question
stringlengths 14
399
| distractor3
stringlengths 1
63
| distractor1
stringlengths 1
57
| distractor2
stringlengths 1
62
| correct_answer
stringlengths 1
67
| support
stringlengths 0
3.56k
|
|---|---|---|---|---|---|
Cells that undergo cell division continue to have their telomeres shortened, thus telomere shortening is associated with what life process? | reproduction | metabolism | reducing | aging | Telomerase and Aging Cells that undergo cell division continue to have their telomeres shortened because most somatic cells do not make telomerase. This essentially means that telomere shortening is associated with aging. With the advent of modern medicine, preventative health care, and healthier lifestyles, the human life span has increased, and there is an increasing demand for people to look younger and have a better quality of life as they grow older. In 2010, scientists found that telomerase can reverse some age-related conditions in mice. This may have potential in [2] regenerative medicine. Telomerase-deficient mice were used in these studies; these mice have tissue atrophy, stem 2. Jaskelioff et al. , “Telomerase reactivation reverses tissue degeneration in aged telomerase-deficient mice,” Nature 469 (2011): 102-7. |
Which two basic parts of a plant develop tough outer coatings to protect the plant from the environment? | bark and stems | roots and leaves | stems and stalks | leaves and stems | |
What is the name for a kind of animal that eats a mix of plant and animal foods. | an herbivore | an smorgasbord | a carnivore | an omnivore | Some mammals are omnivores. Omnivores are heterotrophs that eat a mix of plant and animal foods. Mammals that are omnivores include bears, foxes, rats, pigs, and human beings. The chimpanzees in Figure below are also omnivorous mammals. In the wild, they eat mainly plant foods, but they supplement plants with birds, bird eggs, insects, small monkeys, and other small mammals. Their favorite and most common food, however, is fruit. Animals that eat mainly fruit are called frugivores. |
Oxygenated air, taken in during inhalation, diffuses across the surface of the lungs into the what? | proteins | liver | brain | bloodstream | Types of Breathing Amphibians have evolved multiple ways of breathing. Young amphibians, like tadpoles, use gills to breathe, and they don’t leave the water. Some amphibians retain gills for life. As the tadpole grows, the gills disappear and lungs grow. These lungs are primitive and not as evolved as mammalian lungs. Adult amphibians are lacking or have a reduced diaphragm, so breathing via lungs is forced. The other means of breathing for amphibians is diffusion across the skin. To aid this diffusion, amphibian skin must remain moist. Birds face a unique challenge with respect to breathing: They fly. Flying consumes a great amount of energy; therefore, birds require a lot of oxygen to aid their metabolic processes. Birds have evolved a respiratory system that supplies them with the oxygen needed to enable flying. Similar to mammals, birds have lungs, which are organs specialized for gas exchange. Oxygenated air, taken in during inhalation, diffuses across the surface of the lungs into the bloodstream, and carbon dioxide diffuses from the blood into the lungs and expelled during exhalation. The details of breathing between birds and mammals differ substantially. In addition to lungs, birds have air sacs inside their body. Air flows in one direction from the posterior air sacs to the lungs and out of the anterior air sacs. The flow of air is in the opposite direction from blood flow, and gas exchange takes place much more efficiently. This type of breathing enables birds to obtain the requisite oxygen, even at higher altitudes where the oxygen concentration is low. This directionality of airflow requires two cycles of air intake and exhalation to completely get the air out of the lungs. |
What substances, which serve as catalysts, are involved in most of the chemical reactions that take place in organisms? | carbohydrates | proteins | vitamins | enzymes | Enzymes are involved in most of the chemical reactions that take place in organisms. |
What is the type of plant called when its leaves seasonally turn color and fall off? | evergreen | conifer | verdant plant | deciduous plant | In a deciduous plant, leaves seasonally turn color and fall off the plant. They are replaced with new leaves later in the year. |
Besides the endocrine system, what other system exerts control over all the organ systems of the body? | skeleton system | circulatory system | abnormal system | nervous system | 16.6 | Nervous System By the end of this section, you will be able to: • Describe the form and function of a neuron • Describe the basic parts and functions of the central nervous system • Describe the basic parts and functions of the peripheral nervous system As you read this, your nervous system is performing several functions simultaneously. The visual system is processing what is seen on the page; the motor system controls your eye movements and the turn of the pages (or click of the mouse); the prefrontal cortex maintains attention. Even fundamental functions, like breathing and regulation of body temperature, are controlled by the nervous system. The nervous system is one of two systems that exert control over all the organ systems of the body; the other is the endocrine system. The nervous system’s control is much more specific and rapid than the hormonal system. It communicates signals through cells and the tiny gaps between them rather than through the circulatory system as in the endocrine system. It uses a combination of chemical and electrochemical signals, rather than purely chemical signals used by the endocrine system to cover long distances quickly. The nervous system acquires information from sensory organs, processes it and then may initiate a response either through motor function, leading to movement, or in a change in the organism’s physiological state. Nervous systems throughout the animal kingdom vary in structure and complexity. Some organisms, like sea sponges, lack a true nervous system. Others, like jellyfish, lack a true brain and instead have a system of separate but connected nerve cells (neurons) called a “nerve net. ” Flatworms have both a central nervous system (CNS), made up of a ganglion (clusters of connected neurons) and two nerve cords, and a peripheral nervous system (PNS) containing a system of nerves that extend throughout the body. The insect nervous system is more complex but also fairly decentralized. It contains a brain, ventral nerve cord, and ganglia. These ganglia can control movements and behaviors without input from the brain. Compared to invertebrates, vertebrate nervous systems are more complex, centralized, and specialized. While there is great diversity among different vertebrate nervous systems, they all share a basic structure: a CNS that contains a brain and spinal cord and a PNS made up of peripheral sensory and motor nerves. One interesting difference between the nervous systems of invertebrates and vertebrates is that the nerve cords of many invertebrates are located ventrally (toward the stomach) whereas the vertebrate spinal cords are located dorsally (toward the back). There is debate among evolutionary biologists. |
What is the area where an electron is most likely to be found called? | neucleus | neutron | proton | orbital | wave functions can predict within a certain level of probability where an electron might be at any given time. The area where an electron is most likely to be found is called its orbital. Recall that the Bohr model depicts an atom’s electron shell configuration. Within each electron shell are subshells, and each subshell has a specified number of orbitals containing electrons. While it is impossible to calculate exactly where an electron is located, scientists know that it is most probably located within its orbital path. Subshells are designated by the letter s, p, d, and f. The s subshell is spherical in shape and has one orbital. Principal shell 1n has only a single s orbital, which can hold two electrons. Principal shell 2n has one s and one p subshell, and can hold a total of eight electrons. The p subshell has three dumbbell-shaped orbitals, as illustrated in Figure 2.8. Subshells d and f have more complex shapes and contain five and seven orbitals, respectively. These are not shown in the illustration. Principal shell 3n has s, p, and d subshells and can hold 18 electrons. Principal shell 4n has s, p, d and f orbitals and can hold 32 electrons. Moving away from the nucleus, the number of electrons and orbitals found in the energy levels increases. Progressing from one atom to the next in the periodic table, the electron structure can be worked out by fitting an extra electron into the next available orbital. |
The part of the ecosystem required by a particular species is endangered when human activity threatens loss of what? | biodiversity | primary producers | primary speciation | habitat | Habitat Loss Humans rely on technology to modify their environment and replace certain functions that were once performed by the natural ecosystem. Other species cannot do this. Elimination of their habitat—whether it is a forest, coral reef, grassland, or flowing river—will kill the individuals in the species. Remove the entire habitat within the range of a species and, unless they are one of the few species that do well in human-built environments, the species will become extinct. Human destruction of habitats (habitats generally refer to the part of the ecosystem required by a particular species) accelerated in the latter half of the twentieth century. Consider the exceptional biodiversity of Sumatra: it is home to one species of orangutan, a species of critically endangered elephant, and the Sumatran tiger, but half of Sumatra’s forest is now gone. The neighboring island of Borneo, home to the other species of orangutan, has lost a similar area of forest. Forest loss continues in protected areas of Borneo. The orangutan in Borneo is listed as endangered by the International Union for Conservation of Nature (IUCN), but it is simply the most visible of thousands of species that will not survive the disappearance of the forests of Borneo. The forests are removed for timber and to plant palm oil plantations (Figure 21.8). Palm oil is used in many products including food products, cosmetics, and biodiesel in Europe. A 5-year estimate of global forest cover loss for the years from 2000 to 2005 was 3.1 percent. Much loss (2.4 percent) occurred in the humid tropics where forest loss is primarily from timber extraction. These losses certainly also represent the extinction of species unique to those areas. |
What is the wavelength of light expressed in? | vatts | nanoseconds | millimeters | nanometers (nm) | Light As with auditory stimuli, light travels in waves. The compression waves that compose sound must travel in a medium—a gas, a liquid, or a solid. In contrast, light is composed of electromagnetic waves and needs no medium; light can travel in a vacuum (Figure 36.16). The behavior of light can be discussed in terms of the behavior of waves and also in terms of the behavior of the fundamental unit of light—a packet of electromagnetic radiation called a photon. A glance at the electromagnetic spectrum shows that visible light for humans is just a small slice of the entire spectrum, which includes radiation that we cannot see as light because it is below the frequency of visible red light and above the frequency of visible violet light. Certain variables are important when discussing perception of light. Wavelength (which varies inversely with frequency) manifests itself as hue. Light at the red end of the visible spectrum has longer wavelengths (and is lower frequency), while light at the violet end has shorter wavelengths (and is higher frequency). The wavelength of light is expressed in nanometers (nm); one nanometer is one billionth of a meter. Humans perceive light that ranges between approximately 380 nm and 740 nm. Some other animals, though, can detect wavelengths outside of the human range. For example, bees see near-ultraviolet light in order to locate nectar guides on flowers, and some non-avian reptiles sense infrared light (heat that prey gives off). |
What is found inside the pores of spongy bone? | green marrow | liquid marrow | rupture marrow | bone marrow | Bone marrow is a soft connective tissue that produces blood cells. It is found inside the pores of spongy bone. |
The strength of an acid depends on how many of which ions it produces when it dissolves in water? | helium | silicon | carbon | hydrogen | The strength of an acid depends on how many hydrogen ions it produces when it dissolves in water. A stronger acid produces more hydrogen ions than a weaker acid. For example, sulfuric acid (H 2 SO 4 ), which is found in car batteries, is a strong acid because nearly all of it breaks down into ions when it dissolves in water. On the other hand, acetic acid (CH 3 CO 2 H), which is the acid in vinegar, is a weak acid because less than 1 percent of it breaks down into ions in water. |
How many oxygen ions make up an ozone molecule? | five | eight | one | three | Oxygen is needed to make ozone. Ozone is a molecule made of three oxygen ions. Ozone in the upper atmosphere blocks harmful solar radiation from reaching the surface. Without oxygen, life on Earth would have been very simple. |
While light travels at different speeds in different kinds of matter, the speed of light is constant in what condition? | under water | outer space | through glass | vacuum | Although the speed of light is constant in a vacuum, light travels at different speeds in different kinds of matter. For example, light travels more slowly in glass than in air. Therefore, when light passes from air to glass, it slows down. If light strikes a sheet of glass straight on, or perpendicular to the glass, it slows down but passes straight through. However, if light enters the glass at an angle other than 90°, the wave refracts, or bends. This is illustrated in Figure below . How much light bends when it enters a new medium depends on how much it changes speed. The greater the change in speed, the more light bends. |
What kind of solution might cause animal cells to burst? | eutrophic | Acid Solution | monatomic | hypotonic | Unless an animal cell (such as the red blood cell in the top panel) has an adaptation that allows it to alter the osmotic uptake of water, it will lose too much water and shrivel up in a hypertonic environment. If placed in a hypotonic solution, water molecules will enter the cell, causing it to swell and burst. Plant cells (bottom panel) become plasmolyzed in a hypertonic solution, but tend to do best in a hypotonic environment. Water is stored in the central vacuole of the plant cell. |
Transition metals are superior conductors of heat as well as what else? | cold | light | radiation | electricity | Transition metals are superior conductors of heat as well as electricity. They are malleable, which means they can be shaped into sheets, and ductile, which means they can be shaped into wires. They have high melting and boiling points, and all are solids at room temperature, except for mercury (Hg), which is a liquid. Transition metals are also high in density and very hard. Most of them are white or silvery in color, and they are generally lustrous, or shiny. The compounds that transition metals form with other elements are often very colorful. You can see several examples in the Figure below . |
Our digestive system breaks down starch to what? | pattern sugars | Salts | Waste | simple sugars | Starches are complex carbohydrates. They are polymers of glucose. They consist of hundreds of glucose monomers bonded together. Plants make starch to store extra sugars. Consumers get starch from plants. Common sources of starch in the human diet are pictured in Figure below . Our digestive system breaks down starch to simple sugars, which our cells use for energy. |
What happens to a tectonic plate when it subducts? | it sinks | it warms | it cracks | it melts | Composite volcanoes are common along convergent plate boundaries. When a tectonic plate subducts, it melts. This creates the thick magma needed for these eruptions. The Pacific Ring of Fire is dotted by composite volcanoes. |
A monosaccharide is the simplest carbohydrate and cannot be hydrolyzed to produce a smaller what? | quark | amino acid | glucose atom | carbohydrate molecule | A monosaccharide is the simplest carbohydrate and cannot be hydrolyzed to produce a smaller carbohydrate molecule. Disaccharides contain two monosaccharide units, and polysaccharides contain many monosaccharide units. |
What is the term for if multiple sperm fuse with an egg? | pollenation | fraternization | in vitro fertilization | polyspermy | To ensure that no more than one sperm fertilizes the egg, once the acrosomal reactions take place at one location of the egg membrane, the egg releases proteins in other locations to prevent other sperm from fusing with the egg. If this mechanism fails, multiple sperm can fuse with the egg, resulting in polyspermy. The resulting embryo is not genetically viable and dies within a few days. |
As air pressures inside and outside of the ear equalize, what phenomenon is produced? | heart skipping | eyes blinking | throat scratching | ear popping | Ears pop as air pressures inside and outside of the ear equalize. |
How many pairs of chromosomes are there? | 13 | 17 | 2 | 23 | Humans have 23 pairs of chromosomes in each body cell. |
Food is broken into smaller particles by mastication, a process involving action by what structures? | tonsils | cilia | proteins | teeth | Oral Cavity Both physical and chemical digestion begin in the mouth or oral cavity, which is the point of entry of food into the digestive system. The food is broken into smaller particles by mastication, the chewing action of the teeth. All mammals have teeth and can chew their food to begin the process of physically breaking it down into smaller particles. The chemical process of digestion begins during chewing as food mixes with saliva, produced by the salivary glands (Figure 16.5). Saliva contains mucus that moistens food and buffers the pH of the food. Saliva also contains lysozyme, which has antibacterial action. It also contains an enzyme called salivary amylase that begins the process of converting starches in the food into a disaccharide called maltose. Another enzyme called lipase is produced by cells in the tongue to break down fats. The chewing and wetting action provided by the teeth and saliva prepare the food into a mass called the bolus for swallowing. The tongue helps in swallowing—moving the bolus from the mouth into the pharynx. The pharynx opens to two passageways: the esophagus and the trachea. The esophagus leads to the stomach and the trachea leads to the lungs. The epiglottis is a flap of tissue that covers the tracheal opening during swallowing to prevent food from entering the lungs. |
Cell communication that occurs over short distances is known as what? | cell echo | hypersignaling | contraposition signaling | paracrine signaling | Cells that are communicating may be right next to each other or far apart. In juxtacrine signaling , also known as contact-dependent signaling, two adjacent cells must make physical contact in order to communicate. Cell communication may also occur over short distances, which is known as paracrine signaling , or over large distances, which is known as endocrine signaling . |
Triggering a blink when something touches the surface of the eye, the corneal reflex is what type of reflex? | orgasmic | dendritic | sensory | somatic | connection is the basis of somatic reflexes. The corneal reflex is contraction of the orbicularis oculi muscle to blink the eyelid when something touches the surface of the eye. Stretch reflexes maintain a constant length of muscles by causing a contraction of a muscle to compensate for a stretch that can be sensed by a specialized receptor called a muscle spindle. |
Vascular disorders involve problems with the flow of what? | saliva | mucus | bacteria | blood | Vascular disorders involve problems with blood flow. For example, a stroke occurs when a blood clot blocks blood flow to part of the brain. Brain cells die quickly if their oxygen supply is cut off. This may cause paralysis and loss of other normal functions, depending on the part of the brain that is damaged. |
In eukaryotes, mrna may be modified before leaving what? | epidermis | ribosome | mitochondria | nucleus | During transcription, a copy of mRNA is made that is complementary to a strand of DNA. In eukaryotes, mRNA may be modified before it leaves the nucleus. |
Velocity affects what type of energy more than mass does? | mechanical energy | magnetic energy | harmonic energy | kinetic energy | This equation for kinetic energy shows that velocity affects kinetic energy more than mass does. For example, if mass doubles, kinetic energy also doubles. But if velocity doubles, kinetic energy increases by a factor of four. That’s because velocity is squared in the equation. You can see for yourself how mass and velocity affect kinetic energy by working through the problems below. |
In which way do vertebrates reproduce? | asexually | bisexually | unisexually | sexually | Vertebrates reproduce sexually, and almost all of them have separate male and female sexes. Generally, aquatic species have external fertilization, whereas terrestrial species have internal fertilization. Can you think of a reason why aquatic and terrestrial vertebrates differ in this way?. |
Neutrons and protons reside in which part of the atom? | vacuoles | molecules | nucleolus | nucleus | Neutrons, like protons, reside in the nucleus of an atom. They have a mass of 1 and no charge. The positive (protons) and negative (electrons) charges balance each other in a neutral atom, which has a net zero charge. Because protons and neutrons each have a mass of 1, the mass of an atom is equal to the number of protons and neutrons of that atom. The number of electrons does not factor into the overall mass, because their mass is so small. As stated earlier, each element has its own unique properties. Each contains a different number of protons and neutrons, giving it its own atomic number and mass number. The atomic number of an element is equal to the number of protons that element contains. The mass number, or atomic mass, is the number of protons plus the number of neutrons of that element. Therefore, it is possible to determine the number of neutrons by subtracting the atomic number from the mass number. |
What are the two best known baryons? | shafts and neutrons | flux and neurons | electrons and neutrons | protons and neutrons | Particles that are composed of three quarks are called baryons . The two best known baryons are protons and neutrons. A proton is composed of two up quarks and one down quark (uud). The charge on the proton is the result of adding the charges on these quarks . Neutrons are composed of one up quark and two down quarks (udd). The charge on the neutron is the result of adding the charges on these quarks . |
Mutation creates new genetic variation in what? | form pool | mutation pool | disease pool | gene pool | Mutation creates new genetic variation in a gene pool. |
What hormone controls milk production in mammary glands? | dopamine | melanin | pepsin | prolactin | |
Cellular respiration brings hydrogen and oxygen together to form what? | Salt | cold | air | water | |
What are the two components of the autonomic nervous system? | neurons and sympathetic | empathetic and sympathetic | crystallisation and sympathetic | parasympathetic and sympathetic | 31.3 Peripheral nervous system The peripheral nervous system is broken down into two sub-systems, the somatic nervous system and the autonomic nervous system. ANS - Autonomic Nervous System The ANS has two components - parasympathetic and sympathetic. The sympathetic nervous system is the "fight or flight" or fright response and results in an increased heart rate, increased rate of breathing, and an elevated blood glucose level. There is also decreased digestion. The second neurotransmitter is epinephrine. In this case, the first neuron is short and the second neuron is long. The parasympathetic nervous system is the rest and digest system. Drugs must be able to pass the blood brain barrier to have an effect on the CNS. Drugs act by affecting the neuron and how likely it is to fire an action potential. Stroke occurs when there is a blood clot that goes to the brain and prevent blood flow. |
Where do lancelets live? | deep sea caves | on land | riverbeds | shallow ocean water | There are only about 25 living species of lancelets. They inhabit the ocean floor where the water is shallow. Lancelet larvae are free-swimming. The adults can swim but spend most of their time buried in the sand. Like tunicates, lancelets are filter feeders. They take in water through their mouth and expel it through an opening called the atriopore (see Figure below ). Lancelets reproduce sexually and have separates sexes. |
What is caused when circulating blood puts pressure on the walls of blood vessels? | high cholesterol | aneurysm | atherosclerosis | blood pressure | Blood pressure occurs when circulating blood puts pressure on the walls of blood vessels. |
What is the most common bacterial sti in the u. s.? | influenza | diarrhea | tuberculosis | chlamydia | Chlamydia is the most common bacterial STI in the U. S. Females are more likely to develop it than males. Symptoms may include burning during urination and a discharge from the vagina or penis. |
In what unit is heat measured in? | amperes | velocities | thermals | joules | The heat that is either absorbed or released is measured in joules. The mass is measured in grams. The change in temperature is given by , where is the final temperature and is the initial temperature. |
In which type of cells are most organelles not found? | heterogeneous cells | endoplasmic cells | eukaryotic cells | prokaryotic cells | Eukaryotic cells have many specific functions, so it can be said that a cell is like a factory. A factory has many machines and people, and each has a specific role. Just like a factory, the cell is made up of many different parts. Each part has a special role. The different parts of the cell are called organelles , which means "small organs. " All organelles are found in eukaryotic cells. Prokaryotic cells are "simpler" than eukaryotic cells. Though prokaryotic cells still have many functions, they are not as specialized as eukaryotic cells, lacking membrane-bound organelles. Thus, most organelles are not found in prokaryotic cells. |
Which three colors are called the primary colors of light? | blue, green, violet | red, blue, yellow | black, white, red | red, green, blue | The human eye can distinguish only red, green, and blue light. These three colors are called the primary colors of light. All other colors of light can be created by combining the primary colors. Look at the Venn diagram below . Red and green light combine to form yellow light. Red and blue light combine to form magenta light, and blue and green light combine to form cyan light. Yellow, magenta, and cyan are called the secondary colors of light. Look at the center of the diagram, where all three primary colors of light combine. The result is white light. You can explore the colors of visible light and how they combine at this URL: http://www. phy. ntnu. edu. tw/oldjava/color/color_e. html. |
Water dissolving minerals out of rocks makes ocean water what? | sweet | muddy | bitter | salty | Ocean water is salty because water dissolves minerals out of rocks. This happens whenever water flows over or through rocks. Much of this water and its minerals flow in rivers that end up in the oceans. Minerals dissolved in water form salts. When the water evaporates, it leaves the salts behind. As a result, ocean water is much saltier than other water on Earth. |
Like the energy content in food, the energy expenditures of exercise are also reported in what units? | grams | ironies | gigabytes | kilocalories | To Your Health: Energy Expenditures Most health professionals agree that exercise is a valuable component of a healthy lifestyle. Exercise not only strengthens the body and develops muscle tone but also expends energy. After obtaining energy from the foods we eat, we need to expend that energy somehow, or our bodies will store it in unhealthy ways. Like the energy content in food, the energy expenditures of exercise are also reported in kilocalories, usually kilocalories per hour of exercise. These expenditures vary widely, from about 440 kcal/h for walking at a speed of 4 mph to 1,870 kcal/h for mountain biking at 20 mph. Table 7.2 "Energy Expenditure of a 180-Pound Person during Selected Exercises" lists the energy expenditure for a variety of exercises. Saylor URL: http://www. saylor. org/books. |
What's the term for an allele that's always expressed over another? | recessive | prevalent | mutated | dominant | When two different alleles (heritable factors) are inherited together, one may be expressed, while the effect of the other may be “silenced. ” In the case of pod color, the allele for green pods is always expressed and is dominant . The allele for yellow pods, which is not expressed, is recessive . For instance, if a plant inherits a “yellow-pod” allele and a “green pod” allele, it will have only green pods. |
Series and parallel circuits are two basic types of what? | mutual circuits | mechanical circuits | chemical circuits | electric circuits | There are two basic types of electric circuits, called series and parallel circuits. They differ in the number of loops through which current can flow. You can see an example of each type of circuit in Figure below . |
Transport of water and solutes in plants water potential is a measure of the difference in potential energy between a water sample and this? | salty water | green water | dirty water | pure water | 30.5 Transport of Water and Solutes in Plants Water potential (Ψ) is a measure of the difference in potential energy between a water sample and pure water. The water potential in plant solutions is influenced by solute concentration, pressure, gravity, and matric potential. Water potential and transpiration influence how water is transported through the xylem in plants. These processes are regulated by stomatal opening and closing. Photosynthates (mainly sucrose) move from sources to sinks through the plant’s phloem. Sucrose is actively loaded into the sieve-tube elements of the phloem. The increased solute concentration causes water to move by osmosis from the xylem into the phloem. The positive pressure that is produced pushes water and solutes down the pressure gradient. The sucrose is unloaded into the sink, and the water returns to the xylem vessels. |
Three distinct layers or tunics form the walls of what structures; the first is a smooth, inner lining of endothelial cells in contact with the red blood cells? | alveoli | lungs | white blood cells | blood vessels | The structure of the different types of blood vessels reflects their function or layers. There are three distinct layers, or tunics, that form the walls of blood vessels (Figure 40.16). The first tunic is a smooth, inner lining of endothelial cells that are in contact with the red blood cells. The endothelial tunic is continuous with the endocardium of the heart. In capillaries, this single layer of cells is the location of diffusion of oxygen and carbon dioxide between the endothelial cells and red blood cells, as well as the exchange site via endocytosis and exocytosis. The movement of materials at the site of capillaries is regulated by vasoconstriction, narrowing of the blood vessels, and vasodilation, widening of the blood vessels; this is important in the overall regulation of blood pressure. Veins and arteries both have two further tunics that surround the endothelium: the middle tunic is composed of smooth muscle and the outermost layer is connective tissue (collagen and elastic fibers). The elastic connective tissue stretches and supports the blood vessels, and the smooth muscle layer helps regulate blood flow by altering vascular resistance through vasoconstriction and vasodilation. The arteries have thicker smooth muscle and connective tissue than the veins to accommodate the higher pressure and speed of freshly pumped blood. The veins are thinner walled as the pressure and rate of flow are much lower. In addition, veins are structurally different than arteries in that veins have valves to prevent the backflow of blood. Because veins have to work against gravity to get blood back to the heart, contraction of skeletal muscle assists with the flow of blood back to the heart. |
Groundwater does what to the rock beneath the ground surface? | boosts it | accelerates it | creates it | erodes it | Groundwater erodes rock beneath the ground surface. Limestone is a carbonate and is most easily eroded. |
Technetium is named after the greektechnikos, meaning “artificial,” because all its isotopes are what? | neutral | rare | plastic | radioactive | Group 7 (Mn, Tc, and Re) Continuing across the periodic table, we encounter the group 7 elements (Table 23.5 "Some Properties of the Elements of Groups 6 and 7"). One group 7 metal (Mn) is usually combined with iron in an alloy called ferromanganese, which has been used since 1856 to improve the mechanical properties of steel by scavenging sulfur and oxygen impurities to form MnS and MnO. Technetium is named after the Greektechnikos, meaning “artificial,” because all its isotopes are radioactive. One isotope, 99mTc (m for metastable), has become an important biomedical tool for imaging internal organs. (For more information on biomedical imaging, see Chapter 20 "Nuclear Chemistry", Section 20.5 "Applied Nuclear Chemistry". ) Because of its scarcity, Re is one of the most expensive elements, and its applications are limited. It is, however, used in a bimetallic Pt/Re catalyst for refining high-octane gasoline. All three group 7 elements have seven valence electrons and can form compounds in the +7 oxidation state. Once again, the lightest element exhibits multiple oxidation states. Compounds of Mn in oxidation states ranging from −3 to +7 are known, with the most common being +2 and +4 (Figure 23.5 "Compounds of Manganese in Oxidation States +2 to +7"). In contrast, compounds of Tc and Re in the +2 oxidation state are quite rare. Because the electronegativity of Mn is anomalously low, elemental manganese is unusually reactive. In contrast, the chemistry of Tc is similar to that of Re because of their similar size and electronegativity, again a result of the lanthanide contraction. Due to the stability of the half-filled 3d5 electron configuration, the aqueous Mn3+ ion, with a 3d4 valence electron configuration, is a potent oxidant that is able to oxidize water. It is difficult to generalize about other oxidation states for Tc and Re because their stability depends dramatically on the nature of the compound. Consistent with higher oxidation states being more stable for the heavier transition metals, reacting Mn with F2 gives only MnF3, a high-melting, red-purple solid, whereas Re reacts with F 2 to give ReF7, a volatile, low-melting, yellow solid. Again, reaction with the less oxidizing, heavier halogens produces halides in lower oxidation states. Thus reaction with Cl 2, a weaker oxidant than F2, gives MnCl2 and ReCl6. |
What is a galvanic process that can be prevented using cathodic protection? | vaporization | explosion | sublimation | corrosion | Corrosion is a galvanic process that can be prevented using cathodic protection. CONCEPTUAL PROBLEMS 1. |
What are drumlins, eskers, and kettle lakes formed by? | tsunamis | earthquakes | meteors | glaciers | Drumlins, eskers, and kettle lakes are features made of glacial till. |
What is the vector sum of all the torques acting on the object called? | gross torque | critical torque | total torque | net torque | The net torque is the vector sum of all the torques acting on the object. When adding torques it is necessary to subtract CW from CCW torques. |
An electric current flows in a path called what? | fuse | electric ring | electric course | electric circuit | Electricity refers to a number of phenomena associated with the presence and flow of electric charge. Electricity includes such diverse things as lightning, static electricity, the current generated by a battery as it discharges, and many other influences on our daily lives. The flow or movement of charge is an electric current (Figure 17.2). Electrons or ions may carry the charge. The elementary unit of charge is the charge of a proton, which is equal in magnitude to the charge of an electron. The SI unit of charge is the coulomb (C) and the charge of a proton is 1.602 × 10−19 C. The presence of an electric charge generates an electric field. Electric current is the rate of flow of charge. The SI unit for electrical current is the SI base unit called the ampere (A), which is a flow rate of 1 coulomb of charge per second (1 A = 1 C/s). An electric current flows in a path, called an electric circuit. In most chemical systems, it is necessary to maintain a closed path for current to flow. The flow of charge is generated by an electrical potential difference, or potential, between two points in the circuit. Electrical potential is the ability of the electric field to do work on the charge. The SI unit of electrical potential is the volt (V). When 1 coulomb of charge moves through a potential difference of 1 volt, it gains or loses 1 joule (J) of energy. Table 17.1 summarizes some of this information about electricity. Common Electrical Terms Quantity. |
What gas can be generated by reacting sodium bromide with elemental chlorine? | gaseous bromine gas | Molecular Bromine Gas | photons bromine gas | elemental bromine gas | Elemental bromine gas can be generated by reacting sodium bromide with elemental chlorine. The other product is sodium chloride. Write a balanced chemical equation for this reaction. Saylor URL: http://www. saylor. org/books. |
What is a close relationship between two species in which at least one species benefits? | morphogenesis | endosymbiosis | parasitism | symbiosis | Symbiosis is a close relationship between two species in which at least one species benefits. |
Over many generations, the resulting genetic diversity provides valuable raw material for what? | intelligent selection | coral selection | characteristic selection | natural selection | |
What pulls skydivers towards the earth? | inertia | momentum | impact | gravity | Skydivers are pulled towards the Earth by gravity. Gravity exerts a force on the skydivers. A force is a push or pull. Some pushes and pulls can be seen. |
What occurs when a gas passes through an opening that is smaller than the mean free path of the particles? | dissipation | precipitation | malformation | effusion | Figure 9.28 Diffusion occurs when gas molecules disperse throughout a container. Effusion occurs when a gas passes through an opening that is smaller than the mean free path of the particles, that is, the average distance traveled between collisions. Effectively, this means that only one particle passes through at a time. |
What are the preserved remains of animals, plants, and other organisms called? | basalt | skulls | rocks | fossils | Fossils are the preserved remains of animals, plants, and other organisms from the distant past. Examples of fossils include bones, teeth, and impressions. By studying fossils, evidence for evolution is revealed. Paleontologists are scientists who study fossils to learn about life in the past. Fossils allow these scientists to determine the features of extinct species. Paleontologists compare the features of species from different periods in history. With this information, they try to understand how species have evolved over millions of years ( Figure below ). |
What group of elements cannot conduct electricity? | metals | carbonates | phosphates | nonmetals | Nonmetals are elements that generally cannot conduct electricity. They are the second largest class of elements after metals. Examples of nonmetals include hydrogen, carbon, chlorine, and helium. |
What is the name of a tough, fibrous membrane which protects the outer layer of bone? | the epithelium | cartilage | marrow | the periosteum | Periosteum is a tough, fibrous membrane that covers and protects the outer surfaces of bone. |
Bond lengths are intermediate between covalent single bonds and what? | gravitational double bonds | trivalent bonds | wavefunction double bonds | covalent double bonds | Bond lengths are intermediate between covalent single bonds and covalent double bonds. |
Under a microscope, salt crystals are what shape? | squares | triangles | circles | cubes | Under a microscope, salt crystals are cubes. |
Where part of the atmosphere is the uppermost mantle? | isosphere | troposphere | thermosphere | lithosphere | The lithosphere is the brittle crust and uppermost mantle. |
In a heat map, what color represents the hottest temperatures? | pink | bright red | orange | bright yellow | A heat wave over the United States as indicated by heat radiated from the ground. The bright yellow areas are the hottest, and the blue and white are coolest. |
All living things require what, which most ecosystems obtain from the sun? | heat | oxygen | water | energy | All living things need energy. Most ecosystems get energy from the Sun. Producers use the energy to make food. They pass some of the energy to consumers. Food chains and food webs show how energy flows through ecosystems. |
Kelvin is a temperature measure in which the lowest temperature is what? | definitive zero | anomalous zero | accurate zero | absolute zero | Kelvin is a temperature measure in which the lowest temperature is absolute zero. |
The basic fabric of most biological membranes is a double layer of _________ and other lipids? | antibodies | solids | liquids | phospholipids | |
What is the name for the organs behind the head of a fish that absorb oxygen from water? | lungs | pores | alveoli | gills | Fish have gills. Gills are organs behind the head that absorb oxygen from water. Water enters through the mouth, passes over the gills, and then exits the body. |
What system gets less effective with age, that generally makes older people more disease susceptible? | nervous system | infectious system | reproductive system | immune system | The immune system naturally becomes less effective as people get older. This is why older people are generally more susceptible to disease. |
Which type of tides are created when the sun and moon's tides match? | weak tides | Neap tides | low tides | spring tides | When the Sun's and Moon's tides match, there are spring tides. When the two tides are opposed, there are neap tides. |
What is the process of creating an exact genetic replica of an organism called? | converting | reproducing | copying | cloning | Cloning is the process of creating an exact genetic replica of an organism. The clone’s DNA is exactly the same as the parent’s DNA. Bacteria and other single-celled organisms have long been able to clone themselves through asexual reproduction. Plants can also reproduce asexually. In animals, however, cloning does not happen naturally. In 1997, that all changed when a sheep named Dolly was the first large mammal ever to be successfully cloned. Other animals can now also be cloned in a laboratory. |
An example of hydrolysis working within our bodies is the process of what? | filtration | breathing | absorption | digestion | |
What theory can explain virtually all the properties of metals? | bonding theory | property law theory | formation theory | band theory | Band theory can explain virtually all the properties of metals. Metals conduct electricity, for example, because only a very small amount of energy is required to excite an electron from a filled level to an empty one, where it is free to migrate rapidly throughout the crystal in response to an applied electric field. Similarly, metals have high heat capacities (as you no doubt remember from the last time a doctor or a nurse placed a stethoscope on your skin) because the electrons in the valence band can absorb thermal energy by being excited to the low-lying empty energy levels. Finally, metals are lustrous because light of various wavelengths can be absorbed, causing the valence electrons to be excited into any of the empty energy levels above the highest occupied level. When the electrons decay back to low-lying empty levels, they emit light of different wavelengths. Because electrons can be excited from many different filled levels in a metallic solid and can then decay back to any of many empty levels, light of varying wavelengths is absorbed and reemitted, which results in the characteristic shiny appearance that we associate with metals. |
Serious imbalances, cancer and other diseases can result when expression of what goes awry? | gametes | proteins | ribosomes | genes | |
Which organ's diseases include kidney stones, infections, and kidney failure due to diabetes? | pancreas | lungs | heart | kidney | Kidney diseases include kidney stones, infections, and kidney failure due to diabetes. Kidney failure may be treated with dialysis. |
What single-celled organism can be either a predator, decomposer, herbivore, or parasite in the food chain? | Diatoms | vertebrates | mites | protozoa | Protozoa generally feed by engulfing and digesting other organisms. As consumers, they have various roles in food chains and webs. Some are predators. They prey upon other single-celled organisms, such as bacteria. In fact, protozoa predators keep many bacterial populations in check. Other protozoa are herbivores. They graze on algae. Still others are decomposers. They consume dead organic matter. There are also parasitic protozoa that live in or on living hosts. For example, the protozoan that causes malaria lives inside a human host. For their part, protozoa are important food sources for many larger organisms, including insects and worms. |
What layer, made of hot, solid rock, is beneath the earth's crust? | magma | marble | core | mantle | Beneath the crust is the mantle . The mantle is made of hot, solid rock. Through the process of conduction, heat flows from warmer objects to cooler objects ( Figure below ). The lower mantle is heated directly by conduction from the core. |
Some bacteria can contaminate food and cause what illness? | bacterial spoilage | natural poisoning | bacterial poisoning | food poisoning | Some bacteria can contaminate food and cause food poisoning. |
The enzyme pepsin works only in the presence of what? | oxygen | carbohydrates | sodium | acid | The enzyme pepsin works only in the presence of acid. A strong acid is secreted into the stomach. It provides the acid that pepsin needs. You will learn about acids in the next chapter, "Chemistry of Solutions. " Vinegar and lemon juice are two common acids. |
What organisms known as decomposers break down wastes and dead organisms into smaller molecules? | herbivores | consumers | trees | bacteria | Bacteria known as decomposers break down wastes and dead organisms into smaller molecules. These bacteria use the organic substrates they break down to get their energy, carbon, and nutrients they need for survival. |
Both flukes and tapeworms are parasites with what kind of host? | cells | insect | trees | vertebrate | Both flukes and tapeworms are parasites with vertebrate hosts, including human hosts. Flukes live in the host’s circulatory system or liver. Tapeworms live in the host’s digestive system. Usually, more than one type of host is required to complete the parasite’s life cycle. Look at the life cycle of the liver fluke in Figure below . As an adult, the fluke has a vertebrate host. As a larva, it has an invertebrate host. If you follow the life cycle, you can see how each host becomes infected so the fluke can continue its life cycle. |
What is the transfer of information from rna to dna called? | reverse differentiation | confront transcription | forward transcription | reverse transcription | Reverse transcription is the transfer of information from RNA to DNA. The is the reverse of normal transcription. Reverse transcription occurs in retroviruses, such as HIV, the virus that causes AIDS. Retroviruses are RNA viruses that are duplicated in a host cell by using reverse transcriptase enzyme to produce DNA from its RNA genome. |
In science, anything that has mass and volume is considered what? | an element | renewable | visible | matter | Matter is all the “stuff” that exists in the universe. Everything you can see and touch is made of matter, including you! The only things that aren’t matter are forms of energy, such as light and sound. In science, matter is defined as anything that has mass and volume. Mass and volume measure different aspects of matter. |
Cells with different functions often differ in what physical property? | weight | density | size | shape | Cells come in many different shapes. Cells with different functions often have different shapes. |
Wich disorder arises when defective valves allow blood to accumulate within the veins? | cataracts veins | vascular disease | bulging veins | varicose veins | Edema may be accompanied by varicose veins, especially in the superficial veins of the legs (Figure 20.8). This disorder arises when defective valves allow blood to accumulate within the veins, causing them to distend, twist, and become visible on the surface of the integument. Varicose veins may occur in both sexes, but are more common in women and are often related to pregnancy. More than simple cosmetic blemishes, varicose veins are often painful and sometimes itchy or throbbing. Without treatment, they tend to grow worse over time. The use of support hose, as well as elevating the feet and legs whenever possible, may be helpful in alleviating this condition. Laser surgery and interventional radiologic procedures can reduce the size and severity of varicose veins. Severe cases may require conventional surgery to remove the damaged vessels. As there are typically redundant circulation patterns, that is,. |
Ocean water has what property because water dissolves minerals out of rocks? | muddy | fizzy | sweet | salty | Ocean water is salty because water dissolves minerals out of rocks. The ions enter the water. This happens whenever water flows over or through rocks. Much of this water and its minerals end up in the oceans. Minerals dissolved in water form salts. When the water evaporates, it leaves the salts behind. As a result, ocean water is much saltier than other water on Earth. |
What term refers to patterns of stars seen from earth? | astrology | astronomers | horoscope | constellations | Constellations are patterns of stars seen from Earth. These stars are usually not near each other. |
What gives the plant cell strength and protection? | the genes | the protons | the cell nucleus | a cell wall | Second, plant cells have a cell wall , while animal cells do not ( Figure below ). The cell wall surrounds the plasma membrane but does not keep substances from entering or leaving the cell. A cell wall gives the plant cell strength and protection. |
If pollination occurs, what does the zygote develop into? | an egg | an ovum | a sperm | an embryo | Pollination occurs when pollen is transferred from a male to female cone. If sperm then travel from the pollen to an egg so fertilization can occur, a diploid zygote results. The zygote develops into an embryo within a seed, which forms from the ovule inside the female cone. If the seed germinates, it may grow into a mature sporophyte tree, which repeats the cycle. |
Hiv has proteins called what, internal to the envelope, which help stabilize virion shape? | sphere proteins | reduction proteins | step proteins | matrix proteins | Figure 21.4 Viruses can be either complex in shape or relatively simple. This figure shows three relatively complex virions: the bacteriophage T4, with its DNA-containing head group and tail fibers that attach to host cells; adenovirus, which uses spikes from its capsid to bind to host cells; and HIV, which uses glycoproteins embedded in its envelope to bind to host cells. Notice that HIV has proteins called matrix proteins, internal to the envelope, which help stabilize virion shape. (credit “bacteriophage, adenovirus”: modification of work by NCBI, NIH; credit “HIV retrovirus”: modification of work by NIAID, NIH). |
What are two basic types of pollutants in the air? | pesticides and smog | smog and coal | organic and inorganic | primary and secondary pollutants | There are two basic types of pollutants in air. They are known as primary pollutants and secondary pollutants. |
How do humans learn behaviors? | pressure | Aural pressure | Verbal pressure | conditioning | Humans learn behaviors through conditioning, as well. A young child might learn to put away his toys by being rewarded with a bedtime story. An older child might learn to study for tests in school by being rewarded with better grades. Can you think of behaviors you have learned by being rewarded for them?. |
Just about all life processes depend on what? | meat | air | carbon | water | Water is involved in many biochemical reactions. As a result, just about all life processes depend on water. |
During labor, what do contractions of the muscular walls of the uterus cause? | premature birth | spontaneous abortion | excretion | cervical dilation | Near the time of birth, the amniotic sac breaks in a gush of fluid. Labor usually begins within a day of this event. Labor involves contractions of the muscular walls of the uterus, which cause the cervix to dilate. With the mother’s help, the contractions eventually push the fetus out of the uterus and through the vagina. Within seconds of birth, the umbilical cord is cut. Without this connection to the placenta, the baby cannot exchange gases, so carbon dioxide quickly builds up in the baby’s blood. This stimulates the brain to trigger breathing, and the newborn takes its first breath. |
How is communication initiated and maintained with spacecraft? | wi-fi | sonar | telegraph | radio waves | Radio waves are used for communicating with spacecraft. A round-trip communication from Earth to Mars takes anywhere from 6 to 42 minutes. What challenges might this present for sending unmanned spacecraft and probes to Mars?. |
Dna replication is the first step in what process for both eukaryotic and prokaryotic cells? | cell transfer | cell death | cell growth | cell division | 1. The first step in eukaryotic cell division, as it is in prokaryotic cell division, is DNA replication. As you can see in Figure below , each chromosome then consists of two identical copies. The two copies are called sister chromatids. They are attached to each other at a point called the centromere. |
The prostate is formed of both muscular and which other tissues? | scar | nonvascular tissue | cartilage tissue | glandular | Prostate Gland As shown in Figure 27.2, the centrally located prostate gland sits anterior to the rectum at the base of the bladder surrounding the prostatic urethra (the portion of the urethra that runs within the prostate). About the size of a walnut, the prostate is formed of both muscular and glandular tissues. It excretes an alkaline, milky fluid to the passing seminal fluid—now called semen—that is critical to first coagulate and then decoagulate the semen following ejaculation. The temporary thickening of semen helps retain it within the female reproductive tract, providing time for sperm to utilize the fructose provided by seminal vesicle secretions. When the semen regains its fluid state, sperm can then pass farther into the female reproductive tract. The prostate normally doubles in size during puberty. At approximately age 25, it gradually begins to enlarge again. This enlargement does not usually cause problems; however, abnormal growth of the prostate, or benign prostatic hyperplasia (BPH), can cause constriction of the urethra as it passes through the middle of the prostate gland, leading to a number of lower urinary tract symptoms, such as a frequent and intense urge to urinate, a weak stream, and a sensation that the bladder has not emptied completely. By age 60, approximately 40 percent of men have some degree of BPH. By age 80, the number of affected individuals has jumped to as many as 80 percent. Treatments for BPH attempt to relieve the pressure on the urethra so that urine can flow more normally. Mild to moderate symptoms are treated with medication, whereas severe enlargement of the prostate is treated by surgery in which a portion of the prostate tissue is removed. Another common disorder involving the prostate is prostate cancer. According to the Centers for Disease Control and Prevention (CDC), prostate cancer is the second most common cancer in men. However, some forms of prostate cancer grow very slowly and thus may not ever require treatment. Aggressive forms of prostate cancer, in contrast, involve metastasis to vulnerable organs like the lungs and brain. There is no link between BPH and prostate cancer, but the symptoms are similar. Prostate cancer is detected by a medical history, a blood test, and a rectal exam that allows physicians. |
A mammal that reproduces by laying eggs is called what? | cactaceae | mammal | maidenhair | monotreme | Platypus. The platypus is a monotreme, a mammal that reproduces by laying eggs. |
Adaptations that go along with the active, carnivorous lifestyle of sharks are known as? | Relative traits | acute parameters | similar senses | acute senses |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.