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What is the process of the blastula forming 3 layers of cells called? | fermentation | Mitosis | internalization | gastrulation | Gastrulation The typical blastula is a ball of cells. The next stage in embryonic development is the formation of the body plan. The cells in the blastula rearrange themselves spatially to form three layers of cells. This process is called gastrulation. During gastrulation, the blastula folds upon itself to form the three layers of cells. Each of these layers is called a germ layer and each germ layer differentiates into different organ systems. The three germs layers, shown in Figure 43.26, are the endoderm, the ectoderm, and the mesoderm. The ectoderm gives rise to the nervous system and the epidermis. The mesoderm gives rise to the muscle cells and connective tissue in the body. The endoderm gives rise to columnar cells found in the digestive system and many internal organs. |
How does air pressure change as altitude increases? | It increases | goes up and down | stays the same | it decreases | Like density, the pressure of the air decreases with altitude. There is less air pressing down from above the higher up you go. Look at the bottle pictured below ( Figure below ). It was drained by a hiker at the top of a mountain. Then the hiker screwed the cap on the bottle and carried it down to sea level. At the lower altitude, air pressure crushed it. Can you explain why?. |
In harmonic motion there is always what force, which acts in the opposite direction of the velocity? | locomotion force | magnetic force | inorganic force | restorative force | In harmonic motion there is always a restorative force , which acts in the opposite direction of the velocity. The restorative force changes during oscillation and depends on the position of the object. In a spring the force is the spring force; in a pendulum it is the component of gravity along the path. In both cases, the force on the oscillating object is directly opposite that of the direction of velocity. |
Many of the protist species classified into the supergroup excavata are asymmetrical, single-celled organisms with a feeding groove “excavated” from one side. this supergroup includes heterotrophic predators, photosynthetic species, and these? | mammals | insects | reptiles | parasites | Excavata Many of the protist species classified into the supergroup Excavata are asymmetrical, single-celled organisms with a feeding groove “excavated” from one side. This supergroup includes heterotrophic predators, photosynthetic species, and parasites. Its subgroups are the diplomonads, parabasalids, and euglenozoans. Diplomonads Among the Excavata are the diplomonads, which include the intestinal parasite, Giardia lamblia (Figure 23.10). Until recently, these protists were believed to lack mitochondria. Mitochondrial remnant organelles, called mitosomes, have since been identified in diplomonads, but these mitosomes are essentially nonfunctional. Diplomonads exist in anaerobic environments and use alternative pathways, such as glycolysis, to generate energy. Each diplomonad cell has two identical nuclei and uses several flagella for locomotion. |
What is the thick fluid in the space between bones that cushions the joint? | collagen | interstitial fluid | amniotic fluid | synovial fluid | Movable joints are also known as synovial joints. This is because the space between the bones is filled with a thick fluid, called synovial fluid, that cushions the joint (see Figure below ). |
What is the name of the portion of a nucleotide lacking phosphate groups? | nucleolus | nuclear shell | a nucleobase | a nucleoside | |
The band disappears before metaphase but predicts the future plane of what? | cell solution | cell matter | cell wall | cell division | |
What is a common age-related bone disease in which bone density and strength is decreased? | arthritis | fibrosis | lupus | osteoporosis | View this animation (http://openstaxcollege. org/l/ headblow) to see how a blow to the head may produce a contrecoup (counterblow) fracture of the basilar portion of the occipital bone on the base of the skull. Why may a basilar fracture be life threatening? 3. Osteoporosis is a common age-related bone disease in which bone density and strength is decreased. Watch this video (http://openstaxcollege. org/l/osteoporosis) to get a better understanding of how thoracic vertebrae may become weakened and may fractured due to this disease. How may vertebral osteoporosis contribute to kyphosis? 4. Watch this animation (http://openstaxcollege. org/l/ diskslip) to see what it means to “slip” a disk. Watch this second animation (http://openstaxcollege. org/l/ herndisc) to see one possible treatment for a herniated disc,. |
Bacteria reproduce through what process? | residual fission | binary fusion | tertiary fission | binary fission | Bacteria reproduce through a process called binary fission . During binary fission, the chromosome copies itself, forming two genetically identical copies. Then, the cell enlarges and divides into two new daughter cells. The two daughter cells are identical to the parent cell. Binary fission can happen very rapidly. Some species of bacteria can double their population in less than ten minutes! This process makes it possible for a tremendous bacterial colony to start from a single cell. |
What is the branch of science that studies the physical world? | Ecology | social science | botany | physics | What is physics ? Physics is the branch of science that studies the physical world, including objects as small as subatomic particles and as large as galaxies. It studies the nature of matter and energy and how they interact. Physicists are inquisitive people who want to know the causes of what they see. How does the moon move? Why does the moon move? Why do the stars shine? Why do your hands get warm when you rub them together? Physicists, like all scientists, hope to find explanations that describe more than one phenomenon and offer a better understanding of how the universe works. |
Osteoclasts break down bone to maintain mineral what? | polarity | density | fluctuations | homeostatis | Under the direction of osteocytes, osteoblasts continuously build up bone, while osteoclasts continuously break down bone to maintain mineral homeostasis. Bone tissues include compact bone, spongy bone, bone marrow, and periosteum. |
Which carbohydrates can be classified in terms of chain length? | complex | binary | atomic | simple | Simple carbohydrates can be classified in terms of chain length. |
What is altered by changes in cardiac output by variable contriction of the arterioles? | blood type | heart rhythm | pulse | blood pressure | |
Eukaryotic cells are cells that contain what? | pathogens | inorganic matter | energy | a nucleus | Eukaryotic cells are cells that contain a nucleus. |
What distinctive dna shape forms when the two nucleotide chains wrap around the same axis? | double spiral | single spiral | chain helix | double helix | Simple Model of DNA. In this simple model of DNA, each line represents a nucleotide chain. The double helix shape forms when the two chains wrap around the same axis. |
The oxygen regions of the water molecules have what kind of charge? | certain | positive | neutral | negative | |
Humans use many compounds that were first discovered or derived from living organisms as medicines: secondary plant compounds, animal toxins, and antibiotics produced by these? | tumors and fungi | bacteria and tumors | molecules and fungi | bacteria and fungi | 47.2 The Importance of Biodiversity to Human Life Humans use many compounds that were first discovered or derived from living organisms as medicines: secondary plant compounds, animal toxins, and antibiotics produced by bacteria and fungi. More medicines are expected to be discovered in nature. Loss of biodiversity will impact the number of pharmaceuticals available to humans. Crop diversity is a requirement for food security, and it is being lost. The loss of wild relatives to crops also threatens breeders’ abilities to create new varieties. Ecosystems provide ecosystem services that support human agriculture: pollination, nutrient cycling, pest control, and soil development and maintenance. Loss of biodiversity threatens these ecosystem services and risks making food production more expensive or impossible. Wild food sources are mainly aquatic, but few are being managed for sustainability. Fisheries’ ability to provide protein to human populations is threatened when extinction occurs. Biodiversity may provide important psychological benefits to humans. Additionally, there are moral arguments for the maintenance of biodiversity. |
Millipedes and centipedes are the most commonly found examples of what group of arthropods? | protists myriapoda | unicellular myriapoda | Disperse Myriapoda | subphylum myriapoda | Subphylum Myriapoda includes arthropods with legs that may vary in number from 10 to 750. This subphylum includes 13,000 species; the most commonly found examples are millipedes and centipedes. All myriapods are terrestrial animals and prefer a humid environment (Figure 15.21). |
Glass breaking is an example of what type of change that doesn't affect the makeup of matter? | chemical | reversible | thermal | physical | Physical changes are changes in the physical properties of matter but not in the makeup of matter. An example of a physical change is glass breaking. |
Aldehydes, ketones, carboxylic acids, esters, and ethers all have functional groups containing what element? | carbon | silicon | methane | oxygen | Aldehydes, ketones, carboxylic acids, esters, and ethers h ave oxygencontaining functional groups. |
What forms when an atom gains electrons? | crystals | cations | bonds | anions | Anions form when an atom gains electrons. Nonmetallic atoms typically gain enough electrons to obtain the same electron configuration as the nearest noble gas. All the elements in Group 17 have seven valence electrons, which are arranged into an outer configuration of n s 2 n p 5 . To achieve a noble gas configuration ( n s 2 n p 6 ), each of these elements needs to gain just one electron, resulting in an anion with a 1− charge. Similarly, Group 16 elements can obtain an n s 2 n p 6 valence configuration by forming ions with a 2− charge, and the Group 15 nonmetals will form ions with a 3− charge. Naming anions is slightly different than naming cations. The end of the element’s name is dropped and replaced with the – ide suffix. For example, when the chlorine atom (Cl) gains one electron, it becomes the chloride ion (Cl - ). This structure has the same electron configuration as the noble gas argon. Similarly, sulfur can gain two electrons to become the sulfide ion (S 2- ), which also has a noble gas configuration. |
There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes. the three shared characteristics among these types—what makes them wetlands—are their hydrology, hydrophytic vegetation, and this? | niya soils | stibnite soils | sandy soils | hydric soils | may not be able to use vision as their primary sense to find food. Instead, they are more likely to use taste or chemical cues to find prey. Wetlands Wetlands are environments in which the soil is either permanently or periodically saturated with water. Wetlands are different from lakes because wetlands are shallow bodies of water whereas lakes vary in depth. Emergent vegetation consists of wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water’s surface. There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes (Figure 44.25). The three shared characteristics among these types—what makes them wetlands—are their hydrology, hydrophytic vegetation, and hydric soils. |
What element is typically used to shield things from gamma rays? | aluminum | gold | silver | lead | High-density materials are much more effective protection against gamma emissions than low-density ones. Gamma rays are usually blocked effectively by lead shielding. The thickness of the shielding will determine the effectiveness of the protection offered by the lead. |
What is the combination of tissues that provides a tough, woody external covering on the stems of trees called? | epidermis | cuticle | scale | bark | In trees, some of the epidermal tissue is replaced by bark. Bark is a combination of tissues that provides a tough, woody external covering on the stems of trees. The inner part of bark is alive and growing; the outer part is dead and provides strength, support, and protection. |
Because microorganisms can go through several generations in a matter of hours, their gene expression profiles adapt to the new laboratory environment very quickly. in addition, the vast majority of bacterial species resist being cultured in this? | colonies | water | substrate | isolation | Microbial Genomics: Metagenomics Traditionally, microbiology has been taught with the view that microorganisms are best studied under pure culture conditions, which involves isolating a single type of cell and culturing it in the laboratory. Because microorganisms can go through several generations in a matter of hours, their gene expression profiles adapt to the new laboratory environment very quickly. In addition, the vast majority of bacterial species resist being cultured in isolation. Most microorganisms do not live as isolated entities, but in microbial communities known as biofilms. For all of these reasons, pure culture is not always the best way to study microorganisms. Metagenomics is the study of the collective genomes of multiple species. |
Examples of acute forms of what type of diseases include the common cold and influenza? | attributable diseases | inherited diseases | bacterial diseases | viral diseases | As you will learn in the next module, animal viruses are associated with a variety of human diseases. Some of them follow the classic pattern of acute disease, where symptoms get increasingly worse for a short period followed by the elimination of the virus from the body by the immune system and eventual recovery from the infection. Examples of acute viral diseases are the common cold and influenza. Other viruses cause long-term chronic infections, such as the virus causing hepatitis C, whereas others, like herpes simplex virus, only cause intermittent symptoms. Still other viruses, such as human herpesviruses 6 and 7, which in some cases can cause the minor childhood disease roseola, often successfully cause productive infections without causing any symptoms at all in the host, and thus we say these patients have an asymptomatic infection. In hepatitis C infections, the virus grows and reproduces in liver cells, causing low levels of liver damage. The damage is so low that infected individuals are often unaware that they are infected, and many infections are detected only by routine blood work on patients with risk factors such as intravenous drug use. On the other hand, since many of the symptoms of viral diseases are caused by immune responses, a lack of symptoms is an indication of a weak immune response to the virus. This allows for the virus to escape elimination by the immune system and persist in individuals for years, all the while producing low levels of progeny virions in what is known as a chronic viral disease. Chronic infection of the liver by this virus leads to a much greater chance of developing liver cancer, sometimes as much as 30 years after the initial infection. As already discussed, herpes simplex virus can remain in a state of latency in nervous tissue for months, even years. As the virus “hides” in the tissue and makes few if any viral proteins, there is nothing for the immune response to act against, and immunity to the virus slowly declines. Under certain conditions, including various types of physical and psychological stress, the latent herpes simplex virus may be reactivated and undergo a lytic replication cycle in the skin, causing the lesions associated with the disease. Once virions are produced in the skin and viral proteins are synthesized, the immune response is again stimulated and resolves the skin lesions in a few days by destroying viruses in the skin. As a result of this type of replicative cycle, appearances of cold sores and genital herpes outbreaks only occur intermittently, even though the viruses remain in the nervous tissue for life. Latent infections are common with other herpesviruses as well, including the varicellazoster virus that causes chickenpox. After having a chickenpox infection in childhood, the varicella-zoster virus can remain latent for many years and reactivate in adults to cause the painful condition known as “shingles” (Figure 21.11ab). |
What do red blood cells carry? | hydrogen | carbon dioxide | nitrogen | oxygen | Blood is a fluid connective tissue that contains a liquid component called plasma. It also contains dissolved substances and blood cells. Red blood cells carry oxygen, white blood cells defend the body, and platelets help blood clot. |
The sympathetic division of the vertebrate autonomic nervous system has evolved the fight-or-flight response to counter stress-induced disruptions of this? | blood pressure | body temperature | equilibrium | homeostasis | Fight-or-Flight Response Interactions of the endocrine hormones have evolved to ensure the body’s internal environment remains stable. Stressors are stimuli that disrupt homeostasis. The sympathetic division of the vertebrate autonomic nervous system has evolved the fight-or-flight response to counter stress-induced disruptions of homeostasis. In the initial alarm phase, the sympathetic nervous system stimulates an increase in energy levels through increased blood glucose levels. This prepares the body for physical activity that may be required to respond to stress: to either fight for survival or to flee from danger. However, some stresses, such as illness or injury, can last for a long time. Glycogen reserves, which provide energy in the short-term response to stress, are exhausted after several hours and cannot meet long-term energy needs. If glycogen reserves were the only energy source available, neural functioning could not be maintained once the reserves became depleted due to the nervous system’s high requirement for glucose. In this situation, the body has evolved a response to counter long-term stress through the actions of the glucocorticoids, which ensure that long-term energy requirements can be met. The glucocorticoids mobilize lipid and protein reserves, stimulate gluconeogenesis, conserve glucose for use by neural tissue, and stimulate the conservation of salts and water. The mechanisms to maintain homeostasis that are described here are those observed in the human body. However, the fight-or-flight response exists in some form in all vertebrates. The sympathetic nervous system regulates the stress response via the hypothalamus. Stressful stimuli cause the hypothalamus to signal the adrenal medulla (which mediates short-term stress responses) via nerve impulses, and the adrenal cortex, which mediates long-term stress responses, via the hormone adrenocorticotropic hormone (ACTH), which is produced by the anterior pituitary. |
What light-producing process occurs when a substance absorbs shorter-wavelength ultraviolet light and then gives off the energy as visible light? | luminescence | candescence | resistance | fluorescence | A fluorescent light bulb produces visible light by fluorescence. Fluorescence occurs when a substance absorbs shorter-wavelength ultraviolet light and then gives off the energy as visible light. The compact fluorescent light bulb (CFL) in the Figure below contains mercury gas that gives off ultraviolet light when electricity passes through it. The inside of the bulb is coated with a substance called phosphor. Phosphor absorbs the ultraviolet light and then gives off most of the energy as visible light. |
What lies between the continental shelf and the abyssal plain? | equator | successive slope | continental belt | continental slope | The continental slope lies between the continental shelf and the abyssal plain. It has a steep slope with a sharp drop to the deep ocean floor. |
In the first beaker, distilled water does not conduct a current because water is a what? | magnetic compound | pure element | solute | molecular compound | In the first beaker, distilled water does not conduct a current because water is a molecular compound. In the second beaker, solid sodium chloride also does not conduct a current. Despite being ionic and thus composed of charges particles, the solid crystal lattice does not allow the ions to move between the electrodes. Mobile charged particles are required for the circuit to be complete and the light bulb to light up. In the third beaker, the NaCl has been dissolved into the distilled water. Now the crystal lattice has been broken apart and the individual positive and negative ions can move. Cations move to one electrode, while anions move to the other, allowing electricity to flow (see Figure below ). Melting an ionic compound also frees the ions to conduct a current. Ionic compounds conduct an electric current when melted or dissolved in water. |
What is another term for hydraulic fracturing? | drilling | erupting | permeating | fracking | Hydraulic fracturing, known as fracking, is a relatively new method for extracting natural gas. Fracking may be linked to groundwater contamination and small earthquakes in non-seismic regions. |
In what unit is speed usually measured? | Celcius | radians | calories | miles per hour | |
Unlike liver bile, 'juice' produced by what organ is clear and composed mostly of water along with some salts, sodium bicarbonate, and digestive enzymes? | stomach | spleen | gallbladder | pancreas | Pancreatic Juice The pancreas produces over a liter of pancreatic juice each day. Unlike bile, it is clear and composed mostly of water along with some salts, sodium bicarbonate, and several digestive enzymes. Sodium bicarbonate is responsible for the slight alkalinity of pancreatic juice (pH 7.1 to 8.2), which serves to buffer the acidic gastric juice in chyme, inactivate pepsin from the stomach, and create an optimal environment for the activity of pH-sensitive digestive enzymes in the small intestine. Pancreatic enzymes are active in the digestion of sugars, proteins, and fats. The pancreas produces protein-digesting enzymes in their inactive forms. These enzymes are activated in the duodenum. If produced in an active form, they would digest the pancreas (which is exactly what occurs in the disease, pancreatitis). The intestinal brush border enzyme enteropeptidase stimulates the activation of trypsin from trypsinogen of the pancreas, which in turn changes the pancreatic enzymes procarboxypeptidase and chymotrypsinogen into their active forms, carboxypeptidase and chymotrypsin. The enzymes that digest starch (amylase), fat (lipase), and nucleic acids (nuclease) are secreted in their active forms, since they do not attack the pancreas as do the protein-digesting enzymes. |
What term means opposition to the flow of electric charges that occurs when electric current travels through matter? | diffusion | polarity | antagonism | resistance | Resistance is opposition to the flow of electric charges that occurs when electric current travels through matter. The SI unit of resistance is the ohm (named for the scientist Georg Ohm, whom you can read about below). Resistance is caused by electrons in a current bumping into electrons and ions in the matter through which the current is flowing. Resistance is similar to the friction that resists the movement of one surface as it slides over another. Resistance reduces the amount of current that can travel through the material because some of the electrical energy is converted to other forms of energy. For example, when electric current flows through the tungsten wire inside an incandescent light bulb, the tungsten resists the flow of electric charge, and some of the electrical energy is converted to light and thermal energy. |
According to law, what must packaged foods carry? | country of origin | warnings | pricing | nutrition facts label | Packaged foods are required by law to carry a nutrition facts label, like the one in Figure below . The labels show the nutrient content and ingredients of foods. Reading labels can help you choose foods that are high in nutrients you need more of (such as proteins) and low in nutrients you need less of (such as fats). |
What type of terminal releases neurotransmitters at a synapse? | chloride | acetylcholine, | secretion | axon | At a synapse, neurotransmitters are released by the axon terminal. They bind with receptors on the other cell. |
What chemical affects the onset of puberty and duration? | acids | steroids | enzymes | hormones | Puberty lasts from about ages 12 to 18 years and is controlled by hormones. |
What are the only plants with a life cycle in which the gametophyte generation is dominant? | photoreactive | vascular plants | nonpermeable | nonvascular | Nonvascular plants include mosses, liverworts, and hornworts. They are the only plants with a life cycle in which the gametophyte generation is dominant. Figure below shows the life cycle of moss. The familiar, green, photosynthetic moss plants are gametophytes . The sporophyte generation is very small and dependent on the gametophyte plant. |
What do angiosperms produce? | leaves | scales | needles | flowers and fruit | a phosphate group, which contains phosphorus and oxygen. |
What should you let liquid waste do before placing the container in the trash? | melt | expand | generate | evaporate | Always properly dispose of hazardous waste. For example, let liquid waste evaporate before placing the container in the trash. |
Mammoths, close genetic relatives of modern elephants, are believed to have gone extinct due to hunting by humans and what factor? | migration change | volcanic eruptions | earthquakes | climate change | It's easy to get lost in the discussion of dinosaurs and theories about why they went extinct 65 million years ago. Was it due to a meteor slamming into Earth near the coast of modern-day Mexico, or was it from some long-term weather cycle that is not yet understood? One hypothesis that will never be proposed is that humans had something to do with it. Mammals were small, insignificant creatures of the forest 65 million years ago, and no humans existed. Woolly mammoths, however, began to go extinct about 10,000 years ago, when they shared the Earth with humans who were no different anatomically than humans today (Figure 45.12). Mammoths survived in isolated island populations as recently as 1700 BC. We know a lot about these animals from carcasses found frozen in the ice of Siberia and other regions of the north. Scientists have sequenced at least 50 percent of its genome and believe mammoths are between 98 and 99 percent identical to modern elephants. It is commonly thought that climate change and human hunting led to their extinction. A 2008 study estimated that climate change reduced the mammoth’s range from 3,000,000 square miles 42,000 years [7] ago to 310,000 square miles 6,000 years ago. It is also well documented that humans hunted these animals. A 2012 study showed that no single factor was exclusively responsible for the extinction of these [8] magnificent creatures. In addition to human hunting, climate change, and reduction of habitat, these scientists demonstrated another important factor in the mammoth’s extinction was the migration of humans across the Bering Strait to North America during the last ice age 20,000 years ago. The maintenance of stable populations was and is very complex, with many interacting factors determining the outcome. It is important to remember that humans are also part of nature. Once we contributed to a species’ decline using primitive hunting technology only. |
What is the ph level of neutral, pure water? | six | six and a half | five | seven | The ion concentration of neutral, pure water gives water a pH of 7 and sets the standard for defining acids and bases. Acids have a pH lower than 7, and bases have a pH higher than 7. |
Which organ system defends the body from pathogens and other causes of disease? | respiratory system | digestion system | nervous system | immune system | Vertebrates have an adaptive immune system. The immune system is the organ system that defends the body from pathogens and other causes of disease. Being adaptive means that the immune system can learn to recognize specific pathogens. Then it can produce tailor-made chemicals called antibodies to attack them. This allows the immune system to launch a rapid attack whenever the pathogens invade the body again. |
What is the process where scientific articles are checked and analyzed by other scientists before publication? | process review | mechanism review | embrace review | peer review | Scientists may publish articles about their research in peer-reviewed science journals. Peer review means that the work is analyzed by peers, in other words, by other scientists. The articles are published only if the other scientists are convinced that the research is accurate and honest. |
A mutation is a random change in an organism's what? | babies | power | structure | genes | At some point, the variation probably came from a mutation. A mutation is a random change in an organism's genes. Mutations are natural. Some are harmful, but many are neutral. If the trait from the mutation is beneficial, that organism may have a better chance to survive. An organism that survives is likely to have offspring. If it does, it may pass the mutation on to its offspring. The offspring may be more likely to survive. |
Synovial and ball-and-socket are both types of what? | muscles | bonds | cells | joints | 9.5 | Types of Body Movements By the end of this section, you will be able to: • Define the different types of body movements • Identify the joints that allow for these motions Synovial joints allow the body a tremendous range of movements. Each movement at a synovial joint results from the contraction or relaxation of the muscles that are attached to the bones on either side of the articulation. The type of movement that can be produced at a synovial joint is determined by its structural type. While the ball-and-socket joint gives the greatest range of movement at an individual joint, in other regions of the body, several joints may work together to produce a particular movement. Overall, each type of synovial joint is necessary to provide the body with its great flexibility and mobility. There are many types of movement that can occur at synovial joints (Table 9.1). Movement types are generally paired, with one being the opposite of the other. Body movements are always described in relation to the anatomical position of the body: upright stance, with upper limbs to the side of body and palms facing forward. Refer to Figure 9.12 as you go through this section. |
Who invented dynamite in 1866? | Albert Einstein | Louis Pasteur | Madame Curie | alfred nobel | Dynamite was invented by Alfred Nobel in 1866. Nitroglycerin, a very unstable explosive, was already known. Nobel mixed the nitroglycerin with silica to stabilize it and form a solid material. He made a fortune with this discovery and established the Nobel Foundation, which funds the Nobel Prizes every year. |
Most liquid freshwater is under the ground in layers of what? | soil | forest | sand | rock | Only a tiny fraction of Earth’s freshwater is in the liquid state. Most liquid freshwater is under the ground in layers of rock. Of freshwater on the surface, the majority occurs in lakes and soil. What percentage of freshwater on the surface is found in living things?. |
What phenotype do gain-of-function mutations usually result in? | external | submissive | internal | dominant | Gain-of-function mutations result in the gene product or protein having a new and abnormal function and usually result in a dominant phenotype. Examples of gain of function mutations occur in the thyroid hormone receptor gene. |
What occurs if oxygen cannot be obtained at a sufficient rate? | hyperventilation | aerobic respiration | malolactic respiration | anaerobic respiration | Phil Roeder. Anaerobic respiration occurs if oxygen cannot be obtained at a sufficient rate . CC-BY 2.0. |
What are the key to species evolving? | radiation | microbes | parasites | mutations | Mutations are the key to species evolving. Lets say an organism "mutates" due to a new allele for a gene that determines coat color. There are, theoretically, only three outcomes of that mutation:. |
Cancer develops when what process is unregulated? | cellular respiration | metabolism | meiosis | cell division | In the Cell Cycle: Cancer (Advanced) concept, cancer is described as developing due to unregulated cell division. That is, cancer is a disease characterized by a population of cells that grow and divide without respect to normal limits. These cancerous cells invade and destroy adjacent tissues, and they may spread throughout the body. The process by which normal cells are transformed into cancer cells is known as carcinogenesis . This process is also known as oncogenesis or tumorigenesis. Oncogenes are mutated genes involved in the development of cancer. |
What are needed to oxidize the noble gases to form compounds in positive oxidation states? | bacteria oxidants | metal oxidants | protein oxidants | potent oxidants | Potent oxidants are needed to oxidize the noble gases to form compounds in positive oxidation states. |
Which muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition? | Hybrid | spicule | spirogyra | suprahyoid | The suprahyoid muscles raise the hyoid bone, the floor of the mouth, and the larynx during deglutition. These include the digastric muscle, which has anterior and posterior bellies that work to elevate the hyoid bone and larynx when one swallows; it also depresses the mandible. The stylohyoid muscle moves the hyoid bone posteriorly, elevating the larynx,. |
What type of energy is stored in an object because of its position or shape? | kinetic | magnetic | mechanical | potential | Potential energy is the energy stored in an object because of its position or shape. It includes gravitational potential energy and elastic potential energy. Gravitational potential energy depends on an object’s weight and height above the ground. |
Like plants, animals are multicellular what? | membranes | isolates | prokaryotes | eukaryotes | Like plants, animals are multicellular eukaryotes. However, animals differ from plants in other important ways. |
A doorknob and a ferris wheel are examples of what type of simple machine? | ball and axle | ball and socket | lever and pulley | wheel and axle | A wheel and axle is a simple machine that consists of two connected rings or cylinders, one inside the other. Both rings or cylinders turn in the same direction around a single center point. The inner ring or cylinder is called the axle, and the outer one is called the wheel. Besides the Ferris wheel, the doorknob in the Figure below is another example of a wheel and axle. For more examples, go to this URL:. |
What do ocean mollusks use to absorb oxygen from the water? | pores | shells | scales | gills | Most ocean mollusks have a gill or gills to absorb oxygen from the water. |
What is paleobotany? | study of fresh plants | study of diseased plants | study of new plants | study of extinct plants | Paleobotanist How organisms acquired traits that allow them to colonize new environments—and how the contemporary ecosystem is shaped—are fundamental questions of evolution. Paleobotany (the study of extinct plants) addresses these questions through the analysis of fossilized specimens retrieved from field studies, reconstituting the morphology of organisms that disappeared long ago. Paleobotanists trace the evolution of plants by following the modifications in plant morphology: shedding light on the connection between existing plants by identifying common ancestors that display the same traits. This field seeks to find transitional species that bridge gaps in the path to the development of modern organisms. Fossils are formed when organisms are trapped in sediments or environments where their shapes are preserved. Paleobotanists collect fossil specimens in the field and place them in the context of the geological sediments and other fossilized organisms surrounding them. The activity requires great care to preserve the integrity of the delicate fossils and the layers of rock in which they are found. One of the most exciting recent developments in paleobotany is the use of analytical chemistry and molecular biology to study fossils. Preservation of molecular structures requires an environment free of oxygen, since oxidation and degradation of material through the activity of microorganisms depend on its presence. One example of the use of analytical chemistry and molecular biology is the identification of oleanane, a compound that deters pests. Up to this point, oleanane appeared to be unique to flowering plants; however, it has now been recovered from sediments dating from the Permian, much earlier than the current dates given for the appearance of the first flowering plants. Paleobotanists can also study fossil DNA, which can yield a large amount of information, by analyzing and comparing the DNA sequences of extinct plants with those of living and related organisms. Through this analysis, evolutionary relationships can be built for plant lineages. Some paleobotanists are skeptical of the conclusions drawn from the analysis of molecular fossils. For example, the chemical materials of interest degrade rapidly when exposed to air during their initial isolation, as well as in further manipulations. There is always a high risk of contaminating the specimens with extraneous material, mostly from microorganisms. Nevertheless, as technology is refined, the analysis of DNA from fossilized plants will provide invaluable information on the evolution of plants and their adaptation to an ever-changing environment. |
What happens to the level of relative humidity in the evening as air temperature declines? | nothing | it goes up and down | it falls | it rises | The expression “it’s not the heat, it’s the humidity” makes a valid point. We keep cool in hot weather by evaporating sweat from our skin and water from our breathing passages. Because evaporation is inhibited by high humidity, we feel hotter at a given temperature when the humidity is high. Low humidity, on the other hand, can cause discomfort from excessive drying of mucous membranes and can lead to an increased risk of respiratory infections. When we say humidity, we really mean relative humidity. Relative humidity tells us how much water vapor is in the air compared with the maximum possible. At its maximum, denoted as saturation, the relative humidity is 100%, and evaporation is inhibited. The amount of water vapor in the air depends on temperature. For example, relative humidity rises in the evening, as air temperature declines, sometimes reaching the dew point. At the dew point temperature, relative humidity is 100%, and fog may result from the condensation of water droplets if they are small enough to stay in suspension. Conversely, if you wish to dry something (perhaps your hair), it is more effective to blow hot air over it rather than cold air, because, among other things, the increase in temperature increases the energy of the molecules, so the rate of evaporation increases. The amount of water vapor in the air depends on the vapor pressure of water. The liquid and solid phases are continuously giving off vapor because some of the molecules have high enough speeds to enter the gas phase; see Figure 13.33(a). If a lid is placed over the container, as in Figure 13.33(b), evaporation continues, increasing the pressure, until sufficient vapor has built up for condensation to balance evaporation. Then equilibrium has been achieved, and the vapor pressure is equal to the partial pressure of water in the container. Vapor pressure increases with temperature because molecular speeds are higher as temperature increases. Table 13.5 gives representative values of water vapor pressure over a range of temperatures. |
What term is used to describe a compound that does not conduct an electric current in either aqueous solution or in the molten state? | xerophyte | kilocalorie | porous | nonelectrolyte | A nonelectrolyte is a compound that does not conduct an electric current in either aqueous solution or in the molten state. Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions. The Figure below illustrates the difference between an electrolyte and a nonelectrolyte. |
Peregrine falcons made an incredible recovery after laws were passed banning the use of what? | Acetamiprid | Carbaryl | miticide | ddt | Government policies and laws are needed to protect biodiversity. Such actions have been shown to work in the past. For example, peregrine falcons made an incredible recovery after laws were passed banning the use of DDT. |
What pathway in a plant do water and nutrients travel through from the roots to the leaves? | skin | bark | flowers | stem | |
In the tropics what are the prevailing winds called? | storm winds | a front | crosswinds | tradewinds | The major wind belts push the water in the surface currents. The water moves in the direction of :. |
How many chromosomes are in a diploid human cell? | 47 | 46.63 chromosomes | 41 | 46 chromosomes | Sperm are male gametes , or reproductive cells. When a male gamete meets a female gamete, they can form a new organism. Sperm form when certain cells in the male reproductive system divide by meiosis , resulting in cells with half the amount of DNA as a regular "body" cell. More precisely, sperm cells are haploid sex cells, having one set of chromosomes. Regular body cells are diploid, having two set of chromosomes. As there are 46 chromosomes in a diploid human cell, how many are in a human sperm cell?. |
Motion of water molecules helps break up interactions between what? | enzymes and acids | ions or hormones | acids and bases | solid ions or molecules | Motion of water molecules helps break up interactions between solid ions or molecules. |
Which cycle is named after the scientist melvin calvin? | melcal cycle | krebs cycle | melvin cycle | calvin cycle | The second stage of photosynthesis takes place in the stroma surrounding the thylakoid membranes of the chloroplast. The reactions of this stage can occur without light, so they are sometimes called light-independent or dark reactions. This stage of photosynthesis is also known as the Calvin cycle because its reactions were discovered by a scientist named Melvin Calvin. He won a Nobel Prize in 1961 for this important discovery. |
What is formed when a subducting plate flows under another tectonic plate? | fault line | magma | boundary plate | volcanic arc | As you would expect, where plates collide there are lots of intense earthquakes and volcanic eruptions. The subducting oceanic plate melts as it reenters the mantle. The magma rises and erupts. This creates a volcanic mountain range near the coast of the continent. This range is called a volcanic arc . The Andes Mountains, along the western edge of South America, are a volcanic arc ( Figure below ). |
What force increases a slide downhill and decreases a slide uphill? | tension | nuclear | frictional | gravity | Discussion As might have been expected, the player slides a shorter distance by sliding uphill. Note that the problem could also have been solved in terms of the forces directly and the work energy theorem, instead of using the potential energy. This method would have required combining the normal force and force of gravity vectors, which no longer cancel each other because they point in different directions, and friction, to find the net force. You could then use the net force and the net work to find the distance d that reduces the kinetic energy to zero. By applying conservation of energy and using the potential energy instead, we need only consider the gravitational potential energy. |
Lymphoma is a cancer of a type of what type of cells, called lymphocytes? | red blood cells | lung cells | brain cells | white blood cells | Blood cancers affect the production and function of your blood cells. Most of these cancers start in your bone marrow where blood is produced. In most blood cancers, the normal production of blood cells is replaced by uncontrolled growth of an abnormal type of blood cell. These abnormal blood cells are cancerous cells, and prevent your blood from performing many of its functions, like fighting off infections or preventing serious bleeding. Leukemia is a cancer of the blood or bone marrow. It is characterized by an abnormal production of blood cells, usually white blood cells. Lymphoma is a cancer of a type of white blood cell called lymphocytes. There are many types of lymphoma. |
What type of eggs do fully terrestrial vertebrates carry? | aqueous | epithelial | amphibious | amniotic | The amniotic egg is an important adaptation in fully terrestrial vertebrates. It first evolved in reptiles. The shells of reptile eggs are either hard or leathery. |
What is the time since the beginning of the ice ages? | Jurassic period | Paleolithic era | Mesozoic epocH | quaternary period | The Quaternary Period is the time since the beginning of the ice ages. The climate has been cooler than it was earlier in the Cenozoic. Since the end of the Pleistocene ice ages, which are probably not entirely over, we have been in the Holocene Epoch. The Holocene is also called the Recent. |
What will the contraction of smooth muscles help organs do? | move across distances | fine motor movements | move joints | carry out functions | Muscle tissue in the walls of internal organs such as the stomach and intestines is smooth muscle . When smooth muscle contracts, it helps the organs carry out their functions. For example, when smooth muscle in the stomach contracts, it squeezes the food inside the stomach, which helps break the food into smaller pieces. Contractions of smooth muscle are involuntary. This means they are not under conscious control. |
What is an acid that can be produced from the aerobic fermentation of wine? | grape juice | soda | orange juice | vinegar | Vinegar is an acid that can be produced from the aerobic fermentation of wine. In fact, vinegar is most likely the oldest known acid. It is commonly used as a food additive (to give things an acidic or sour taste) and as a mild cleaning agent. |
Weathering is fundamental to the creation of what, which exists as a very thin layer over solid rock? | aquifers | fungus | moss | soil | Without weathering, we would not have any soil on Earth. People could not live on Earth without soil! Your life and the lives of most organisms depend on soil. Soil is only a very thin layer over solid rock. Yet, it is the place where reactions between solid rock, liquid water and air take place. We get wood, paper, cotton, medicines, and even pure water from soil. So soil is a very important resource. Our precious soil needs to be carefully managed and cared for. If we don’t take care of the soil we have, we may not be able to use it in the future. |
What type of weathering causes the minerals in a rock to change? | artificial | toxic | natural | chemical | Chemical weathering is different than mechanical weathering. The minerals in the rock change. The rock changes composition and becomes a different type of rock. Most minerals form at high pressure or high temperatures deep within Earth. But at Earth's surface, temperatures and pressures are much lower. Minerals that were stable deeper in the crust are not stable at the surface. That’s why chemical weathering happens. Minerals that formed at higher temperature and pressure change into minerals that are stable at the surface. Chemical weathering is important. It starts the process of changing solid rock into soil. We need soil to grow food and create other materials we need. Chemical weathering works through chemical reactions that change the rock. |
What is the process in which a liquid changes to a solid? | melting | condensation | boiling | freezing | Freezing is the process in which a liquid changes to a solid. It occurs when a liquid cools to a point at which its particles no longer have enough energy to overcome the force of attraction between them. |
By pulling out grass by its roots and over-grazing, livestock contribute to what negative process? | immigration | migration | evolution | erosion | As pictured below ( Figure below ), some grazing animals, especially sheep and goats, eat grass right down to the roots. They may even pull the grass entirely out of the ground. Grazing animals can kill the grass. They may thin it out so much that it offers little protection to the soil. If animals are kept in the same place too long, the soil may become completely bare. The bare soil is easily eroded by wind and water. |
What are the three types of isomers? | structural, cis-trans, Polystyrene | structural, Polypropylene , enatiomers | structural , chromosome - trans , enatiomers | structural, cis-trans, enatiomers | |
The chloroplasts contain a green pigment called what? | melanin | chloroplasm | sodium | chlorophyll | The chloroplasts contain a green pigment called chlorophyll, which captures the energy of sunlight for photosynthesis. Like plant cells, photosynthetic protists also have chloroplasts. Some bacteria also perform photosynthesis, but they do not have chloroplasts. Their photosynthetic pigments are located in the thylakoid membrane within the cell itself. |
What state occurs when the amount of solute dissolved exceeds the solubility? | alkalinity | polymerisation | density | supersaturation | supersaturated : When the amount of solute dissolved exceeds the solubility. Occurs when a solution is saturated and the temperature slowly drops. |
What occurs when spores from two parents fuse and form a zygospore? | internal reproduction | twins | asexual reproduction | sexual reproduction | The majority of fungi can reproduce both asexually and sexually. This allows them to adjust to conditions in the environment. Yeast reproduce asexually by budding. Other fungi reproduce asexually by producing spores. Sexual reproduction occurs when spores from two parents fuse and form a zygospore. |
Macrophages and dendritic cells are types of what" | mast cells | amoena cells | supercapacitor cells | phagocytic cells | |
What side of a mountain does the rainshadow effect occur on? | due north | starboard | windward | the leeward side | Rainshadow effect occurs on the leeward side of a mountain range. |
Centrioles are a very important part of what? | enterocytes | centricles | tubercles | centrosomes | Centrioles are a very important part of centrosomes, which are involved in organizing microtubules in the cytoplasm. Centrosomes are associated with the nuclear membrane during prophase of the mitosis. In mitosis, the nuclear membrane breaks down and the microtubule organizing center (MTOC) of the centrosome arranges microtubules such that they interact with the chromosomes to build the mitotic spindle. |
What is the volume of the molecules of an ideal gas? | one | three | two | zero | Because the molecules of an ideal gas are assumed to have zero volume, the volume available to them for motion is always the same as the volume of the container. In contrast, the molecules of a real gas have small but measurable volumes. At low pressures, the gaseous molecules are relatively far apart, but as the pressure of the gas increases, the intermolecular distances become smaller and smaller (Figure 10.23 "The Effect of Nonzero Volume of Gas Particles on the Behavior of Gases at Low and High Pressures"). As a result, the volume occupied by the molecules becomes significant compared with the volume of the container. Consequently, the total volume occupied by the gas is greater than the volume predicted by the ideal gas law. Thus at very high pressures, the experimentally measured value of PV/nRT is greater than the value predicted by the ideal gas law. Figure 10.23 The Effect of Nonzero Volume of Gas Particles on the Behavior of Gases at Low and High Pressures. |
What part of the body are eggs formed in? | pancreas | brain | intestine | ovaries | Eggs form in the ovaries. After puberty, an egg is released from an ovary each month in the process of ovulation. The egg passes through the fallopian tube where fertilization may take place. |
What is the first digestive organ that food enters? | kidneys | intestine | digestive system | mouth | The mouth is the first organ that food enters. But digestion may start even before you put the first bite of food into your mouth. Just seeing or smelling food can cause the release of saliva and digestive enzymes in your mouth. |
Soda fizzes when what common gas comes out of solution? | helium | nitrous oxide | carbon monoxide | carbon dioxide | Soda fizzes when carbon dioxide comes out of solution. Which do you think will fizz more, warm soda or cold soda?. |
The voltage and current are exactly in phase in a what? | harmonic | battery | capacitor | resistor | Resistors in an AC Circuit Just as a reminder, consider Figure 23.47, which shows an AC voltage applied to a resistor and a graph of voltage and current versus time. The voltage and current are exactly in phase in a resistor. There is no frequency dependence to the behavior of plain resistance in a circuit:. |
Combining the voltages of the oxidation and reduction half reactions helps to determine what? | magnetic | slimy | moisture | voltage | To determine the overall voltage of a particular voltaic cell, simply combine the voltages of the oxidation and reduction half reactions. Even if you need to take a multiple of a half reaction for the electrons to cancel, do not take the multiple of the E1/2. Use the values directly as is from - ball-ch14_s03_t01. Spontaneous redox reactions have positive overall voltages. If the voltage of the reaction as written is negative, it is not spontaneous in that direction. Rather, the reverse reaction is the spontaneous redox reaction. |
What occurs when an unstable nucleus emits a beta particle and energy? | methane decay | nucleus decay | alpha decay | beta decay | Beta decay occurs when an unstable nucleus emits a beta particle and energy. A beta particle is an electron. It has a charge of -1. In nuclear equations, a beta particle is represented by the symbol . The subscript -1 represents the particle’s charge, and the superscript 0 shows that the particle has virtually no mass. Nuclei contain only protons and neutrons, so how can a nucleus emit an electron? A neutron first breaks down into a proton and an electron (see Figure below ). Then the electron is emitted from the nucleus, while the proton stays inside the nucleus. The proton increases the atomic number by one, thus changing one element into another. |
A chemical property describes the ability of a substance to undergo a specific what? | liquid change | weight Change | radiation change | chemical change | A chemical property describes the ability of a substance to undergo a specific chemical change. A chemical property of iron is that it is capable of combining with oxygen to form iron oxide, the chemical name of rust. The more general term for rusting and other similar processes is corrosion. Other terms that are commonly used in descriptions of chemical changes are burn, rot, explode, decompose, and ferment. Chemical properties are very useful in identifying substances. However, unlike physical properties, chemical properties can only be observed as the substance is in the process of being changed into a different substance. |
When energy is captured or transformed, it inevitably degrades and becomes what less useful form of energy? | motion | chemical | temperature | heat | Physics also tells us that, although energy can be captured or transformed, it inevitably degrades, becoming heat, a less useful form of energy. This is why organisms require a constant input of energy; the work they must do uses up the energy they take in. Energy, unlike materials, cannot be recycled. The story of life is a story of energy flow – its capture, transformation, use for work, and loss as heat. |
The periodic table is one of the cornerstones of chemistry because it organizes all the known elements on the basis of their what? | acid properties | size properties | liquid properties | chemical properties | The periodic table is one of the cornerstones of chemistry because it organizes all the known elements on the basis of their chemical properties. A modern version is shown in Figure 2.7 "A Modern Periodic Table". Most periodic tables provide additional data (such as atomic mass) in a box that contains each element’s symbol. The elements are listed in order of atomic number. |
What organs filter wastes from blood so they can be excreted from the body? | liver | lungs | pancreas | kidneys | Vertebrates have an excretory system that includes a pair of kidneys. Kidneys are organs that filter wastes from blood so they can be excreted from the body. |
The tidal forces near what celestial phenomena are so great they can actually tear matter from a companion star? | wormholes | dwarf star | large holes | black holes | Tides are not unique to Earth but occur in many astronomical systems. The most extreme tides occur where the gravitational force is the strongest and varies most rapidly, such as near black holes (see Figure 6.26). A few likely candidates for black holes have been observed in our galaxy. These have masses greater than the Sun but have diameters only a few kilometers across. The tidal forces near them are so great that they can actually tear matter from a companion star. |
What are female gonads normally called? | glands | testes | tubules | ovaries | Animals often have gonads , organs that produce eggs or sperm. The male gonads are the testes , and the female gonads are the ovaries . Testes produce sperm; ovaries produce eggs. Sperm and egg, the two sex cells, are known as gametes , and can combine two different ways, both of which combine the genetic material from the two parents. Gametes have half the amount of the genetic material of a regular body cell; they are haploid cells. In humans, gametes have one set of 23 chromosomes. Gametes are produced through a special type of cell division known as meiosis . Normal human cells have 46 chromosomes. They are diploid cells, with two sets of 23 chromosomes (23 pairs). |
Starch and glycogen, as well as simple sugars like glucose and fructose, can all be categorized broadly as what? | vegetables | impurities | acids | carbohydrates | Of the four major macromolecular groups (carbohydrates, lipids, proteins, and nucleic acids) that are processed by digestion, carbohydrates are considered the most common source of energy to fuel the body. They take the form of either complex carbohydrates, polysaccharides like starch and glycogen, or simple sugars (monosaccharides) like glucose and fructose. Sugar catabolism breaks polysaccharides down into their individual monosaccharides. Among the monosaccharides, glucose is the most common fuel for ATP production in cells, and as such, there are a number of endocrine control mechanisms to regulate glucose concentration in the bloodstream. Excess glucose is either stored as an energy reserve in the liver and skeletal muscles as the complex polymer glycogen, or it is converted into fat (triglyceride) in adipose cells (adipocytes). Among the lipids (fats), triglycerides are most often used for energy via a metabolic process called β-oxidation. About onehalf of excess fat is stored in adipocytes that accumulate in the subcutaneous tissue under the skin, whereas the rest is stored in adipocytes in other tissues and organs. Proteins, which are polymers, can be broken down into their monomers, individual amino acids. Amino acids can be used as building blocks of new proteins or broken down further for the production of ATP. When one is chronically starving, this use of amino acids for energy production can lead to a wasting away of the body, as more and more proteins are broken down. Nucleic acids are present in most of the foods you eat. During digestion, nucleic acids including DNA and various RNAs are broken down into their constituent nucleotides. These nucleotides are readily absorbed and transported throughout the body to be used by individual cells during nucleic acid metabolism. |