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Why does water infiltrate the ground? | run-off from flooding | gravity | prolonged drought conditions | because soil and rocks are porous | Water infiltrates the ground because soil and rock are porous. Between the grains are pores, or tiny holes. Since water can move through this rock it is permeable. Eventually, the water reaches a layer of rock that is not porous and so is impermeable. Water stops moving downward when it reaches this layer of rock. |
What is the upward force exerted by fluids when any object, such as a boat, is placed in it? | impetuous force | human force | atomic force | bouyant force | Objects such as ships may float in a fluid like water because of buoyant force. This is an upward force that a fluid exerts on any object that is placed in it. Archimedes discovered that the buoyant force acting on an object equals the weight of the fluid displaced by the object. This is known as Archimedes’ law (or Archimedes’ principle). For an entertaining video presentation of Archimedes’ law, go to this URL:. |
What do dendrites receive signals from? | electrons | hormones | fibers | neurons | |
What is the term for the exchange of genetic material between non-sister chromatids of homologous chromosomes? | meiosis | inheritance | asexual reproduction | crossing-over | When homologous chromosomes pair up during meiosis I, crossing-over can occur. Crossing-over is the exchange of genetic material between non-sister chromatids of homologous chromosomes. It results in new combinations of genes on each chromosome. |
What must be overcome to change the motion of an object? | density | pressure | weight | inertia | To change the motion of an object, inertia must be overcome by an unbalanced force acting on the object. Until the soccer player kicks the ball in Figure below , the ball remains motionless on the ground. However, when the ball is kicked, the force on it is suddenly unbalanced. The ball starts moving across the field because its inertia has been overcome. |
Which action of the stomach helps chemical digestion by gastric juice? | contraction | peristalsis | chewing | churning action | |
What two lenses comprise a compound microscope? | concave and convex | polarized and focal | scope and focus | objective and eyepiece | Figure 26.16 A compound microscope composed of two lenses, an objective and an eyepiece. The objective forms a case 1 image that is larger than the object. This first image is the object for the eyepiece. The eyepiece forms a case 2 final image that is further magnified. |
Physical and chemical differences help ecologists distinguish between freshwater and marine types of what? | microbiomes | cities | habitats | biomes | |
What are the organic compounds that the body needs in small amounts to function properly; humans need 13 different ones? | nutrients | minerals | proteins | vitamins | Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table below ). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B 9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. |
To undo the tarnish on copper pennies, you can place them in what liquid? | seawater | distilled water | honey | vinegar | Because chemical changes produce new substances, they often cannot be undone. For example, you can’t change a fried egg back to a raw egg. Some chemical changes can be reversed, but only by other chemical changes. For example, to undo the tarnish on copper pennies, you can place them in vinegar. The acid in the vinegar reacts with the tarnish. This is a chemical change that makes the pennies bright and shiny again. You can try this yourself at home to see how well it works. |
What kind of bonding between alcohol molecules means that more energy is required to convert the liquid to vapor, and boiling points are therefore high? | stronger diffusion bonding | weaker carbon bonding | stronger mineral bonding | stronger hydrogen bonding | Only weak London dispersion forces hold molecules of nonpolar alkanes together in the liquid phase. Consequently, less energy is required to break these molecules away from the surface of the liquid and turn them into a vapor. The stronger hydrogen bonding between alcohol molecules means that more energy is required to convert the liquid to vapor, and boiling points are therefore high. |
During summer in the northern hemisphere, the north pole is tilted toward what? | horizon | moon | the north star | sun | During summer in the Northern Hemisphere, the North Pole is tilted toward the Sun. The Sun's rays strike the Northern Hemisphere more directly ( Figure below ). The region gets a lot of sunlight. Summer solstice is June 21 or 22. At that time, the Sun's rays hit directly at the Tropic of Cancer (23.5°N). This is the farthest north that the Sun will be directly overhead. Summer solstice in the Northern Hemisphere is winter solstice in the Southern Hemisphere. |
Also called lodestone, the mineral magnetite is the most powerful what? | healing magnet | material on Earth | synthetic magnet | natural permanent magnet | Some materials are natural permanent magnets. The most magnetic material in nature is the mineral magnetite, also called lodestone (see Figure below ). The magnetic domains of magnetite naturally align with Earth’s axis. The picture on the left shows a chunk of magnetite attracting small bits of iron. The magnetite spoon compass shown on the right dates back about 2000 years and comes from China. The handle of the spoon always points north. Clearly, the magnetic properties of magnetite have been recognized for thousands of years. |
How many valves are in the heart? | two | one | six | four | So how is the blood kept from flowing back on itself? Valves ( Figure below ) in the heart keep the blood flowing in one direction. The valves do this by opening and closing in one direction only. Blood only moves forward through the heart. The valves stop the blood from flowing backward. There are four valves of the heart. |
Momentum is directly related to both mass and? | speed | mass | intensity | velocity | This equation shows that momentum is directly related to both mass and velocity. An object has greater momentum if it has greater mass, greater velocity, or both. For example, a bowling ball has greater momentum than a softball when both are moving at the same velocity because the bowling ball has greater mass. However, a softball moving at a very high velocity — say, 100 miles an hour — would have greater momentum than a slow-rolling bowling ball. If an object isn’t moving at all, it has no momentum. That’s because its velocity is zero, and zero times anything is zero. |
Bones are made up of different types of what? | fiber | blood cells | cartilage | tissue | Christopher Auyeung. Bones are made up of different types of tissues . CC BY-NC 3.0. |
What do metals typically lose to achieve stability? | molecules | ions | atoms | electrons | Metals will typically lose electrons to achieve stability, while non-metals typically gain electrons to achieve stability. Two atoms or ions with the same number of electrons are referred to as isoelectronic . |
What happens when a sperm and an egg cell combine? | stimulation | migration | manipulation | fertilization | Sexual reproduction happens when a sperm and an egg cell combine together. This is called fertilization . Sperm are released into the vagina during sexual intercourse. They “swim” through the uterus and enter a fallopian tube . This is where fertilization normally takes place. |
What is the ability to change or move matter? | density | volume | temperature | energy | Energy is the ability to change or move matter. All living things need energy. They need energy for everything they do, whether it is to move long distances or simply to carry out basic biochemical processes inside cells. Energy enters most ecosystems in the form of sunlight. In a few ecosystems, energy enters in the form of chemical compounds. All ecosystems need a constant input of energy in one of these two forms. |
How many weeks are in the life cycle of ladybugs | three to six | two to four | nine to six | four to six | Ladybugs, also known as ladybird beetles, have a life cycle of four to six weeks. In one year, as many as six generations of ladybird beetles may hatch. In the spring, each adult female lays up to 300 eggs in small clusters on plants where aphids are present. After a week, the wingless larvae hatch. Both the ladybird beetle larvae and adults are active predators, eating only aphids, scales, mites and other plant-eating insects. The ladybugs live on the vegetation where their prey is found, which includes roses, oleander, milkweed and broccoli. Adult ladybugs don’t taste very good. A bird careless enough to try to eat one will not swallow it. |
What is the respiratory pigment of almost every vertebrate? | iron | insulin | plasma | hemoglobin | |
Objects moving at different speeds, in different directions have different what? | electrons | protons | vibrations | velocities | Objects have the same velocity only if they are moving at the same speed and in the same direction. Objects moving at different speeds, in different directions, or both have different velocities. |
What type of compounds make up the cells and tissues of organisms? | organic compounds | hormonal compounds | productive compounds | biochemical compounds | Biochemical compounds make up the cells and tissues of organisms. They are also involved in life processes, such as making and using food for energy. Given their diversity of functions, it’s not surprising that there are millions of different biochemical compounds. However, they can be grouped into just four main classes: carbohydrates, proteins, lipids, and nucleic acids. The classes are summarized in Table below and described in the rest of this lesson. |
Meiosis and what process are both preceded by one round of dna replication; however, they differ in producing haploid or diploid daughter cells? | photosynthesis | fertilization | cloning | mitosis | Figure 7.6 Meiosis and mitosis are both preceded by one round of DNA replication; however, meiosis includes two nuclear divisions. The four daughter cells resulting from meiosis are haploid and genetically distinct. The daughter cells resulting from mitosis are diploid and identical to the parent cell. |
In their pure form, all elements have an oxidation number of what? | 7 | 3 | 2 | zero | All elements have an oxidation number of zero in their pure form. |
What is a close relationship between two species in which at least one species benefits called? | competition | parasitic | morphogenesis | symbiosis | Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the relationship may be positive, negative, or neutral. There are three basic types of symbiosis: mutualism, commensalism, and parasitism. |
Multiple sclerosis, huntington’s disease, parkinson’s disease, and alzheimer’s disease are example of diseases of which body system? | circulatory system | muscular system | lymphatic system | nervous system | There are many other nervous system diseases. They include multiple sclerosis, Huntington’s disease, Parkinson’s disease, and Alzheimer’s disease. However, these diseases rarely, if ever, occur in young people. Their causes and symptoms are listed below ( Table below ). The diseases have no known cure, but medicines may help control their symptoms. |
What includes the living organisms in an area and the non-living aspects of the environment? | degradation | outpost | habitat | ecosystem | An ecosystem includes the living organisms (all the populations) in an area and the non-living aspects of the environment ( Figure below ). An ecosystem is made of the biotic and abiotic factors in an area. |
Bacteria may become untreatable if they develop what in response to multiple antibiotics? | acceptance | affinity | weakness | resistance | Evasion of the Immune System by Pathogens It is important to keep in mind that although the immune system has evolved to be able to control many pathogens, pathogens themselves have evolved ways to evade the immune response. An example already mentioned is in Mycobactrium tuberculosis, which has evolved a complex cell wall that is resistant to the digestive enzymes of the macrophages that ingest them, and thus persists in the host, causing the chronic disease tuberculosis. This section briefly summarizes other ways in which pathogens can “outwit” immune responses. But keep in mind, although it seems as if pathogens have a will of their own, they do not. All of these evasive “strategies” arose strictly by evolution, driven by selection. Bacteria sometimes evade immune responses because they exist in multiple strains, such as different groups of Staphylococcus aureus. aureus is commonly found in minor skin infections, such as boils, and some healthy people harbor it in their nose. One small group of strains of this bacterium, however, called methicillin-resistant Staphylococcus aureus, has become resistant to multiple antibiotics and is essentially untreatable. Different bacterial strains differ in the antigens on their surfaces. The immune response against one strain (antigen) does not affect the other; thus, the species survives. Another method of immune evasion is mutation. Because viruses’ surface molecules mutate continuously, viruses like influenza change enough each year that the flu vaccine for one year may not protect against the flu common to the next. New vaccine formulations must be derived for each flu season. Genetic recombination—the combining of gene segments from two different pathogens—is an efficient form of immune evasion. For example, the influenza virus contains gene segments that can recombine when two different viruses infect the same cell. Recombination between human and pig influenza viruses led to the 2010 H1N1 swine flu outbreak. Pathogens can produce immunosuppressive molecules that impair immune function, and there are several different types. Viruses are especially good at evading the immune response in this way, and many types of viruses have been shown to suppress the host immune response in ways much more subtle than the wholesale destruction caused by HIV. |
What grows through blue cheese that gives it the distinctive appearance and flavor? | Bacteria | Viruses | Roots | fungus | Humans have collected and grown mushrooms for food for thousands of years. Figure below shows some of the many types of mushrooms that people eat. Yeasts are used in bread baking and brewing alcoholic beverages. Other fungi are used in fermenting a wide variety of foods, including soy sauce, tempeh, and cheeses. Blue cheese has its distinctive appearance and flavor because of the fungus growing though it (see Figure below ). |
The two main types of phagocytic cells in the mammalian body are neutrophils and what other? | eukaryotes | histones | leukocytes | macrophages | |
What is aggravated by practices such as logging, mining, construction, and paving surfaces? | water pollution | global warming | seismic activity | soil erosion | Logging, mining, construction, and paving surfaces are some of the ways that soil erosion increases. |
What type of hydrocarbon is coal? | liqued | mineral | gas | solid | Coal is a solid hydrocarbon. Coal is useful as a fuel, especially for generating electricity. Coal is relatively inexpensive and abundant. Developing nations, like China, rely heavily on coal. Around the world, coal is the largest source of energy for electricity. |
What chemicals in the liver support glucose homeostasis? | Force and insulin | cytosol and insulin | lactobacilli and insulin | glucagon and insulin | |
When resources become limiting, populations follow a logistic growth curve in which the size will level off at a point called what? | containing capacity | believed capacity | full capacity | carrying capacity | 19.2 Population Growth and Regulation Populations with unlimited resources grow exponentially—with an accelerating growth rate. When resources become limiting, populations follow a logistic growth curve in which population size will level off at the carrying capacity. Populations are regulated by a variety of density-dependent and density-independent factors. Life-history characteristics, such as age at first reproduction or numbers of offspring, are characteristics that evolve in populations just as anatomy or behavior can evolve over time. The model of r- and K-selection suggests that characters, and possibly suites of characters, may evolve adaptations to population stability near the carrying capacity (K-selection) or rapid population growth and collapse (r-selection). Species will exhibit adaptations somewhere on a continuum between these two extremes. |
Along with climate, this also influences the type of vegetation that can grow in the region? | population density | gravity | fertilizer use | soil type | Soil type also influences the type of vegetation that can grow in the region. We can identify climate types by the types of plants that grow there. |
What is defined as anything that takes up space and has mass? | atoms | electrons | elements | matter | |
What is the name of the simplest carbon molecule? | butane | Buckminsterfullerine | graphite | methane | Figure 2.13 Carbon can form four covalent bonds to create an organic molecule. The simplest carbon molecule is methane (CH4), depicted here. |
Hyperparathyroidism results from an overproduction of what? | elevated hormone | inhibited hormone | tharayroid hormone | parathyroid hormone | Hyperparathyroidism results from an overproduction of parathyroid hormone. This results in excessive calcium being removed from bones and introduced into blood circulation, producing structural weakness of the bones, which can lead to deformation and fractures, plus nervous system impairment due to high blood calcium levels. Hypoparathyroidism, the underproduction of PTH, results in extremely low levels of blood calcium, which causes impaired muscle function and may result in tetany (severe sustained muscle contraction). The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys. This results in calcium being added to the bones to promote structural integrity. Calcitonin is most important in children (when it stimulates bone growth), during pregnancy (when it reduces maternal bone loss), and during prolonged starvation (because it reduces bone mass loss). In healthy nonpregnant, unstarved adults, the role of calcitonin is unclear. |
What is formed when different gases are confined to the same container? | compact mixture | linear mixture | particulate mixture | homogeneous mixture | Gases mix homogeneously when confined to same container. When several gases are added to a container, the individual gas particles mix freely, forming a homogeneous mixture in which each type of gas is randomly distributed throughout all the available volume. |
What property of fluids causes something to stay on or near the surface of water? | weight | density | strength | buoyancy | The fishing float in Figure below bobs on the surface of the water. The fish in the figure is suspended in the water near the surface. Why do the float and fish stay on or near the surface? Why don’t they sink? The answer is buoyancy, another property of fluids. |
What are the tiny sacs in the lungs where gas exchange takes place? | chambers | vacuoles | ganglion | alveoli | Pneumonia is an illness that occurs when the alveoli, the tiny sacs in the lungs where gas exchange takes place, become inflamed and filled with fluid. When a person has pneumonia, gas exchange cannot occur properly across the alveoli. Pneumonia can be caused by many things. Infection by bacteria, viruses, fungi, or parasites can cause pneumonia. An injury caused by chemicals or a physical injury to the lungs can also cause pneumonia. Symptoms of pneumonia include cough, chest pain, fever, and difficulty breathing. Treatment depends on the cause of pneumonia. Bacterial pneumonia is treated with antibiotics. |
What is the stage between a zygote and polyp? | worm | pupa | egg | larva | Cnidarians in the polyp form usually reproduce asexually. One type of asexual reproduction in polyps leads to the formation of new medusae. Medusae usually reproduce sexually with sperm and eggs. Fertilization forms a zygote. The zygote develops into a larva, and the larva develops into a polyp. There are many variations on this general life cycle. Obviously, species that exist only as polyps or medusae have a life cycle without the other form. |
What is the term for a particle outside the nucleus of an atom that has a negative electric charge? | neutron | proton | ion | electron | An electron is a particle outside the nucleus of an atom that has a negative electric charge. The charge of an electron is opposite but equal to the charge of a proton. Atoms have the same number of electrons as protons. As a result, the negative and positive charges "cancel out. " This makes atoms electrically neutral. For example, a carbon atom has six electrons that "cancel out" its six protons. |
Scientists goal is develop nuclear fusion power plants, where the energy from fusion of hydrogen nuclei can be converted to what? | wind | oil | gasoline | electricity | Scientists are searching for ways to create controlled nuclear fusion reactions on Earth. Their goal is develop nuclear fusion power plants, where the energy from fusion of hydrogen nuclei can be converted to electricity. How this might work is shown in Figure below . |
In which state of matter are particles completely separate from one another? | liquid state | phosphorus state | solid state | gaseous state | Most substances may exist in any of the three common states of matter. In the gaseous state, the molecular motion has completely overcome any attraction between the particles and the particles are totally separate from each other. There are large spaces between the particles and they move large distances between collisions. In the liquid state, the molecular motion and the molecular attractions are more balanced. While the particles stay more or less in contact with each other, they are still free to move and can slide past one another easily. In the solid state, the attractive forces dominate. The particles are pulled together into a tightly packed pattern which does not allow the particles to pass each other. The molecular motion in this form is essentially reduced to vibration in place. Increasing the temperature of a substance means increasing the molecular motion (kinetic energy) of the molecules in the substance. The phase in which a substance exists is the result of a competition between attractive forces and molecular motion. |
Van der waals forces are weak interactions between molecules that involve what? | photons | atoms | particles | dipoles | Van der Waals forces are weak interactions between molecules that involve dipoles. |
What part of the body does emphysema affect? | heart | bones | brain | lungs | Emphysema is a lung disease in which walls of the alveoli break down so less gas can be exchanged in the lungs (see Figure below ). This causes shortness of breath. The damage to the alveoli is usually caused by smoking and is irreversible. |
What number is the sum of the numbers of protons and neutrons present in the nucleus of an atom? | mass total | nuclear number | combined number | mass number | As you learned in Chapter 1 "Introduction to Chemistry", the mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom. The mass number is an integer that is approximately equal to the numerical value of the atomic mass. Although the mass number is unitless, it is assigned units called atomic mass. |
What kind of tool, often based on mathematical equations or computer simulations, helps us understand complex systems? | panels | levels | planes | models | Food Chains. These two food chains represent complex systems in nature. They make the systems easier to understand. These are simple conceptual models. Models of very complex systems are often based on mathematical equations or computer simulations. |
An ecosystem consists of all the living things and what? | local environment | living environment | phosphorescent environment | nonliving environment | An ecosystem consists of all the living things ( biotic factors ) in a given area, together with the nonliving environment ( abiotic factors ). The nonliving environment includes water, sunlight, soil, and other physical factors. |
Mesophyll consists mainly of parenchyma cells specialized for what? | digestion | circulation | respiration | photosynthesis | |
Antibiotic drugs are usually effective in treating what kind of infections? | biological | viral | lethal | bacterial | Bacterial infections of urinary organs, especially the urinary bladder, are common. They are called urinary tract infections. Generally, they can be cured with antibiotic drugs. However, if they aren’t treated, they can lead to more serious infections and damage to the kidneys. |
What is earth’s geographic north pole also called? | right north | mere north | vertical north | true north | A compass needle lines up with Earth’s magnetic north pole. This is different from Earth’s geographic north pole, also called true north. The geographic north pole is the top of an imaginary line. This line is the axis around which Earth rotates. The geographic north pole is much like the spindle of a spinning top. The location of the geographic north pole does not change. However, the magnetic north pole shifts in location over time. Depending on where you live, you can correct for the difference between the two poles when you use a map and a compass ( Figure below ). |
What are the nonliving aspects of the environment called? | antibiotic factors | metastatic factors | nucleic factors | abiotic factors | Abiotic factors are the nonliving aspects of the environment. They include factors such as sunlight, soil, temperature, and water. |
Chemical reactions follow the laws of what? | photosynthesis | Newton | quantum physics | thermodynamics | Chemical reactions follow the laws of thermodynamics. |
What do you call a mixture of two or more substances in which dissolved particles are distributed evenly throughout? | water | concentrate | liquid | solution | A solution is a mixture of two or more substances in which dissolved particles are distributed evenly throughout the solution. The substance that dissolves in a solution is called the solute, and the substance that does the dissolving is called the solvent. The concentration of a solution is the amount of solute in a given amount of solution. A solution with a lot of dissolved solute has a high concentration and is called a concentrated solution. A solution with little dissolved solute has a low concentration and is called a dilute solution. |
What is the water that falls from the sky called? | moisture | evaporation | condensation | precipitation | Clouds are needed for precipitation. Precipitation is water that falls from the sky. This may fall as liquid water, mostly as rain . It may fall also as frozen water, such as snow. |
What returns blood from capillaries to an atrium? | the liver | the lymph system | arteries | veins | |
Hemolymph bathes organs directly in arthropods and most molluscs, due to an open type of what system? | reproductive | nervous | pulmonary | circulatory | |
According to the table, aluminum has an atomic number of 13. therefore, every aluminum atom has 13 protons in its what? | components | processes | membrane | nucleus | According to the table, aluminum has an atomic number of 13. Therefore, every aluminum atom has 13 protons in its nucleus. Iron has an atomic number of 26. Therefore, every iron atom has 26 protons in its nucleus. Carbon has an atomic number of 6. Therefore, every carbon atom has 6 protons in its nucleus. Saylor URL: http://www. saylor. org/books. |
Anemia, leukemia, hemophilia, and sickle-cell disease are examples of conditions that primarily affect what? | heart | Lungs | brain | blood | Some diseases affect mainly the blood or its components. They include anemia, leukemia, hemophilia, and sickle-cell disease. |
What kind of variation does a rate measure? | construction to time | environment to time | value to time | property to time | A rate is a measure of how some property varies with time. Speed is a familiar rate that expresses the distance traveled by an object in a given amount of time. Wage is a rate that represents the amount of money earned by a person working for a given amount of time. Likewise, the rate of a chemical reaction is a measure of how much reactant is consumed, or how much product is produced, by the reaction in a given amount of time. The rate of reaction is the change in the amount of a reactant or product per unit time. Reaction rates are therefore determined by measuring the time dependence of some property that can be related to reactant or product amounts. Rates of reactions that consume or produce gaseous substances, for example, are conveniently determined by measuring changes in volume or pressure. For reactions involving one or more colored substances, rates may be monitored via measurements of light absorption. For reactions involving aqueous electrolytes, rates may be measured via changes in a solution’s conductivity. For reactants and products in solution, their relative amounts (concentrations) are conveniently used for purposes of expressing reaction rates. If we measure the concentration of hydrogen peroxide, H2O2, in an aqueous solution, we find that it changes slowly over time as the H2O2 decomposes, according to the equation: 2H 2 O 2(aq) ⟶ 2H 2 O(l) + O 2(g) The rate at which the hydrogen peroxide decomposes can be expressed in terms of the rate of change of its concentration, as shown here: change in concentration of reactant time interval ⎡ ⎤ ⎡ ⎤ − ⎣H 2 O 2⎦ t ⎣H 2 O 2⎦ t 1 2 = − t2 − t1. |
What is the name of the process that changes some chemical substances into others? | hypodermic reaction | acid reaction | mixture | chemical reaction | A chemical reaction is a process that changes some chemical substances into others. It involves breaking and forming chemical bonds. Types of chemical reactions include synthesis reactions and decomposition reactions. |
What is the term for the gases that surround a planet? | biosphere | hemisphere | galaxy | the atmosphere | An atmosphere is the gases that surround a planet. The early Earth had no atmosphere. Conditions were so hot that gases were not stable. |
Pressure and vibration are examples of what type of stimuli? | thermal | chemical | atmospheric | physical | Functional Receptor Types A third classification of receptors is by how the receptor transduces stimuli into membrane potential changes. Stimuli are of three general types. Some stimuli are ions and macromolecules that affect transmembrane receptor proteins when these chemicals diffuse across the cell membrane. Some stimuli are physical variations in the environment that affect receptor cell membrane potentials. Other stimuli include the electromagnetic radiation from visible light. For humans, the only electromagnetic energy that is perceived by our eyes is visible light. Some other organisms have receptors that humans lack, such as the heat sensors of snakes, the ultraviolet light sensors of bees, or magnetic receptors in migratory birds. Receptor cells can be further categorized on the basis of the type of stimuli they transduce. Chemical stimuli can be interpreted by a chemoreceptor that interprets chemical stimuli, such as an object’s taste or smell. Osmoreceptors respond to solute concentrations of body fluids. Additionally, pain is primarily a chemical sense that interprets the presence of chemicals from tissue damage, or similar intense stimuli, through a nociceptor. Physical stimuli, such as pressure and vibration, as well as the sensation of sound and body position (balance), are interpreted through a mechanoreceptor. Another physical stimulus that has its own type of receptor is temperature, which is sensed through a thermoreceptor that is either sensitive to temperatures above (heat) or below (cold) normal body temperature. |
In the chest, what divides as it enters the lungs to form the right and left bronchi? | nerves | Aorta | thyroid | trachea | In the chest, the trachea divides as it enters the lungs to form the right and left bronchi (bronchus, singular). These passages are covered with mucus and tiny hairs called cilia. The mucus traps any remaining particles in the air. The cilia move and sweep the particles and mucus toward the throat so they can be expelled from the body. |
When does an oocyte complete meiosis? | anaphase | metaphase | prophase | after sperm penetration | |
The electroplating process transfers metal from the anode to which part of the cell? | atom tube | plasma | electrode | cathode | The concentration of copper ions in the solution is effectively constant. This is because the electroplating process transfers metal from the anode to the cathode of the cell. Other metals commonly plated onto objects include chromium, gold, silver, and platinum. |
Compression, tension and shear refer to what type of force that can cause rock to change? | gravity | seismic force | process | stress | Stress is the force applied to a rock, which can cause the rock to change. The three main types of stress go along with the three types of plate boundaries. Compression is common at convergent boundaries, tension at divergent boundaries, and shear at transform boundaries. |
Unlike the biological species concept, the ecological species concept can accommodate asexual as well as ________ species. | homologous | homosexual | artificial | sexual | |
A basic function of cells includes obtaining what from glucose? | acids | food | proteins | energy | Obtaining energy from glucose is one of the basic functions of cells. Another basic function of living cells is dividing. |
What is the term for a test to see if a scientific explanation is right or wrong? | generation | invention | hypothesis | experiment | Scientists find answers using tests : When scientists want to answer a question, they search for evidence using experiments. An experiment is a test to see if their explanation is right or wrong. Evidence is made up of the observations a scientist makes during an experiment. To study the cause of death in the chimpanzees, scientists may give the chimps nutrients in the form of nuts, berries, and vitamins to see if they are dying from a lack of food. This test is the experiment. If fewer chimps die, then the experiment shows that the chimps may have died from not having enough food. This is the evidence. |
When a solvent with a gas dissolved in it is heated, the kinetic energy of both the solvent and solute _________? | decreases | evaporates | generates | increases | Several substances – HCl, NH 3 , and SO 2 – have solubility that decreases as temperature increases. They are all gases at standard pressure. When a solvent with a gas dissolved in it is heated, the kinetic energy of both the solvent and solute increases. As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return to the gas phase. Therefore, the solubility of a gas decreases as the temperature increases. |
How does the bacteria look when seen with the naked eye? | oily smear | slippery smear | dry smear | slimy smear | With the naked eye, bacteria just look like a slimy smear on a petri dish. How can we study them in more detail? The invention of the microscope has allowed us to see bacteria, cells, and other things too small to be seen with the naked eye. |
What is a device used to measure temperature changes during chemical processes called? | thermometer | altimeter | alethiometer | calorimeter | The subfield of thermochemistry studies the energy changes that occur over the course of various chemical reactions. We will first look at how these changes are measured and then go into quantitative descriptions of heat transfer. Calorimetry is a term used to describe the measurement of heat transfers, usually by monitoring changes in the temperature of an isolated system. A calorimeter is a device used to measure temperature changes during chemical processes. The simplest type of calorimeter is the constant-pressure device illustrated in Figure below . |
Ebola is an example of a disease spread by what kind of infectious agent? | flus | bacteria | colds | virus | Ebola is a rare and deadly disease caused by infection with a strain of Ebola virus. The 2014 Ebola epidemic is the largest in history, affecting multiple countries in West Africa, including Guinea, Sierra Leone and Liberia. Ebola is spread through direct contact with blood and body fluids of a person infected by and already showing symptoms of Ebola. Ebola is not spread through the air, water, food, or mosquitoes. See Ebola virus disease at http://www. who. int/mediacentre/factsheets/fs103/en/ for additional information. |
The tiny hair present on mucus membranes is known as? | dendrites | tissue | collagen | cilia | Mucous membranes provide a mechanical barrier at body openings. They also line the respiratory, GI, urinary, and reproductive tracts. Mucous membranes secrete mucus , a slimy substance that traps pathogens. The membranes also have hair-like cilia. The cilia sweep mucus and pathogens toward body openings where they can be removed from the body. When you sneeze or cough, pathogens are removed from the nose and throat (see Figure below ). Tears wash pathogens from the eyes, and urine flushes pathogens out of the urinary tract. You can watch the sweeping action of cilia at the following link: http://mcdb. colorado. edu/courses/2115/units/Other/mucus%20animation. swf . |
What elements do lipids primarily consist of? | helium, hydrogen , and oxygen | silicon, hydrogen , and oxygen | iron, hydrogen , and oxygen | carbon, hydrogen, and oxygen | Lipids are organic compounds that contain mainly carbon, hydrogen, and oxygen. They include substances such as fats and oils, as well as waxes, sterols, some vitamins (A, D, E and K) and phospholipids. Lipid molecules consist of fatty acids, with or without additional molecules. Fatty acids are organic compounds that have the general formula CH 3 (CH 2 ) n COOH, where n usually ranges from 2 to 28 and is always an even number. |
Polychaetes make up a large and diverse group. which category do the majority of these worms fall into? | amphibian | carnivorous | terrestrial | marine | |
What is the main makeup of the cell membrane? | filaments | glucose | antibodies | phospholipids | You can see a model of the cell membrane in Figure below . The molecules that make up the cell membrane are mainly phospholipids. There are two layers of phospholipids. They are arranged so the lipid tails are on the inside of the membrane. They make the interior of the membrane hydrophobic, or "water fearing". The lipid heads point toward the outside of the membrane. The make the outer surfaces of the membrane hydrophilic, or "water loving". Different types of proteins are embedded in the lipid layers. The proteins are needed to help transport many substances across the membrane. |
When a host attacks a parasitic bacteria, the bacteria release what to surround the cell wall? | protoplasma | bacteriophages | pathogens | layer of slime | Some bacteria depend on a host organism for energy and nutrients. These bacteria are known as parasites . If the host starts attacking the parasitic bacteria, the bacteria release a layer of slime that surrounds the cell wall. This slime offers an extra layer of protection. |
Solutions can also become supersaturated , where the amount of solute dissolved exceeds what? | its concentration | part solubility | its dissolution | its solubility | Solutions can also become supersaturated , where the amount of solute dissolved exceeds its solubility. Supersaturation most commonly occurs when a saturated solution is slowly cooled. They occur frequently in geological and meteorological processes. Supersaturated systems are unstable, and eventually, the solute will precipitate until a saturated solution is regenerated. We can quantify supersaturation by looking at solubility curves. If the ratio of solute to solvent is above the saturation curve at the given temperature, the solution is supersaturated. If it is on the curve, the solution is saturated, and if it is below the curve, the solution is unsaturated. |
What is the biggest risk associated with using nuclear energy? | fire | explosion | mutation | radiation | The main concern over the use of nuclear energy is the risk of radiation. Accidents at nuclear power plants can release harmful radiation that endangers people and other living things. Even without accidents, the used fuel that is left after nuclear fission reactions is still radioactive and very dangerous. It takes thousands of years for it to decay until it no longer releases harmful radiation. Therefore, used fuel must be stored securely to protect people and other living things. You can learn more about the problem of radioactive waste at this URL: http://www. youtube. com/watch?v=OPQ97LVRuuM. |
What property is the result of the force of gravity being opposed by the normal force? | sound | light | density | weight | For a full description of weight, look at Forces: Mass versus Weight. In sum, weight is the result of the force of gravity being opposed by the normal force. As we just learned, objects in orbit are in freefall; they have nothing exerting a normal force against them and thus no weight. |
What are the cliffs called which are created when waves erode a rocky shoreline, leaving a vertical wall of exposed rock layers? | wave - theory | shear face | widow-makers | wave-cut | Wave-cut cliffs form when waves erode a rocky shoreline. They create a vertical wall of exposed rock layers. |
When boron10 absorbs a neutron, what does it emit? | proteins | calcium | light | particle | Boron neutron capture therapy is a potential treatment for many diseases. As the name implies, when boron10, one of the naturally occurring isotopes of boron, is bombarded with neutrons, it absorbs a neutron and emits an α particle. Write a balanced nuclear reaction for this reaction. One advantage of this process is that neutrons cause little damage on their own, but when they are absorbed by boron-10, they can cause localized emission of alpha radiation. Comment on the utility of this treatment and its potential difficulties. |
What is the most common life form in the ocean? | coral | algae | kelp | plankton | When you think of life in the ocean, do you think of fish? Actually, fish are not the most common life forms in the ocean. Plankton are the most common. Plankton make up one of three major groups of marine life. The other two groups are nekton and benthos. Figure below shows the three groups. |
What circulates with the blood or hemolymph and are often contained within specialized cells | fat pigments | structural pigments | muscular pigments | respiratory pigments | |
What are the two possible reduction products for brf3? | brf and brf4 | brg and brf | brf2 and brf4 | brf and br2 | redox reaction will occur. The only question is whether lead will be oxidized to Pb(II) or Pb(IV). Because BrF3 is a powerful oxidant and fluorine is able to stabilize high oxidation states of other elements, it is likely that PbF4 will be the product. The two possible reduction products for BrF3 are BrF and Br2. The actual product will likely depend on the ratio of the reactants used. With excess BrF3, we expect the more oxidized product (BrF). With lower ratios of oxidant to lead, we would probably obtain Br2 as the product. Exercise Predict the products of each reaction and write a balanced chemical equation for each reaction. |
Normal blood is comprised of nearly half erythrocytes, which is another word for what cells? | plateletes | monocytes | white blood cells | red blood cells | Composition of Blood You have probably had blood drawn from a superficial vein in your arm, which was then sent to a lab for analysis. Some of the most common blood tests—for instance, those measuring lipid or glucose levels in plasma—determine which substances are present within blood and in what quantities. Other blood tests check for the composition of the blood itself, including the quantities and types of formed elements. One such test, called a hematocrit, measures the percentage of RBCs, clinically known as erythrocytes, in a blood sample. It is performed by spinning the blood sample in a specialized centrifuge, a process that causes the heavier elements suspended within the blood sample to separate from the lightweight, liquid plasma (Figure 18.2). Because the heaviest elements in blood are the erythrocytes, these settle at the very bottom of the hematocrit tube. Located above the erythrocytes is a pale, thin layer composed of the remaining formed elements of blood. These are the WBCs, clinically known as leukocytes, and the platelets, cell fragments also called thrombocytes. This layer is referred to as the buffy coat because of its color; it normally constitutes less than 1 percent of a blood sample. Above the buffy coat is the blood plasma, normally a pale, strawcolored fluid, which constitutes the remainder of the sample. The volume of erythrocytes after centrifugation is also commonly referred to as packed cell volume (PCV). In normal blood, about 45 percent of a sample is erythrocytes. The hematocrit of any one sample can vary significantly, however, about 36–50 percent, according to gender and other factors. Normal hematocrit values for females range from 37 to 47, with a mean value of 41; for males, hematocrit ranges from 42 to 52, with a mean of 47. The percentage of other formed elements, the WBCs and platelets, is extremely small so it is not normally considered with the hematocrit. So the mean plasma percentage is the percent of blood that is not erythrocytes: for females, it is approximately 59 (or 100 minus 41), and for males, it is approximately 53 (or 100 minus 47). |
What type of intense storm is a system of winds that rotate around a low pressure center, resulting in swirling air that rises and cools to create clouds and precipitation? | monsoon | hurricane | drought | cyclone | Cyclones can be the most intense storms on Earth. A cyclone is a system of winds that rotate around a low pressure center. The swirling air rises and cools. This creates clouds and precipitation. |
Blood flows into the kidney through which artery? | pulminary artery | main artery | blood artery | renal artery | Blood flows into the kidney through the renal artery. The renal artery connects to capillaries inside the kidney. Capillaries and nephrons lie very close to each other in the kidney. |
Growth and development in humans is most rapid during what two stages? | flutter and adolescence | bounce and adolescence | teen and adults | infancy and adolescence | Growth and development are most rapid during infancy and slower throughout the rest of childhood until adolescence. |
What are used to write nuclear equations for radioactive decay? | energy symbols | special symbols | chemical symbols | nuclear symbols | Nuclear symbols are used to write nuclear equations for radioactive decay. Let’s consider an example. Uranium-238 undergoes alpha decay to become thorium-234. (The numbers following the chemical names refer to the number of protons plus neutrons. ) In this reaction, uranium-238 loses two protons and two neutrons to become the element thorium-234. The reaction can be represented by this nuclear equation:. |
The pull of gravity is expressed as a force of what? | volt | joule | pascal | newtons | One force acting on you—and all the other objects on Earth—is gravity. Look at the physics book in the Figure below . Gravity pulls the book downward with a force of 20 Newtons. Why doesn’t the book fall to the ground? The table pushes upward on the book with the same amount of force. The combined force, or net force , acting on the book is 0 Newtons. That’s because upward and downward forces are balanced, so they cancel out. You can learn more about net force at this URL:. |
What type of physics explains the behavior of visible light and electromagnetic waves? | statistics | Quantum mechanics | Thermodynamics | optics | We already know that visible light is the type of electromagnetic waves to which our eyes respond. That knowledge still leaves many questions regarding the nature of light and vision. What is color, and how do our eyes detect it? Why do diamonds sparkle? How does light travel? How do lenses and mirrors form images? These are but a few of the questions that are answered by the study of optics. Optics is the branch of physics that deals with the behavior of visible light and other electromagnetic waves. In particular, optics is concerned with the generation and propagation of light and its interaction with matter. What we have already learned about the generation of light in our study of heat transfer by radiation will be expanded upon in later topics, especially those on atomic physics. Now, we will concentrate on the propagation of light and its interaction with matter. It is convenient to divide optics into two major parts based on the size of objects that light encounters. When light interacts with an object that is several times as large as the light’s wavelength, its observable behavior is like that of a ray; it does not prominently display its wave characteristics. We call this part of optics “geometric optics. ” This chapter will concentrate on such situations. When light interacts with smaller objects, it has very prominent wave characteristics, such as constructive and destructive interference. Wave Optics will concentrate on such situations. |
The duodenum has a major role in regulating what digestive organ and its emptying? | respiratory | kidneys | skin | stomach | stretch receptors. This stimulates parasympathetic neurons to release acetylcholine, which then provokes increased secretion of gastric juice. Partially digested proteins, caffeine, and rising pH stimulate the release of gastrin from enteroendocrine G cells, which in turn induces parietal cells to increase their production of HCl, which is needed to create an acidic environment for the conversion of pepsinogen to pepsin, and protein digestion. Additionally, the release of gastrin activates vigorous smooth muscle contractions. However, it should be noted that the stomach does have a natural means of avoiding excessive acid secretion and potential heartburn. Whenever pH levels drop too low, cells in the stomach react by suspending HCl secretion and increasing mucous secretions. The intestinal phase of gastric secretion has both excitatory and inhibitory elements. The duodenum has a major role in regulating the stomach and its emptying. When partially digested food fills the duodenum, intestinal mucosal cells release a hormone called intestinal (enteric) gastrin, which further excites gastric juice secretion. This stimulatory activity is brief, however, because when the intestine distends with chyme, the enterogastric reflex inhibits secretion. One of the effects of this reflex is to close the pyloric sphincter, which blocks additional chyme from entering the duodenum. |
What are misfolded versions of normal brain proteins? | humans | ribosomes | protons | prions | |
By impacting plant species and the animals they support, destruction of habitat threatens what event? | mutation | overpopulation | depletion | extinction |
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