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The cytoplasm is all the contents of the cell inside the cell membrane, with the exception of what? | molecules | vacuole | lysosome | nucleus | Both prokaryotic and eukaryotic cells have structures in common. All cells have a plasma membrane, ribosomes, cytoplasm, and DNA. The plasma membrane , or cell membrane, is the phospholipid layer that surrounds the cell and protects it from the outside environment. Ribosomes are the non-membrane bound organelles where proteins are made, a process called protein synthesis. The cytoplasm is all the contents of the cell inside the cell membrane, not including the nucleus. |
What is the study of forces in equilibrium? | law of conservation | law of inertia | genomics | statics | • Statics is the study of forces in equilibrium. • Two conditions must be met to achieve equilibrium, which is defined to be motion without linear or rotational acceleration. • The first condition necessary to achieve equilibrium is that the net external force on the system must be zero, so that net F = 0 . |
What body joint incurs the most common overuse injury among runners and other athletes? | ankle | arm | heel | knee | Runner’s Knee Runner’s knee, also known as patellofemoral syndrome, is the most common overuse injury among runners. It is most frequent in adolescents and young adults, and is more common in females. It often results from excessive running, particularly downhill, but may also occur in athletes who do a lot of knee bending, such as jumpers, skiers, cyclists, weight lifters, and soccer players. It is felt as a dull, aching pain around the front of the knee and deep to the patella. The pain may be felt when walking or running, going up or down stairs, kneeling or squatting, or after sitting with the knee bent for an extended period. Patellofemoral syndrome may be initiated by a variety of causes, including individual variations in the shape and movement of the patella, a direct blow to the patella, or flat feet or improper shoes that cause excessive turning in or out of the feet or leg. These factors may cause in an imbalance in the muscle pull that acts on the patella, resulting in an abnormal tracking of the patella that allows it to deviate too far toward the lateral side of the patellar surface on the distal femur. Because the hips are wider than the knee region, the femur has a diagonal orientation within the thigh, in contrast to the vertically oriented tibia of the leg (Figure 8.17). The Q-angle is a measure of how far the femur is angled laterally away from vertical. The Q-angle is normally 10–15 degrees, with females typically having a larger Q-angle due to their wider pelvis. During extension of the knee, the quadriceps femoris muscle pulls the patella both superiorly and laterally, with the lateral pull greater in women due to their large Q-angle. This makes women more vulnerable to developing patellofemoral syndrome than men. Normally, the large lip on the lateral side of the patellar surface of the femur compensates for the lateral pull on the patella, and thus helps to maintain its proper tracking. However, if the pull produced by the medial and lateral sides of the quadriceps femoris muscle is not properly balanced, abnormal tracking of the patella toward the lateral side may occur. With continued use, this produces pain and could result in damage to the articulating surfaces of the patella and femur, and the possible future development of arthritis. Treatment generally involves stopping the activity that produces knee pain for a period of time, followed by a gradual resumption of activity. Proper strengthening of the quadriceps femoris muscle to correct for imbalances is also important to help prevent reoccurrence. |
Who is called the father of genetics? | raphael | Nostradamus | Vincent van Gogh | mendel | People have long known that the characteristics of living things are similar in parents and their offspring. Whether it’s the flower color in pea plants or nose shape in people, it is obvious that offspring resemble their parents. However, it wasn’t until the experiments of Gregor Mendel that scientists understood how characteristics are inherited. Mendel’s discoveries formed the basis of genetics , the science of heredity. That’s why Mendel is often called the "father of genetics. " It’s not common for a single researcher to have such an important impact on science. The importance of Mendel’s work was due to three things: a curious mind, sound scientific methods, and good luck. You’ll see why when you read about Mendel’s experiments. |
Each endocrine hormone affects only certain "target" cells, which have molecules of what on the surface that enable binding of a given hormone? | gas | lipids | rna | protein | Each endocrine hormone affects only certain cells, called target cells. A target cell has proteins on its surface to which a given hormone can bind. Most endocrine hormones are controlled by negative feedback loops. Negative feedback occurs when low levels of a hormone feed back to increase its secretion—and vice versa. |
What do we call the scientific study of heredity and hereditary variation? | chemistry | geneology | biology | genetics | |
What do you call any substance in food that the body needs? | beneficial | dietary | antioxidant | a nutrient | There are a variety of substances in foods that the body needs. Any substance in food that the body needs is called a nutrient. There are six major types of nutrients: carbohydrates, proteins, lipids, water, minerals, and vitamins. Carbohydrates, proteins, and lipids can be used for energy. Proteins also provide building materials. Proteins, minerals, and vitamins help control body processes. Water is needed by all cells just to stay alive. |
What type of waves start when a source of energy causes a disturbance in the medium? | magnetic waves | fluid waves | mechanical currents | mechanical waves | Mechanical waves are waves that transfer energy through matter, called the medium. Mechanical waves start when a source of energy causes a disturbance in the medium. Types of mechanical waves include transverse, longitudinal, and surface waves. |
What term describes the process where organisms convert atmospheric nitrogen into biologically useful chemicals? | photosynthesis | carbon cycle | cellular respiration | nitrogen fixation | Most pure nitrogen comes from the fractional distillation of liquid air. The atmosphere consists of 78% nitrogen by volume. This means there are more than 20 million tons of nitrogen over every square mile of the earth’s surface. Nitrogen is a component of proteins and of the genetic material (DNA/RNA) of all plants and animals. Under ordinary conditions, nitrogen is a colorless, odorless, and tasteless gas. It boils at 77 K and freezes at 63 K. Liquid nitrogen is a useful coolant because it is inexpensive and has a low boiling point. Nitrogen is very unreactive because of the very strong triple bond between the nitrogen atoms. The only common reactions at room temperature occur with lithium to form Li3N, with certain transition metal complexes, and with hydrogen or oxygen in nitrogenfixing bacteria. The general lack of reactivity of nitrogen makes the remarkable ability of some bacteria to synthesize nitrogen compounds using atmospheric nitrogen gas as the source one of the most exciting chemical events on our planet. This process is one type of nitrogen fixation. In this case, nitrogen fixation is the process where organisms convert atmospheric nitrogen into biologically useful chemicals. Nitrogen fixation also occurs when lightning passes through air, causing molecular nitrogen to react with oxygen to form nitrogen oxides, which are then carried down to the soil. |
As per the kinetic-molecular theory, in what direction do the molecules and ions of liquids move? | same direction | alter directions | opposite direction | random directions | We discussed earlier some basic principles about the behavior of gases called the kinetic-molecular theory. Among other things, this theory suggests that gas molecules are in constant motion, and the average speed of the individual gas particles is dependent upon temperature – the higher the temperature, the faster the molecules move. It is not just gas particles that are in constant motion. The molecules and ions that make up liquids and solutions are also continually moving in nearly random directions. As a result, molecules and ions in a solution will collide with one another fairly frequently. As with gases, a temperature increase will produce an increase in the average particle speed. |
Cephalization refers to the development of what anatomical region, which evolved at the same time as bilateral symmetry in animals? | heart | tail | chest | head | Example Problem: The density of steel is 9000. kg/m 3 and the density of water is 1000. kg/m 3 . If a cube of steel that is 0.100 m on each side is placed in a tank of water and weighed while under water, what is the apparent weight of the cube?. |
What term describes a region of space around an atom that has a non-zero probability for an electron with a particular energy? | related orbital | orbital lobe | minimal orbital | atomic orbital | An atomic orbital is a region of space around an atom that has a non-zero probability for an electron with a particular energy. Analogously, a molecular orbital is a region of space in a molecule that has a non-zero probability for an electron with a particular energy. Both an atomic orbital and a molecular orbital can contain two electrons. |
How do the male gorillas show display behaviors? | spontaneous mutation | food gathering | vocalization | showing aggression | In many species display behaviors, rather than actual physical attacks, are used to show aggression. This helps prevent injury and death. Male gorillas, for example, are more likely to put on a display of aggression than to attack another male. In fact, gorillas have a whole series of display behaviors that they use to show aggression. They beat on their chest, dash back and forth, and pound the ground with their hands. |
A genetic molecule is called dna, which stands for this? | dense ribonucleic acid | di-nitrous ammonia | dark nitrogen amine | deoxyribonucleic acid | How Sciences Interconnect DNA in Forensics and Paternity The genetic material for all living things is a polymer of four different molecules, which are themselves a combination of three subunits. The genetic information, the code for developing an organism, is contained in the specific sequence of the four molecules, similar to the way the letters of the alphabet can be sequenced to form words that convey information. The information in a DNA sequence is used to form two other types of polymers, one of which are proteins. The proteins interact to form a specific type of organism with individual characteristics. A genetic molecule is called DNA, which stands for deoxyribonucleic acid. The four molecules that make up DNA are called nucleotides. Each nucleotide consists of a single- or double-ringed molecule containing nitrogen, carbon, oxygen, and hydrogen called a nitrogenous base. Each base is bonded to a five-carbon sugar called deoxyribose. The sugar is in turn bonded to a phosphate group (−PO 4 3−) When new DNA is made, a polymerization reaction occurs that binds the phosphate group of one nucleotide to the sugar group of a second nucleotide. The nitrogenous bases of each nucleotide stick out from this sugar-phosphate backbone. DNA is actually formed from two such polymers coiled around each other and held together by hydrogen bonds between the nitrogenous bases. Thus, the two backbones are on the outside of the coiled pair of strands, and the bases are on the inside. The shape of the two strands wound around each other is called a double helix (see Figure 20.18). It probably makes sense that the sequence of nucleotides in the DNA of a cat differs from those of a dog. But it is also true that the sequences of the DNA in the cells of two individual pugs differ. Likewise, the sequences of DNA in you and a sibling differ (unless your sibling is an identical twin), as do those between you and an unrelated individual. However, the DNA sequences of two related individuals are more similar than the sequences of two unrelated individuals, and these similarities in sequence can be observed in various ways. This is the principle behind DNA fingerprinting, which is a method used to determine whether two DNA samples came from related (or the same) individuals or unrelated individuals. |
Is sleep an active or inactive state in the brain? | inactive | intense | different | active | |
What is is a measurement of the force amplification of a machine? | force multiplier | mechanical push | mechanical pull | mechanical advantage | We use simple machines because they give us a mechanical advantage . Mechanical advantage is a measurement of the force amplification of a machine. In ideal machines, where there is no friction and the input work and output work are the same,. |
What branch of science is the study of the solid earth? | biology | palentology | ecology | geology | Geology is the study of the solid Earth. Geologists study how rocks and minerals form. The way mountains rise up is part of geology. The way mountains erode away is another part. Geologists also study fossils and Earth’s history. There are many other branches of geology. There is so much to know about our home planet that most geologists become specialists in one area. For example, a mineralogist studies minerals ( Figure below ). |
What is harmless water vapor, for a powerplant? | fog | wind | plasma | steam | Steam rises from the cooling towers of this nuclear power plant. The steam is only harmless water vapor. Unlike a power plant that burns fossil fuel, a nuclear power plant doesn’t release pollution into the air. That’s because a nuclear power plant produces power by nuclear fission, a type of nuclear reaction. |
What regulates the passage of blood into capillary beds? | cell membrane | bicellular sphincters | diocesan sphincters | precapillary sphincters | |
What do you call the symbiotic relationship where a parasite benefits while the host is harmed? | invasion | hostism | symbolic damage | parasitism | Parasitism is a symbiotic relationship in which the parasitic species benefits while the host species is harmed. |
What length of time is human gestation commonly divided into? | four quarters | two halves | fifty weeks | three trimesters | |
What substance, involved in most biochemical reactions, is essential to life? | air | carbon | nitrogen | water | Water is involved in most biochemical reactions. Therefore, water is essential to life. |
What type of tissue covers the outside of a plant? | epidermal | porous | anterior | dermal | Dermal tissue covers the outside of a plant in a single layer of cells called the epidermis. It mediates most of the interactions between a plant and its environment. |
Metamorphic rocks form when an existing rock is changed by heat or what? | cold | radiation | chemical reaction | pressure | Metamorphic rocks form when an existing rock is changed by heat or pressure. The minerals in the rock change but do not melt. The rock experiences these changes within the Earth. |
What anatomical structure serves as the conduit of the oocyte from the ovary to the uterus? | nephrons | urethra | ureters | uterine tubes | The Uterine Tubes The uterine tubes (also called fallopian tubes or oviducts) serve as the conduit of the oocyte from the ovary to the uterus (Figure 27.14). Each of the two uterine tubes is close to, but not directly connected to, the ovary and divided into sections. The isthmus is the narrow medial end of each uterine tube that is connected to the uterus. The wide distal infundibulum flares out with slender, finger-like projections called fimbriae. The middle region of the tube, called the ampulla, is where fertilization often occurs. The uterine tubes also have three layers: an outer serosa, a middle smooth muscle layer, and an inner mucosal layer. In addition to its mucus-secreting cells, the inner mucosa contains ciliated cells that beat in the direction of the uterus, producing a current that will be critical to move the oocyte. Following ovulation, the secondary oocyte surrounded by a few granulosa cells is released into the peritoneal cavity. The nearby uterine tube, either left or right, receives the oocyte. Unlike sperm, oocytes lack flagella, and therefore cannot move on their own. So how do they travel into the uterine tube and toward the uterus? High concentrations of estrogen that occur around the time of ovulation induce contractions of the smooth muscle along the length of the uterine tube. These contractions occur every 4 to 8 seconds, and the result is a coordinated movement that sweeps the surface of the ovary and the pelvic cavity. Current flowing toward the uterus is generated by coordinated beating of the cilia that line the outside and lumen of the length of the uterine tube. These cilia beat more strongly in response to the high estrogen concentrations that occur around the time of ovulation. As a result of these mechanisms, the oocyte–granulosa cell complex is pulled into the interior of the tube. Once inside, the muscular contractions and beating cilia move the oocyte slowly toward the uterus. When fertilization does occur, sperm typically meet the egg while it is still moving through the ampulla. |
What cell structures are like storage centers and tend to be larger in plant cells? | nuclei | alleles | tubules | vacuoles | The vacuoles are like storage centers. Plant cells have larger vacuoles than animal cells. Plants store water and nutrients in their large central vacuoles. |
Oscillations in the transcription of certain genes are at the heart of the molecular mechanisms underlying what biological rhythms? | reproductive rhythms | metastasis rhythms | brain rhythms | circadian rhythms | |
Give an example of a ball-and-socket joint, which has the greatest range of motion, allowing movement in several directions. | monkey wrench | pulley | lever | shoulder | There are a variety of types of movable joints, which are illustrated in Figure below . The joints are classified by how they move. For example, a ball-and-socket joint , such as the shoulder, has the greatest range of motion, allowing movement in several directions. Other movable joints, including hinge joints such as the knee, allow less movement. |
Difference in electric potential energy are measured in what basic unit? | knots | moles | watts | volts | The difference in electric potential energy is measured with a voltmeter in units called volts. |
How many stars are in our solar system? | three | two | none | one | Our solar system has only one star. But many stars are in systems of two or more stars. Two stars that orbit each other are called a binary star system . If more than two stars orbit each other, it is called a multiple star system. Figure below shows two binary star systems orbiting each other. This creates an unusual quadruple star system. |
Landslides and mudslides are the most destructive types of what geologic phenomenon? | intensity movement | land momentum | formation movement | mass movement | The most destructive types of mass movement are landslides and mudslides. Both occur suddenly. |
What scientific word, which gives its name to a type of rock, means "to change form"? | igneous | evaporation | evolution | metamorphism | Metamorphism. This long word means “to change form. “ A rock undergoes metamorphism if it is exposed to extreme heat and pressure within the crust. With metamorphism , the rock does not melt all the way. The rock changes due to heat and pressure. A metamorphic rock may have a new mineral composition and/or texture. |
The sporophyte phase is the longest phase in the life of what? | angiosperm | echinoderm | arthropod | gymnosperm | Figure 26.8 illustrates the life cycle of a conifer. The sporophyte (2n) phase is the longest phase in the life of a gymnosperm. The gametophytes (1n)—microspores and megaspores—are reduced in size. It may take more than year between pollination and fertilization while the pollen tube grows towards the megasporocyte (2n), which undergoes meiosis into megaspores. The megaspores will mature into eggs (1n). |
Hair color and skin color are known as what? | mutations | habits | abominations | traits | What is the difference between a trait and a genetic disorder ? Could a disorder be considered a trait? We tend to think of traits as hair color or skin color and disorders as something that is bad for you. But in terms of genetics, a genetic disorder is a trait. Both may be due to your genes. Traits may be inherited in any of a number of ways: autosomal dominant or recessive, sex-linked inheritance, or a more complex pattern of inheritance. |
Amines are classified according to the number of carbon atoms bonded directly to what atom? | hydrogen | helium | oxygen | nitrogen | 15.11 Amines: Structures and Names LEARNING OBJECTIVES Identify the general structure for an amine. Identify the functional group for amines. Determine the structural feature that classifies amines as primary, secondary, or tertiary. Use nomenclature systems to name amines. Amines are classified according to the number of carbon atoms bonded directly to the nitrogen atom. A primary (1°) amine has one alkyl (or aryl) group on the nitrogen atom, a secondary (2°) amine has two, and a tertiary (3°) amine has three (http://catalog. flatworldknowledge. com/bookhub/reader/2547. |
Because core electrons are closer to the nucleus, they are not involved in what? | fission | diffusion | splitting | bonding | Core electrons are the electrons that are closer to the nucleus and therefore do not participate in bonding. |
The upper portion of the septum is formed by the perpendicular plate of which bone? | colossal bone | concomitant bone | duodenum bone | ethmoid bone | The Nasal Septum and Nasal Conchae The nasal septum consists of both bone and cartilage components (Figure 7.17; see also Figure 7.11). The upper portion of the septum is formed by the perpendicular plate of the ethmoid bone. The lower and posterior parts of the septum are formed by the triangular-shaped vomer bone. In an anterior view of the skull, the perpendicular plate of the ethmoid bone is easily seen inside the nasal opening as the upper nasal septum, but only a small portion of the vomer is seen as the inferior septum. A better view of the vomer bone is seen when looking into the posterior nasal cavity with an inferior view of the skull, where the vomer forms the full height of the nasal septum. The anterior nasal septum is formed by the septal cartilage, a flexible plate that fills in the gap between the perpendicular plate of the ethmoid and vomer bones. This cartilage also extends outward into the nose where it separates the right and left nostrils. The septal cartilage is not found in the dry skull. Attached to the lateral wall on each side of the nasal cavity are the superior, middle, and inferior nasal conchae (singular = concha), which are named for their positions (see Figure 7.13). These are bony plates that curve downward as they project into the space of the nasal cavity. They serve to swirl the incoming air, which helps to warm and moisturize it before the air moves into the delicate air sacs of the lungs. This also allows mucus, secreted by the tissue lining the nasal cavity, to trap incoming dust, pollen, bacteria, and viruses. The largest of the conchae is the inferior nasal concha, which is an independent bone of the skull. The middle concha and the superior conchae, which is the smallest, are both formed by the ethmoid bone. When looking into the anterior nasal opening of the skull, only the inferior and middle conchae can be seen. The small superior nasal concha is well hidden above and behind the middle concha. |
Cells in green algae divide along cell plates called what? | xanthophylls | chloroplasts | cellulose | phragmoplasts | Streptophytes Until recently, all photosynthetic eukaryotes were considered members of the kingdom Plantae. The brown, red, and gold algae, however, have been reassigned to the Protista kingdom. This is because apart from their ability to capture light energy and fix CO2, they lack many structural and biochemical traits that distinguish plants from protists. The position of green algae is more ambiguous. Green algae contain the same carotenoids and chlorophyll a and b as land plants, whereas other algae have different accessory pigments and types of chlorophyll molecules in addition to chlorophyll a. Both green algae and land plants also store carbohydrates as starch. Cells in green algae divide along cell plates called phragmoplasts, and their cell walls are layered in the same manner as the cell walls of embryophytes. Consequently, land plants and closely related green algae are now part of a new monophyletic group called Streptophyta. The remaining green algae, which belong to a group called Chlorophyta, include more than 7000 different species that live in fresh or brackish water, in seawater, or in snow patches. A few green algae even survive on soil, provided it is covered by a thin film of moisture in which they can live. Periodic dry spells provide a selective advantage to algae that can survive water stress. Some green algae may already be familiar, in particular Spirogyra and desmids. Their cells contain chloroplasts that display a dizzying variety of shapes, and their cell walls contain cellulose, as do land plants. Some green algae are single cells, such as Chlorella and Chlamydomonas, which adds to the ambiguity of green algae classification, because plants are multicellular. Other algae, like Ulva (commonly called sea lettuce), form colonies (Figure 25.7). |
What are saprobes that decompose organic matter? | protists | sponges | chordates | fungi | 24.3 Ecology of Fungi Fungi have colonized nearly all environments on Earth, but are frequently found in cool, dark, moist places with a supply of decaying material. Fungi are saprobes that decompose organic matter. Many successful mutualistic relationships involve a fungus and another organism. Many fungi establish complex mycorrhizal associations with the roots of plants. Some ants. |
Because complex plant carbohydrates such as cellulose are more difficult to digest, what animal diet is associated with a complicated digestive system? | carnivore | polyvore | omnivore | herbivore | Different diets require different types of digestive systems. Mammals that eat a carnivorous diet generally have a relatively simple digestive system. Their food consists mainly of proteins and fats that are easily and quickly digested. Herbivorous mammals, on the other hand, tend to have a more complicated digestive system. Complex plant carbohydrates such as cellulose are more difficult to digest. Some herbivores have more than one stomach. The stomachs store and slowly digest plant foods. |
What are all cells surrounded by? | amino acids | cytoplasm | cell substrate | cell membrane | Heat waves have increased in frequency and duration in recent years. The summer 2011 North American heat wave brought record temperatures across the Midwestern and Eastern United States. Many states and localities broke records for temperature and for the most days above 100 o F. |
The leaves of all of what type of plants have two basic parts in common: the blade and petiole? | evergreen | perennials | deciduous | flowering plants | Flowering vascular plants also have diverse leaves. However, the leaves of all flowering plants have two basic parts in common: the blade and petiole (see Figure above ). The blade of the leaf is the relatively wide, flat part of the leaf that gathers sunlight and undergoes photosynthesis. The petiole is the part that attaches the leaf to a stem of the plant. This occurs at a node. |
Through what do plants move enormous amounts of water from the soil to the atmosphere? | respiration | perspiration | evaporation | transpiration | Plants recycle matter in biogeochemical cycles. For example, through transpiration, plants move enormous amounts of water from the soil to the atmosphere. Plants such as peas host bacteria that fix nitrogen. This makes nitrogen available to all plants, which pass it on to consumers. |
What explains why two different species cannot occupy the same niche in the same place for very long? | survival exclusion princple | evolution | natural selection | competive exclusion princple | A given habitat may contain many different species, but each species must have a different niche. Two different species cannot occupy the same niche in the same place for very long. This is known as the competitive exclusion principle . If two species were to occupy the same niche, what do you think would happen? They would compete with one another for the same food and other resources in the environment. Eventually, one species would be likely to outcompete and replace the other. |
The cytoplasm of prokaryotic cells has a high concentration of dissolved solutes. therefore, the osmotic pressure within the cell is what? | relative | relatively normal | relatively low | relatively high | The Cell Wall The cytoplasm of prokaryotic cells has a high concentration of dissolved solutes. Therefore, the osmotic pressure within the cell is relatively high. The cell wall is a protective layer that surrounds some cells and gives them shape and rigidity. It is located outside the cell membrane and prevents osmotic lysis (bursting due to increasing volume). The chemical composition of the cell walls varies between archaea and bacteria, and also varies between bacterial species. Bacterial cell walls contain peptidoglycan, composed of polysaccharide chains that are cross-linked by unusual peptides containing both L- and D-amino acids including D-glutamic acid and D-alanine. Proteins normally have only L-amino acids; as a consequence, many of our antibiotics work by mimicking D-amino acids and therefore have specific effects on bacterial cell wall development. There are more than 100 different forms of peptidoglycan. S-layer (surface layer) proteins are also present on the outside of cell walls of both archaea and bacteria. Bacteria are divided into two major groups: Gram positive and Gram negative, based on their reaction to Gram staining. Note that all Gram-positive bacteria belong to one phylum; bacteria in the other phyla (Proteobacteria, Chlamydias, Spirochetes, Cyanobacteria, and others) are Gram-negative. The Gram staining method is named after its inventor, Danish scientist Hans Christian Gram (1853–1938). The different bacterial responses to the staining procedure are ultimately due to cell wall structure. Gram-positive organisms typically lack the outer membrane found in Gram-negative organisms (Figure 22.15). Up to 90 percent of the cell wall in Gram-positive bacteria is composed of peptidoglycan, and most of the rest is composed of acidic substances called teichoic acids. Teichoic acids may be covalently linked to lipids in the plasma membrane to form lipoteichoic acids. Lipoteichoic acids anchor the cell wall to the cell membrane. Gram-negative bacteria have a relatively thin cell wall composed of a few layers of peptidoglycan (only 10 percent of the total cell wall), surrounded by an outer envelope containing lipopolysaccharides (LPS) and lipoproteins. This outer envelope is sometimes referred to as a second lipid bilayer. The chemistry of this outer envelope is very different, however, from that of the typical lipid bilayer that forms plasma membranes. |
What are the ultimate source of genetic variation? | proteins | parasites | gravity | mutations | Mutations and evolution There are often multiple alleles of a particular gene in the population and they all may be equally normal, that is have similar effects on reproductive success andin terms of the phenotypes they produce. If there is no significant selective advantage between them, their relative frequencies within a population will drift. At the same time, the phenotype associated with a particular allelecan be influenced by which alleles are present at other genetic loci, known as the genetic background. Since most traits are the results of hundreds or thousands of genes functioning together, and different combinations of alleles can produce different effects, the universe of variation is large. This can make identifying the genetic basis of a disease difficult, particularly when variation at any one locus may make only a minor contribution to the disease phenotype. On top of that, environmental and developmental differences can outweigh genetic influence on phenotype. Such genetic background effects can lead to a particular allele producing a disease in one person and not another.270 Mutations are the ultimate source of genetic variation – without them evolution would not occur. Mutations can lead to a number of effects, in particular, they can create new activities. At the same time these changes may reduce the original (and necessary) activity of an important gene. Left unresolved such molecular level conflicts would greatly limit the flexibility of evolutionary mechanisms. For example, it is common to think of a gene (or rather the particular gene product it encodes) as having one and only one function or activity, but in fact, when examined closely many catalytic gene products (typically proteins) can catalyze “off-target” reactions or carry out, even if rather inefficiently, other activities - they interact with other molecules within the cell and the organism. Assume for the moment that a gene encodes a gene product with an essential function as well as potentially useful (from a reproductive success perspective) activities. Mutations that enhance these “ancillary functions” will survive (that is be passed on to subsequent generations) only to the extent that they do not (overly) negatively influence the gene’s primary and essential function. The evolution of ancillary functions may be severely constrained or blocked altogether. This problem can be circumvented based on the fact that the genome is not static (→). There are molecular level processes through 270. |
The electron beam scans the surface of the sample, usually coated with a thin film of which metal? | copper | platinum | silver | gold | |
In a longitudinal wave, what term is a measure of how compressed particles of the medium become when the wave passes through? | voltage | magnitude | frequency | amplitude | In a longitudinal wave, amplitude is a measure of how compressed particles of the medium become when the wave passes through. The closer together the particles are, the greater the amplitude. |
All cells have certain parts in common. these parts include the cell membrane, cytoplasm, dna, and what? | crystals | lipids | chromosomes | ribosomes | All cells have certain parts in common. These parts include the cell membrane, cytoplasm, DNA, and ribosomes. |
Competition within a species is called what? | internal competition | reproducible competition | species competion | intraspecific competition | Competition within a species is called intraspecific competition. It leads to natural selection within the species, so the species becomes better adapted to its environment. |
What occurs when rain falls more quickly than water can be absorbed into the ground or carried away by rivers or streams? | landslides | typhoons | greenhouse effect | floods | Floods may occur when deep snow melts quickly in the spring. More often, floods are due to heavy rainfall. Floods happen when rain falls more quickly than water can be absorbed into the ground or carried away by rivers or streams. |
What are the building blocks of dna? | genes | prokaryotes | peptides | nucleotides | The building blocks of DNA are nucleotides. The important components of the nucleotide are a nitrogenous base, deoxyribose (5-carbon sugar), and a phosphate group (Figure 14.5). The nucleotide is named depending on the nitrogenous base. The nitrogenous base can be a purine such as adenine (A) and guanine (G), or a pyrimidine such as cytosine (C) and thymine (T). |
Each line in a structural formula represents a pair of shared what? | atoms | waves | ions | electrons | |
What do vertebrate chordates possess that invertebrate chordates do not? | Milk production | parasite | Thumb | backbone | Chordates include vertebrates and invertebrates that have a notochord. Chordates also have a post-anal tail, dorsal hollow nerve cord, and pharyngeal slits. Vertebrate chordates have a backbone, while invertebrate chordates do not. Invertebrate chordates include tunicates and lancelets; both are primitive marine organisms. |
In vascular plants, what two basic structures are made of dermal, vascular, and ground tissues? | fruits and nuts | stems and flowers | roots and seed | roots and stems | Like roots, the stems of vascular plants are made of dermal, vascular, and ground tissues. |
What is the process resulting in living things with beneficial traits producing more offspring? | natural change | fluid selection | Natural choice. | natural selection | The other idea is that evolution occurs by natural selection . Natural selection is the process that results in living things with beneficial traits producing more offspring than others. This results in changes in the traits of living things over time. |
Solar cells create voltages directly from light, while thermoelectric devices create voltage from differences in what? | wattage | oxygen | wire width | temperature | Electromotive Force You can think of many different types of voltage sources. Batteries themselves come in many varieties. There are many types of mechanical/electrical generators, driven by many different energy sources, ranging from nuclear to wind. Solar cells create voltages directly from light, while thermoelectric devices create voltage from temperature differences. |
What theory goes beyond classical mechanics to describe the behavior of near-light-speed objects? | spacial relativity | normal relativity | simple relativity | special relativity | A great many experiments have been performed to test the predictions of special relativity. No contradictions have been found. Scientists have therefore accepted special relativity as an accurate description of nature. When the relative velocities of objects are considerably less than the speed of light, the formulas for relativistic time, length, and mass all reduce to the classical formulas. It is required that the two theories correspond where they overlap at speeds much less than . Special relativity does not contradict classical mechanics. Rather, it is a more general theory needed for object speeds approaching the speed of light. |
What type of structure between the esophagus and the stomach normally opens only when a bolus arrives? | gland | larynx | intestine | sphincter | |
Viroids are plant pathogens much simpler than what, but like them can reproduce only within a host cell? | parasites | pests | bacteria | viruses | Viroids Viroids are plant pathogens: small, single-stranded, circular RNA particles that are much simpler than a virus. They do not have a capsid or outer envelope, but like viruses can reproduce only within a host cell. Viroids do not, however, manufacture any proteins, and they only produce a single, specific RNA molecule. Human diseases caused by viroids have yet to be identified. Viroids are known to infect plants (Figure 21.18) and are responsible for crop failures and the loss of millions of dollars in agricultural revenue each year. Some of the plants they infect include potatoes, cucumbers, tomatoes, chrysanthemums, avocados, and coconut palms. |
"crossing over" occurs during what phase of mitosis? | prophase iii | Prophase ii | prophase VI | prophase i | |
What is the preferred food for almost all primates except for humans? | corn | grass | wheat | fruit | Fruit is the preferred food for almost all primates except humans. However, most primate species are omnivorous and consume a variety of plant and animal foods. For example, they may eat leaves, seeds, bird eggs, insects, and other small animals. Chimpanzees may band together and hunt for animals to kill and eat. They may even sharpen sticks and use them as spears when they hunt. Watch this video to see the incredible teamwork of a group of chimpanzees hunting a monkey: https://www. youtube. com/watch?v=A1WBs74W4ik . |
What property means that something can return to its original shape after being stretched or compressed? | friction | viscosity | homeostasis | elasticity | Something that is elastic can return to its original shape after being stretched or compressed. This property is called elasticity . As you stretch or compress an elastic material like a bungee cord, it resists the change in shape. It exerts a counter force in the opposite direction. This force is called elastic force . The farther the material is stretched or compressed, the greater the elastic force becomes. As soon as the stretching or compressing force is released, elastic force causes the material to spring back to its original shape. You can watch a demonstration of elastic force at this URL:. |
Where does all igneous rock come from? | oceans | the moon | stratosphere | magma or lava | Great volcanic explosions and glowing red rivers of lava are fascinating. All igneous rock comes from magma or lava. Remember that magma is molten rock that is below Earth's surface. Lava is molten rock at Earth's surface. |
Three ways that waves may interact with matter are reflection, refraction, and what? | dispose | distortion | absorption | diffraction | Three ways that waves may interact with matter are reflection, refraction, and diffraction. |
Sucrose consists of one molecule of glucose and one molecule of what else? | alcohol | protein | lactose | fructose | You can see the structural formula of glucose and two other sugars in Figure below . The other sugars in the figure are fructose and sucrose. Fructose is an isomer of glucose. It is found in fruits. It has the same atoms as glucose, but they are arranged differently. Sucrose is table sugar. It consists of one molecule of glucose and one molecule of fructose. |
Many countries have attempted to reduce the human impact on climate change by reducing their emission of what greenhouse gas? | nitrous oxide | methane | acid dioxide | carbon dioxide | Efforts to control population growth led to the one-child policy in China, which used to include more severe consequences, but now imposes fines on urban couples who have more than one child. Due to the fact that some couples wish to have a male heir, many Chinese couples continue to have more than one child. The policy itself, its social impacts, and the effectiveness of limiting overall population growth are controversial. In spite of population control policies, the human population continues to grow. At some point the food supply may run out because of the subsequent need to produce more and more food to feed our population. The United Nations estimates that future world population growth may vary from 6 billion (a decrease) to 16 billion people by the year 2100. There is no way to know whether human population growth will moderate to the point where the crisis described by Dr. Ehrlich will be averted. Another result of population growth is the endangerment of the natural environment. Many countries have attempted to reduce the human impact on climate change by reducing their emission of the greenhouse gas carbon dioxide. However, these treaties have not been ratified by every country, and many underdeveloped countries trying to improve their economic condition may be less likely to agree with such provisions if it means slower economic development. Furthermore, the role of human activity in causing climate change has become a hotly debated socio-political issue in some developed countries, including the United States. Thus, we enter the future with considerable uncertainty about our ability to curb human population growth and protect our environment. |
What occurs when arterioles lose their normal muscular tone and dilate dramatically? | congenital shock | cardio shock | respiration shock | vascular shock | • Vascular shock occurs when arterioles lose their normal muscular tone and dilate dramatically. It may arise from a variety of causes, and treatments almost always involve fluid replacement and medications, called inotropic or pressor agents, which restore tone to the muscles of the vessels. In addition, eliminating or at least alleviating the underlying cause of the condition is required. This might include antibiotics and antihistamines, or select steroids, which may aid in the repair of nerve damage. A common cause is sepsis (or septicemia), also called “blood poisoning,” which is a widespread bacterial infection that results in an organismal-level inflammatory response known as septic shock. Neurogenic shock is a form of vascular shock that occurs with cranial or spinal injuries that damage the cardiovascular centers in the medulla oblongata or the nervous fibers originating from this region. Anaphylactic shock is a severe allergic response that causes the widespread release of histamines, triggering vasodilation throughout the body. • Obstructive shock, as the name would suggest, occurs when a significant portion of the vascular system is blocked. It is not always recognized as a distinct condition and may be grouped with cardiogenic shock, including pulmonary embolism and cardiac tamponade. Treatments depend upon the underlying cause and, in addition to administering fluids intravenously, often include the administration of anticoagulants, removal of fluid from the pericardial cavity, or air from the thoracic cavity, and surgery as required. The most common cause is a pulmonary embolism, a clot that lodges in the pulmonary vessels and interrupts blood flow. Other causes include stenosis of the aortic valve; cardiac tamponade, in which excess fluid in the pericardial cavity interferes with the ability of the heart to fully relax and fill with blood (resulting in decreased preload); and a pneumothorax, in which an excessive amount of air is present in the thoracic cavity, outside of the lungs, which interferes with venous return, pulmonary function, and delivery of oxygen to the tissues. |
Large or small numbers are expressed in scientific notation, which use powers of this? | 16 | 2 | 4 | 10 | Large or small numbers are expressed in scientific notation, which use powers of 10. |
Budding in sponges is a form of what type of reproduction? | competitive | sexual | reasonable | asexual | Sponges reproduce both asexually and sexually. Asexual reproduction occurs by budding. Sexual reproduction occurs by the production of eggs and sperm. Males release sperm into the water through the osculum. Sperm may enter a female sponge through a pore and fertilize her eggs. The resulting zygotes develop into larvae. |
Behaviors that are closely controlled by genes and have little to no environmental influence are called what kinds of behaviors? | learned behaviors | generalized behaviors | diverse behaviors | innate behaviors | Behaviors that are closely controlled by genes with little or no environmental influence are called innate behaviors . These are behaviors that occur naturally in all members of a species whenever they are exposed to a certain stimulus . Innate behaviors do not have to be learned or practiced. They are also called instinctive behaviors. An instinct is the ability of an animal to perform a behavior the first time it is exposed to the proper stimulus. For example, a dog will drool the first time—and every time—it is exposed to food. |
Mutations which benefit the organism in which they occur are known as? | healthy mutations | extraordinary mutations | helpful mutations | beneficial mutations | Some mutations have a positive effect on the organism in which they occur. They are called beneficial mutations . They lead to new versions of proteins that help organisms adapt to changes in their environment. Beneficial mutations are essential for evolution to occur. They increase an organism’s changes of surviving or reproducing, so they are likely to become more common over time. There are several well-known examples of beneficial mutations. Here are just two:. |
When gas particles collide, what kinds of collisions are these considered? | conservative | inelastic | perfect | elastic | Collisions of gas particles are elastic, so no energy is lost. |
Around 1200 species of what broad animal group are currently at risk of extinction due to human activity? | amphibians | mammals | reptiles | birds | Today, some 1,200 species of birds are threatened with extinction by human actions. Humans need to take steps to protect this precious and important natural resource. What can you do to help?. |
The galápagos islands are a group of 16 volcanic islands 600 miles off the west coast of what continent? | asia | north america | europe | south america | The Galápagos Islands are a group of 16 volcanic islands 600 miles off the west coast of South America. The islands are famous for their many species found nowhere else. It was on these islands where Darwin began to develop his theory of evolution. |
What structures on the gastrodermal cells keep the contents of the gastrovascular cavity agitated and help distribute nutrients? | nucleus | telomeres | sporangia | flagella | |
What is the factor that affects the solubility of solutes in all three states? | heat | oxygen | color | temperature | Temperature affects the solubility of solutes in all three states. Pressure also affects the solubility of gases. |
What kind of ph would you find in water from bogs? | regular ph | normal ph | higher ph | lower ph | 44.4 Aquatic Biomes Aquatic ecosystems include both saltwater and freshwater biomes. The abiotic factors important for the structuring of aquatic ecosystems can be different than those seen in terrestrial systems. Sunlight is a driving force behind the structure of forests and also is an important factor in bodies of water, especially those that are very deep, because of the role of photosynthesis in sustaining certain organisms. Density and temperature shape the structure of aquatic systems. Oceans may be thought of as consisting of different zones based on water depth and distance from the shoreline and light penetrance. Different kinds of organisms are adapted to the conditions found in each zone. Coral reefs are unique marine ecosystems that are home to a wide variety of species. Estuaries are found where rivers meet the ocean; their shallow waters provide nourishment and shelter for young crustaceans, mollusks, fishes, and many other species. Freshwater biomes include lakes, ponds, rivers, streams, and wetlands. Bogs are an interesting type of wetland characterized by standing water, lower pH, and a lack of nitrogen. |
Where do most of the digestion reactions occur? | mouth | liver | large intestine | small intestine | Most of the digestion reactions occur in the small intestine. |
What is the name of the process where light is produced without heat? | fluorescence | radiation | effervescence | luminescence | Some objects produce light without becoming very hot. They generate light through chemical reactions or other processes. Producing light without heat is called luminescence . Luminescence, in turn, can occur in several different ways:. |
Meats and dairy products link to photosynthesis because the animals were fed what? | biofuel | carnivorous diets | chloroplasts | plant-based foods | Major grocery stores in the United States are organized into departments, such as dairy, meats, produce, bread, cereals, and so forth. Each aisle contains hundreds, if not thousands, of different products for customers to buy and consume (Figure 5.4). Although there is a large variety, each item links back to photosynthesis. Meats and dairy products link to photosynthesis because the animals were fed plant-based foods. The breads, cereals, and pastas come largely from grains, which are the seeds of photosynthetic plants. What about desserts and drinks? All of these products contain sugar—the basic carbohydrate molecule produced directly from photosynthesis. The photosynthesis connection applies to every meal and every food a person consumes. |
What the scientific concept stating that when looking at two competing theories, the one with fewer assumptions should be chosen? | law of averages | law of thermodynamics | law of simplicity | law of parsimony | The formation of scientific theories is generally guided by the law of parsimony. The word parsimony means “thriftiness. ” The law of parsimony states that, when choosing between competing theories, you should select the theory that makes the fewest assumptions. In other words, the simpler theory is more likely to be correct. For example, you probably know that Earth and the other planets of our solar system orbit around the sun. But several centuries ago, it was believed that Earth is at the center of the solar system and the other planets orbit around Earth. While it is possible to explain the movement of planets according to this theory, the explanation is unnecessarily complex. |
What type of map would show average temperatures and rainfall? | carbon map | landscape map | rainfall map | climate map | Climate maps show average temperatures and rainfall. |
What is the name of the sugar that plants produce to be used as food? | insulin | glucosamine | chlorophyll | glucose | |
Just under their skin, marine mammals have a very thick layer of insulating fat called what? | cellulose | tissue | lipisomes | blubber | |
While in the lungs, blood gives up carbon dioxide and picks up what element before returning to the heart? | hydrogen | nitrogen | methane | oxygen | Pulmonary circulation is the part of the circulatory system that carries blood between the heart and lungs (the term pulmonary means “of the lungs”). It is illustrated in Figure below . Deoxygenated blood leaves the right ventricle through pulmonary arteries, which transport it to the lungs. In the lungs, the blood gives up carbon dioxide and picks up oxygen. The oxygenated blood then returns to the left atrium of the heart through pulmonary veins. |
White blood cells called what travel to areas of the body that are inflamed? | spirochetes | platelets | gametocytes | phagocytes | White blood cells called phagocytes travel to areas of the body that are inflamed. |
How many valence electrons can be found in a carbon atom? | One | five | three | four | Let’s briefly review the basics of covalent bonding as they pertain to carbon. Carbon has four valence electrons, which have a 2s 2 2p 2 configuration in isolated carbon atoms. These four electrons allow carbon to form four covalent bonds, which can mean four single bonds or some combination of single, double, and triple bonds. |
Diaphragm, lungs, and trachea take air deep into the body and provide oxygen gas to what? | brain | molecules | heart | bloodstream | (left) The human respiratory system is only part of the story of respiration. Diaphragm, lungs, and trachea take air deep into the body and provide oxygen gas to the bloodstream. The fate of that oxygen is the story of cellular respiration. (center) Spiracles in this Cluentius Sphinx ( Neococytius cluentius ) caterpillar connect to a system of internal tubes (tracheae), which carry oxygen throughout the animal's body. (right) Gills in this alpine newt larva, Ichthyosaura alpestris , bring blood close to an extensive surface area so that the newt can absorb dissolved oxygen gas from its watery habitat. |
What gases move in and out of blood during gas exchange? | oxygen, nitrogen | oxygen, carbon monoxide | nitrogen, carbon dioxide | oxygen, carbon dioxide | User:helix84/Wikimedia Commons. Gas exchange is the movement of oxygen into the blood and carbon dioxide out of the blood . CC BY 2.5. |
What keeps various species from mating and reproducing outside their own species? | cancer organ incompatibility | digestive system incompatibility | brain organ incompatibility | reproductive organ incompatibility | Figure 18.19 The shape of the male reproductive organ varies among male damselfly species, and is only compatible with the female of that species. Reproductive organ incompatibility keeps the species reproductively isolated. |
A refrigerator must do work to reverse the normal direction of what? | spectral energy flow | visible energy flow | coolant energy flow | thermal energy flow | A refrigerator must do work to reverse the normal direction of thermal energy flow. Work involves the use of force to move something, and doing work takes energy. In a refrigerator, the energy is usually provided by electricity. You can read in detail in the Figure below how a refrigerator does its work. For an animation of how a refrigerator works, go to this URL: http://www. chemistry. wustl. edu/~edudev/LabTutorials/CourseTutorials/LabTutorials/Thermochem/fridge_movie. html. |
The bone matrix consists of tough protein fibers—mainly what? | tendons | tissues | hemoglobin | collagen | Many people think of bones as being dead, dry, and brittle. These adjectives correctly describe the bones of a preserved skeleton, but the bones in a living human being are very much alive. As shown in Figure below , the basic structure of bones is bone matrix , which forms the underlying rigid framework of bones, formed of both compact and spongy bone. The bone matrix consists of tough protein fibers—mainly collagen—that become hard and rigid due to mineralization with calcium crystals. Bone matrix is crisscrossed by blood vessels and nerves and also contains specialized bone cells that are actively involved in metabolic processes. |
Alkynes are what type of compound? | Split Hydrocarbons | reversible hydrocarbons | proteins hydrocarbons | unsaturated hydrocarbons | Unsaturated hydrocarbons that contain one or more triple bonds are called alkynes . The names of specific alkynes always end in –yne and have a prefix for the number of carbon atoms. The structural formula in the Figure below represents the smallest alkyne, named ethyne, which has two carbon atoms and two hydrogen atoms (C 2 H 2 ). Ethyne is also called acetylene. It is burned in acetylene torches, like the one pictured in the Figure below . The flame of an acetylene torch is so hot that it can melt metal. |
Solar cells turn sunlight directly into what? | cold | gas | water | electricity | Solar energy is used to heat homes and water, and to make electricity. Scientists and engineers have many ways to get energy from the Sun ( Figure below ). One is by using solar cells. Solar cells are devices that turn sunlight directly into electricity. Lots of solar cells make up an individual solar panel. You may have seen solar panels on roof tops. The Sun’s heat can also be trapped in your home by using south facing windows and good insulation. |
What type of invertebrate typically has a single spiraled shell? | anthropod | bipod | arthropod | gastropod | |
What are nutrients the body needs in relatively large amounts called? | vitamins | adulterants | abundances | macronutrients | Nutrients the body needs in relatively large amounts are called macronutrients . They include carbohydrates, proteins, lipids, and water. All macronutrients except water can be used by the body for energy. (The energy in food is measured in a unit called a Calorie . ) The exact amount of each macronutrient that an individual needs depends on many factors, including gender and age. Recommended daily intakes by teens of three macronutrients are shown in Table below . Based on your gender and age, how many grams of proteins should you eat each day?. |
What is observed when two perpendicular flagella moves? | shaking motion | turning motion | pushing motion | spinning motion | Figure 23.12 The dinoflagellates exhibit great diversity in shape. Many are encased in cellulose armor and have two flagella that fit in grooves between the plates. Movement of these two perpendicular flagella causes a spinning motion. |
What is the name of a branch of the chemistry that deals with the interconversion of chemical energy and electrical energy? | Theoretical Chemistry | Inorganic chemistry | Biochemistry | electrochemistry | Chemical reactions either absorb or release energy, which can be in the form of electricity. Electrochemistry is a branch of chemistry that deals with the interconversion of chemical energy and electrical energy. Electrochemistry has many common applications in everyday life. All sorts of batteries, from those used to power a flashlight to a calculator to an automobile, rely on chemical reactions to generate electricity. Electricity is used to plate objects with decorative metals like gold or chromium. Electrochemistry is important in the transmission of nerve impulses in biological systems. Redox chemistry, the transfer of electrons, is behind all electrochemical processes. |
Which system in the body exchanges gases with the outside air? | vascular | immune | digestive | respiratory | The respiratory system is the body system that exchanges gases with the outside air. It brings air containing oxygen into the body for the cells. It also releases carbon dioxide from the cells into the air. This exchange of gases is called respiration. |
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