being motile. They may move with pseudopods or flagella. Although not plants themselves, algae were probably the ancestors of plants. |
What do fungi produce to digest nutrients? | sporozoans | pores | amino | exoenzymes | The ability of fungi to degrade many large and insoluble molecules is due to their mode of nutrition. As seen earlier, digestion precedes ingestion. Fungi produce a variety of exoenzymes to digest nutrients. The enzymes are either released into the substrate or remain bound to the outside of the fungal cell wall. Large molecules are broken down into small molecules, which are transported into the cell by a system of protein carriers embedded in the cell membrane. Because the movement of small molecules and enzymes is dependent on the presence of water, active growth depends on a relatively high percentage of moisture in the environment. As saprobes, fungi help maintain a sustainable ecosystem for the animals and plants that share the same habitat. In addition to replenishing the environment with nutrients, fungi interact directly with other organisms in beneficial, and sometimes damaging, ways (Figure 24.19). |
When light passes from one medium to another, it changes what? | density | color | temperature | speed | When light passes from one medium to another, it changes speed. For example, when light passes from air to glass, it slows down. If light strikes a sheet of glass at a 90° angle, or perpendicular to the glass, it slows down but still passes straight through the glass. However, if light enters the glass at an angle other than 90°, the light bends as it slows down. The bending of light as it changes speed in a new medium is called refraction . The Figure below shows how refraction occurs. Notice that the speed of light changes again as it passes from the glass back to the air. In this case, the speed increases, and the ray of light resumes its initial direction. For a more detailed explanation of refraction, watch this video: http://www. youtube. com/watch?v=8RM46yvDOHI . |
The distance between the crests of electromagnetic waves is called what? | crest | trough | variation | wavelength | |
People with celiac disease have an immune response to what, which ultimately leads to malnutrition, cramping, and diarrhea? | seeds | fish | lactose | gluten | The plasma membranes of cells that specialize in absorption are folded into fingerlike projections called microvilli (singular = microvillus). This folding increases the surface area of the plasma membrane. Such cells are typically found lining the small intestine, the organ that absorbs nutrients from digested food. This is an excellent example of form matching the function of a structure. People with celiac disease have an immune response to gluten, which is a protein found in wheat, barley, and rye. The immune response damages microvilli, and thus, afflicted individuals cannot absorb nutrients. This leads to malnutrition, cramping, and diarrhea. Patients suffering from celiac disease must follow a gluten-free diet. |
Chlorophyll is used in what food-making process that plants carry out? | digestion | colorization | isolation | photosynthesis | |
What does an ammeter measure the flow of? | magnetic fields | water under pressure | wind | current through a circuit | When a contractor builds a new home, she uses a set of plans called blueprints that show her how to build the house. The blueprints include circuit diagrams. The diagrams show how the wiring and other electrical components are to be installed in order to supply current to appliances, lights, and other electric devices. You can see an example of a very simple circuit in the Figure below . Different parts of the circuit are represented by standard circuit symbols. An ammeter measures the flow of current through the circuit, and a voltmeter measures the voltage. A resistor is any device that converts some of the electricity to other forms of energy. For example, a resistor might be a light bulb or doorbell. |
Burning forests, growing rice and raising livestock all cause a release of what into the atmosphere? | glucose gases | oxide gases | carbonate gases | greenhouse gases | Burning forests also releases carbon dioxide into the atmosphere. Other human activities release greenhouse gases into the atmosphere. For example, growing rice and raising livestock both produce methane. |
What type of pollution comes from sewage, storm drains, septic tanks, boats, and runoff from yards? | social | collective | urban | municipal | “Municipal” refers to the community. Households and businesses in a community can pollute the water supply. Municipal pollution comes from sewage, storm drains, septic tanks, boats, and runoff from yards. For example:. |
What does oil do when mixed with water? | dissappears | dissolves | precipitates | forms droplets | Figure 2.13 Oil and water do not mix. As this macro image of oil and water shows, oil does not dissolve in water but forms droplets instead. This is due to it being a nonpolar compound. (credit: Gautam Dogra). |
What is the term for the movement of individuals out of a population? | immigration | succession | colonization | emigration | Emigration is the movement of individuals out of a population. This decreases the population size and growth rate. |
What might a scientist do to confirm the work of another? | study their work | question their methods | develop a completely different experiment | replicate their work | Scientists may work together on a project. One reason is that they can share equipment and personnel. Another reason is that they can share ideas. Scientists may also work separately. Even then, they use each other's data and interpretations. When one scientist publishes a paper, others will replicate the work to make sure they get the same result. If they do, the work is valid. If they don't, someone needs to find the source of the problem. Scientists openly communicate with each other on their results. They also discuss and sometimes disagree on their interpretations. If scientists do disagree, they will look for evidence so that they may resolve the disagreement. |
Polar molecules result from differences in electronegativity of what in the molecule? | iron | ions | protons | atoms | Polar molecules result from differences in electronegativity of the atoms in the molecule. |
A diver's air bubbles increase in size as he approaches the surface because what decreases? | water energy | water direction | water weight | water pressure | A scuba diver, like the one in Figure below , releases air bubbles when he breathes under water. As he gets closer to the surface of the water, the air bubbles get bigger. Boyle’s law explains why. The pressure of the water decreases as the diver gets closer to the surface. Because the bubbles are under less pressure, they increase in volume even though the amount of gas in the bubbles remains the same. |
Positive charge is mostly found in what part of an atom? | ions | electron shell | neutrons | nucleus | Rutherford’s discoveries meant that Thomson’s plum pudding model was incorrect. Positive charge is not spread evenly throughout an atom. Instead, it is all concentrated in the tiny nucleus. The rest of the atom is empty space except for the electrons scattered through it. In Rutherford’s model of the atom, which is shown in the Figure below , the electrons move around the massive nucleus like planets orbiting the sun. That’s why his model is called the planetary model. Rutherford didn’t know exactly where or how electrons orbit the nucleus. That research would be undertaken by later scientists, beginning with Niels Bohr in 1913. New and improved atomic models would also be developed. Nonetheless, Rutherford’s model is still often used to represent the atom. You can see an animated version of the model at this URL: http://www. clickandlearn. org/gr9_sci/atoms/modelsoftheatom. html . |
In the lens makers' equation, diverging lenses and virtual images are associated with what kinds of numbers? | fractional numbers | positive numbers | variable numbers | negative numbers | When using the lens makers equation, remember that real things get positive numbers and virtual things get negative numbers. Thus, diverging lenses and virtual images get negative numbers. The object distance is always positive. |
What is another name for producers? | allergens | plants | rotifers | autotrophs | Producers are organisms that produce food for themselves and other organisms. They use energy and simple inorganic molecules to make organic compounds. The stability of producers is vital to ecosystems because all organisms need organic molecules. Producers are also called autotrophs. There are two basic types of autotrophs: photoautotrophs and chemoautotrophs. |
Consisting of a stigma, style, and ovary, the pistil of a flower is what type of organ? | female respiratory organ | female neural organ | female immune organ | female reproductive organ | The female reproductive organ in a flower is the pistil . It consists of a stigma, style, and ovary. The stigma is the top of the pistil. It is sticky to help it "catch" pollen. The style connects the stigma to the ovary. The ovary is where eggs form and seeds develop. As seeds develop, the ovary turns into a fruit . The fruit protects the seeds. It also attracts animals that may eat the fruit and help disperse the seeds. |
Chewing insects such as dragonflies and grasshoppers have how many sets of jaws? | three | one | four | two | If all three bulbs are set a full intensity, the person sees __________. |
What kind of change occurs whenever matter changes into an entirely different substance with different chemical properties? | carbon change | reversible change | physical change | chemical change | A chemical change occurs whenever matter changes into an entirely different substance with different chemical properties. Burning is an example of a chemical change. |
What is a small, relatively simple single-celled organism called? | eukaryote | ribosome | amoeba | prokaryote | Even though large life forms have been very successful on Earth, most of the life forms on Earth today are still prokaryotes—small, relatively simple single-celled organisms. As it is difficult to identify, observe and study such small forms of life, most of these organisms remain unknown to scientists. Advancing technologies, however, do allow for the identification and study of such organisms. |
The golgi apparatus works like a mail room by receiving and sending what? | enzymes | acids | particles | proteins | The Golgi apparatus works like a mail room. The Golgi apparatus receives proteins from the rough ER and puts "shipping addresses" on them. The Golgi then packages the proteins into vesicles and sends them to the right place in the cell or to the cell membrane. Some of these proteins are secreted from the cell (they exit the cell); others are placed into the cell membrane. |
Which part of the body has mucus and hair to trap dust and also warms and moistens air so to not harm lung tissue? | the ear | the tongue | the throat | the nose | In the nose, mucus and hairs trap any dust or other particles in the air. The air is also warmed and moistened so it won’t harm delicate tissues of the lungs. |
What are the structures in the cytoplasm where proteins are made? | prokaryotes | nucleus | chromosomes | ribosomes | Ribosomes are structures in the cytoplasm where proteins are made. |
What is the key issue in the small-population approach? | alternative variation | disease variation | genetic mutation | genetic variation | |
What is the minimum depth in the aphotic zone? | 10 meters | 150 meters | 450 meters | 200 meters | The aphotic zone is water deeper than 200 meters. This is where too little sunlight penetrates for photosynthesis to occur. As a result, food must be made by chemosynthesis or else drift down from the water above. |
What is the process by which plants gain energy and produce sugar? | chemosynthesis | glycolysis | respiration | photosynthesis | 13 Photosynthesis 6 CO2 + 6 H2 O → C6 H12 O6 + 6 O2 • One of most important reactions in history of life: • source of atmospheric O2 • ultimately led to aerobic respiration and eukaryotes • Responsible for bulk of glucose production • Early experiments showed that mass of plant must be derived from substances in the air, not the soil • Experiments with isotopes showed that liberated oxygen comes from water • Experiments also showed that light is essential but that some reactions (e. , reduction of CO2 ) continue in the dark • Plants do two big, important things during photosynthesis: gain energy (absorb light) and build sugar (glucose). • Photosynthesis can be divided into two series of chemical reactions: the light (lightdependent) reactions and the dark (light-independent) reactions. In light reactions, light is absorbed; in dark reactions, sugar is built. • Occurs when plants, algae, and autotrophic bacteria absorb light energy and build glucose. |
What are embedded in the membranes of b cells and bind a variety of antigens through their variable regions? | er cell receptors | b.a.p cell receptors | a.m. cell receptors | b cell receptors | Figure 42.13 B cell receptors are embedded in the membranes of B cells and bind a variety of antigens through their variable regions. The signal transduction region transfers the signal into the cell. |
A statement that describes what always happens under certain conditions in nature is also known as what? | scientific motion | theory | hypothesis | scientific law | Scientists think of nature as a single system controlled by natural laws. Scientists strive to increase their understanding of the natural world by discovering natural laws. Laws of nature are expressed as scientific laws. A scientific law is a statement that describes what always happens under certain conditions in nature. |
What developmental stage do alligators lack that most other amphibians have? | Egg Stage | Tadpole stage | metamorphosis | larval stage | Young reptiles, like the baby alligator in Figure below , look like smaller versions of the adults. They don’t have a larval stage as most amphibians do. Baby reptiles are able to move and search for food but are at high risk of predation. Adult reptiles rarely provide any care for their offspring once the eggs are laid. The only exceptions are female alligators and crocodiles. They defend their eggs and hatchlings from predators and help them reach the water. |
What attaches a muscle to a bone? | veins | marrow | arteries | tendons | When skeletal muscles contract, bones move. But how do muscles make your bones move? A voluntary muscles usually works across a joint. It is attached to both the bones on either side of the joint by strong cords called tendons. A tendon is a tough band of connective tissue that connects a muscle to a bone. Tendons are similar to ligaments, except that ligaments join bones to each other. Muscles move the body by contracting against the skeleton. When muscles contract, they get shorter. By contracting, muscles pull on bones and allow the body to move. |
What are two common weather characteristics of hurricanes? | small winds and rainfall | low winds and sandstorms | high winds and snowfall | high winds and rainfall | Volcanoes and earthquakes are common at active margins. Active margins are near plate boundaries. |
What kind of organism causes the often fatal lung disease tuberculosis? | algae | pathogens | virus | bacteria | |
Where do plates move apart in oceans and on land? | unsettled plate boundaries | volcanic ridges | coastal zones | divergent plate boundaries | Plates move apart at divergent plate boundaries. This can occur in the oceans or on land. |
Zeros that appear in front of all of the nonzero digits are called what? | non-numbers | zero sum game | significant digits | left-end zeros | 3. Zeros that appear in front of all of the nonzero digits are called left-end zeros. Left-end zeros are never significant. A. 0.008 has one significant figure. |
What consists of thylakoid membranes surrounded by stroma? | a stem | a photon | a nucleus | a chloroplast | A chloroplast consists of thylakoid membranes surrounded by stroma. The thylakoid membranes contain molecules of the green pigment chlorophyll. |
Portable amplifiers have batteries that store what type of energy? | carbon energy | kinetic energy | mechanical energy | chemical energy | Amplifier: Tim Walker; Battery: Emilian Robert Vicol. Portable amplifiers have batteries that store chemical energy . Amplifier: CC BY 2.0; Battery: Public Domain. |
The movement of ice causes glaciers to have cracks referred to as? | anomalies | slides | fissures | crevasses | Because the ice is moving, glaciers have cracks called crevasses ( Figure below ). There is a large crevasse at the top of an alpine glacier called a bergshrund . Below the bergshrund, the ice is moving downhill. Above the bergshrund, the ice is stuck to the mountain. |
A muscle can return to its original length when relaxed due to a quality of muscle tissue called what? | moisture | reach | viscosity | elasticity | The muscles all begin the actual process of contracting (shortening) when a protein called actin is pulled by a protein called myosin. This occurs in striated muscle (skeletal and cardiac) after specific binding sites on the actin have been exposed in response to the interaction between calcium ions (Ca++) and proteins (troponin and tropomyosin) that “shield” the actinbinding sites. Ca++ also is required for the contraction of smooth muscle, although its role is different: here Ca++ activates enzymes, which in turn activate myosin heads. All muscles require adenosine triphosphate (ATP) to continue the process of contracting, and they all relax when the Ca++ is removed and the actin-binding sites are re-shielded. A muscle can return to its original length when relaxed due to a quality of muscle tissue called elasticity. It can recoil back to its original length due to elastic fibers. Muscle tissue also has the quality of extensibility; it can stretch or extend. Contractility allows muscle tissue to pull on its attachment points and shorten with force. Differences among the three muscle types include the microscopic organization of their contractile proteins—actin and myosin. The actin and myosin proteins are arranged very regularly in the cytoplasm of individual muscle cells (referred to as fibers) in both skeletal muscle and cardiac muscle, which creates a pattern, or stripes, called striations. The striations are visible with a light microscope under high magnification (see Figure 10.2). Skeletal muscle fibers are multinucleated structures that compose the skeletal muscle. Cardiac muscle fibers each have one to two nuclei and are physically and electrically connected to each other so that the entire heart contracts as one unit (called a syncytium). Because the actin and myosin are not arranged in such regular fashion in smooth muscle, the cytoplasm of a smooth muscle fiber (which has only a single nucleus) has a uniform, nonstriated appearance (resulting in the name smooth muscle). However, the less organized appearance of smooth muscle should not be interpreted as less efficient. Smooth muscle in the walls of arteries is a critical component that regulates blood pressure necessary to push blood through the circulatory system; and smooth muscle in the skin, visceral organs, and internal passageways is essential for moving all materials through the body. |
What feature of the spine helps with flexibility and strength? | arrangement | shape | angle | curves | Curvatures of the Vertebral Column The adult vertebral column does not form a straight line, but instead has four curvatures along its length (see Figure 7.20). These curves increase the vertebral column’s strength, flexibility, and ability to absorb shock. When the load on the spine is increased, by carrying a heavy backpack for example, the curvatures increase in depth (become more curved) to accommodate the extra weight. They then spring back when the weight is removed. The four adult curvatures are classified as either primary or secondary curvatures. Primary curves are retained from the original fetal curvature, while secondary curvatures develop after birth. |
How does a cell's membrane keep extracellular materials from mixing with it's internal components? | destroys extracellular materials | absorbs extracellular materials | repels extracellular materials | provides a barrier | CHAPTER REVIEW 3.1 The Cell Membrane The cell membrane provides a barrier around the cell, separating its internal components from the extracellular environment. It is composed of a phospholipid bilayer, with hydrophobic internal lipid “tails” and hydrophilic external phosphate “heads. ” Various membrane proteins are scattered throughout the bilayer, both inserted within it and attached to it peripherally. The cell membrane is selectively permeable, allowing only a limited number of materials to diffuse through its lipid bilayer. All materials that cross the membrane do so using passive (non energy-requiring) or active (energy-requiring) transport processes. During passive transport, materials move by simple diffusion or by facilitated diffusion through the membrane, down their concentration gradient. Water passes through the membrane in a diffusion process called osmosis. During active transport, energy is expended to assist material movement across the membrane in a direction against their concentration gradient. Active transport may take place with the help of protein pumps or through the use of vesicles. |
Respiratory development in the embryo begins around week 4. ectodermal tissue from the anterior head region invaginates posteriorly to form olfactory pits, which fuse with endodermal tissue of the developing pharynx. an olfactory pit is one of a pair of structures that will enlarge to become this? | fluid cavity | anal cavity | eye cavity | nasal cavity | Weeks 4–7 Respiratory development in the embryo begins around week 4. Ectodermal tissue from the anterior head region invaginates posteriorly to form olfactory pits, which fuse with endodermal tissue of the developing pharynx. An olfactory pit is one of a pair of structures that will enlarge to become the nasal cavity. At about this same time, the lung bud forms. The lung bud is a dome-shaped structure composed of tissue that bulges from the foregut. The foregut is endoderm just inferior to the pharyngeal pouches. The laryngotracheal bud is a structure that forms from the longitudinal extension of the lung bud as development progresses. The portion of this structure nearest the pharynx becomes the trachea, whereas the distal end becomes more bulbous, forming bronchial buds. A bronchial bud is one of a pair of structures that will eventually become the bronchi and all other lower respiratory structures (Figure 22.29). |
Anything that occupies space and has mass is known as what? | dense | opaque | solid | matter | All living things are made of matter . In fact, matter is the “stuff” of which all organisms are made. Anything that occupies space and has mass is known as matter. Matter, in turn, consists of chemical substances. It is the carbons, hydrogens, oxygens and other elements that combine to form molecules, compounds, organelles, cells and eventually tissues, organs and organisms. In addition to being made of matter, all living organisms also need energy to survive. |
The temperature dependence of solubility can be exploited to prepare what solutions of certain compounds? | instantiated | mineralized | isolated | supersaturated | The temperature dependence of solubility can be exploited to prepare supersaturated solutions of certain compounds. A solution may be saturated with the compound at an elevated temperature (where the solute is more soluble) and subsequently cooled to a lower temperature without precipitating the solute. The resultant solution contains solute at a concentration greater than its equilibrium solubility at the lower temperature (i. , it is supersaturated) and is relatively stable. Precipitation of the excess solute can be initiated by adding a seed crystal (see the video in the Link to Learning earlier in this module) or by mechanically agitating the solution. Some hand warmers, such as the one pictured in Figure 11.18, take advantage of this behavior. |
Glasses are mixtures of oxides, the main component of which is silica (sio2). silica is called the glass former, while additives are referred to as this? | glass actors | natural modifiers | addition modifiers | glass modifiers | ♦ Glasses are mixtures of oxides, the main component of which is silica (SiO2). Silica is called the glass former, while additives are referred to as glass modifiers. The crystalline lattice of the glass former breaks down during heating, producing the random atomic arrangements typical of a liquid. Adding a modifier and cooling the melt rapidly produces a glass. How does the three-dimensional structure of the glass differ from that of the crystalline glass former? Would you expect the melting point of a glass to be higher or lower than that of pure SiO2? Lead glass, a particular favorite of the Romans, was formed by adding lead oxide as the modifier. |
What type of tissue produces and secretes several hormones involved in lipid metabolism and storage? | somatic tissue | hormonal tissue | metabolism tissue | adipose tissue | Adipose Tissue Adipose tissue produces and secretes several hormones involved in lipid metabolism and storage. One important example is leptin, a protein manufactured by adipose cells that circulates in amounts directly proportional to levels of body fat. Leptin is released in response to food consumption and acts by binding to brain neurons involved in energy intake and expenditure. Binding of leptin produces a feeling of satiety after a meal, thereby reducing appetite. It also appears that the binding of leptin to brain receptors triggers the sympathetic nervous system to regulate bone metabolism, increasing deposition of cortical bone. Adiponectin—another hormone synthesized by adipose cells—appears to reduce cellular insulin resistance and to protect blood vessels from inflammation and atherosclerosis. Its levels are lower in people who are obese, and rise following weight loss. |
What is the process in which organ systems work to maintain a stable internal environment? | organ balance | ketosis | homogeneity | homeostasis | The process in which organ systems work to maintain a stable internal environment is called homeostasis. Keeping a stable internal environment requires constant adjustments. Here are just three of the many ways that human organ systems help the body maintain homeostasis:. |
What must people with type 1 and type 2 diabetes frequently check? | blood density levels | blood plasma levels | muscle glucose levels | blood glucose levels | You can greatly reduce your risk of developing type 2 diabetes by maintaining a healthy body weight. Some cases of type 2 diabetes can be cured with weight loss. However, most people with the disease need to take medicine to control their blood glucose. Regular exercise and balanced eating also help. Like people with type 1 diabetes, people with type 2 diabetes must frequently check their blood glucose. |
What is it called when two alleles are both expressed in the heterozygous individual? | shared dominance | weak dominance | low dominance | codominance | Codominance is when two alleles are both expressed in the heterozygous individual. |
What part of a spider is equipped with poison glands? | vacuole | baleen | pedipalps | chelicerae | |
Esters are neutral compounds that undergo what process, which is a reaction with water? | replication | osmosis | cellular respiration | hydrolysis | conditions. Esters are neutral compounds that undergo hydrolysis, a reaction with water. Under acidic conditions, hydrolysis is essentially the reverse of esterification. When carried out under basic conditions, the process is called saponification. Inorganic acids also react with alcohols to form esters. Some of the most important esters in biochemistry are those formed from phosphoric acid. Amines are nitrogen-containing organic molecules derived from ammonia (NH3). A primary (1°) amine (RNH2) has one organic group bonded to the nitrogen atom, a secondary (2°) amine (R2NH) has two organic groups bonded to the nitrogen atom, and a tertiary (3°) amine (R3N) has three organic groups bonded to the nitrogen atom. Amines are basic compounds that react with strong acids to produce ammonium (NH4+) salts. A cyclic compound in which the ring contains one or more noncarbon atoms is called a heterocyclic compound. There are many heterocyclic amines, including many physiologically important ones. Alkaloids are heterocyclic amines found in many plants. Caffeine, nicotine, and cocaine are familiar alkaloids. Organic compounds containing a carbonyl group bonded to a nitrogen atom are amides, and the carbon-to-nitrogen bond is an amide linkage (or a peptide linkage). Most amides are colorless and odorless, and the lighter ones are soluble in water. Because they are polar molecules, amides have comparatively high boiling points and melting points. Amides are synthesized from carboxylic acids and NH3 or amines. Amides are neutral compounds. They resist hydrolysis in water, but acids, bases, and enzymes catalyze the reaction. |
Evolution occurs because of changes in what over time? | atoms | mitochondria | genomes | alleles | We now know how variation in traits is inherited. Variation in traits is controlled by different alleles for genes. Alleles, in turn, are passed to gametes and then to offspring. Evolution occurs because of changes in alleles over time. How long a time? That depends on the time scale of evolution you consider. |
When does coal release most of its energy? | when falling | when forming | when compressed | when burning | To prepare coal for use, the coal is first crushed into powder and burned in a furnace. Like other fuels, coal releases most of its energy as heat when it burns. The heat from the burning coal is used to boil water. This makes steam. The steam spins turbines, which creates electricity. |
What was once believed to be the smallest of all particles, as dalton's theory proposed? | neutron | nucleus | molecule | atom | Dalton’s theory was soon widely accepted. Most of it is still accepted today. The only part that is no longer accepted is his idea that atoms are the smallest particles. Scientists now know that atoms consist of even smaller particles. |
The actinides are all what type of elements? | multiple | large | nuclear | radioactive | actinide: The actinides are the 14 elements from thorium (atomic number 90) to lawrencium (atomic number 103). The sublevel is in the process of being filled. The actinides are all radioactive elements and only the first four have been found naturally on Earth. |
What type of feeders are sea lilies and feather stars? | silt feeders | deposit feeder | bottom feeder | suspension feeders | Explore the sea star’s body plan (http://openstaxcollege. org/l/sea_star) up close, watch one move across the sea floor, and see it devour a mussel. Brittle stars belong to the class Ophiuroidea. Unlike sea stars, which have plump arms, brittle stars have long, thin arms that are sharply demarcated from the central disk. Brittle stars move by lashing out their arms or wrapping them around objects and pulling themselves forward. Sea urchins and sand dollars are examples of Echinoidea. These echinoderms do not have arms, but are hemispherical or flattened with five rows of tube feet that help them in slow movement; tube feet are extruded through pores of a continuous internal shell called a test. Sea lilies and feather stars are examples of Crinoidea. Both of these species are suspension feeders. Sea cucumbers of class Holothuroidea are extended in the oral-aboral axis and have five rows of tube feet. These are the only echinoderms that demonstrate “functional” bilateral symmetry as adults, because the uniquely extended oral-aboral axis compels the animal to lie horizontally rather than stand vertically. |
What are the proteins called that speed up biochemical reactions in cells? | carbohydrates | peptides | hormones | enzymes | Enzymes are proteins that speed up biochemical reactions in cells. Antibodies are proteins that target pathogens for destruction. |
What isotope of carbon is typically used to date ancient items? | carbon 12 | uranium 14 | nitrogen 14 | carbon 14 | |
What two planets is the asteroid belt found between? | Jupiter and Saturn | Jupiter and Earth | Mars and Earth | mars and jupiter | Asteroids are irregularly-shaped, rocky bodies that orbit the Sun. Most of them are found in the asteroid belt, between the orbits of Mars and Jupiter. |
When wood is burned what kind of energy allows the wood to burn? | carbon | physical | radiation | chemical | Chemical energy is stored in wood and released when the wood burns. |
The cubic crystal system is composed of how many different types of unit cells? | five | one | four | three | Unit cells occur in many different varieties. As one example, the cubic crystal system is composed of three different types of unit cells: (1) simple cubic , (2) face-centered cubic , and (3) body-centered cubic . These are shown in three different ways in the Figure below . |
In which solution is the amount of dissolved material equal both inside and outside of the cell? | hypotonic | supersaturated | exothermic | isotonic | An isotonic solution is a solution in which the amount of dissolved material is equal both inside and outside of the cell. Water still flows in both directions, but an equal amount enters and leaves the cell. |
What element is the most common element in the universe? | nitrogen | carbon | helium | hydrogen | An element is a pure substance. It cannot be separated into any other substances. There are more than 90 different elements that occur in nature. Some are much more common than others. Hydrogen is the most common element in the universe. Oxygen is the most common element in Earth’s crust. Figure below shows other examples of elements. Still others are described in the video below. |
What is the term for anything that has mass and volume? | liquid | gass | energy | matter | Matter is anything that has mass and volume. Mass is the amount of matter in a substance. Volume is the amount of space matter takes up. |
What is in danger of happening when thick magma is formed? | earthquakes | focused eruptions | continuous eruptions | explosive eruptions | Composite volcanoes are also called stratovolcanoes. This is because they are formed by alternating layers (strata) of magma and ash ( Figure below ). The magma that creates composite volcanoes tends to be thick. The steep sides form because the lava cannot flow too far from the vent. The thick magma may also create explosive eruptions. Ash and pyroclasts erupt into the air. Much of this material falls back down near the vent. This creates the steep sides of stratovolcanoes. |
The important equation pv = nrt holds true for substances in what state of matter? | products | solids | liquids | gas | PV = nRT This equation is known as the ideal gas law. An ideal gas is defined as a hypothetical gaseous substance whose behavior is independent of attractive and repulsive forces and can be completely described by the ideal gas law. In reality, there is no such thing as an ideal gas, but an ideal gas is a useful conceptual model that allows us to understand how gases respond to changing conditions. As we shall see, under many conditions, most real gases exhibit behavior that closely approximates that of an ideal gas. The ideal gas law can therefore be used to predict the behavior of real gases under most conditions. As you will learn in Section 10.8 "The Behavior of Real Gases", the ideal gas law does not work well at very low temperatures or very high pressures, where deviations from ideal behavior are most commonly observed. |
The measurement of the extent of something along its greatest dimension is its what? | portion | depth | stretch | length | Length is the measurement of the extent of something along its greatest dimension. The SI basic unit of length, or linear measure, is the meter (m). All measurements of length may be made in meters, though the prefixes listed in various tables will often be more convenient. The width of a room may be expressed as about 5 meters (m), whereas a large distance, such as the distance between New York City and Chicago, is better expressed as 1150 kilometers (km). Very small distances can be expressed in units such as the millimeter or the micrometer. The width of a typical human hair is about 20 micrometers (μm). |
What force explains why objects may float in water? | gravity force | warm force | cool force | buoyant force | What explains buoyant force? Recall from the earlier lesson "Pressure of Fluids" that a fluid exerts pressure in all directions but the pressure is greater at greater depth. Therefore, the fluid below an object exerts greater force on the object than the fluid above the object. This is illustrated in Figure below . Buoyant force explains why objects may float in water. No doubt you’ve noticed, however, that some objects do not float in water. If buoyant force applies to all objects in fluids, why do some objects sink instead of float? The answer has to do with their weight. |
Which organelle is made up of 5 to eight cup shaped, membrane covered stacks of discs known as cisternae? | endoplasmic reticulum | vacuole | nucleus | golgi apparatus | The Golgi apparatus is usually made up of five to eight cup-shaped, membrane-covered stacks of discs called cisternae (singular, cisterna ), as shown in Figure below . Both plant and animal cells have a Golgi apparatus. A typical mammalian cell will have 40 to 80 of these stacks. While plant cells can have up to several hundred Golgi stacks scattered throughout the cytoplasm. In plants, the Golgi apparatus contains enzymes that synthesize some of the cell wall polysaccharides. |
How many bones does the mammalian middle ear have? | four | two | twelve | three | The mammalian middle ear has three tiny bones that carry sound vibrations from the outer to inner ear. The bones give mammals exceptionally good hearing. In other vertebrates, the three bones are part of the jaw and not involved in hearing. |
What can echinoderms sense with their simple eyes? | electricity | colors | shapes | light | Echinoderms lack respiratory and excretory systems. Instead, the thin walls of their tube feet allow oxygen to diffuse in and wastes to diffuse out. Echinoderms also lack a centralized nervous system. They have an open circulatory system and lack a heart. On the other hand, echinoderms have a well-developed coelom and a complete digestive system. Echinoderms use pheromones to communicate with each other. They detect the chemicals with sensory cells on their body's surface. Some echinoderms also have simple eyes (ocelli) that can sense light. Like annelids, echinoderms have the ability to regenerate a missing body part. |
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