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Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as what? | cells | chromosomes | hormones | embryos | Eight invertebrate phyla contain most invertebrate species. Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos. |
Which chemist developed a process to remove carbon and dust particles in smoke? | harold black | james carpenter | roger granger | frederick cottrell | The carbon and dust particles in smoke are often colloidally dispersed and electrically charged. Frederick Cottrell, an American chemist, developed a process to remove these particles. |
What are gases called that absorb heat in the atmosphere? | carbonate gases | microwave gases | ozone gases | greenhouse gases | Gases that absorb heat in the atmosphere are called greenhouse gases . They include carbon dioxide and water vapor. Human actions have increased the levels of greenhouse gases in the atmosphere ( Figure below ). The added gases have caused a greater greenhouse effect. How do you think this affects Earth’s temperature?. |
What are the specialized cells that sponges have? | blood cells | tune cells | magnet cells | collar cells | Sponges have specialized cells called collar cells. Describe how collar cells are specialized for the functions they serve. |
What shape are the muscles that control the anus? | triangular | elliptical | irregular | circular | Circular muscles control the anus. They relax to let the feces pass out of the body through the anus. After feces pass out of the body, they are called stool. Releasing the stool from the body is referred to as a bowel movement. |
What are the small molecules or proteins produced by bacteria that regulate gene expression? | sporozoans | fluxes | protazoas | autoinducers | Figure 9.17 Autoinducers are small molecules or proteins produced by bacteria that regulate gene expression. |
Channel proteins form what in the membrane? | atoms | walls | fibers | pores | Channel proteins form pores, or tiny holes, in the membrane. This allows water molecules and small ions to pass through the membrane without coming into contact with the hydrophobic tails of the lipid molecules in the interior of the membrane. |
The sun gives off energy in tiny packets called what? | atoms | ions | electrons | photons | The Sun gives off energy in tiny packets called photons . Photons travel in waves. These waves make up electromagnetic radiation . The image below models a wave of light ( Figure below ). Notice the wavelength in the figure. Waves with shorter wavelengths have more energy. |
What is a rock that contains important minerals called? | copper | carbonic | steel | ore | A rock that contains important minerals is called an ore . The concentration of valuable minerals in an ore may be high or low. |
A high metabolic rate and hair are ways mammals generate and conserve what? | water | resources | energy | heat | Mammals have several ways of generating and conserving heat, such as a high metabolic rate and hair to trap heat. They also have several ways to stay cool, including sweating or panting. Mammals may be herbivores, carnivores, or omnivores. They have four types of teeth, so they can eat a wide range of foods. Traits of the heart and lungs keep the cells of mammals well supplied with oxygen and nutrients. |
What is made of molecules of many different gases, and is something we usually can’t see, taste, or smell; we can only feel it when it moves? | sound | water | light | air | Air is easy to forget about. We usually can’t see it, taste it, or smell it. We can only feel it when it moves. But air is actually made of molecules of many different gases. It also contains tiny particles of solid matter. |
What navigation technology works on the same principle as echolocation? | topography | radar | GPS | sonar | Sonar works on the same principle as echolocation. |
A reaction producing heat is what type of reaction? | physical | chemistry | carbon | chemical | In the last lesson, we began investigating how a chemical equation can represent a given chemical reaction. In this lesson, we are going to study the ways in which chemical reactions are classified. There are literally thousands of chemical reactions that take place every day in our lives. Some reactions take place in the atmosphere, such as the combustion of fossil fuels. Others occur in solution, like the reactions responsible for photosynthesis or the reactions that break down our food to give us energy. Chemical reactions can take place in a variety of environments. Reactions happen on the sea floor, in our cells, and in the upper atmosphere. As we look at chemical reactions, we notice some commonalities and trends. When we studied the elements, we saw characteristics that allowed us to categorize them by family. There are also various ways to categorize chemical reactions. Some reactions produce heat, while others consume it. Some reactions are spontaneous, while others are not. Some reactions happen in nanoseconds, while others happen over longer spans of time. Some produce electricity, some emit light, and some release gaseous products. The products of chemical reactions tell us a lot about the chemistry of the process. In the above video, we see mercury(II) oxide decomposing into elemental mercury and oxygen gas. Decomposition was one of the first reaction types to be identified by chemists. Decomposition is one type of reaction you'll learn about in this lesson. |
What evolutionary process has adapted protonephridia to different tasks in different environments? | natural change | natural reproduction | natural variety | natural selection | |
Some bacteria cannot be cultured because they are obligate intracellular parasites and cannot be grown outside what? | brain cell | sponsor cell | anchor cell | host cell | Some prokaryotes, however, cannot grow in a laboratory setting. In fact, over 99 percent of bacteria and archaea are unculturable. For the most part, this is due to a lack of knowledge as to what to feed these organisms and how to grow them; they have special requirements for growth that remain unknown to scientists, such as needing specific micronutrients, pH, temperature, pressure, co-factors, or co-metabolites. Some bacteria cannot be cultured because they are obligate intracellular parasites and cannot be grown outside a host cell. In other cases, culturable organisms become unculturable under stressful conditions, even though the same organism could be cultured previously. Those organisms that cannot be cultured but are not dead are in a viable-but-non-culturable (VBNC) state. The VBNC state occurs when prokaryotes respond to environmental stressors by entering a dormant state that allows their survival. The criteria for entering into the VBNC state are not completely understood. In a process called resuscitation, the prokaryote can go back to “normal” life when environmental conditions improve. Is the VBNC state an unusual way of living for prokaryotes? In fact, most of the prokaryotes living in the soil or in oceanic waters are non-culturable. It has been said that only a small fraction, perhaps one percent, of prokaryotes can be cultured under laboratory conditions. If these organisms are non-culturable, then how is it known whether they are present and alive? Microbiologists use molecular techniques, such as the polymerase chain reaction (PCR), to amplify selected portions of DNA of prokaryotes, demonstrating their existence. Recall that PCR can make billions of copies of a DNA segment in a process called amplification. |
What are living things that produce food for themselves and other organisms called? | refiners | growers | harvesters | producers | Producers are living things that produce food for themselves and other organisms. They use energy and simple inorganic molecules to make organic compounds. Producers are vital to all ecosystems because all organisms need organic compounds for energy. |
What is the second largest class of elements? | metalloids | carbonates | silicates | nonmetals | Nonmetals are elements that do not conduct electricity. They are the second largest class of elements. Find the nonmetals in Figure above . They are all the elements on the right side of the table that are color-coded green. Examples of nonmetals include helium (He), carbon (C), and oxygen (O). |
The process in which a gas changes to a liquid is called what? | vaporing | diffusion | fermentation | condensation | The process in which a gas changes to a liquid is called condensation . Other examples of condensation are shown in Figure below . A gas condenses when it is cooled below its boiling point. At what temperature does water vapor condense?. |
What are solids with high melting and boiling points? | metal alloys | magnetic compounds | superheated compounds | ionic compounds | Ionic compounds are solids with high melting and boiling points. They are good conductors of electricity but only when dissolved in water. Their crystals are rigid and brittle. |
What kind of cells are polyribosomes found in? | yeast and prokaryotic | chloroplasts and nuclei | Prokaryotic and eukaryotic | bacterial and eukaryotic | |
Which gland is controlled by a negative feedback loop that includes the hypothalamus and pituitary gland? | pituitary | stomach | adrenal | thyroid | The thyroid gland is controlled by a negative feedback loop that includes the hypothalamus and pituitary gland. |
What term means the set of processes by which metals are extracted from their ores and converted to more useful forms? | ceramics | metamorphisis | introversion | metallurgy | Very few of the transition metals are found in nature as free metals. Consequently, almost all metallic elements must be isolated from metal oxide or metal sulfide ores. Metallurgy is the set of processes by which metals are extracted from their ores and converted to more useful forms. Metallurgy consists of three general steps: (1) mining the ore, (2) separating and concentrating the metal or the metal-containing compound, and (3) reducing the ore to the metal. Additional processes are sometimes required to improve the mechanical properties of the metal or increase its purity. Many ores contain relatively low concentrations of the desired metal; for example, copper ores that contain even 1% Cu by mass are considered commercially useful. After an ore has been mined, the first step in processing is usually to crush it because the rate of chemical reactions increases dramatically with increased surface area. Next, one of three general strategies is used to separate and concentrate the compound(s) of interest: settling and flotation, which are based on differences in density between the desired compound and impurities; pyrometallurgy, which uses chemical reduction at high temperatures; and hydrometallurgy, which employs chemical or electrochemical reduction of an aqueous solution of the metal. Other methods that take advantage of unusual physical or chemical properties of a particular compound may also be used. For example, crystals of magnetite (Fe3O4) are tiny but rather powerful magnets; in fact, magnetite (also known as lodestone) was used to make the first compasses in China during the first century BC. If a crushed ore that contains magnetite is passed through a powerful magnet, the Fe3O4 particles are attracted to the poles of the magnet, allowing them to be easily separated from other minerals. |
What blood-carrying structures contain one-way valves that contribute to the return of blood to the heart? | brains | glands | clots | veins | |
What type of components of the biosphere do chemical elements and water pass through during ecosystem recycle? | water and air | photic and aphotic | tropic and subtropic | biotic and abiotic | The chemical elements and water that are needed by organisms continuously recycle in ecosystems. They pass through biotic and abiotic components of the biosphere. That’s why their cycles are called biogeochemical cycles . For example, a chemical might move from organisms ( bio ) to the atmosphere or ocean ( geo ) and back to organisms again. Elements or water may be held for various periods of time in different parts of a cycle. |
The relationship between a nucleotide codon and its corresponding amino acid is called what? | protein | rna | dna | genetic code | The Genetic Code To summarize what we know to this point, the cellular process of transcription generates messenger RNA (mRNA), a mobile molecular copy of one or more genes with an alphabet of A, C, G, and uracil (U). Translation of the mRNA template converts nucleotide-based genetic information into a protein product. Protein sequences consist of 20 commonly occurring amino acids; therefore, it can be said that the protein alphabet consists of 20 letters. Each amino acid is defined by a threenucleotide sequence called the triplet codon. The relationship between a nucleotide codon and its corresponding amino acid is called the genetic code. Given the different numbers of “letters” in the mRNA and protein “alphabets,” combinations of nucleotides corresponded to single amino acids. Using a three-nucleotide code means that there are a total of 64 (4 × 4 × 4) possible combinations; therefore, a given amino acid is encoded by more than one nucleotide triplet (Figure 9.20). |
Traditionally, what preventative measure used weakened or inactive forms of microorganisms or viruses to stimulate the immune system? | pathogen | infection | assimilation | vaccine | Production of Vaccines, Antibiotics, and Hormones Traditional vaccination strategies use weakened or inactive forms of microorganisms or viruses to stimulate the immune system. Modern techniques use specific genes of microorganisms cloned into vectors and mass-produced in bacteria to make large quantities of specific substances to stimulate the immune system. The substance is then used as a vaccine. In some cases, such as the H1N1 flu vaccine, genes cloned from the virus have been used to combat the constantly changing strains of this virus. Antibiotics kill bacteria and are naturally produced by microorganisms such as fungi; penicillin is perhaps the most wellknown example. Antibiotics are produced on a large scale by cultivating and manipulating fungal cells. The fungal cells have typically been genetically modified to improve the yields of the antibiotic compound. Recombinant DNA technology was used to produce large-scale quantities of the human hormone insulin in E. coli as early as 1978. Previously, it was only possible to treat diabetes with pig insulin, which caused allergic reactions in many humans because of differences in the insulin molecule. In addition, human growth hormone (HGH) is used to treat growth disorders. |
What is the measurement of something along it's greatest dimension called? | height | stretch | stretch | length | Length is the measurement of the extent of something along its greatest dimension. |
What form the skeletons of most organic molecules? | peptide groups | hydrocarbons | amino acid chains | carbon chains | |
What term describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell? | endocytosis | biosynthesis | plasmosis | exocytosis | Exocytosis describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell, as shown in Figure below . Exocytosis occurs when a cell produces substances for export, such as a protein, or when the cell is getting rid of a waste product or a toxin. Newly made membrane proteins and membrane lipids are moved on top the plasma membrane by exocytosis. For a detailed animation of cellular secretion, see http://vcell. ndsu. edu/animations/constitutivesecretion/first. htm . |
A sealed, vacuum-insulated reaction flask approximates what condition, in which neither matter nor heat can be exchanged between system and surroundings? | sure system | shared system | changing system | isolated system | Depending on the specific setup, a few different types of systems can be described. In an open system , both matter and heat can be freely exchanged between the reaction container (the system) and the surroundings. An example would be an open beaker, where any gaseous materials or vaporized molecules are free to leave the system and float off into the atmosphere. In a closed system , matter cannot enter or leave, but heat can flow between the system and surroundings. A stoppered reaction flask would be an example of a closed system. Finally, a situation in which neither matter nor heat can be exchanged between system and surroundings is referred to as an isolated system . Although truly isolated systems are not really possible, a sealed, vacuum-insulated reaction flask would come very close. |
A metarteriole is a type of vessel that has structural characteristics of both an arteriole and this? | layer | tendon | electron | capillary | Metarterioles and Capillary Beds A metarteriole is a type of vessel that has structural characteristics of both an arteriole and a capillary. Slightly larger than the typical capillary, the smooth muscle of the tunica media of the metarteriole is not continuous but forms rings of smooth muscle (sphincters) prior to the entrance to the capillaries. Each metarteriole arises from a terminal arteriole and branches to supply blood to a capillary bed that may consist of 10–100 capillaries. The precapillary sphincters, circular smooth muscle cells that surround the capillary at its origin with the metarteriole, tightly regulate the flow of blood from a metarteriole to the capillaries it supplies. Their function is critical: If all of the capillary beds in the body were to open simultaneously, they would collectively hold every drop of blood in the body and there would be none in the arteries, arterioles, venules, veins, or the heart itself. Normally, the precapillary sphincters are closed. When the surrounding tissues need oxygen and have excess waste products, the precapillary sphincters open, allowing blood to flow through and exchange to occur before closing once more (Figure 20.6). If all of the precapillary sphincters in a capillary bed are closed, blood will flow from the metarteriole directly into a thoroughfare channel and then into the venous circulation, bypassing the capillary bed entirely. This creates what is known as a vascular shunt. In addition, an arteriovenous anastomosis may bypass the capillary bed and lead directly to the venous system. Although you might expect blood flow through a capillary bed to be smooth, in reality, it moves with an irregular, pulsating flow. This pattern is called vasomotion and is regulated by chemical signals that are triggered in response to changes in. |
What sort of walls are helpful for keeping a slope stable? | managing walls | relocating walls | diverting walls | retaining walls | Help to keep a slope stable by building retaining walls. Installing good drainage in a hillside may keep the soil from getting saturated. |
What is the most direct way of recovering a metal from its ores? | osmosis | drilling | molecules | electrolysis | Electrolysis is the most direct way of recovering a metal from its ores. However, the Na (aq)/Na(s), 2+. |
What is the term used to describe the minerals and vitamins that are not needed for providing the body with energy but are still essential for good health? | non-energetic nutrients | salts | pigments | micronutrients | Micronutrients are nutrients the body needs in relatively small amounts. They include minerals and vitamins. These nutrients don’t provide the body with energy, but they are still essential for good health. |
What type of map reveals the shape of a landscape? | geographic | meteorological | geologic | topographic | Topographic maps reveal the shape of a landscape. Elevations indicate height above sea level. |
Does atmospheric pressure increase or decrease as the altitude increases? | depends on other factors | increase | stays the same | decreases | Atmospheric pressure decreases as the altitude increases. |
What term always refers to acceleration in the direction opposite to the direction of the velocity and always reduces speed, unlike negative acceleration? | calibration | progression | extraction | deceleration | Misconception Alert: Deceleration vs. Negative Acceleration Deceleration always refers to acceleration in the direction opposite to the direction of the velocity. Deceleration always reduces speed. Negative acceleration, however, is acceleration in the negative direction in the chosen coordinate system. Negative acceleration may or may not be deceleration, and deceleration may or may not be considered negative acceleration. For example, consider Figure 2.14. |
What do you call a quantity of motion that has both size as well as direction? | speed | wave | vibration | vector | Direction is just as important as distance in describing motion. A vector is a quantity that has both size and direction. It can be used to represent the distance and direction of motion. |
What process done by bacteria makes them important producers in aquatic ecosystems? | reproduction | maturation | infection | photosynthesis | type of bacteria that carry out photosynthesis and are important producers in aquatic ecosystems. |
Monosaccharides, disaccharides, and polysaccharides are types of what kind of macromolecule? | nutrients | glucose | protein | carbohydrate | 3.2 Carbohydrates Carbohydrates are a group of macromolecules that are a vital energy source for the cell and provide structural support to plant cells, fungi, and all of the arthropods that include lobsters, crabs, shrimp, insects, and spiders. Carbohydrates are classified as monosaccharides, disaccharides, and polysaccharides depending on the number of monomers in the molecule. Monosaccharides are linked by glycosidic bonds that are formed as a result of dehydration reactions, forming disaccharides and polysaccharides with the elimination of a water molecule for each bond formed. Glucose, galactose, and fructose are common monosaccharides, whereas common disaccharides include lactose, maltose, and sucrose. Starch and glycogen, examples of polysaccharides, are the storage forms of glucose in plants and animals, respectively. The long polysaccharide chains may be branched or unbranched. Cellulose is an example of an unbranched polysaccharide, whereas amylopectin, a constituent of starch, is a highly branched molecule. Storage of glucose, in the form of polymers like starch of glycogen, makes it slightly less accessible for metabolism; however, this prevents it from leaking out of the cell or creating a high osmotic pressure that could cause excessive water uptake by the cell. |
What action do particles of the same charge do to each other? | pull | propagate | destroy | repel | Matter and Antimatter The positron was only the first example of antimatter. Every particle in nature has an antimatter counterpart, although some particles, like the photon, are their own antiparticles. Antimatter has charge opposite to that of matter (for example, the positron is positive while the electron is negative) but is nearly identical otherwise, having the same mass, intrinsic spin, half-life, and so on. When a particle and its antimatter counterpart interact, they annihilate one another, usually totally converting their masses to pure energy in the form of photons as seen in Figure 33.13. Neutral particles, such as neutrons, have neutral antimatter counterparts, which also annihilate when they interact. Certain neutral particles are their own antiparticle and live 0 −8 correspondingly short lives. For example, the neutral pion π is its own antiparticle and has a half-life about 10 shorter than + − π and π , which are each other’s antiparticles. Without exception, nature is symmetric—all particles have antimatter counterparts. For example, antiprotons and antineutrons were first created in accelerator experiments in 1956 and the antiproton is negative. Antihydrogen atoms, consisting of an antiproton and antielectron, were observed in 1995 at CERN, too. It is possible to contain large-scale antimatter particles such as antiprotons by using electromagnetic traps that confine the particles within a magnetic field so that they don't annihilate with other particles. However, particles of the same charge repel each other, so the more particles that are contained in a trap, the more energy is needed to power the magnetic field that contains them. It is not currently possible to store a significant quantity of antiprotons. At any rate, we now see that negative charge is associated with both low-mass (electrons) and high-mass particles (antiprotons) and the apparent asymmetry is not there. But this knowledge does raise another question—why is there such a predominance of matter and so little antimatter? Possible explanations emerge later in this and the next chapter. |
A cold front is formed when a cold air mass runs into what? | dry air mass | hurricane | cool air mass | warm air mass | A cold front forms when a cold air mass runs into a warm air mass ( Figure below ). The cold air mass moves faster than the warm air mass. So the cold air mass lifts the warm air mass out of its way. As the warm air rises, its water vapor condenses. Clouds form, and precipitation falls. If the warm air is very humid, precipitation can be heavy. Temperature and pressure differences between the two air masses cause winds. Winds may be very strong along a cold front. |
What is the the process by which remains or traces of living things become fossils called? | fasciculation | extirpation | gentrification | fossilization | The process by which remains or traces of living things become fossils is called fossilization ( Figure below ). Most fossils are preserved in sedimentary rocks. |
Light is a form of what kind of energy? | gravitational energy | magnetic energy | static energy | electromagnetic energy | |
When compared to anaerobic respiration, what does aerobic respiration release more of? | pressure | heat | carbon dioxide | energy | A major advantage of aerobic respiration is the amount of energy it releases. Without oxygen, organisms can just split glucose into two molecules of pyruvate. This releases only enough energy to make two ATP molecules. With oxygen, organisms can break down glucose all the way to carbon dioxide. This releases enough energy to produce up to 38 ATP molecules. Thus, aerobic respiration releases much more energy than anaerobic respiration. |
As the telencephalon enlarges and grows into the cranial cavity, it is limited by the space within what bone structure? | chest | skeleton | spine | skull | As the telencephalon enlarges and grows into the cranial cavity, it is limited by the space within the skull. The telencephalon is the most anterior region of what was the neural tube, but cannot grow past the limit of the frontal bone of the skull. Because the cerebrum fits into this space, it takes on a C-shaped formation, through the frontal, parietal, occipital, and finally temporal regions. The space within the telencephalon is stretched into this same C-shape. The two ventricles are in the left and right sides, and were at one time referred to as the first and second ventricles. The interventricular foramina connect the frontal region of the lateral ventricles with the third ventricle. The third ventricle is the space bounded by the medial walls of the hypothalamus and thalamus. The two thalami touch in the center in most brains as the massa intermedia, which is surrounded by the third ventricle. The cerebral aqueduct opens just inferior to the epithalamus and passes through the midbrain. The tectum and tegmentum of the midbrain are the roof and floor of the cerebral aqueduct, respectively. The aqueduct opens up into the fourth ventricle. The floor of the fourth ventricle is the dorsal surface of the pons and upper medulla (that gray matter making a continuation of the tegmentum of the midbrain). The fourth ventricle then narrows into the central canal of the spinal cord. The ventricular system opens up to the subarachnoid space from the fourth ventricle. The single median aperture and the pair of lateral apertures connect to the subarachnoid space so that CSF can flow through the ventricles and around the outside of the CNS. Cerebrospinal fluid is produced within the ventricles by a type of specialized membrane called a choroid plexus. Ependymal cells (one of the types of glial cells described in the introduction to the nervous system) surround blood capillaries and filter the blood to make CSF. The fluid is a clear solution with a limited amount of the constituents of blood. It is essentially water, small molecules, and electrolytes. Oxygen and carbon dioxide are dissolved into the CSF, as they are in blood, and can diffuse between the fluid and the nervous tissue. |
What is a relationship where one species benefits and the other is unaffected? | parasitism | pollenation | mutualism | commensalism | Commensalism is a symbiotic relationship in which one species benefits while the other is not affected. |
Quarks are very tiny particles of matter that make up what? | atoms and neutrons | electrons and neutrons | protons and electrons | protons and neutrons | Quarks are even tinier particles of matter that make up protons and neutrons. Scientists have identified six different types of quarks. |
What term is used to describe is the spontaneous emission of particles and radiation from atomic nuclei? | microscopic | intensity | vibration | radioactivity | Radioactivity is the spontaneous emission of particles and radiation from atomic nuclei. |
The right and left hip bones, with the addition of the sacrum and coccyx form what section of the skeleton? | uterus | necklash | tail bone | pelvis | Figure 8.12 Pelvis The pelvic girdle is formed by a single hip bone. The hip bone attaches the lower limb to the axial skeleton through its articulation with the sacrum. The right and left hip bones, plus the sacrum and the coccyx, together form the pelvis. |
What do metals start out as? | nickel | Metal molecules | aluminum | ore | Minerals have to be removed from the ground and made into the products. All the metals we use start out as an ore. Mining the ore is just the first step. Next, the ore must be separated from the rest of the rock that is mined. Then, the minerals need to be separated out of the ore. |
What is the si unit for weight? | pounds (lbs) | kilograms (kg) | meters (m) | newton (n) | Weight measures the force of gravity pulling on an object. Because weight measures force, the SI unit for weight is the newton (N) . On Earth, a mass of 1 kilogram has a weight of about 10 newtons because of the pull of Earth’s gravity On the moon, which has less gravity, the same mass would weigh less. Weight is measured with a scale, like the spring scale in Figure below . The scale measures the force with which gravity pulls an object downward. |
The flower is an angiosperm structure specialized for what function? | protection from cold | asexual reproduction | nutrient production | sexual reproduction | |
Recent evidence indicates some of what type of cells remain within the heart, continuing to divide and potentially replace dead cells? | dendritic cells | osteoclast cells | human cells | stem cells | Repair and Replacement Damaged cardiac muscle cells have extremely limited abilities to repair themselves or to replace dead cells via mitosis. Recent evidence indicates that at least some stem cells remain within the heart that continue to divide and at least potentially replace these dead cells. However, newly formed or repaired cells are rarely as functional as the original cells, and cardiac function is reduced. In the event of a heart attack or MI, dead cells are often replaced by patches of scar tissue. Autopsies performed on individuals who had successfully received heart transplants show some proliferation of original cells. If researchers can unlock the mechanism that generates new cells and restore full mitotic capabilities to heart muscle, the prognosis for heart attack survivors will be greatly enhanced. To date, myocardial cells produced within the patient (in situ) by cardiac stem cells seem to be nonfunctional, although those grown in Petri dishes (in vitro) do beat. Perhaps soon this mystery will be solved, and new advances in treatment will be commonplace. |
About what percentage of the earth's water is fresh water? | thirty percent | two percent | nine percent | three percent | Of all the water on Earth, about two percent is stored underground in spaces between rocks. A fraction of a percent exists in the air as water vapor, clouds, or precipitation. Another fraction of a percent occurs in the bodies of plants and animals. So where is most of Earth’s water? It’s on the surface of the planet. In fact, water covers about 70 percent of Earth’s surface. Of water on Earth’s surface, 97 percent is salt water, mainly in the ocean. Only 3 percent is fresh water . Most of the fresh water is frozen in glaciers and polar ice caps. The remaining fresh water occurs in rivers, lakes, and other fresh water features. |
While numerous elements can undergo fission, only a few can be used as fuels in what nuclear devices? | accelerators | colliders | laser beams | reactors | Numerous elements can undergo fission, but only a few can be used as fuels in a reactor. What aspect of nuclear fission allows a nuclear chain reaction to occur?. |
What is an estimation of all of the organic matter available as food, and involves measuring biomass in terrestrial environments? | trophic level total | food chain | decomposition energy | net primary productivity | Abiotic Factors Influencing Plant Growth Temperature and moisture are important influences on plant production (primary productivity) and the amount of organic matter available as food (net primary productivity). Net primary productivity is an estimation of all of the organic matter available as food; it is calculated as the total amount of carbon fixed per year minus the amount that is oxidized during cellular respiration. In terrestrial environments, net primary productivity is estimated by measuring the aboveground biomass per unit area, which is the total mass of living plants, excluding roots. This means that a large percentage of plant biomass which exists underground is not included in this measurement. Net primary productivity is an important variable when considering differences in biomes. Very productive biomes have a high level of aboveground biomass. Annual biomass production is directly related to the abiotic components of the environment. Environments with the greatest amount of biomass have conditions in which photosynthesis, plant growth, and the resulting net primary productivity are optimized. The climate of these areas is warm and wet. Photosynthesis can proceed at a high rate, enzymes can work most efficiently, and stomata can remain open without the risk of excessive transpiration; together, these factors lead to the maximal amount of carbon dioxide (CO2) moving into the plant, resulting in high biomass production. The aboveground biomass produces several important resources for other living things, including habitat and food. Conversely, dry and cold environments have lower photosynthetic rates and therefore less biomass. The animal communities living there will also be affected by the decrease in available food. |
Twenty-four hours before fertilization, the egg has finished meiosis and becomes a mature what? | zygote | spermatozoa | fetus | oocyte | Human Gestation Twenty-four hours before fertilization, the egg has finished meiosis and becomes a mature oocyte. When fertilized (at conception) the egg becomes known as a zygote. The zygote travels through the oviduct to the uterus (Figure 43.18). The developing embryo must implant into the wall of the uterus within seven days, or it will deteriorate and die. The outer layers of the zygote (blastocyst) grow into the endometrium by digesting the endometrial cells, and wound healing of the endometrium closes up the blastocyst into the tissue. Another layer of the blastocyst, the chorion, begins releasing a hormone called human beta chorionic gonadotropin (β-HCG) which makes its way to the corpus luteum and keeps that structure active. This ensures adequate levels of progesterone that will maintain the endometrium of the uterus for the support of the developing embryo. Pregnancy tests determine the level of β-HCG in urine or serum. If the hormone is present, the test is positive. |
Oxygen is combined with what to form water? | carbon | glucose | helium | hydrogen | Photosynthesis makes the glucose that is used in cellular respiration to make ATP. The glucose is then turned back into carbon dioxide, which is used in photosynthesis. While water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water. While photosynthesis requires carbon dioxide and releases oxygen, cellular respiration requires oxygen and releases carbon dioxide. It is the released oxygen that is used by us and most other organisms for cellular respiration. We breathe in that oxygen, which is carried through our blood to all our cells. In our cells, oxygen allows cellular respiration to proceed. Cellular respiration works best in the presence of oxygen. Without oxygen, much less ATP would be produced. |
Does lava flow quickly or slowly when thick? | steadily | quickly | rapidly | slowly | When lava is thick, it flows slowly. If thick lava makes it to the surface, it cannot flow far from the vent. It often stays right in the middle of a crater at the top of a volcano. Here the lava creates a large, round lava dome ( Figure below ). |
The evaporative loss of the most energetic water molecules does what to a surface? | charges it | heats it | vents it | cools it | |
Habitat loss caused by human actions is a prime culprit in what phenomenon, which appears to be occurring for a sixth time? | Big Bang | spontaneous mutation | mass migrations | mass extinction | Evidence shows that a sixth mass extinction is occurring. The single biggest cause is habitat loss caused by human actions. There are many steps you can take to help protect biodiversity. For example, you can use less energy. |
What patterns in trees can be used to determine its age? | veins | bark ridges | colors | rings | The distinctive patterns of tree rings, ice cores, and varves go back thousands of years. They can be used to determine the time they were made. |
All of the petals together are called what? | stalk | stamen | anthers | corolla | All of the petals ( Figure below ) together are called the corolla . They are bright and colorful to attract a particular pollinator , an animal that carries pollen from one flower to another. Examples of pollinators include birds and insects. |
Any nucleus that is unstable and decays spontaneously is said to be what? | magnetic | neutral | dull | radioactive | -16O817O17oxygen -17O818O18oxygen -18 Because the number of neutrons is equal to A − Z, we see that the first isotope of oxygen has 8 neutrons, the second isotope 9 neutrons, and the third isotope 10 neutrons. Isotopes of all naturally occurring elements on Earth are present in nearly fixed proportions, with each proportion constituting an isotope’s natural abundance. For example, in a typical terrestrial sample of oxygen, 99.76% of the O atoms is oxygen-16, 0.20% is oxygen-18, and 0.04% is oxygen-17. Any nucleus that is unstable and decays spontaneously is said to be radioactive, emitting subatomic particles and electromagnetic radiation. The emissions are collectively called radioactivity and can be measured. Isotopes that emit radiation are called radioisotopes. As you learned in Chapter 14 "Chemical Kinetics", the rate at which radioactive decay occurs is characteristic of the isotope and is generally reported as a half-life (t1/2), the amount of time required for half of the initial number of nuclei present to decay in a first-order reaction. (For more information on half-life, seeChapter 14 "Chemical Kinetics", Section 14.5 "Half-Lives and Radioactive Decay Kinetics". ) An isotope’s half-life can range from fractions of a second to billions of years and, among other applications, can be used to measure the age of ancient objects. Example 1 and its corresponding exercise review the calculations involving radioactive decay rates and half-lives. |
What is the term for viscous magmas that are high in silica and tend to stay below the surface or erupt explosively? | combustible magmas | sedimentary magmas | compacted magmas | felsic magmas | The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. The higher the amount of silica in the magma, the higher the viscosity. Viscosity is a liquid's resistance to flow. Viscous magmas tend to stay below the surface or erupt explosively. These are felsic magmas, which are high in silica. When magma is fluid and runny, it is not viscous. This magma often reaches the surface by flowing out in rivers of lava. These are low-silica mafic magmas. |
How many meters deep does the photic zone extend? | 900 | 400 | 100 | 200 | The photic zone extends to a maximum depth of 200 meters (656 feet) below the surface of the water. This is where enough sunlight penetrates for photosynthesis to occur. Algae and other photosynthetic organisms can make food and support food webs. |
What is the name of the process in which the nuclei of uranium atoms are split? | nuclear fusion | critical fission | atomic fusion | nuclear fission | Like fossil fuels, the radioactive element uranium can be used to generate electrical energy in power plants. In a nuclear power plant, the nuclei of uranium atoms are split in the process of nuclear fission. This process releases a tremendous amount of energy from just a small amount of uranium. The total supply of uranium in the world is quite limited, however, and cannot be replaced once it is used up. This makes nuclear energy a nonrenewable resource. Although using nuclear energy does not release carbon dioxide or cause air pollution, it does produce dangerous radioactive wastes. Accidents at nuclear power plants also have the potential to release large amounts of radioactive material into the environment. Figure below describes the nuclear disaster caused by a Japanese tsunami in 2011. You can learn more about the disaster and its aftermath at the URLs below. |
What type of bonds are formed between atoms sharing electrons? | ionic | neutron bonds | hydroxyl | covalent | Covalent bonds are formed between atoms sharing electrons. |
An individual virus is called what? | a pathogen | a toxin | a polymer | a virion | An individual virus is called a virion. It is a tiny particle much smaller than a prokaryotic cell. Because viruses do not consist of cells, they also lack cell membranes, cytoplasm, ribosomes, and other cell organelles. Without these structures, they are unable to make proteins or even reproduce on their own. Instead, they must depend on a host cell to synthesize their proteins and to make copies of themselves. Viruses infect and live inside the cells of living organisms. When viruses infect the cells of their host, they may cause disease. For example, viruses cause AIDS, influenza (flu), chicken pox, and the common cold. |
What type of particle collides with an atom of u-235 during the basic nuclear fission process? | a proton | an electron | a nuclei | a neutron | The example above illustrates the basic nuclear fission process. A neutron (generally produced by some controlled process, not usually a natural event) collides with an atom of U-235. Momentarily, a U-236 atom forms which then splits into two smaller atoms (Kr-93 and Ba-141) in the diagram. This process results in the release of three new neutrons, which can then initiate fission reactions with more atoms. We will see later how this propagation of neutrons can be employed in a reactor for the generation of electricity. |
What color is phosphate mineral turquoise? | purple | white | green | blue | Turquoise is a phosphate mineral with a beautiful blue color. The stone is not as rare as some minerals and is commonly used for jewelry. |
Groups of three bases form codons, and each codon stands for one what? | sulferic acid | compound acid | minimal acid | amino acid | The genetic code consists of the sequence of bases in DNA or RNA. Groups of three bases form codons, and each codon stands for one amino acid (or start or stop). The codons are read in sequence following the start codon until a stop codon is reached. The genetic code is universal, unambiguous, and redundant. |
Bees, wasps, ants, butterflies, moths, flies and beetles belong to what animal phylum? | cephalopods | insects | crustaceans | arthropods | Many arthropods have extremely important roles in ecosystems. Arthropods are of ecological importance because of their sheer numbers and extreme diversity. As mentioned above, bees, wasps, ants, butterflies, moths, flies and beetles are invaluable agents of pollination. Pollens and grains became accidentally attached to their chests and legs and are transferred to other agricultural crops as these animals move about, either by walking or flying. Most plants actually produce scents to send signals to insects that food (in the form of nectar) is available. |
How many ways are there for a species to go extinct? | Ten | four | eight | two | Most of the species that have lived have also gone extinct. There are two ways to go extinct. The most obvious way is to die out completely. The other way a species goes extinct is if it evolves into a different species. Extinction is a normal part of Earth's history. Most of the organisms that have lived have gone extinct. |
Often generated by molecular cloning, transgenic organisms possess what from a different species? | RNA | memories | organs | dna | 10.2 Biotechnology in Medicine and Agriculture Genetic testing is performed to identify disease-causing genes, and can be used to benefit affected individuals and their relatives who have not developed disease symptoms yet. Gene therapy—by which functioning genes are incorporated into the genomes of individuals with a non-functioning mutant gene—has the potential to cure heritable diseases. Transgenic organisms possess DNA from a different species, usually generated by molecular cloning techniques. Vaccines, antibiotics, and hormones are examples of products obtained by recombinant DNA technology. Transgenic animals have been created for experimental purposes and some are used to produce some human proteins. Genes are inserted into plants, using plasmids in the bacterium Agrobacterium tumefaciens, which infects plants. Transgenic plants have been created to improve the characteristics of crop plants—for example, by giving them insect resistance by inserting a gene for a bacterial toxin. |
The skin disease impetigo is caused by spread of what type of microorganism? | algae | viruses | tumors | bacteria | Bacteria that cause the skin disease impetigo, which causes blisters, can spread when people share towels or clothes. The bacteria can also spread through direct skin contact in sports like wrestling. |
Plants go through seasonal changes after detecting differences in what? | week length | temperature | weather | day length | Plants go through seasonal changes after detecting differences in day length. |
What cycle is part of cellular respiration and makes atp and naph? | carbon cycle | vireos | water cycle | krebs | The Calvin cycle is part of the light-independent reactions of photosynthesis. The Calvin cycle uses ATP and NADPH. The Krebs cycle is part of cellular respiration. This cycle makes ATP and NAPH. |
What type of mechanical weathering occurs when one rock bumps against another rock? | disintegration | absorption | refraction | abrasion | Abrasion is another type of mechanical weathering. With abrasion, one rock bumps against another rock. Gravity causes abrasion as a rock tumbles down a slope. Moving water causes abrasion; it moves rocks so that they bump against one another ( Figure below ). Strong winds cause abrasion by blasting sand against rock surfaces. Finally, the ice in glaciers cause abrasion. Pieces of rock embedded in ice at the bottom of a glacier scrape against the rock below. If you have ever collected beach glass or pebbles from a stream, you have witnessed the work of abrasion. |
What kind of hormones serve many functions in addition to promoting gamete production? | Utility hormones | Multifaceted hormones | reflection hormones | sex hormones | |
The tissue that will become the scrotum in a male becomes the labia in a female, thus, they are regarded as having what relationship? | mutual | opposite | symbiotic | homologous | produce a penis in males produce a clitoris in females. The tissue that will become the scrotum in a male becomes the labia in a female; that is, they are homologous structures. Male Reproductive Anatomy In the male reproductive system, the scrotum houses the testicles or testes (singular: testis), including providing passage for blood vessels, nerves, and muscles related to testicular function. The testes are a pair of male reproductive organs that produce sperm and some reproductive hormones. Each testis is approximately 2.5 by 3.8 cm (1.5 by 1 in) in size and divided into wedge-shaped lobules by connective tissue called septa. Coiled in each wedge are seminiferous tubules that produce sperm. Sperm are immobile at body temperature; therefore, the scrotum and penis are external to the body, as illustrated in Figure 43.8 so that a proper temperature is maintained for motility. In land mammals, the pair of testes must be suspended outside the body at about 2° C lower than body temperature to produce viable sperm. Infertility can occur in land mammals when the testes do not descend through the abdominal cavity during fetal development. |
How frequently do high tides occur? | Every 48 hours | Every 96 hours | Every 24 hours | every 12 hours | 9. If the tidal cycle was actually 12 hours then high tides would occur at the same time every day. In reality, high tides occur about every 12 hours and 25 minutes. Can you think of why this would be the case?. |
What phase does the cell make final preparations to divide? | dioxide phase 2 | growth phase 1 | carbonate phase 2 | growth phase 2 | Growth Phase 2 (G2): during this phase, the cell makes final preparations to divide. For example, it makes additional proteins and organelles. This phase is sometimes referred to as Gap 2. |
How do multicellular organisms grow in size? | increase size and number of genes | reduce size and number of cells | increase number of limbs | increase size and number of cells | Like plants, all living things have the capacity for growth. The ducklings in Figure below have a lot of growing to do to catch up in size to their mother. Multicellular organisms like ducks grow by increasing the size and number of their cells. Single-celled organisms just grow in size. |
What symbol is used to indicate directionality in chemical reactions? | line | triangle | circle | arrow | The arrow (→) shows the direction in which the reaction occurs. In many reactions, the reaction also occurs in the opposite direction. This is represented with another arrow pointing in the opposite direction (←). |
Who wrote the book on the origin of species? | cannon | Scopes | Sagan | darwin | In his book On the Origin of Species , Darwin included evidence to show that evolution had taken place. He also made logical arguments to support his theory that evolution occurs by natural selection. Since Darwin’s time, much more evidence has been gathered. The evidence includes a huge number of fossils. It also includes more detailed knowledge of living things, right down to their DNA. |
What is considered a good source of calcium? | corn | wheat | egg | milk | Milk is naturally a good source of calcium. Vitamin D is also often added to milk. Both these nutrients help build strong bones. |
Exons are cut out before what leaves the nucleus? | rna | gene | dna | mrna | |
What nervous system is divided into two parts, the sensory division and the motor division? | central | physiological | developmental | peripheral | The peripheral nervous system is divided into two parts, the sensory division and the motor division. How these divisions of the peripheral nervous system are related to the rest of the nervous system is shown below ( Figure below ). Refer to the figure as you read more about the peripheral nervous system in the text that follows. |
What crucial role does beneficial fungi play? | killing bacteria | cleaning the soil | cleaning water | balance of ecosystems | Beneficial Fungi Fungi play a crucial role in the balance of ecosystems. They colonize most habitats on Earth, preferring dark, moist conditions. They can thrive in seemingly hostile environments, such as the tundra, thanks to a most successful symbiosis with photosynthetic organisms, like lichens. Fungi are not obvious in the way that large animals or tall trees are. Yet, like bacteria, they are major decomposers of nature. With their versatile metabolism, fungi break down organic matter that is insoluble and would not be recycled otherwise. Importance to Ecosystems Food webs would be incomplete without organisms that decompose organic matter and fungi are key participants in this process. Decomposition allows for cycling of nutrients such as carbon, nitrogen, and phosphorus back into the environment so they are available to living things, rather than being trapped in dead organisms. Fungi are particularly important because they have evolved enzymes to break down cellulose and lignin, components of plant cell walls that few other organisms are able to digest, releasing their carbon content. Fungi are also involved in ecologically important coevolved symbioses, both mutually beneficial and pathogenic with organisms from the other kingdoms. Mycorrhiza, a term combining the Greek roots myco meaning fungus and rhizo. |
When mendel crossed purple flowered-plants and white flowered-plants, all the offspring had what color flowers? | yellow | blue | red | purple | Do you remember what happened when Mendel crossed purple flowered-plants and white flowered-plants? All the offspring had purple flowers. There was no blending of traits in any of Mendel's experiments. Mendel had to come up with a theory of inheritance to explain his results. He developed a theory called the law of segregation . |
When statoliths settle to the low point in the chamber, they stimulate what in that location? | nociceptors | dendrites | axons | mechanoreceptors | |
The goal of this is the understand how and why things happen? | theory | experience | inquiry | science | The goal of science is to understand how and why things happen. |
What are the most diverse organisms on earth, which are often classified by shape or how they react to gram stain? | algae | cultures | pathogens | bacteria | Bacteria are the most diverse organisms on Earth. They are often classified by shape or how they react to Gram stain. |
Breathing involves differences in what, measured in torr, between the inside of the lungs and the air outside? | resistance | temperature | gravity | pressure | Breathing involves pressure differences between the inside of the lungs and the air outside. The pressure differences are only a few torr. A normal breath is about 0.50 L. If room temperature is about 22°C, then the air has a temperature of about 295 K. With normal pressure being 1.0 atm, how many moles of air do we take in for every breath? The ideal gas law gives us an answer:. |
Gymnamoebas constitute a large and varied group of what? | sporozoans | newborns | cells | amoebozoans | |
Lymph vessels make up a circulatory system that is similar to the blood vessels of what system? | gastrointestinal | nervous | cardiac | cardiovascular | Lymph vessels make up a circulatory system that is similar to the blood vessels of the cardiovascular system. However, lymph vessels circulate lymph instead of blood, and the heart does not pump lymph through the vessels. |
In weather terms, what do you call the boundary between two air masses? | cover | cloud | mass | front | When cold air masses move south from the poles, they run into warm air masses moving north from the tropics. The boundary between two air masses is called a front . Air masses usually don’t mix at a front. The differences in temperature and pressure cause clouds and precipitation. Types of fronts include cold, warm, occluded, and stationary fronts. |
What process takes place when plants release water vapor through pores in their leaves called stomata? | propagation | evaporation | expiration | transpiration | Transpiration takes place when plants release water vapor through pores in their leaves called stomata. |