text stringlengths 0 3.56k | source stringlengths 6 10 |
|---|---|
The amount of reactants and products do not have to be equal. However, after equilibrium is attained, the amounts of reactants and products will be constant. | sciq_100 |
Sepals protect the developing flower while it is still a bud. Sepals are usually green, which camouflages the bud from possible consumers. | sciq_101 |
Gravity has traditionally been defined as a force of attraction between things that have mass. According to this conception of gravity, anything that has mass, no matter how small, exerts gravity on other matter. Gravity can act between objects that are not even touching. In fact, gravity can act over very long distanc... | sciq_102 |
sciq_103 | |
Kidney failure may be treated with dialysis. | sciq_104 |
Children as young as 2 years of age can be vaccinated against viral meningitis. | sciq_105 |
Renal plasma flow equals the blood flow per minute times the hematocrit. If a person has a hematocrit of 45, then the renal plasma flow is 55 percent. 1050*0.55 = 578 mL plasma/min. | sciq_106 |
Lattice energy of an ionic solid is a measure of the strength of bonds in that ionic compound. | sciq_107 |
sciq_108 | |
Homo sapiens is our species. We originated about 200,000 years ago in Africa. Evidence of a spiritual life appears about 32,000 years ago. The evidence includes stone figurines that probably have religious significance ( Figure below ). | sciq_109 |
The concentration of an acid or base can be determined by titration. | sciq_110 |
There are 20 amino acids that make up proteins. With three bases per codon, there are 64 possible codons. This is more than enough to code for the 20 amino acids plus start and stop signals. You can see how to translate the genetic code in Figure below . Start at the center of the chart for the first base of each three... | sciq_111 |
Ulcers are sores in the lining of the stomach or duodenum that are usually caused by bacterial infections. They may also be caused by the acidic environment of the stomach. Stomach acids may damage the lining of the stomach. Symptoms typically include abdominal pain and bleeding. You can see how stomach ulcers develop ... | sciq_112 |
sciq_113 | |
As a cell prepares to divide, its DNA first forms one or more structures called chromosomes. A chromosome consists of DNA and protein molecules coiled into a definite shape. Chromosomes are circular in prokaryotes and rodlike in eukaryotes. You can see an example of a human chromosome in Figure below . The rest of the ... | sciq_114 |
Less energy is needed to get renewable energy sources. Solar energy is a good example. Sunlight is everywhere, so no one needs to go out and find it. We don’t have to drill for it or pump it to the surface. We just need to install solar panels like the ones in Figure below and let sunlight strike them. The energy from ... | sciq_115 |
Arteries Serving the Upper Limbs As the subclavian artery exits the thorax into the axillary region, it is renamed the axillary artery. Although it does branch and supply blood to the region near the head of the humerus (via the humeral circumflex arteries), the majority of the vessel continues into the upper arm, or b... | sciq_116 |
Immovable joints allow no movement because the bones at these joints are held securely together by dense collagen. The bones of the skull are connected by immovable joints. | sciq_117 |
The troposphere is the lowest layer of the atmosphere. All of the air you breathe is in the troposphere. All of Earth's weather—wind, rain, snow, heat—is in the troposphere. The troposphere is the lowest and most important layer of the atmosphere!. | sciq_118 |
The key to continued growth and repair of plant cells is meristem . Meristem is a type of plant tissue consisting of undifferentiated cells that can continue to divide and differentiate. Meristem at the tips of roots and stems allows them to grow in length. This is called primary growth. Meristem within and around vasc... | sciq_119 |
The Phosphorus Cycle Phosphorus is an essential nutrient for living processes; it is a major component of nucleic acids and phospholipids, and, as calcium phosphate, makes up the supportive components of our bones. Phosphorus is often the limiting nutrient (necessary for growth) in aquatic, particularly freshwater, eco... | sciq_120 |
Erosion moves the pieces of broken rock. | sciq_121 |
Genetics is the study of inheritance. Inheritance is the passing of traits from parents to offspring. How are these traits "passed"? Through DNA, which is the genetic material of all organisms. This concept will focus on genetics, inheritance, and DNA. | sciq_122 |
If you’re like Tanya in this picture, you prefer your iced tea sweetened with sugar. Sweetened iced tea is a solution in which solid sugar (the solute) is dissolved in cold liquid tea, which is mostly water (the solvent). When you add sugar to tea, particles of water pull apart particles of sugar. The particles of suga... | sciq_123 |
The remaining 5% are scattered around other plate boundaries. A few earthquakes take place away from plate boundaries. These are intraplate earthquakes. | sciq_124 |
Red litmus paper turns blue when placed in a basic solution. | sciq_125 |
can occur in electrolytic cells by introducing a power supply, which supplies the energy to force the electrons to flow in the nonspontaneous direction. Electrolysis is done in solutions, which contain enough ions so current can flow. If the solution contains only one material, like the electrolysis of molten sodium ch... | sciq_126 |
While the egg is developing, other changes are taking place in the uterus. It develops a thick lining that is full of tiny blood vessels. The lining prepares the uterus to receive a fertilized egg if fertilization actually takes place. | sciq_127 |
called growth factors signal some cells at the edge of the ectoderm to become epidermis cells. The remaining cells in the center form the neural plate. If the signaling by growth factors were disrupted, then the entire ectoderm would differentiate into neural tissue. The neural plate undergoes a series of cell movement... | sciq_128 |
Small nonpolar molecules can easily diffuse across the cell membrane. However, due to the hydrophobic nature of the lipids that make up cell membranes, polar molecules (such as water) and ions cannot do so. Instead, they diffuse across the membrane through transport proteins. A transport protein completely spans the me... | sciq_129 |
Vertebrates reproduce sexually, and almost all have separate male and female sexes. Aquatic species generally have external fertilization, whereas terrestrial species usually have internal fertilization. Vertebrates have one of three reproductive strategies, known as ovipary, ovovivipary, or vivipary. | sciq_130 |
sciq_131 | |
A cell membrane is essentially a mixture of phospholipids that form a phospholipid bilayer. One definition of a cell is a collection of molecules surrounded by a phospholipid bilayer that is capable of reproducing itself. The simplest cells are bacteria, which consist of only a single compartment surrounded by a single... | sciq_132 |
Role of Feedback Loops The contribution of feedback loops to homeostasis will only be briefly reviewed here. Positive feedback loops are characterized by the release of additional hormone in response to an original hormone release. The release of oxytocin during childbirth is a positive feedback loop. The initial relea... | sciq_133 |
Connective Tissue Fibers and Ground Substance Three main types of fibers are secreted by fibroblasts: collagen fibers, elastic fibers, and reticular fibers. Collagen fiber is made from fibrous protein subunits linked together to form a long and straight fiber. Collagen fibers, while flexible, have great tensile strengt... | sciq_134 |
Pneumonia is a disease in which some of the alveoli of the lungs fill with fluid so they can no longer exchange gas. Symptoms of pneumonia typically include coughing, chest pain, difficulty breathing, and fatigue. Pneumonia may be caused by an infection or an injury to the lungs. | sciq_135 |
Sympatric speciation occurs when groups from the same species stop mating because of something other than physical or geographic separation. The behavior of two groups that live in the same region is an example of such separation. The separation may be caused by different mating seasons, for example. Sympatric speciati... | sciq_136 |
sciq_137 | |
Melting and boiling points are somewhat unique identifiers, especially of compounds. In addition to giving some idea as to the identity of the compound, important information can be obtained about the purity of the material. | sciq_138 |
Types of organisms that make glucose by photosynthesis are pictured in Figure below . They include plants, plant-like protists such as algae, and some kinds of bacteria. Living things that make glucose are called autotrophs ("self feeders"). All other living things obtain glucose by eating autotrophs (or organisms that... | sciq_139 |
Introduction Virtually every task performed by living organisms requires energy. Energy is needed to perform heavy labor and exercise, but humans also use energy while thinking, and even during sleep. In fact, the living cells of every organism constantly use energy. Nutrients and other molecules are imported into the ... | sciq_140 |
sciq_141 | |
sciq_142 | |
Compounds like sodium chloride form structures called crystals. A crystal is a rigid framework of many ions locked together in a repeating pattern. Ions are electrically charged forms of atoms. You can see a crystal of sodium chloride in the Figure below . It is made up of many sodium and chloride ions. | sciq_143 |
Lipids are made of long chains consisting almost solely of carbon and hydrogen. These long chains are called fatty acids. Fatty acids may be saturated or unsaturated. Figure below shows an example of each type of fatty acid. | sciq_144 |
0 .033 g 1 .117 g × 100 = 3 .0% When a series of measurements is precise but not accurate, the error is usually systematic. Systematic errors can be caused by faulty instrumentation or faulty technique. The difference between accuracy and precision is demonstrated in Skill Builder ES7. | sciq_145 |
treat genetic disorders. For example, copies of a normal gene might be inserted into a patient with a defective gene. This is called gene therapy . Ideally, it can cure a genetic disorder. | sciq_146 |
sciq_147 | |
All forms of energy can be interconverted. Three things can change the energy of an object: the transfer of heat, work performed on or by an object, or some combination of heat and work. | sciq_148 |
Earth science includes many fields of science related to our home planet. | sciq_149 |
Alloys that are mostly composed of mercury are known as amalgams . Amalgams often have special properties that stem from the fact that mercury exists as a liquid at room temperature. As a result, metal amalgams are used for a variety of purposes, including dentistry and the extraction of other pure metals such as gold. | sciq_150 |
Mirrors are made from highly reflective metal that is applied to a curved or flat piece of glass. Converging mirrors can be used to focus light – headlights, telescopes, satellite TV receivers, and solar cookers all rely on this principle. | sciq_151 |
sciq_152 | |
Surface waves travel along the ground outward from an earthquake’s epicenter. Surface waves are the slowest of all seismic waves. They travel at 2.5 km (1.5 miles) per second. There are two types of surface waves. Love waves move side-to-side, much like a snake. Rayleigh waves produce a rolling motion as they move up a... | sciq_153 |
A cell wall is a rigid layer that is found outside the cell membrane and surrounds the cell. The cell wall contains not only cellulose and protein, but other polysaccharides as well. In fact, two other classes of polysaccharides, hemicelluloses and pectic polysaccharides, can comprise 30% of the dry mass of the cell wa... | sciq_154 |
Intrapleural pressure is the pressure of the air within the pleural cavity, between the visceral and parietal pleurae. Similar to intra-alveolar pressure, intrapleural pressure also changes during the different phases of breathing. However, due to certain characteristics of the lungs, the intrapleural pressure is alway... | sciq_155 |
sciq_156 | |
Protection. The skeleton supports and protects the soft organs of the body. For example, the skull surrounds the brain to protect it from injury. The bones of the rib cage help protect the heart and lungs. | sciq_157 |
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 Earth mostly as visible light. The energy is carried through the empty space by radiation . We can use sunlight as an e... | sciq_158 |
Strawberry plants have horizontal stems called stolons that run over the ground surface. If they take root, they form new plants. | sciq_159 |
Glaciers are incredibly powerful agents of erosion. | sciq_160 |
Atmospheric pressure is the pressure exerted by gas particles in Earth’s atmosphere as those particles collide with objects. A barometer is an instrument used to measure atmospheric pressure. A traditional mercury barometer consists of an evacuated tube immersed in a container of mercury. Air molecules push down on the... | sciq_161 |
The plasma membrane also contains other molecules, primarily other lipids and proteins. The green molecules in Figure above , for example, are the lipid cholesterol. Molecules of cholesterol help the plasma membrane keep its shape. Many of the proteins in the plasma membrane assist other substances in crossing the memb... | sciq_162 |
Asexual reproduction involves just one parent. It produces offspring that are genetically identical to the parent. Methods of asexual reproduction include binary fission, fragmentation, and budding. | sciq_163 |
Cell division is just one of several stages that a cell goes through during its lifetime. The cell cycle is a repeating series of events that include growth, DNA synthesis, and cell division. The cell cycle in prokaryotes is quite simple: the cell grows, its DNA replicates, and the cell divides. In eukaryotes, the cell... | sciq_164 |
How metalloids behave in chemical interactions with other elements depends mainly on the number of electrons in the outer energy level of their atoms. Metalloids have from three to six electrons in their outer energy level. Boron, pictured in the Figure below , is the only metalloid with just three electrons in its out... | sciq_165 |
Annelids are divided into many repeating segments. The earthworm in Figure below is an annelid. You can clearly see its many segments. Segmentation of annelids is highly adaptive. Each segment has its own nerve and muscle tissues. This allows the animal to move very efficiently. Some segments can also be specialized to... | sciq_166 |
The spermatids are transported from the testes to the epididymis. Involuntary muscular contraction moves the spermatids along. | sciq_167 |
sciq_168 | |
Grain boundaries. As a polycrystalline material solidifies, grains with irregular shapes form. The interfaces between grains constitute grain boundaries. (Squares represent unit cells within grains. | sciq_169 |
22.8 Torque on a Current Loop: Motors and Meters Motors are the most common application of magnetic force on current-carrying wires. Motors have loops of wire in a magnetic field. When current is passed through the loops, the magnetic field exerts torque on the loops, which rotates a shaft. Electrical energy is convert... | sciq_170 |
Chromoplasts make and store pigments that give petals and fruit their orange and yellow colors. | sciq_171 |
Boiling Points When the vapor pressure increases enough to equal the external atmospheric pressure, the liquid reaches its boiling point. The boiling point of a liquid is the temperature at which its equilibrium vapor pressure is equal to the pressure exerted on the liquid by its gaseous surroundings. For liquids in op... | sciq_172 |
When electrons return to a lower energy level, they emit energy in the form of light. | sciq_173 |
Nearsightedness, or myopia, is the condition in which nearby objects are seen clearly, but distant objects are blurry. It occurs when the eyeball is longer than normal. This causes images to be focused in front of the retina. Myopia can be corrected with concave lenses. The lenses focus images farther back in the eye, ... | sciq_174 |
Basic to Bohr’s model is the idea of energy levels. Energy levels are areas located at fixed distances from the nucleus of the atom. They are the only places where electrons can be found. Energy levels are a little like rungs on a ladder. You can stand on one rung or another but not between the rungs. The same goes for... | sciq_175 |
A liquid is a state of matter in which particles can slip past one another and take the shape of their container. However, the particles cannot pull apart and spread out to take the volume of their container. | sciq_176 |
Runoff is likely to cause more erosion if the land is bare. Plants help hold the soil in place. The runoff water in Figure below is brown because it eroded soil from a bare, sloping field. Can you find evidence of erosion by runoff where you live? What should you look for?. | sciq_177 |
Cations have positive charges, and anions have negative charges. | sciq_178 |
Colon The cecum blends seamlessly with the colon. Upon entering the colon, the food residue first travels up the ascending colon on the right side of the abdomen. At the inferior surface of the liver, the colon bends to form the right colic flexure (hepatic flexure) and becomes the transverse colon. The region defined ... | sciq_179 |
sciq_180 | |
Recall that our DNA is wound into chromosomes . Each of our chromosomes contains a long chain of DNA that encodes hundreds, if not thousands, of genes. Each of these genes can have slightly different versions from individual to individual. These variants of genes are called alleles . Each parent only donates one allele... | sciq_181 |
Some of the best known types of fungi are mushrooms, which can be edible or poisonous ( Figure below ). Many species are grown commercially, but others are harvested from the wild. When you order a pizza with mushrooms or add them to your salad, you are most likely eating Agaricus bisporus , known as white or button mu... | sciq_182 |
21.6 Comparing genome sequences provides clues to evolution and development. | sciq_183 |
There are other units in chemistry that are important, and we will cover others in the course of the entire book. One of the fundamental quantities in science is temperature. Temperature is a measure of the average amount of energy of motion, or kinetic energy, a system contains. Temperatures are expressed using scales... | sciq_184 |
U92235 + n01® B56141a + K3692r + 3n01 This hypothesis was confirmed by detecting the krypton-92 fission product. As discussed in Section 20.2 "Nuclear Reactions", the nucleus usually divides asymmetrically rather than into two equal parts, and the fission of a given nuclide does not give the same products every time. I... | sciq_185 |
Many hydrocarbons are cyclic and adopt specific three-dimensional structures that influence their physical and chemical properties. | sciq_186 |
Microtubules guide the formation of the plant cell wall. Cellulose is laid down by enzymes to form the primary cell wall. Some plants also have a secondary cell wall. The secondary wall contains a lignin, a secondary cell component in plant cells that have completed cell growth/expansion. | sciq_187 |
The cell cycle is a repeating series of events, characterizing the life of a eukaryotic cell. | sciq_188 |
Inside the nasal area of the skull, the nasal cavity is divided into halves by the nasal septum. The upper portion of the nasal septum is formed by the perpendicular plate of the ethmoid bone and the lower portion is the vomer bone. Each side of the nasal cavity is triangular in shape, with a broad inferior space that ... | sciq_189 |
Bacteria can also be chemotrophs. Chemosynthetic bacteria, or chemotrophs , obtain energy by breaking down chemical compounds in their environment. An example of one of these chemicals broken down by bacteria is nitrogen-containing ammonia. These bacteria are important because they help cycle nitrogen through the envir... | sciq_190 |
sciq_191 | |
sciq_192 | |
distinctly differ from the adult form, spending 3 to 15 years as suspension feeders. Once they attain sexual maturity, the adults reproduce and die within days. Lampreys possess a notochord as adults; however, this notochord is surrounded by a cartilaginous structure called an arcualia, which may resemble an evolutiona... | sciq_193 |
sciq_194 | |
sciq_195 | |
Recall from the kinetic-molecular theory that gas particles move randomly and in straight lines until they elastically collide with either other gas particles or with one of the walls of the container. It is these collisions with the walls of the container that defines the pressure of the gas. Four variables are used t... | sciq_196 |
In order to explain the observed phenomenon, scientists develop a number of possible explanations, or hypotheses. A hypothesis is a suggested explanation for a phenomenon or a suggested explanation for a relationship between many phenomena. Hypotheses are always based on evidence that can be tested by observation or ex... | sciq_197 |
The Major Divisions of Land Plants Land plants are classified into two major groups according to the absence or presence of vascular tissue, as detailed in Figure 14.8. Plants that lack vascular tissue formed of specialized cells for the transport of water and nutrients are referred to as nonvascular plants. The bryoph... | sciq_198 |
In some people, a food allergy can trigger a severe allergic reaction called anaphylaxis. Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause a coma or death. Anaphylaxis is vary rare. The vast majority of people will never have an anaphylactic reaction. The life-threatening symptoms of an... | sciq_199 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.