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Compounds that are capable of accepting electrons, such as o 2 or f2, are called what? | residues | antioxidants | Oxygen | oxidants | Oxidants and Reductants Compounds that are capable of accepting electrons, such as O 2 or F2, are calledoxidants (or oxidizing agents) because they can oxidize other compounds. In the process of accepting electrons, an oxidant is reduced. Compounds that are capable of donating electrons, such as sodium metal or cyclohexane (C6H12), are calledreductants (or reducing agents) because they can cause the reduction of another compound. In the process of donating electrons, a reductant is oxidized. These relationships are summarized in Equation 3.30: Equation 3.30 Saylor URL: http://www. saylor. org/books. |
What term in biotechnology means a genetically exact copy of an organism? | phenotype | adult | male | clone | But transgenic animals just have one novel gene. What about an animal with a whole new genome? Could a clone , a genetically exact copy of an organism, be developed using techniques associated with biotechnology? It could be argued that human cloning is one of the inevitable outcomes of modern biotechnology. It "simply" involves the removal of the nucleus from a somatic cell and its placement into an unfertilized egg cell whose nucleus has either been deactivated or removed. This new cell would mimic the zygote, the first diploid cell of a new organism. This new zygote is allowed to become established, and a few days later is placed into the uterus of a surrogate mother. Theoretically this would result in an individual genetically identical to the donor. Obviously, there are many ethical and legal issues associated with human cloning, and of course, it is not a "simple" procedure. But animal cloning is arguably a different story. |
Vertebrata are characterized by the presence of what? | Thumbs | Bones | Muscles | backbone | Figure 29.7 Vertebrata are characterized by the presence of a backbone, such as the one that runs through the middle of this fish. All vertebrates are in the Craniata clade and have a cranium. (credit: Ernest V. More; taken at Smithsonian Museum of Natural History, Washington, D. |
What is the height above or below sea level called? | variation | depth | latitude | elevation | As you know, the surface of Earth is not flat. Some places are high, and some places are low. For example, mountain ranges like the Sierra Nevada in California or the Andes in South America are high above the surrounding areas. An accurate location must take into account the third dimension. Elevation is the height above or below sea level. Sea level refers to the height of the ocean’s surface. This is the midpoint between high and low tide. Sea level can vary from place to place, but scientists base their elevation measurements on the average, or mean, sea level to make sure they have a standard reference point. |
Ice cores, varves and what else indicate the environmental conditions at the time of their creation? | magma | mountain ranges | fossils | tree rings | Tree rings, ice cores, and varves indicate the environmental conditions at the time they were made. |
What chemical signals in plants control different processes? | Human Hormones | produce hormones | nitrogen hormones | plant hormones | Plant hormones are chemical signals that control different processes in plants. |
Meiosis is part of the process of gametogenesis, which is the production of what? | sperm only | chromosomes | egg only | sperm and eggs | Gametogenesis (Spermatogenesis and Oogenesis) Gametogenesis, the production of sperm and eggs, involves the process of meiosis. During meiosis, two nuclear divisions separate the paired chromosomes in the nucleus and then separate the chromatids that were made during an earlier stage of the cell’s life cycle. Meiosis and its associated cell divisions produces haploid cells with half of each pair of chromosomes normally found in diploid cells. The production of sperm is called spermatogenesis and the production of eggs is called oogenesis. Spermatogenesis Spermatogenesis occurs in the wall of the seminiferous tubules, with the most primitive cells at the periphery of the tube and the most mature sperm at the lumen of the tube (Figure 18.14). Immediately under the capsule of the tubule are diploid, undifferentiated cells. These stem cells, each called a spermatogonium (pl. spermatogonia), go through mitosis to produce one cell that remains as a stem cell and a second cell called a primary spermatocyte that will undergo meiosis to produce sperm. The diploid primary spermatocyte goes through meiosis I to produce two haploid cells called secondary spermatocytes. Each secondary spermatocyte divides after meiosis II to produce two cells called spermatids. The spermatids eventually reach the lumen of the tubule and grow a flagellum, becoming sperm cells. Four sperm result from each primary spermatocyte that goes through meiosis. |
Which type of tree is dominant in temperate forests? | shrubs | vines | fungus | deciduous | Figure 44.18 Deciduous trees are the dominant plant in the temperate forest. (credit: Oliver Herold). |
What kind of viscosity is found in long-chain hydrocarbons? | intense viscosity | increased viscosity | low viscosity | highly viscous | There is also a correlation between viscosity and molecular shape. Liquids consisting of long, flexible molecules tend to have higher viscosities than those composed of more spherical or shorter-chain molecules. The longer the molecules, the easier it is for them to become “tangled” with one another, making it more difficult for them to move past one another. London dispersion forces also increase with chain length. Due to a combination of these two effects, long-chain hydrocarbons (such as motor oils) are highly viscous. |
Ionic compounds have strong electrostatic attractions between oppositely charged ions in this? | occasional array | incorrect array | normal array | regular array | Ionic compounds have strong electrostatic attractions between oppositely charged ions in a regular array. The lattice energy (U) of an ionic substance is defined as the energy required to dissociate the solid into gaseous ions; U can be calculated from the charges on the ions, the arrangement of the ions in the solid, and the internuclear distance. Because U depends on the product of the ionic charges, substances with dior tripositive cations and/or di- or trinegative anions tend to have higher lattice energies than their singly charged counterparts. Higher lattice energies typically result in higher melting points and increased hardnessbecause more thermal energy is needed to overcome the forces that hold the ions together. Lattice energies cannot be measured directly but are obtained from a thermochemical cycle called the Born–Haber cycle, in which Hess’s law is used to calculate the lattice energy from the measured enthalpy of formation of the ionic compound, along with other thermochemical data. The Born–Haber cycle can be used to predict which ionic compounds are likely to form. Sublimation, the conversion of a solid directly to a gas, has an accompanying enthalpy change called the enthalpy of sublimation. |
About how tall can mid-ocean ridges be? | 2 inches | about 2 meters | about 2 feet | about 2 km | Besides seamounts, there are long, very tall (about 2 km) mountain ranges. These ranges are connected so that they form huge ridge systems called mid-ocean ridges ( Figure below ). The mid-ocean ridges form from volcanic eruptions. Lava from inside Earth breaks through the crust and creates the mountains. |
What are by far the most common type of invertebrate? | corals | spiders | crustaceans | insects | This Monarch caterpillar is an invertebrate. It is also an insect and an arthropod. Of all the animal species, it is estimated that well over 90% are invertebrates. Of all invertebrates, the insects are by far the most numerous. There are so many species of insects that scientists have yet to discover them all, let alone name or count them. Estimates of the total number of insect species fall in the range of 1 to 30 million. So, it helps if there are methods to classify not just the insects, but all invertebrates. |
What do waves deposit to form sandbars and barrier islands? | glaciers | magma | organisms | sediments | Waves may also deposit sediments to form sandbars and barrier islands . You can see examples of these landforms in Figure below . |
Penis, testes, and epididymis are organs in what system? | female reproductive system | virus reproductive system | plant reproductive system | male reproductive system | Male reproductive organs include the penis, testes, and epididymis. |
Only about one percent of plants have lost what ability, turning them into consumers and even predators, instead of producers? | growth | flowering | rooting | photosynthesis | Almost all plants make food by photosynthesis . Only about 1 percent of the estimated 300,000 species of plants have lost the ability to photosynthesize. These other species are consumers, many of them predators. How do plants prey on other organisms? The Venus fly trap in Figure below shows one way this occurs. |
How does a neon light produce visible light? | mitosis | luminescence | radiation | electroluminescence | A neon light produces visible light by electroluminescence. The bulb is a glass tube that contains the noble gas neon. When electricity passes through the gas, it excites electrons of neon atoms, causing them to give off visible light. Neon produces red light. Other noble gases are also used in lights, and they produce light of different colors. For example, krypton produces violet light, and argon produces blue light. |
The bird ancestor that lived in trees developed what feature commonly associated with birds? | beaks | tails | webbed feet | wings | Wings evolved in a bird ancestor that lived in trees. Thus, wings are modified arms that helped the animal glide from branch to branch. |
What do most living things use to make atp from glucose? | nitrogen | enzymes | carbon | oxygen | Today, most living things use oxygen to make ATP from glucose. However, many living things can also make ATP without oxygen. This is true of some plants and fungi and also of many bacteria. These organisms use aerobic respiration when oxygen is present, but when oxygen is in short supply, they use anaerobic respiration instead. Certain bacteria can only use anaerobic respiration. In fact, they may not be able to survive at all in the presence of oxygen. |
What are the two most common silicates? | Micas and quartz | Olivine and quartz | Micas and feldspar | feldspar and quartz | Feldspar and quartz are the two most common silicates. In beryl, the silicate pyramids join together as rings. Biotite is mica. It can be broken apart into thin, flexible sheets. Compare the beryl and the biotite shown in Figure below . |
What term means the amount of water vapor in the air? | ambient | temperature | pressure | humidity | Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. |
Paracrine signals move by what method through the extracellular matrix? | transfusion | osmosis | deposition | diffusion | Paracrine Signaling Signals that act locally between cells that are close together are called paracrine signals. Paracrine signals move by diffusion through the extracellular matrix. These types of signals usually elicit quick responses that last only a short amount of time. In order to keep the response localized, paracrine ligand molecules are normally quickly degraded by enzymes or removed by neighboring cells. Removing the signals will reestablish the concentration gradient for the signal, allowing them to quickly diffuse through the intracellular space if released again. One example of paracrine signaling is the transfer of signals across synapses between nerve cells. A nerve cell consists of a cell body, several short, branched extensions called dendrites that receive stimuli, and a long extension called an axon, which transmits signals to other nerve cells or muscle cells. The junction between nerve cells where signal transmission occurs is called a synapse. A synaptic signal is a chemical signal that travels between nerve cells. Signals within the nerve cells are propagated by fast-moving electrical impulses. When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters by the presynaptic cell (the cell emitting the signal). The neurotransmitters are transported across the very small distances between nerve cells, which are called chemical synapses (Figure 9.3). The small distance between nerve cells allows the signal to travel quickly; this enables an immediate response, such as, Take your hand off the stove! When the neurotransmitter binds the receptor on the surface of the postsynaptic cell, the electrochemical potential of the target cell changes, and the next electrical impulse is launched. The neurotransmitters that are released into the chemical synapse are degraded quickly or get reabsorbed by the presynaptic cell so that the recipient nerve cell can recover quickly and be prepared to respond rapidly to the next synaptic signal. |
Presence of a cell wall, large central vacuole, and organelles called plastids distinguish what type of cell? | heterotroph | animal | reproductive | plant | All but one of the structures described above are found in plant cells as well as animal cells. The only exception is centrioles, which are not found in plant cells. Plant cells have three additional structures that are not found in animals cells. These include a cell wall, large central vacuole, and organelles called plastids. You can see these structures in the model of a plant cell in Figure below . You can also see them in the interactive plant cell at this link:. |
What happens when mammals raise their hair with tiny muscles in the skin? | bruising | bleeding | balding | goosebumps | Mammals raise their hair with tiny muscles in the skin. Even humans automatically contract these muscles when they are cold. They cause “goosebumps,” as shown here. |
What are people with osteoporosis at increased risk of? | growth spurt | epilepsy | senility | bone fractures | For a long time, scientists considered fungi to be members of the plant kingdom because they have obvious similarities with plants. Both fungi and plants are immobile, have cell walls, and grow in soil. Some fungi, such as lichens , even look like plants (see Figure below ). |
Where is energy stored in a chemical substance? | inside atoms | on the surface | in molecules | between atoms | energy that is stored in the connections between atoms in a chemical substance. |
By the year 2050, 25 percent of the population of the united states will be 60 years of age or older. the cdc estimates that 80 percent of those 60 years and older have one or more chronic disease associated with deficiencies of this? | blood vessels | respiratory system | cardiovascular system | immune system | Immune System By the year 2050, 25 percent of the population of the United States will be 60 years of age or older. The CDC estimates that 80 percent of those 60 years and older have one or more chronic disease associated with deficiencies of the immune systems. This loss of immune function with age is called immunosenescence. To treat this growing population, medical professionals must better understand the aging process. One major cause of age-related immune deficiencies is thymic involution, the shrinking of the thymus gland that begins at birth, at a rate of about three percent tissue loss per year, and continues until 35–45 years of age, when the rate declines to about one percent loss per year for the rest of one’s life. At that pace, the total loss of thymic epithelial tissue and thymocytes would occur at about 120 years of age. Thus, this age is a theoretical limit to a healthy human lifespan. Thymic involution has been observed in all vertebrate species that have a thymus gland. Animal studies have shown that transplanted thymic grafts between inbred strains of mice involuted according to the age of the donor and not of the recipient, implying the process is genetically programmed. There is evidence that the thymic microenvironment, so vital to the development of naïve T cells, loses thymic epithelial cells according to the decreasing expression of the FOXN1 gene with age. It is also known that thymic involution can be altered by hormone levels. Sex hormones such as estrogen and testosterone enhance involution, and the hormonal changes in pregnant women cause a temporary thymic involution that reverses itself, when the size of the thymus and its hormone levels return to normal, usually after lactation ceases. What does all this tell us? Can we reverse immunosenescence, or at least slow it down? The potential is there for using thymic transplants from younger donors to keep thymic output of naïve T cells high. Gene therapies that target gene expression are also seen as future possibilities. The more we learn through immunosenescence research, the more opportunities there will be to develop therapies, even though these therapies will likely take decades to develop. The ultimate goal is for everyone to live and be healthy longer, but there may be limits to immortality imposed by our genes and hormones. |
Upon death of an organism, during composition, what returns to the soil as ammonium ions? | hydrogen | potasium | calcium | nitrogen | When organisms die and decompose, their nitrogen is returned to the soil as ammonium ions. Nitrifying bacteria change some of the ammonium ions into nitrates. |
Most insects reproduce quickly and through what type of reproduction? | asexual reproduction | spores | photosynthesis | sexual reproduction | Most insects can reproduce very quickly within a short period of time. With a short generation time, they evolve faster and can quickly adjust to environmental changes. Most insects reproduce by sexual reproduction . The female produces eggs, which are fertilized by the male, and then the eggs are usually placed near the required food. In some insects, there is asexual reproduction during which the offspring come from a single parent. In this type of reproduction, the offspring are almost identical to the mother. This is most often seen in aphids and scale insects. |
Digestion of proteins begins with acids in what organ? | brain | colon | liver | stomach | 24.4 Protein Metabolism Digestion of proteins begins in the stomach, where HCl and pepsin begin the process of breaking down proteins into their constituent amino acids. As the chyme enters the small intestine, it mixes with bicarbonate and digestive enzymes. The bicarbonate neutralizes the acidic HCl, and the digestive enzymes break down the proteins into smaller peptides and amino acids. Digestive hormones secretin and CCK are released from the small intestine to aid in digestive processes, and digestive proenzymes are released from the pancreas (trypsinogen and chymotrypsinogen). Enterokinase, an enzyme located in the wall of the small intestine, activates trypsin, which in turn activates chymotrypsin. These enzymes liberate the individual amino acids that are then transported via sodium-amino acid transporters across the intestinal wall into the cell. The amino acids are then transported into the bloodstream for dispersal to the liver and cells throughout the body to be used to create new proteins. When in excess, the amino acids are processed and stored as glucose or ketones. The nitrogen waste that is liberated in this process is converted to urea in the urea acid cycle and eliminated in the urine. In times of starvation, amino acids can be used as an energy source and processed through the Krebs cycle. |
Many species of rotifers exhibit haplodiploidy, which is a method of what? | respiration | circulation | digestion | gender determination | Watch this video (http://openstaxcollege. org/l/rotifers) to see rotifers feeding. Rotifers are pseudocoelomates commonly found in fresh water and some salt water environments throughout the world. Figure 28.17 shows the anatomy of a rotifer belonging to class Bdelloidea. About 2,200 species of rotifers have been identified. Rotifers are dioecious organisms (having either male or female genitalia) and exhibit sexual dimorphism (males and females have different forms). Many species are parthenogenic and exhibit haplodiploidy, a method of gender determination in which a fertilized egg develops into a female and an unfertilized egg develops into a male. In many dioecious species, males are short-lived and smaller with no digestive system and a single testis. Females can produce eggs that are capable of dormancy for protection during harsh environmental conditions. |
What is the most abundant metal of the earth's crust? | magnetite | calcium | copper | aluminum | Metals represent approximately 25% of the elemental makeup of the Earth's crust. The bulk of these metals, primarily aluminum, iron, calcium, sodium, potassium, and magnesium, are typically found in combined form. The most abundant metal is aluminum, which occurs almost exclusively as the ionic mineral bauxite. The other most common metals, including iron, sodium, potassium, magnesium, and calcium, are also found primarily as the cationic portion of an ionic compound. Very few metals actually occur naturally as pure substances. The ones that do are often referred to as precious or semi-precious metals. |
What is the term for the total kinetic energy of moving particles of matter? | Newton's energy | heavy energy | mechanical energy | thermal energy | The total kinetic energy of moving particles of matter is called thermal energy. |
What part of the eye allows light to enter? | iris | eyelid | retina | pupil | Take-Home Experiment: The Pupil Look at the central transparent area of someone’s eye, the pupil, in normal room light. Estimate the diameter of the pupil. Now turn off the lights and darken the room. After a few minutes turn on the lights and promptly estimate the diameter of the pupil. What happens to the pupil as the eye adjusts to the room light? Explain your observations. The eye can detect an impressive amount of detail, considering how small the image is on the retina. To get some idea of how small the image can be, consider the following example. |
The body cannot sustain for very long the bursts of energy mediated by epinephrine and norepinephrine, hormones associated with what stress response? | sink-or-swim | do-or-die | fainting | fight-or-flight | Watch this Discovery Channel animation (http://openstaxcollege. org/l/adrenaline) describing the flight-or-flight response. Long-term Stress Response Long-term stress response differs from short-term stress response. The body cannot sustain the bursts of energy mediated by epinephrine and norepinephrine for long times. Instead, other hormones come into play. In a long-term stress response, the hypothalamus triggers the release of ACTH from the anterior pituitary gland. The adrenal cortex is stimulated by ACTH to release steroid hormones called corticosteroids. Corticosteroids turn on transcription of certain genes in the nuclei of target cells. They change enzyme concentrations in the cytoplasm and affect cellular metabolism. There are two main corticosteroids: glucocorticoids such as cortisol, and mineralocorticoids such as aldosterone. These hormones target the breakdown of fat into fatty acids in the adipose tissue. The fatty acids are released into the bloodstream for other tissues to use for ATP production. The glucocorticoids primarily affect glucose metabolism by stimulating glucose synthesis. Glucocorticoids also have anti-inflammatory properties through inhibition of the immune system. For example, cortisone is used as an anti-inflammatory medication; however, it cannot be used long term as it increases susceptibility to disease due to its immune-suppressing effects. Mineralocorticoids function to regulate ion and water balance of the body. The hormone aldosterone stimulates the reabsorption of water and sodium ions in the kidney, which results in increased blood pressure and volume. Hypersecretion of glucocorticoids can cause a condition known as Cushing’s disease, characterized by a shifting of fat storage areas of the body. This can cause the accumulation of adipose tissue in the face and neck, and excessive glucose in the blood. Hyposecretion of the corticosteroids can cause Addison’s disease, which may result in bronzing of the skin, hypoglycemia, and low electrolyte levels in the blood. |
What system enters the brain stem and influences activity in the cerebellum, spinal cord, and cerebral cortex? | lipids system | vasculature system | ventrical system | vestibular system | 14.2 Central Processing Sensory input to the brain enters through pathways that travel through either the spinal cord (for somatosensory input from the body) or the brain stem (for everything else, except the visual and olfactory systems) to reach the diencephalon. In the diencephalon, sensory pathways reach the thalamus. This is necessary for all sensory systems to reach the cerebral cortex, except for the olfactory system that is directly connected to the frontal and temporal lobes. The two major tracts in the spinal cord, originating from sensory neurons in the dorsal root ganglia, are the dorsal column system and the spinothalamic tract. The major differences between the two are in the type of information that is relayed to the brain and where the tracts decussate. The dorsal column system primarily carries information about touch and proprioception and crosses the midline in the medulla. The spinothalamic tract is primarily responsible for pain and temperature sensation and crosses the midline in the spinal cord at the level at which it enters. The trigeminal nerve adds similar sensation information from the head to these pathways. The auditory pathway passes through multiple nuclei in the brain stem in which additional information is extracted from the basic frequency stimuli processed by the cochlea. Sound localization is made possible through the activity of these brain stem structures. The vestibular system enters the brain stem and influences activity in the cerebellum, spinal cord, and cerebral cortex. The visual pathway segregates information from the two eyes so that one half of the visual field projects to the other side of the brain. Within visual cortical areas, the perception of the stimuli and their location is passed along two streams, one ventral and one dorsal. The ventral visual stream connects to structures in the temporal lobe that are important for long-term memory formation. The dorsal visual stream interacts with the somatosensory cortex in the parietal lobe, and together they can influence the activity in the frontal lobe to generate movements of the body in relation to visual information. |
In what type of animals may a body cavity be present or absent? | nonvascular | vertebrate | bicellular | triploblastic | |
Chemical reactions involve a transfer of heat energy. measured in what? | thermals | amps | amperes | joules | Chemical reactions involve a transfer of heat energy. Measured in joules. |
Trees and shrubs are example of what type of plant? | grasses | biennial | annuals | perennials | |
The products of what process are needed for cellular respiration, and vice versa? | circulation | digestion | spermatogenesis | photosynthesis | Cellular respiration and photosynthesis are like two sides of the same coin. This is clear from the diagram in Figure below . The products of photosynthesis are needed for cellular respiration. The products of cellular respiration are needed for photosynthesis. Together, the two processes store and release energy in virtually all living things. |
Most fungi get organic compounds from what? | carnivorous organisms | inorganic material | living organisms | dead organisms | Most fungi get organic compounds from dead organisms. They are decomposers called saprotrophs. A saprotroph feeds on any remaining organic matter after other decomposers do their work. Fungi use enzymes to digest organic remains and then absorb the resulting organic compounds. As decomposers, fungi are vital for the health of ecosystems. They break down nonliving organic matter and release the nutrients into the soil. Plants can then use the nutrients and pass them on to herbivores and other consumers. |
How do very massive stars end their lives? | consumed by black hole | become super novas | explode | become red supergiants | A more massive star ends its life in a more dramatic way. Very massive stars become red supergiants . Unlike a red giant, when all the helium in a red supergiant is gone, fusion continues. Lighter atoms fuse into heavier atoms up to iron atoms. Creating elements heavier than iron through fusion uses more energy than it produces. For this reason, stars do not ordinarily form any heavier elements. When there are no more elements for the star to fuse, the core succumbs to gravity and collapses. |
Pairs of nitrogenous bases are attached to each other by? | magnetism | potassium bonds | ionic bonds | hydrogen bonds | |
Rupture can cause fragments of what to travel via the bloodstream and become lodged in other arteries? | white blood cells | enamel | red blood cells | plaque | |
The strength of a base depends on the concentration of _______ it produces when dissolved in water? | monoxide ions | combustion ions | calcium ions | hydroxide ions | The strength of a base depends on the concentration of hydroxide ions it produces when dissolved in water. For example, sodium hydroxide completely breaks down into ions in water, so it is a strong base. However, only a fraction of ammonia breaks down into ions, so it is a weak base. |
The overall voltage of the battery is therefore the sum of ________ of the individual cells. | weights | currents | resistances | voltages | Batteries There are two basic kinds of batteries: disposable, or primary, batteries, in which the electrode reactions are effectively irreversible and which cannot be recharged; andrechargeable, or secondary, batteries, which form an insoluble product that adheres to the electrodes. These batteries can be recharged by applying an electrical potential in the reverse direction. The recharging process temporarily converts a rechargeable battery from a galvanic cell to an electrolytic cell. Batteries are cleverly engineered devices that are based on the same fundamental laws as galvanic cells. The major difference between batteries and the galvanic cells we have previously described is that commercial batteries use solids or pastes rather than solutions as reactants to maximize the electrical output per unit mass. The use of highly concentrated or solid reactants has another beneficial effect: the concentrations of the reactants and the products do not change greatly as the battery is discharged; consequently, the output voltage remains remarkably constant during the discharge process. This behavior is in contrast to that of the Zn/Cu cell, whose output decreases logarithmically as the reaction proceeds (Figure 19.11 "The Variation of "). When a battery consists of more than one galvanic cell, the cells are usually connected in series—that is, with the positive (+) terminal of one cell connected to the negative (−) terminal of the next, and so forth. The overall voltage of the battery is therefore the sum of the voltages of the individual cells. |
Organisms that live deep in the ocean must be able to withstand what? | tsunamis | the sun | significant water pressure | extreme water pressure | Organisms that live deep in the ocean must be able to withstand extreme water pressure, very cold water, and complete darkness. However, even here, thriving communities of living things can be found. Organisms cluster around hydrothermal vents in the ocean floor. The vents release hot water containing chemicals that would be toxic to most other living things. The producers among them are single-celled chemoautotrophs. They make food using energy stored in the chemicals. The tube worms in this chapter's opening photo depend on these chemoautotrophs for food. |
Which system are the brain and spinal cord apart of? | limbic system | large nervous system | cerebral cortex | central nervous system | The central nervous system includes the brain and spinal cord. The brain serves as the control center of the nervous system and the body as a whole. It consists of three major parts: the cerebrum, cerebellum, and brain stem. The spinal cord carries nerve impulses back and forth between the body and brain. |
What are biochemical catalysts that speed up biochemical reactions? | polymers | inhibitor | metabolites | enzymes | Enzymes are biochemical catalysts that speed up biochemical reactions. Without enzymes, most chemical reactions in living things would occur too slowly to keep organisms alive. |
What process can cause harmful alleles to become fixed? | mutation | natural selection | migration | genetic drift | |
What record shows that dinosaurs originated 200-250 million years ago? | species record | ancient record | biological record | fossil record | |
What instrument is used to make very sensitive mass measurements in a laboratory, usually in grams? | scale | speedometer | thermometer | analytical balance | An analytical balance makes very sensitive mass measurements in a laboratory, usually in grams. |
What is the purpose of bright colors on a flower's petals? | to attract a mate | to distract predators | to absorb light | to attract pollinators | Flowers Flowers are modified leaves, or sporophylls, organized around a central stalk. Although they vary greatly in appearance, all flowers contain the same structures: sepals, petals, carpels, and stamens. The peduncle attaches the flower to the plant. A whorl of sepals (collectively called the calyx) is located at the base of the peduncle and encloses the unopened floral bud. Sepals are usually photosynthetic organs, although there are some exceptions. For example, the corolla in lilies and tulips consists of three sepals and three petals that look virtually identical. Petals, collectively the corolla, are located inside the whorl of sepals and often display vivid colors to attract pollinators. Flowers pollinated by wind are usually small, feathery, and visually inconspicuous. Sepals and petals together form the perianth. The sexual organs (carpels and stamens) are located at the center of the flower. As illustrated in Figure 26.14, styles, stigmas, and ovules constitute the female organ: the gynoecium or carpel. Flower structure is very diverse, and carpels may be singular, multiple, or fused. Multiple fused carpels comprise a pistil. The megaspores and the female gametophytes are produced and protected by the thick tissues of the carpel. A long, thin structure called a style leads from the sticky stigma, where pollen is deposited, to the ovary, enclosed in the carpel. The ovary houses one or more ovules, each of which will develop into a seed upon fertilization. The male reproductive organs, the stamens (collectively called the androecium), surround the central carpel. Stamens are composed of a thin stalk called a filament and a sac-like structure called the anther. The filament supports the anther, where the microspores are produced by meiosis and develop into pollen grains. |
Collateral ganglia controls organs in which cavity in the body? | cardiac | cranial | pelvic | abdominal | To continue with the analogy of the circuit diagram, there are three different types of “junctions” that operate within the sympathetic system (Figure 15.3). The first type is most direct: the sympathetic nerve projects to the chain ganglion at the same level as the target effector (the organ, tissue, or gland to be innervated). An example of this type is spinal nerve T1 that synapses with the T1 chain ganglion to innervate the trachea. The fibers of this branch are called white rami communicantes (singular = ramus communicans); they are myelinated and therefore referred to as white (see Figure 15.3a). The axon from the central neuron (the preganglionic fiber shown as a solid line) synapses with the ganglionic neuron (with the postganglionic fiber shown as a dashed line). This neuron then projects to a target effector—in this case, the trachea—via gray rami communicantes, which are unmyelinated axons. In some cases, the target effectors are located superior or inferior to the spinal segment at which the preganglionic fiber emerges. With respect to the “wiring” involved, the synapse with the ganglionic neuron occurs at chain ganglia superior or inferior to the location of the central neuron. An example of this is spinal nerve T1 that innervates the eye. The spinal nerve tracks up through the chain until it reaches the superior cervical ganglion, where it synapses with the postganglionic neuron (see Figure 15.3b). The cervical ganglia are referred to as paravertebral ganglia, given their location adjacent to prevertebral ganglia in the sympathetic chain. Not all axons from the central neurons terminate in the chain ganglia. Additional branches from the ventral nerve root continue through the chain and on to one of the collateral ganglia as the greater splanchnic nerve or lesser splanchnic nerve. For example, the greater splanchnic nerve at the level of T5 synapses with a collateral ganglion outside the chain before making the connection to the postganglionic nerves that innervate the stomach (see Figure 15.3c). Collateral ganglia, also called prevertebral ganglia, are situated anterior to the vertebral column and receive inputs from splanchnic nerves as well as central sympathetic neurons. They are associated with controlling organs in the abdominal cavity, and are also considered part of the enteric nervous system. The three collateral ganglia are the celiac ganglion, the superior mesenteric ganglion, and the inferior mesenteric ganglion (see Figure 15.2). The word celiac is derived from the Latin word “coelom,” which refers to a body cavity (in this case, the abdominal cavity), and the word mesenteric refers to the digestive system. |
A bee will sometimes do a dance to tell other bees in the hive where to find what? | honey | enemies | water | food | There are many other examples of innate behaviors. For example, did you know that honeybees dance? The honeybee pictured below has found a source of food ( Figure below ). When the bee returns to its hive, it will do a dance. This dance is called the waggle dance . The way the bee moves during its dance tells other bees in the hive where to find the food. Honeybees can do the waggle dance without learning it from other bees, so it is an innate behavior. |
The lens focuses light on the retina , which covers the back of the inside of the eye. the retina has light-sensing photoreceptor cells called? | tubes and rods | cones and tubes | holes and cones | rods and cones | The lens focuses light on the retina , which covers the back of the inside of the eye. The retina has light-sensing photoreceptor cells called rods and cones. Rods let us see in dim light. Cones let us detect light of different colors. |
Temperature, water, soil, and air are examples of nonliving factors of an ecosystem, also termed what? | diverse factors | nucleic factors | conditional factors | abiotic factors | Ecology is the study of ecosystems. That is, ecology is the study of how living organisms interact with each other and with the nonliving part of their environment. An ecosystem consists of all the nonliving factors and living organisms interacting in the same habitat . Recall that living organisms are biotic factors . The biotic factors of an ecosystem include all the populations in a habitat, such as all the species of plants, animals, and fungi, as well as all the micro-organisms. Also recall that the nonliving factors are called abiotic factors . Abiotic factors include temperature, water, soil, and air. |
Ibuprofen and albuterol are examples of drugs whose _________ have different effects. | analogous | nanoparticles | misnomers | enantiomers | |
Although magma once filled our moon's craters, what is thought to have ended there over a billion years ago? | deserts activity | mineral activity | oceanic activity | volcanic activity | When you look at the Moon from Earth, you notice dark and light areas. The maria are dark, solid, flat areas of lava (mostly basalt). Maria covers around 16% of the Moon’s surface, mostly on the near side. The maria formed about 3.0 to 4.0 billion years ago, when the Moon was continually bombarded by meteoroids ( Figure below ). Large meteorites broke through the Moon’s newly formed surface. This eventually caused magma to flow out and fill the craters. Scientists estimate volcanic activity on the Moon ended about 1.2 billion years ago. |
Sensory nerves carry nerve impulses from sensory receptors to what system? | IRCULATORY SYSTEM | MUSCULAR SYSTEM | ENDOCRINE SYSTEM | central nervous | Human senses include sight, hearing, balance, taste, smell, and touch. Sensory organs such as the eyes contain cells called sensory receptors that respond to particular sensory stimuli. Sensory nerves carry nerve impulses from sensory receptors to the central nervous system. The brain interprets the nerve impulses to form a response. |
Which kind of muscle regulates air flow in lungs? | alveoli | vascular | striated | smooth | Smooth muscle regulates air flow in lungs. |
What type of bonds are formed by the side-to-side overlap of p orbitals? | theta bonds | sigma bonds | omega bonds | pi bonds | Sigma bonds are formed by the end-to-end overlap of bonding orbitals. Pi bonds are formed by the side-to-side overlap of p orbitals. Single bonds are normally sigma bonds. A double or triple bond consists of one sigma bond and either one or two pi bonds. |
On what day of the cycle does ovulation usually occur? | 1st | 17th | 7th | 14th | After menstruation, the endometrium begins to build up again. At the same time, a follicle starts maturing in an ovary. Ovulation occurs around day 14 of the cycle. After it occurs, the endometrium continues to build up in preparation for a fertilized egg. What happens next depends on whether the egg is fertilized. |
The majority of animals belong to what category, characterized by the lack of a backbone? | arthropod | vertebrate | nematode | invertebrate | The majority of living animals are invertebrates. Invertebrates lack a backbone. |
What is another name for the vertebral column? | brain stem | nerve column | pillar | backbone | animal in Phylum Chordata that has a vertebral column, or backbone. |
The temperature at which a substance melts is called its what point? | freezing | boiling | change | melting | The temperature at which a substance melts is called its melting point. Melting point is a physical property of matter. The gold pictured in the Figure above , for example, has a melting point of 1064°C. This is a high melting point, and most other metals also have high melting points. The melting point of ice, in comparison, is much lower at 0°C. Many substances have even lower melting points. For example, the melting point of oxygen is -222°C. |
Oogenesis, which is gametogenesis in females, begins with what type of ste cells? | uterian | secretion | digestive | ovarian | Oogenesis Gametogenesis in females is called oogenesis. The process begins with the ovarian stem cells, or oogonia (Figure 27.11). Oogonia are formed during fetal development, and divide via mitosis, much like spermatogonia in the testis. Unlike spermatogonia, however, oogonia form primary oocytes in the fetal ovary prior to birth. These primary oocytes are then arrested in this stage of meiosis I, only to resume it years later, beginning at puberty and continuing until the woman is near menopause (the cessation of a woman’s reproductive functions). The number of primary oocytes present in the ovaries declines from one to two million in an infant, to approximately 400,000 at puberty, to zero by the end of menopause. The initiation of ovulation—the release of an oocyte from the ovary—marks the transition from puberty into reproductive maturity for women. From then on, throughout a woman’s reproductive years, ovulation occurs approximately once every 28 days. Just prior to ovulation, a surge of luteinizing hormone triggers the resumption of meiosis in a primary oocyte. This initiates the transition from primary to secondary oocyte. However, as you can see in Figure 27.11, this cell division does not result in two identical cells. Instead, the cytoplasm is divided unequally, and one daughter cell is much larger than the other. This larger cell, the secondary oocyte, eventually leaves the ovary during ovulation. The smaller cell, called the first polar body, may or may not complete meiosis and produce second polar bodies; in either case, it eventually disintegrates. Therefore, even though oogenesis produces up to four cells, only one survives. |
Humans are among the most versatile of mammals with what type of diet? | vegetarian | carnivore | herbivore | omnivore | |
Solute potential is also called osmotic potential because solutes affect the direction of what? | electrolysis | permeability | electrolysis | osmosis | |
Newton’s second law of what is more than a definition; it is a relationship among acceleration, force, and mass? | interference | gravity | change | motion | 9.80 m/s 2 . When we say that an acceleration is 45 g 's, it is 45×9.80 m/s 2 , which is approximately 440 m/s 2 . ) While living subjects are not used any more, land speeds of 10,000 km/h have been obtained with rocket sleds. In this example, as in the preceding one, the system of interest is obvious. We will see in later examples that choosing the system of interest is crucial—and the choice is not always obvious. Newton’s second law of motion is more than a definition; it is a relationship among acceleration, force, and mass. It can help us make predictions. Each of those physical quantities can be defined independently, so the second law tells us something basic and universal about nature. The next section introduces the third and final law of motion. |
What is the physical transformation of an insect moving through stages of life? | parthenogenesis | Transition | Growth and Development | metamorphosis | With a few exceptions, all insect life begins as an egg. After leaving the egg, insects must grow and transform until reaching adulthood. Only the adult insect can mate and reproduce. The physical transformation of an insect from one stage of its life cycle to another is known as metamorphosis . |
When equal amounts of a strong acid such as hydrochloric acid are mixed with a strong base such as sodium hydroxide, the result is what kind of solution? | a thermodynamic one | a economical one | a lateral one | a neutral one | When equal amounts of a strong acid such as hydrochloric acid are mixed with a strong base such as sodium hydroxide, the result is a neutral solution. The products of the reaction do not have the characteristics of either an acid or a base. Here is the balanced molecular equation. |
What are fast moving rivers of air that are going in opposite directions called? | burst streams | air streams | cause streams | jet streams | Jet streams are fast moving rivers of air going in opposite directions. |
Nephrons, renal tubules and the loop of henle are part of the process of blood filtration by what organs? | liver | bladder | lungs | kidneys | Kidney Function and Physiology Kidneys filter blood in a three-step process. First, the nephrons filter blood that runs through the capillary network in the glomerulus. Almost all solutes, except for proteins, are filtered out into the glomerulus by a process called glomerular filtration. Second, the filtrate is collected in the renal tubules. Most of the solutes get reabsorbed in the PCT by a process called tubular reabsorption. In the loop of Henle, the filtrate continues to exchange solutes and water with the renal medulla and the peritubular capillary network. Water is also reabsorbed during this step. Then, additional solutes and wastes are secreted into the kidney tubules during tubular secretion, which is, in essence, the opposite process to tubular reabsorption. The collecting ducts collect filtrate coming from the nephrons and fuse in the medullary papillae. From here, the papillae deliver the filtrate, now called urine, into the minor calyces that eventually connect to the ureters through the renal pelvis. This entire process is illustrated in Figure 41.7. |
Fungi, such as black bread mold (rhizopus nigricans), have haploid-dominant what? | mutations | birth cycles | gene pools | life cycles | Figure 11.9 Fungi, such as black bread mold (Rhizopus nigricans), have haploid-dominant life cycles. The haploid multicellular stage produces specialized haploid cells by mitosis that fuse to form a diploid zygote. The zygote undergoes meiosis to produce haploid spores. Each spore gives rise to a multicellular haploid organism by mitosis. (credit “zygomycota” micrograph: modification of work by “Fanaberka”/Wikimedia Commons). |
The electrode at which oxidation occurs is called? | calomel | diode | cathode | the anode | The electrode at which oxidation occurs is called the anode . The zinc anode gradually diminishes as the cell operates due to the loss of zinc metal. The zinc ion concentration in the half-cell increases. Because of the production of electrons at the anode, it is labeled as the negative electrode. |
There are about 6200 known species of what? | reptiles | primates | mammals | amphibians | |
The lens and other parts of the eye work together to focus a real image on what eye structure? | cornea | iris | pupil | retina | As just described, the eyes collect and focus visible light. The lens and other structures of the eye work together to focus a real image on the retina. The image is upside-down and reduced in size, as you can see in Figure below . The image reaches the brain as electrical signals that travel through the optic nerve. The brain interprets the signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see is always right-side up. The brain also “tells” us what we are seeing. |
What is required to move or change matter from one state to another? | evolution | food | gravity | energy | Energy provides the ability to move or change matter from one state to another (for example, from solid to liquid). Every living thing needs energy to live and grow. Your body gets its energy from food, but that is only a small part of the energy you use every day. Cooking your food takes energy, and so does keeping it cold in the refrigerator or the freezer. The same is true for heating or cooling your home. Whether you are turning on a light in the kitchen or riding in a car to school, you are using energy. Billions of people all around the world use energy, so there is a huge demand for resources to provide all of this energy. Why do we need so much energy? The main reason is that almost everything that happens on Earth involves energy. |
A food web can be broken up into what further subdivision that usually has a few links in it? | water chain | food pyramid | oxygen chain | food chain | |
What living species of bird is considered the largest of the raptors? | pteradactyl | California condor | peregrine falcon | golden eagles | Although not as famous as its bald cousin, Golden Eagles are much easier to find in Northern California - one of the largest breeding populations for Golden Eagles. The largest of the raptors, Golden Eagles weigh typically between 8 and 12 pounds, and their wing span is around 6 to 7 feet. These eagles dive towards earth to catch prey, and can reach speeds of up to 200 mph! Meet one of the largest birds of prey at http://www. kqed. org/quest/television/cool-critters-the-golden-eagle . |
What contains positive protons and neutral neutrons? | epidermis | electrons | ions | nucleus | The nucleus is at the center of the atom. It contains positive protons and neutral neutrons. Negative electrons constantly move about the nucleus. |
Horny ridges on the jaws serve the same function as what, for turtles? | hairs | skin | taste buds | teeth | Turtles may appear slow and harmless when they are out of the water, but in the water is another story. Turtles can be either herbivores or carnivores, with most sea turtles carnivorous . Turtles have a rigid beak and use their jaws to cut and chew food. Instead of teeth, the upper and lower jaws of the turtle are covered by horny ridges. Carnivorous, or animal-eating turtles usually have knife-sharp ridges for slicing through their prey. But as the turtle is not a very fast animal, and it cannot quickly turn its head to snap at prey, it does have some limitations. Sea turtles typically feed on jellyfish, sponges and other soft-bodied organisms. Some species of sea turtle with stronger jaws eat shellfish, while other species, such as the green sea turtle, do not eat any meat at all. Herbivorous turtles have serrated ridges that help them cut through tough plants. |
Natural gas is the predominately made up of? | sulfur | hydrogen | carbon | methane | Natural gas is mostly methane. Natural gas is usually found with petroleum. People prefer to burn natural gas when possible because it is relatively clean. |
Which organs control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine? | ears | lungs | tongue | kidneys | The kidneys play many vital roles in homeostasis. They filter all the blood in the body many times each day and produce a total of about 1.5 liters of urine. The kidneys control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine. The kidneys also secrete hormones that help maintain homeostasis. Erythropoietin, for example, is a kidney hormone that stimulates bone marrow to produce red blood cells when more are needed. The kidneys themselves are also regulated by hormones. For example, antidiuretic hormone from the hypothalamus stimulates the kidneys to produce more concentrated urine when the body is low on water. |
What unit of measurement is defined to be the number of atoms in 12g of carbon-12? | one ohm | one quark | one joule | one mole | The relative scale of atomic masses in amu is also a relative scale of masses in grams. We said before that the mole is officially equal to the number of carbon atoms in exactly 12 g of carbon-12. In other words, one carbon-12 atom has a mass of exactly 12 amu, and one mole of carbon atoms has a mass of exactly 12 grams. This relationship is true for all substances. If one atom of helium has a mass of 4.00 amu, one mole of helium atoms has a mass of 4.00 g. One molecule of water has a mass of 18.0 amu, so one mole of water molecules has a mass of 18.0 grams. Molar mass is defined as the mass of one mole of representative particles of a substance. It is expressed in units of grams per mole (g/mol). |
What involves sensing and focusing light from people and objects? | projection | echolocation | sensory perception | vision | Vision involves sensing and focusing light from people and objects. The steps involved are as follows:. |
What is a therian mammal in which the embryo is born at an early, immature stage? | carnivore | rodent | bat | a marsupial | Marsupials have a different way of reproducing that reduces the mother’s risks. A marsupial is a therian mammal in which the embryo is born at an early, immature stage. The embryo completes its development outside the mother’s body in a pouch on her belly. Only a minority of therian mammals are marsupials. They live mainly in Australia. Examples of marsupials are pictured in Figure below . |
What are fungi which feed on living cells called? | symbiotic | static | predatory | parasitic | 23.24 Nutrition Fungi are saprophytes. When they find a source of food (e. dead wood, orange peel) , they decompose it and digest it. The enzymes break down larger organic molecules in the substrate into smaller molecules. These smaller molecules diffuse into the fungus, where they are used to allow growth and repair. Fungi which feed on living cells are parasitic. For example, athlete's foot grows on the human foot. These kinds of fungi produce hyphae called haustoria, which can penetrate host cells without immediately killing them. However, they are friendlier species of fungi. Many fungi live symbiotically with plants or animals. For example, most trees have fungi living in close contact with their roots. In this relationship, known as a mycorrhiza, there are many benefits: • Growing around the plant roots and often entering plant cells, the hyphae absorb minerals from the soil and release them in the roots. The fungi gets its source of food (organic nutrients) while delivering food to the plant. • The mycelium here would increase the surface area, thus the absorptive surface, of the plant roots. • The fungal cells help to maintain air and water flow in the soil around the roots. • The fungi may prevent other potentially pathogenic fungi to attack the tree. |
What rock group offers the richest source of fossils? | geode | metamorphic | igneous | sedimentary | |
What is the diffusion of water through a semipermeable membrane down its concentration gradient | Permable | nutrients | mirrors | osmosis | Figure 3.7 Osmosis Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic. |
Isotopes are named for their number of protons plus what? | nuclei | isomers | electrons | neutrons | Isotopes are named for their number of protons plus neutrons. If a carbon atom had seven neutrons, what would it be named?. |
Movements in the mantle cause the plates to move over time in a process called what? | boundary drift | continental expansion | continental shift | continental drift | |
In phyisics, what is considered to be the rotational version of force? | pressure | work | energy | torque | Torque is equal to the cross product as stated above. In general, one can simplify by saying that the torque is equal to the force acting on the object multiplied by the perpendicular distance from the application of the force to the rotational axis. Say you had a seesaw. It is easier to exert torque, get the seesaw to move, if you pushed on the board near the end rather than near the middle. It is the rotational version of Force. |
Skeletal muscles are attached to the skeleton by tough connective tissues called what? | cords | fibers | veins | tendons | Skeletal muscles are attached to the skeleton by tough connective tissues called tendons (see Figure above ). Many skeletal muscles are attached to the ends of bones that meet at a joint . The muscles span the joint and connect the bones. When the muscles contract, they pull on the bones, causing them to move. |
What is the ability to see called? | hearing | thought | smell | vision | The ability to see is called vision . This ability depends on more than healthy eyes. It also depends on certain parts of the brain, because the brain and eyes work together to allow us to see. The eyes collect and focus visible light. The lens and other structures of the eye work together to focus an image on the retina. The image is upside-down and reduced in size, as you can see in the Figure below . Cells in the retina change the image to electrical signals that travel to the brain through the optic nerve. The brain interprets the electrical signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see always appears right-side up. The brain also interprets what we are seeing. |
Which two major innovations allowed seed plants to reproduce in the absence of water? | salt and pollen | bee and pollen | root and pollen | seed and pollen | CHAPTER SUMMARY 26.1 Evolution of Seed Plants Seed plants appeared about one million years ago, during the Carboniferous period. Two major innovations—seed and pollen—allowed seed plants to reproduce in the absence of water. The gametophytes of seed plants shrank, while the sporophytes became prominent structures and the diploid stage became the longest phase of the lifecycle. Gymnosperms became the dominant group during the Triassic. In these, pollen grains and seeds protect against desiccation. The seed, unlike a spore, is a diploid embryo surrounded by storage tissue and protective layers. It is equipped to delay germination until growth conditions are optimal. Angiosperms bear both flowers and fruit. The structures protect the gametes and the embryo during its development. Angiosperms appeared during the Mesozoic era and have become the dominant plant life in terrestrial habitats. |
Water can be broken down into hydrogen and oxygen gases by the addition of what? | demand | motion | mineral | energy | Chemistry in Everyday Life Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15). |
What anatomical feature is shared by all chordates? | laxchord | isochord | botachord | notochord | Did you know that fish, amphibians, reptiles, birds, and mammals are all related? They are all chordates. Chordates are a group of animals that includes vertebrates, as well as several closely related invertebrates. Chordates (phylum Chordata ) are named after a feature they all share, a notochord. A notochord is a hollow nerve cord along the back. |
With wavelengths from 400-700 nm, what kind of light represents only a very small portion of the spectrum? | ultraviolet light | invisible light | sunlight | visible light | The electromagnetic spectrum encompasses a very wide range of wavelengths and frequencies. Visible light is only a very small portion of the spectrum with wavelengths from 400-700 nm. |
In humans, the only haploid cells are what reproductive cells? | uteral and sperm | dna and egg | sperm and dna | sperm and egg | The life cycle of a plant is very different from the life cycle of an animal. Humans are made entirely of diploid cells (cells with two sets of chromosomes, referred to as ''2n''). Our only cells that are haploid cells (cells with one set of chromosomes, ''n'') are sperm and egg cells. Plants, however, can live when they are are at the stage of having haploid cells or diploid cells. If a plant has a haploid chromosome number of 20, what is the diploid chromosome number? If the diploid chromosome number is 20, what is the haploid number?. |