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What process would be impossible without some variation in the inherited traits of organisms within a species? | characteristic selection | environmental selection | darwin's selection | natural selection | There is some variation in the inherited traits of organisms within a species. Without this variation, natural selection would not be possible. |
Monoecious flowers are also known as “perfect” flowers because they contain both types of what organ? | phloem | vascular organ | respiratory organ | sex organ | groups of angiosperms: the monocots and the eudicots. Seed food reserves are stored outside the embryo, in the form of complex carbohydrates, lipids or proteins. The cotyledons serve as conduits to transmit the broken-down food reserves from their storage site inside the seed to the developing embryo. The seed consists of a toughened layer of integuments forming the coat, the endosperm with food reserves, and at the center, the well-protected embryo. Most flowers are monoecious or bisexual, which means that they carry both stamens and carpels; only a few species selfpollinate. Monoecious flowers are also known as “perfect” flowers because they contain both types of sex organs (Figure 26.14). Both anatomical and environmental barriers promote cross-pollination mediated by a physical agent (wind or water), or an animal, such as an insect or bird. Cross-pollination increases genetic diversity in a species. |
Human beings depend on learned behaviors more than any other? | mammals | Organisms | Beings | species | Human beings depend on learned behaviors more than any other species. Think about some of the behaviors you have learned. They might include making a bed, riding a bicycle, using a computer, and playing a sport, to name just a few. You may have learned each of the behaviors in different ways. There are several different ways in which animals learn. They include habituation, observational learning, conditioning, learning through play, and insight learning. |
Oxygen, carbon, hydrogen and what other element make up approximately 96% of living matter? | silicon | calcium | helium | nitrogen | |
What type electrical circuits have multiple paths the current may take? | serial | perpendicular | single loop | parallel | Parallel electrical circuits have multiple paths the current may take. |
Hydrophobic interactions arise because water molecules engage in what type of bonding with other water molecules? | helium bonding | aquatic bonding | oxygen bonding | hydrogen bonding | high proportion of amino acids in the protein have nonpolar side chains. The term hydrophobic interaction is often misused as a synonym for dispersion forces. Hydrophobic interactions arise because water molecules engage in hydrogen bonding with other water molecules (or groups in proteins capable of hydrogen bonding). Saylor URL: http://www. saylor. org/books. |
What is the second most common skin cancer? | precancerous cell carcinoma | basal cell carcinoma | melanoma | squamous cell carcinoma | Squamous Cell Carcinoma Squamous cell carcinoma is a cancer that affects the keratinocytes of the stratum spinosum and presents as lesions commonly found on the scalp, ears, and hands (Figure 5.19). It is the second most common skin cancer. The American Cancer Society reports that two of 10 skin cancers are squamous cell carcinomas, and it is more aggressive than basal cell carcinoma. If not removed, these carcinomas can metastasize. Surgery and radiation are used to cure squamous cell carcinoma. |
Species divergence often, but not always, occurs because of what type of barrier between species? | language | emotional | visible | physical | Sympatric Speciation Can divergence occur if no physical barriers are in place to separate individuals who continue to live and reproduce in the same habitat? The answer is yes. The process of speciation within the same space is called sympatric speciation; the prefix “sym” means same, so “sympatric” means “same homeland” in contrast to “allopatric” meaning “other homeland. ” A number of mechanisms for sympatric speciation have been proposed and studied. One form of sympatric speciation can begin with a serious chromosomal error during cell division. In a normal cell division event chromosomes replicate, pair up, and then separate so that each new cell has the same number of chromosomes. However, sometimes the pairs separate and the end cell product has too many or too few individual chromosomes in a condition called aneuploidy (Figure 18.14). |
The chytrids the only class in the phylum chytridiomycota is the chytridiomycetes. the chytrids are the simplest and most primitive eumycota, or true this? | organisms | acids | proteins | fungi | Chytridiomycota: The Chytrids The only class in the Phylum Chytridiomycota is the Chytridiomycetes. The chytrids are the simplest and most primitive Eumycota, or true fungi. The evolutionary record shows that the first recognizable chytrids appeared during the late preCambrian period, more than 500 million years ago. Like all fungi, chytrids have chitin in their cell walls, but one group of chytrids has both cellulose and chitin in the cell wall. Most chytrids are unicellular; a few form multicellular organisms and hyphae, which have no septa between cells (coenocytic). They produce gametes and diploid zoospores that swim with the help of a single flagellum. The ecological habitat and cell structure of chytrids have much in common with protists. Chytrids usually live in aquatic environments, although some species live on land. Some species thrive as parasites on plants, insects, or amphibians (Figure 24.10), while others are saprobes. The chytrid species Allomyces is well characterized as an experimental organism. Its reproductive cycle includes both asexual and sexual phases. Allomyces produces diploid or haploid flagellated zoospores in a sporangium. |
Almost all vascular plants have mycorrhizae and rely on their fungal partners for what? | air | respiration | sunlight | nutrients | |
What occurs when there is a sudden and large falling of rocks down a slope? | tsunami | earthquake | avalanche | landslide | Landslides are sudden and massive falls of rock down a slope. Landslides may be very destructive or even deadly. Slump and creep are slower types of mass wasting. |
What are gymnosperms lacking compared to most angiosperms? | vascular elements | muscle elements | use elements | vessel elements | |
Calculations are described showing conversions between molar mass and what for gases? | weight | volume | length | density | Calculations are described showing conversions between molar mass and density for gases. |
What sudden ground movement is caused by the sudden release of the energy stored in rocks, which is transmitted in seismic waves? | quicksand | eruption | sandstorm | earthquake | An earthquake is sudden ground movement. This movement is caused by the sudden release of the energy stored in rocks. An earthquake happens when so much stress builds up in the rocks that the rocks break. An earthquake’s energy is transmitted by seismic waves. |
What is the name for the cooler, darker areas on the sun’s surface? | anomalies | corona | aurora borealis | sunspots | The most noticeable magnetic activity of the Sun is the appearance of sunspots. Sunspots are cooler, darker areas on the Sun’s surface ( Figure below ). Sunspots occur in an 11 year cycle. The number of sunspots begins at a minimum. The number gradually increases to the maximum. Then the number returns to a minimum again. |
Plants need sunlight for what process? | glycolysis | metamorphosis | cyclogenesis | photosynthesis | The water in a large lake may be so deep that sunlight cannot penetrate all the way to the bottom. Without sunlight, water plants and algae cannot live on the bottom of the lake. That’s because plants need sunlight for photosynthesis. |
The vast majority of what phenomena occurs along one of three types of plate boundaries? | volcanoes | tornados | hurricane | earthquake | Nearly 95% of all earthquakes take place along one of the three types of plate boundaries. As you learned in the Plate Tectonics chapter, scientists use the location of earthquakes to draw plate boundaries. |
What weather events move with the prevailing winds and originate in the trade winds in the northern hemisphere? | droughts | tsunamis | earthquakes | hurricanes | Hurricanes move with the prevailing winds. In the Northern Hemisphere, they originate in the trade winds and are blown to the west. When they reach the westerlies, they switch direction. So they travel toward the north or northeast. You can look at a map of hurricane tracks to see this happen ( Figure below ). Hurricanes may cover 800 km (500 miles) in one day. |
What is the name for the male reproductive organs or gonads? | ovaries | nucleus | anus | testes | Testes The testes (singular = testis) are the male gonads—that is, the male reproductive organs. They produce both sperm and androgens, such as testosterone, and are active throughout the reproductive lifespan of the male. Paired ovals, the testes are each approximately 4 to 5 cm in length and are housed within the scrotum (see Figure 27.3). They are surrounded by two distinct layers of protective connective tissue (Figure 27.4). The outer tunica vaginalis is a serous membrane that has both a parietal and a thin visceral layer. Beneath the tunica vaginalis is the tunica albuginea, a tough, white, dense connective tissue layer covering the testis itself. Not only does the tunica albuginea cover the outside of the testis, it also invaginates to form septa that divide the testis into 300 to 400 structures called lobules. Within the lobules, sperm develop in structures called seminiferous tubules. During the seventh month of the developmental period of a male fetus, each testis moves through the abdominal musculature to descend into the scrotal cavity. This is called the “descent of the testis. ” Cryptorchidism is the clinical term used when one or both of the testes fail to descend into the scrotum prior to birth. |
What glands in the breast secrete milk? | fetal glands | primordial glands | adrenal glands | mammary glands | The breasts are not directly involved in reproduction, but they nourish a baby after birth. Each breast contains mammary glands, which secrete milk. The milk drains into ducts leading to the nipple. A suckling baby squeezes the milk out of the ducts and through the nipple. |
Sutures, gomphoses, and syndesmoses are types of what, which are found where adjacent bones are strongly united by connective tissue? | ligaments | cartilage | metallic joints | fibrous joints | 9.2 Fibrous Joints Fibrous joints are where adjacent bones are strongly united by fibrous connective tissue. The gap filled by connective tissue may be narrow or wide. The three types of fibrous joints are sutures, gomphoses, and syndesmoses. A suture is the narrow fibrous joint that unites most bones of the skull. At a gomphosis, the root of a tooth is anchored across a narrow gap by periodontal ligaments to the walls of its socket in the bony jaw. A syndesmosis is the type of fibrous joint found between parallel bones. The gap between the bones may be wide and filled with a fibrous interosseous membrane, or it may narrow with ligaments spanning between the bones. Syndesmoses are found between the bones of the forearm (radius and ulna) and the leg (tibia and fibula). Fibrous joints strongly unite adjacent bones and thus serve to provide protection for internal organs, strength to body regions, or weight-bearing stability. |
Heat, electricity, or light might provide what necessary input to the process of decomposition? | food | source | material | energy | Most decomposition reactions require an input of energy in the form of heat, light, or electricity. |
What is made up of a watery substance called cytosol and contains other cell structures such as ribosomes? | cytoskeleton | rna | plasma | cytoplasm | Cytoplasm refers to all of the cellular material inside the plasma membrane. Cytoplasm is made up of a watery substance called cytosol and contains other cell structures such as ribosomes. |
What type of energy is required in all chemical reactions? | solar | conduction | function | activation | All chemical reactions require activation energy, which is the energy needed to get a reaction started. |
What type of image is formed when light rays diverge in front of a mirror? | reversed | fake | large | virtual | When light rays diverge in front of a mirror, a virtual image is formed. A virtual image is formed by your brain tracing diverging rays backwards and is kind of a trick, like the person you see “behind” a mirror’s surface when you brush your teeth (there's obviously no real light focused behind a mirror!). Since virtual images aren’t actually “anywhere,” you can’t place photographic film anywhere to capture them. |
What is the condition of a plant in which the fluid in a cell exerts a pressure against the cell wall? | hydration | constriction | tumor | turgor | called the relative osmotic pressure if neither solution is pure water, and it is called the osmotic pressure if one solution is pure water. Osmotic pressure can be large, depending on the size of the concentration difference. For example, if pure water and sea water are separated by a semipermeable membrane that passes no salt, osmotic pressure will be 25.9 atm. This value means that water will diffuse through the membrane until the salt water surface rises 268 m above the pure-water surface! One example of pressure created by osmosis is turgor in plants (many wilt when too dry). Turgor describes the condition of a plant in which the fluid in a cell exerts a pressure against the cell wall. This pressure gives the plant support. Dialysis can similarly cause substantial pressures. |
What phenomenon, crucial for evolution, creates new genetic variation in a gene pool and is how all new alleles first arise? | adaptation | radiation | natural selection | mutation | Mutation creates new genetic variation in a gene pool. It is how all new alleles first arise. In sexually reproducing species, the mutations that matter for evolution are those that occur in gametes. Only these mutations can be passed to offspring. For any given gene, the chance of a mutation occurring in a given gamete is very low. Thus, mutations alone do not have much effect on allele frequencies. However, mutations provide the genetic variation needed for other forces of evolution to act. |
What is the name of the stage of life when a child becomes sexually mature? | reproductive stage | pre-adolescence | adulthood | puberty | Puberty is the stage of life when a child becomes sexually mature. Puberty begins when the pituitary gland tells the testes to secrete testosterone in boys, and in girls the pituitary gland signals the ovaries to secrete estrogen. Changes that occur during puberty are discussed in the Male Reproductive Development and Female Reproductive Development concepts. |
A man made lake is known as what? | Lagoon | Pond | Lake | resevoirs | Many lakes are not natural, but are human-made. People dam a stream in a suitable spot. Water backs up behind the dam, creating a lake. These lakes are "reservoirs" ( Figure below ). |
Alchemy helped improve the study of metallurgy and the extraction of metals from what? | wood | air | water | ores | However, out of all this secrecy came several contributions to modern-day chemistry. Early acids and bases were discovered. Glassware for running chemical reactions was developed. Alchemy helped improve the study of metallurgy and the extraction of metals from ores. More systematic approaches to research were being developed, although the idea of orderly scientific experimentation had not become well-established yet. But the groundwork was laid to the development of chemistry as a foundational science. |
What are the two types of vascular tissues? | ganglia and phloem | ectoderm and phloem | epidermis and phloem | xylem and phloem | Vascular tissue runs through the ground tissue inside a plant. It transports fluids throughout the plant. Vascular tissue actually consists of two types of tissues, called xylem and phloem. The two types of vascular tissue are packaged together in bundles. You can see them in the celery in Figure below . |
The spinal cord develops, cells making up the wall of the neural tube proliferate and differentiate into what? | jelly and glia | membrane and glia | muscles and glia | neurons and glia | Spinal Cord Development While the brain is developing from the anterior neural tube, the spinal cord is developing from the posterior neural tube. However, its structure does not differ from the basic layout of the neural tube. It is a long, straight cord with a small, hollow space down the center. The neural tube is defined in terms of its anterior versus posterior portions, but it also has a dorsal–ventral dimension. As the neural tube separates from the rest of the ectoderm, the side closest to the surface is dorsal, and the deeper side is ventral. As the spinal cord develops, the cells making up the wall of the neural tube proliferate and differentiate into the neurons and glia of the spinal cord. The dorsal tissues will be associated with sensory functions, and the ventral tissues will be associated with motor functions. |
Eventually the parent cell will pinch apart to form two identical types of what cells? | son cells | brother cells | father cells | daughter cells | Cell division is relatively simple in prokaryotic cells. The two cells divide by binary fission. Green and orange lines indicate old and newly-generated bacterial cell walls, respectively. Eventually the parent cell will pinch apart to form two identical daughter cells. Left, growth at the center of bacterial body, such as in Bacillus subtilis and E. coli . Right, apical growth from the ends of the bacterial body, such as in Corynebacterium diphtheriae . |
The body cells cannot use insulin properly in which type of diabetes? | type 4 diabetes | type 1 diabetes | type 3 diabates | type 2 diabetes | In type 2 diabetes, the body cells cannot use insulin properly. |
Birds belong to a group of diapsids called the what? | aviators | conifers | mammals | archosaurs | Evolution of Birds The evolutionary history of birds is still somewhat unclear. Due to the fragility of bird bones, they do not fossilize as well as other vertebrates. Birds are diapsids, meaning they have two fenestrations or openings in their skulls. Birds belong to a group of diapsids called the archosaurs, which also includes crocodiles and dinosaurs. It is commonly accepted that birds evolved from dinosaurs. Dinosaurs (including birds) are further subdivided into two groups, the Saurischia (“lizard like”) and the Ornithischia (“bird like”). Despite the names of these groups, it was not the bird-like dinosaurs that gave rise to modern birds. Rather, Saurischia diverged into two groups: One included the long-necked herbivorous dinosaurs, such as Apatosaurus. The second group, bipedal predators called theropods, includes birds. This course of evolution is suggested by similarities between theropod. |
How many limbs to birds have? | ten | five | six | four | Birds are four-limbed, endothermic vertebrates with wings and feathers. They produce amniotic eggs and are the most numerous class of vertebrates. |
Planes fly in what layer of the atmosphere because there is less friction and turbulence? | crust | mesosphere | ozone layer | stratosphere | Sure we can! If you've ever flown on a jet airplane, you've been in the stratosphere. Airplanes fly in the stratosphere, because there is less friction. They get better gas mileage and so costs are lower. There is also less turbulence, so passengers are happier. Can you identify the bottom of the stratosphere in the photo? It's where the clouds begin. Remember that all weather is in the troposphere. |
What is a group of similar ecosystems with the same general abiotic factors and primary producers? | taxon | ecoregion | family | biome | The two photos in Figure above represent two different biomes. A biome is a group of similar ecosystems with the same general abiotic factors and primary producers. Producers are organisms that produce food for themselves and other organisms. Biomes may be terrestrial or aquatic. |
Interferons are produced in virally infected cells and cause them to secrete signals for surrounding cells to make what? | Raising Proteins | overwhelm proteins | resist proteins | antiviral proteins | Chapter 21 1 The three main components are the lymph vessels, the lymph nodes, and the lymph. 3 The bacterium is digested by the phagocyte’s digestive enzymes (contained in its lysosomes). 5 B 7 C 9 A 11 D 13 C 15 B 17 B 19 D 21 D 23 B 25 C 27 B 29 C 31 D 33 A 35 B 37 B 39 The lymph enters through lymphatic capillaries, and then into larger lymphatic vessels. The lymph can only go in one direction due to valves in the vessels. The larger lymphatics merge to form trunks that enter into the blood via lymphatic ducts. 41 Interferons are produced in virally infected cells and cause them to secrete signals for surrounding cells to make antiviral proteins. C-reactive protein is induced to be made by the liver and will opsonize certain species of bacteria. 43 Antigen-specific clones are stimulated as their antigen receptor binds to antigen. They are then activated and proliferate, expanding their numbers. The result is a large number of antigen-specific lymphocytes. 45 IgM is an antigen receptor on naïve B cells. Upon activation, naïve B cells make IgM first. IgM is good at binding complement and thus has good antibacterial effects. IgM is replaced with other classes of antibodies later on in the primary response due to class switching. 47 Tuberculosis is caused by bacteria resistant to lysosomal enzymes in alveolar macrophages, resulting in chronic infection. The immune response to these bacteria actually causes most of the lung damage that is characteristic of this life-threatening disease. 49 Antibody response to the cell walls of β-Streptococcus cross-reacts with the heart muscle. Complement is then activated and the heart is damaged, leading to abnormal function. Tolerance is broken because heart myosin antigens are similar to antigens on the β- Streptococcus bacteria. |
What slow process is required for formation of soil? | fossilization | leaching | digestion | weathering | Soil formation requires weathering. Where there is less weathering, soils are thinner. However, soluble minerals may be present. Where there is intense weathering, soils may be thick. Minerals and nutrients would have been washed out. Soil development takes a very long time. It may take hundreds or even thousands of years to form the fertile upper layer of soil. Soil scientists estimate that in the very best soil forming conditions, soil forms at a rate of about 1mm/year. In poor conditions, it may take thousands of years!. |
What is defined as superheated gas with a positive electrical charge? | ion | supernova | greenhouse gas | plasma | The Sun is made mostly of plasma. Plasma is superheated gas with a positive electrical charge. |
Materials, such as iron, that exhibit strong magnetic effects are labeled what? | ultramagnetic | paramagnetic | superconducting | ferromagnetic | Magnetic poles always occur in pairs of north and south—it is not possible to isolate north and south poles. All magnetism is created by electric current. Ferromagnetic materials, such as iron, are those that exhibit strong magnetic effects. The atoms in ferromagnetic materials act like small magnets (due to currents within the atoms) and can be aligned, usually in millimeter-sized regions called domains. • Domains can grow and align on a larger scale, producing permanent magnets. Such a material is magnetized, or induced to be magnetic. • Above a material’s Curie temperature, thermal agitation destroys the alignment of atoms, and ferromagnetism disappears. • Electromagnets employ electric currents to make magnetic fields, often aided by induced fields in ferromagnetic materials. |
Like birds, most other reptiles excrete their nitrogenous wastes as what acid? | lactic | hydrochloric | sulphuric | uric | |
The two main fundamental particles that make up neutrons are quarks and what else? | atoms | prions | leptons | gluons | Neutrons consist of fundamental particles known as quarks and gluons. Gluons carry the strong nuclear force that binds together the quarks in a neutron. |
Birds have evolved a respiratory system that enables them to fly. flying is a high-energy process and requires a lot of this? | adaptation | weight | nitrogen | oxygen | Avian Respiration Birds have evolved a respiratory system that enables them to fly. Flying is a high-energy process and requires a lot of oxygen. Furthermore, many birds fly in high altitudes where the concentration of oxygen in low. How did birds evolve a respiratory system that is so unique? Decades of research by paleontologists have shown that birds evolved from therapods, meat-eating dinosaurs (Figure 39.14). In fact, fossil evidence shows that meat-eating dinosaurs that lived more than 100 million years ago had a similar flow-through respiratory system with lungs and air sacs. Archaeopteryx and Xiaotingia, for example, were flying dinosaurs and are believed to be early precursors of birds. |
Lysosomes have what type of enzymes that break down old molecules into parts that can be recycled? | probiotics | corrosive | bacterial | digestive | Lysosomes are like the recycling trucks that carry waste away from the factory. Lysosomes have digestive enzymes that break down old molecules into parts that can be recycled. |
The breasts contain what to give milk to feed a baby? | fetal glands | sebaceous glands | primordial glands | mammary glands | The female reproductive organs include the vagina, uterus, fallopian tubes, and ovaries ( Figure below ). The breasts are not shown in this figure. They are not considered reproductive organs, even though they are involved in reproduction. They contain mammary glands that give milk to feed a baby. The milk leaves the breast through the nipple when the baby sucks on it. |
What form when water vapor condenses in the air around specs of matter? | condensation | humidity | storms | clouds | Clouds form when water vapor condenses in the air around specs of matter. Clouds are classified on the basis of where and how they form. Types of clouds include cirrus, stratus, and cumulus clouds. |
All other forms of life, including plants and animals, are composed of what kind of cells? | bacterial | cytoplasmic | synthetic | eukaryotic | |
A mycorrhiza refers to what kind of relationship between a fungus and the roots of a plant? | familial | predator-prey | semantic | symbiotic | A mycorrhiza (Greek for "fungus roots") is a symbiotic association between a fungus and the roots of a plant. In a mycorrhizal association, the fungus may colonize the roots of a host plant by either growing directly into the root cells, or by growing around the root cells. This association provides the fungus with relatively constant and direct access to glucose, which the plant produces by photosynthesis. The mycelia of the fungi increase the surface area of the plant’s root system. The larger surface area improves water and mineral nutrient absorption from the soil. |
What is earth's main source of energy? | the core | the atmosphere | the moon | the sun | The Sun is Earth’s main source of energy. The Sun gives us both light and heat. The Sun changes hydrogen into helium through nuclear fusion. This releases huge amounts of energy. The energy travels to the Earth mostly as visible light. The energy is carried through the empty space by radiation . We can use sunlight as an energy resource, called solar energy ( Figure above ). |
Kirchhoff’s second rule (the loop rule) is an application of conservation of what? | mineral | heating | Rock | energy | Kirchhoff’s Second Rule Kirchhoff’s second rule (the loop rule) is an application of conservation of energy. The loop rule is stated in terms of potential, V , rather than potential energy, but the two are related since PE elec = qV . Recall that emf is the potential difference of a source when no current is flowing. In a closed loop, whatever energy is supplied by emf must be transferred into other forms by devices in the loop, since there are no other ways in which energy can be transferred into or out of the circuit. Figure 21.23 illustrates the changes in potential in a simple series circuit loop. Kirchhoff’s second rule requires emf equals the sum of the. |
Evolution over a short period of time at the level of the population is called what? | macroevolution | grammaticalization | redistributions | microevolution | The time scale of evolution can vary. Evolution over a short period of time at the level of the population is called microevolution. Evolution over a long period of time above the level of the species is called macroevolution. |
When water is heated by magma and makes it's way to the surface what is created? | trough | eruption | volcanic | geyser | Water works its way through porous rocks or soil. Sometimes this water is heated by nearby magma. If the water makes its way to the surface, it forms a hot spring or a geyser. |
The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of what? | alveoli | bile ducts | stomach cilia | intestinal villi | Absorption The mechanical and digestive processes have one goal: to convert food into molecules small enough to be absorbed by the epithelial cells of the intestinal villi. The absorptive capacity of the alimentary canal is almost endless. Each day, the alimentary canal processes up to 10 liters of food, liquids, and GI secretions, yet less than one liter enters the large intestine. Almost all ingested food, 80 percent of electrolytes, and 90 percent of water are absorbed in the small intestine. Although the entire small intestine is involved in the absorption of water and lipids, most absorption of carbohydrates and proteins occurs in the jejunum. Notably, bile salts and vitamin B12 are absorbed in the terminal ileum. By the time chyme passes from the ileum into the large intestine, it is essentially indigestible food residue (mainly plant fibers like cellulose), some water, and millions of bacteria (Figure 23.32). |
Influenza virus is packaged in a viral envelope, which fuses with the what? | bacteria | nucleus | cell wall | plasma membrane | Influenza virus is packaged in a viral envelope, which fuses with the plasma membrane. This way, the virus can exit the host cell without killing it. What advantage does the virus gain by keeping the host cell alive?. |
A desert is a type of what community in an ecosystem? | colony | culture | population | biome | This scene is from Anza-Borrago California Desert Park. However, deserts exist around the globe. You might find a similar picture of a desert in Africa. The desert is one type of biome. |
What are the two types of properties that matter has? | size and shape | nature and purpose | composition and weight | physical and chemical | Matter has both physical and chemical properties. Physical properties can be measured or observed without matter changing to a different substance. |
What is the hormone produced in high-stress situations? | somatostatin | testosterone | thyroxine | adrenalin | In the health sciences, the concentration of a solution is typically expressed asparts per thousand (ppt), indicated as a proportion. For example, adrenalin, the hormone produced in high-stress situations, is available in a 1:1000 solution, or one gram of adrenalin per 1000 g of solution. The labels on bottles of commercial reagents often describe the contents in terms of mass percentage. Sulfuric acid, for example, is sold as a 95% aqueous solution, or 95 g of H2SO4 per 100 g of solution. Parts per million and parts per billion are used to describe concentrations of highly dilute solutions. These measurements correspond to milligrams and micrograms of solute per kilogram of solution, respectively. For dilute aqueous solutions, this is equal to milligrams and micrograms of solute per liter of solution (assuming a density of 1.0 g/mL). |
What type of reaction causes two substances to combine to make a single substance? | metabolism | component reaction | spontaneous mutation | composition reaction | In this equation, two substances combine to make a single substance. This is a composition reaction. Two different substances react to make two new substances. This does not fit the definition of either a composition reaction or a decomposition reaction, so it is neither. In fact, you may recognize this as a double-replacement reaction. A single substance reacts to make multiple substances. This is a decomposition reaction. |
Hay fever is actually an allergy to what substance, vital to plant reproduction? | grass | nitrogen | fungi | pollen | Did you ever hear of hay fever? It’s not really a fever at all. It’s an allergy to plant pollens. People with this type of allergy have symptoms such as watery eyes, sneezing, and a runny nose. A common cause of hay fever is the pollen of ragweed. Many people are also allergic to poison ivy ( Figure below ). Skin contact with poison ivy leads to an itchy rash in people who are allergic to the plant. |
Endotherms are warmed mostly by heat generated by what? | the sun | movement | electricity | metabolism | |
If a ball is released from rest when air resistance is negligible, velocity is seen to increase linearly, while what related property is a constant? | density | time | speed | acceleration | Figure 2.43 Positions and velocities of a metal ball released from rest when air resistance is negligible. Velocity is seen to increase linearly with time while displacement increases with time squared. Acceleration is a constant and is equal to gravitational acceleration. |
What term is used to describe the ability of matter to burn? | volatility | permeability | reactivity | flammability | Flammability is the ability of matter to burn. When matter burns, it combines with oxygen and changes to different substances. Wood is an example of flammable matter, as seen in Figure below . |
What is the evolutionary history of group of related organisms | iteration | substructure | history | phylogeny | Phylogeny is the evolutionary history of group of related organisms. It is represented by a phylogenetic tree that shows how species are related to each other through common ancestors. |
What forms a ketone when oxidized? | carbolic acid | enzyme | aldehyde | secondary alcohol | A secondary alcohol forms a ketone when oxidized. The secondary alcohol cannot be further oxidized to produce a carboxylic acid. Tertiary alcohols cannot be oxidized in this way, because the carbon atom bonded to the OH group is not also bonded to any hydrogens. |
What is the energy that flows as a result of a difference in temperature? | magnetism | electricity | polarity | heat | Heat is the energy that flows as a result of a difference in temperature. We use the symbol for heat. Heat, like all forms of energy, is measured in joules. |
Exposure to toxins is most damaging during weeks 4 through 8 of the embryonic stage due to development of what during this period? | pain | samples | faith | organs | Embryonic Development (Weeks 4–8). Most organs develop in the embryo during weeks 4 through 8. If the embryo is exposed to toxins during this period, the effects are likely to be very damaging. Can you explain why? (Note: the drawings of the embryos are not to scale. ). |
What evolutionary process may affect the distribution of a polygenic trait? | characteristic selection | artificial selection | flow selection | natural selection | Natural Selection for a Polygenic Trait. Natural selection may affect the distribution of a polygenic trait. These graphs show three ways this can happen. |
What type of force exists between two touching surfaces? | tension | opposing | centrifugal | friction | Friction is the force that resists motion. In most beginning physics classes, friction is ignored. Concepts can be understood and calculations made assuming friction to be nonexistent. Whenever physics intersects with the real world, however, friction must be taken into account. Friction exists between two touching surfaces because even the smoothest looking surface is quite rough on a microscopic scale. |
A short reflex is completely what and only involves the local integration of sensory input with motor output? | central | neuronal | physiological | peripheral | Short and Long Reflexes Somatic reflexes involve sensory neurons that connect sensory receptors to the CNS and motor neurons that project back out to the skeletal muscles. Visceral reflexes that involve the thoracolumbar or craniosacral systems share similar connections. However, there are reflexes that do not need to involve any CNS components. A long reflex has afferent branches that enter the spinal cord or brain and involve the efferent branches, as previously explained. A short reflex is completely peripheral and only involves the local integration of sensory input with motor output (Figure 15.8). |
The urea cycle, a set of biochemical reactions that produces urea from ammonium ions to prevent toxicity, occurs to some extent in the kidney, but primarily in what organ? | colon | spleen | skin | liver | Urea Cycle The urea cycle is a set of biochemical reactions that produces urea from ammonium ions in order to prevent a toxic level of ammonium in the body. It occurs primarily in the liver and, to a lesser extent, in the kidney. Prior to the urea cycle, ammonium ions are produced from the breakdown of amino acids. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule. This transamination event creates a molecule that is necessary for the Krebs cycle and an ammonium ion that enters into the urea cycle to be eliminated. In the urea cycle, ammonium is combined with CO2, resulting in urea and water. The urea is eliminated through the kidneys in the urine (Figure 24.18). |
Cellular respiration is the reverse or opposite of what? | glycolysis | spermatogenesis | reproduction | photosynthesis | Specifically, during cellular respiration, the energy stored in glucose is transferred to ATP ( Figure below ). ATP , or adenosine triphosphate, is chemical energy the cell can use. It is the molecule that provides energy for your cells to perform work, such as moving your muscles as you walk down the street. But cellular respiration is slightly more complicated than just converting the energy from glucose into ATP. Cellular respiration can be described as the reverse or opposite of photosynthesis. During cellular respiration, glucose, in the presence of oxygen, is converted into carbon dioxide and water. Recall that carbon dioxide and water are the starting products of photosynthesis. What are the products of photosynthesis?. |
What force pulls object downwards to the earth? | motion | momentum | kinetic energy | gravity | Gravity near the Earth pulls an object downwards toward the surface of the Earth with an acceleration of . In the absence of air resistance, all objects will fall with the same acceleration. The letter is used as the symbol for the acceleration of gravity. When talking about an object's acceleration, whether it is due to gravity or not, the acceleration of gravity is sometimes used as a unit of measurement where . So an object accelerating at 2g's is accelerating at or. |
How does deeper material cause convection in the mantle? | sinks then rises | remains stable | folds | rises then sinks | Not long after Wegener's death, scientists recognized that there is convection in the mantle. Deeper material is hotter and so it rises. Near the surface, it becomes cooler and denser so it sinks. This creates a convection cell in the mantle. |
From what did the first proto-oncogenes arise? | bacteria | spores | carcinogens | viral infections | |
What material used for helium-filled balloons is dense, strong and opaque, with a high molecular mass that forms films that have many fewer pores than rubber? | foil | fiberglass | cellophane | mylar | times faster than air. For this reason, high-quality helium-filled balloons are usually made of Mylar, a dense, strong, opaque material with a high molecular mass that forms films that have many fewer pores than rubber. Mylar balloons can retain their helium for days. |
What do erythrocytes carry and deliver to tissues in the body? | oxide | Helium | carbon | oxygen | The cell found in greatest abundance in blood is the erythrocyte. Erythrocytes are counted in millions in a blood sample: the average number of red blood cells in primates is 4.7 to 5.5 million cells per microliter. Erythrocytes are consistently the same size in a species, but vary in size between species. For example, the average diameter of a primate red blood cell is 7.5 µl, a dog is close at 7.0 µl, but a cat’s RBC diameter is 5.9 µl. Sheep erythrocytes are even smaller at 4.6 µl. Mammalian erythrocytes lose their nuclei and mitochondria when they are released from the bone marrow where they are made. Fish, amphibian, and avian red blood cells maintain their nuclei and mitochondria throughout the cell’s life. The principal job of an erythrocyte is to carry and deliver oxygen to the tissues. Leukocytes are the predominant white blood cells found in the peripheral blood. Leukocytes are counted in the thousands in the blood with measurements expressed as ranges: primate counts range from 4,800 to 10,800 cells per µl, dogs from 5,600 to 19,200 cells per µl, cats from 8,000 to 25,000 cells per µl, cattle from 4,000 to 12,000 cells per µl, and pigs from 11,000 to 22,000 cells per µl. Lymphocytes function primarily in the immune response to foreign antigens or material. Different types of lymphocytes make antibodies tailored to the foreign antigens and control the production of those antibodies. Neutrophils are phagocytic cells and they participate in one of the early lines of defense against microbial invaders, aiding in the removal of bacteria that has entered the body. Another leukocyte that is found in the peripheral blood is the monocyte. Monocytes give rise to. |
How many neutrons do 99% of carbon atoms have? | eight | sixteen | five | six | All the atoms of a given element have the same number of protons and electrons. The number of neutrons, however, may vary for atoms of the same element. For example, almost 99 percent of carbon atoms have six neutrons, but the rest have either seven or eight neutrons. Atoms of an element that differ in their numbers of neutrons are called isotopes. The nuclei of these isotopes of carbon are shown in the Figure below . The isotope called carbon-14 is used to find the ages of fossils. You can learn how at this URL: http://science. howstuffworks. com/environmental/earth/geology/carbon-14. htm . |
What are the two metals within a battery called? | anode and diode | sheath and a cathode | anode and sheath | anode and a cathode | These values suggest that water should be oxidized at the anode because a smaller potential would be needed—using reaction (ii) for the oxidation would give a less-negative cell potential. When the experiment is run, it turns out chlorine, not oxygen, is produced at the anode. The unexpected process is so common in electrochemistry that it has been given the name overpotential. The overpotential is the difference between the theoretical cell voltage and the actual voltage that is necessary to cause electrolysis. It turns out that the overpotential for oxygen is rather high and effectively makes the reduction potential more positive. As a result, under normal conditions, chlorine gas is what actually forms at the anode. Now consider the cathode. Three reductions could occur:. |
What is one thing that can not happen to energy? | it cannot decrease | it cannot stay the same | it cannot increase | it can not be destroyed | If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure below show the chemical energy of reactants and products in each type of reaction. |
Where do most biochemical reactions take place? | outside of cells | stomach | upper atmosphere | within cells | Most biochemical reactions take place within cells. Cells are the microscopic building blocks of organisms. |
The ends of linear chromosomes are maintained by the action of which enzyme? | insulin | cytokine | pepsin | telomerase | Figure 9.11 The ends of linear chromosomes are maintained by the action of the telomerase enzyme. |
Through which process does water from the oceans enter the atmosphere? | absorption | oxidation | perspiration | evaporation | |
In what type of process does heat flow into its surroundings and cause an increase in kinetic energy? | oscillating process | biochemical process | chemical process | exothermic process | In general, the process of interest is taking place in the system, and there are no changes in the composition of the surroundings. However, the temperature of the surroundings does generally change. Entropy changes in the surroundings are determined primarily by the flow of heat into or out of the system. In an exothermic process, heat flows into the surroundings, increasing the kinetic energy of the nearby particles. For an exothermic reaction, ΔS surr is positive. Conversely, heat flows from the surroundings into the system during an endothermic process, lowering the kinetic energy available to the surroundings and resulting in a negative value for ΔS surr . |
Prokaryotic organisms, like bacteria, reproduce through what process, where they grow and divide in half? | multiple fission | symbiotic fission | singular fission | binary fission | Prokaryotic organisms, like bacteria. Bacteria reproduce through binary fission , where they grow and divide in half ( Figure below ). First, their chromosome replicates and the cell enlarges. The cell then divides into two cells as new membranes form to separate the two cells. After cell division, the two new cells each have one identical chromosome. This simple process allows bacteria to reproduce very rapidly. |
Displacement is a vector quantity, which means it has both direction and what else? | waves | radiation | rate | magnitude | What is the difference between distance and displacement? Whereas displacement is defined by both direction and magnitude, distance is defined only by magnitude. Displacement is an example of a vector quantity. Distance is an example of a scalar quantity. A vector is any quantity with both magnitude and direction. Other examples of vectors include a velocity of 90 km/h east and a force of 500 newtons straight down. The direction of a vector in one-dimensional motion is given simply by a plus. |
Waste leaves the body in the form of what? | impurities | saliva | stomach acid | feces | |
What process can occur when atoms are exposed to high levels of radiation or when atoms transfer electrons to or from other atoms? | oxidation | fusion | diffusion | ionization | The process in which an atom becomes an ion is called ionization. It may occur when atoms are exposed to high levels of radiation or when atoms transfer electrons to or from other atoms. |
Who should an obese person with an eating disorder seek for help? | social worker | psychiatrist | body builder | health professional | Some people who are obese have an eating disorder. Eating disorders are mental illnesses that require treatment by health professionals. |
The period of life between the start of puberty and the beginning of adulthood is called? | youth | prenatal | old age | adolescence | Adolescence is the period of life between the start of puberty and the beginning of adulthood. Adolescence includes the physical changes of puberty. It also includes many other changes, including significant mental, emotional, and social changes. During adolescence:. |
What element once commonly used in paint and gasoline has now been found to have dangerous effects? | niacin | plastic | chromium | lead | lead: An element that was once commonly used in gasoline and paint, is now found to have dangerous effects, such as brain damage. Lead contamination has many harmful effects on the body. |
What can happen spontaneously or as a result of mutagens in the environment? | traits | lesions | combustion | mutations | Many mutations are not caused by errors in replication. Mutations can happen spontaneously, and they can be caused by mutagens in the environment. Some chemicals, such as those found in tobacco smoke, can be mutagens. Sometimes mutagens can also cause cancer. Tobacco smoke, for example, is often linked to lung cancer. |
Abnormally high activity or low activity of the parathyroid gland can cause disorders related to levels of what bone mineral? | magnesium | potassium | collagen | calcium | Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium deposits may collect in the body’s tissues and organs, impairing their functioning. In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism, which may develop following injury or surgery involving the thyroid gland. Low blood calcium. |
Unlike other tetrapod vertebrates (reptiles, birds, and mammals), amphibians do not produce what type of eggs? | umbilical | epithelial | prokaryotic | amniotic | Unlike other tetrapod vertebrates (reptiles, birds, and mammals), amphibians do not produce amniotic eggs. Therefore, they must lay their eggs in water so they won’t dry out. Their eggs are usually covered in a jelly-like substance, like the frog eggs shown in Figure below . The jelly helps keep the eggs moist and offers some protection from predators. |
What is the name for an underground layer of rock that is saturated with groundwater? | artesian well | gradient | aqueous cavity | aquifer | An underground layer of rock that is saturated with groundwater is called an aquifer . A diagram of an aquifer is pictured below ( Figure below ). Aquifers are generally found in porous rock, such as sandstone. Water infiltrates the aquifer from the surface. The water that enters the aquifer is called recharge . |
What are prepared by the oxidation of secondary alcohols? | ions | protons | more alcohol | ketones | The carbonyl group, a carbon-to-oxygen double bond, is the defining feature ofaldehydes and ketones. In aldehydes at least one bond on the carbonyl group is a carbon-to-hydrogen bond; in ketones, both available bonds on the carbonyl carbon atom are carbon-to-carbon bonds. Aldehydes are synthesized by the oxidation of primary alcohols. The aldehyde can be further oxidized to a carboxylic acid. Ketones are prepared by the oxidation of secondary alcohols. Mild oxidizing agents oxidize aldehydes to carboxylic acids. Ketones are not oxidized by these reagents. A thiol is a compound with an SH functional group. |
Saturated and unsaturated are the two main kinds of what? | polymers | sugars | acids | fats | There are two main types of fats, saturated and unsaturated. |
Most reptiles lay what kind of eggs? | roe | hard-shelled | umbilical | amniotic | All reptiles have a cloaca , a single exit and entrance for sperm, eggs, and waste, located at the base of the tail. Most reptiles lay amniotic eggs covered with leathery or hard shell. These eggs can be placed anywhere as they don't have to be in a moist environment, like the eggs of amphibians. However, not all species lay eggs, as certain species of squamates can give birth to live young. |
Sulfur can combine with oxygen to produce what? | sulfur oxide | sulfur bioxide | sulfur dioxide | sulfur trioxide | When nonmetals react with one another, the product is a molecular compound. Often, the nonmetal reactants can combine in different ratios and produce different products. Sulfur can also combine with oxygen to produce sulfur trioxide. |
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