praxis gen science

Jar 1: Open to air Jar 2: Opening of jar tightly closed Jar 3: Opening of jar covered with fine mesh In an attempt to disprove the belief that living things, such as maggots, can originate spontaneously from decaying meat, fresh meat was placed in jars as shown above. The hypothesis that flies are the source of maggots that appear on decaying meat would best be supported if maggots are later found in which jar?

"Maggot" is the common name for the larvae of certain species of flies, in particular, those that lay their eggs on fresh meat or carrion. Since flies would not be able to enter jars 2 or 3 to lay eggs on the meat, maggots would be expected to be found only in jar 1. Francesco Redi conducted this experiment in the seventeenth century, thus disproving the theory of spontaneous generation. Jar 1

The pHp H of a 0.001 M KOH solution is approximately

11

Which of the following solutions is most resistant to a change in pH when a small amount of an acid or a base is added?

A buffer solution is a solution that is resistant to changes in pH when a small amount of an acid or base is added. Buffer solutions are commonly prepared by mixing equal amounts of a weak acid and a soluble salt of its conjugate base as in (C). 0.1 M HC2H3O2 and 0.1 M NaC2H3O2

p53 is a tumor-suppressor gene that helps to control cell division and is often mutated in certain skin cancers. Which of the following is most likely true of skin cells with a p53 mutation?

A common characteristic of tumor cells is that they divide more rapidly than normal cells. This is because a DNA mutation shortens the length of time the cells spend in interphase, and particularly in the G1G one phase of interphase. In normal cells, the p53 gene is activated when a DNA mutation is detected, which is why the gene is referred to as a tumor-suppressor gene. The protein encoded by the p53 gene causes production of another protein that blocks the interaction of S cyclins with cyclin-dependent kinases, an interaction that is required for DNA replication and ultimately cell division. If the p53 gene is mutated, the interaction of S cyclins with cyclin-dependent kinases cannot be blocked and the abnormal cells will continue to replicate their mutated DNA and to divide The cell cycle is shorter in length than in normal skin cells

Which of the following is an example of a parasitic relationship?

A parasitic relationship is one in which one organism benefits and the other is harmed. The ticks obtain nourishment from the blood they suck from the deer. The deer may be harmed if it loses too much blood, if too many ticks are attached, or if it contracts an infection from the ticks. Ticks attached to a white-tailed deer

Which TWO of the following are appropriate laboratory safety standards?

A safety shower must be located within 10 seconds of the work area in case of exposure to injurious corrosive materials. Closed-toe shoes should always be worn as a barrier to chemical and physical injury. Prescription glasses do not provide sufficient protection against splashes or impact hazards. Short pants do not protect against chemical contact hazards. 1. An emergency shower is located within a travel time of 10 seconds. 2. Closed-toe shoes should always be worn

True statements about simple machines include which THREE of the following?

A simple machine does make work easier (e.g., by reducing the force that has to be exerted to perform a task), and a simple machine can change the magnitude or direction of a force. The mechanical advantage of a simple machine is defined as the amount by which the machine multiplies the input force and is essentially a measure of how much effort is saved by using the machine. A simple machine never changes the total amount of work required to perform a task; the total work done is the same. 1. simple machine makes the work required to perform a task easier. 2. .A simple machine can change the magnitude or direction of a force. 3. The mechanical advantage of a simple machine is the amount by which the machine multiplies the input force

Based on the graph above of a vehicle's progress along a highway, which of the following is true for the car? (question 29)

A straight line on a speed-versus-time graph represents constant acceleration, and the slope of the straight line gives the acceleration of the vehicle. The steeper the slope is, the greater the magnitude of the acceleration. The steepest slope occurs during the first 5 minutes of motion. It has the highest acceleration in the time interval 0-5 minutes

The distance between the adjacent nodes of a one-dimensional standing wave is 0.500 mzero point five zero zero meter. If the frequency of the wave is 100.0 Hz100 point zero hertz, then the speed of the wave is

A wavelength is the distance between wave crests for a traveling wave, or twice the distance between adjacent nodes for a standing wave. Thus the wavelength is 1.000 m. The speed of the wave is equal to the frequency times the wavelength v=fλv=fλ = 100.0 Hz × 1.000 m = 100.0 m/s 100.0 m/s

For which of the following positive charges, separated by the distances shown, will the electrostatic force of repulsion be smallest? (question 30)

According to Coulomb's law, the electrostatic force F between two charges q1 and q2 is directly proportional to the product of the charges and inversely proportional to the square of the distance r between the charges; that is F= k q1q2/r^2 where k is constant.

The spring shown above stretches 3 cm3 centimeters when a mass of 4 kg4 kilograms is suspended from it. How far would this spring stretch if a 12 kg12 kilograms mass were suspended from the spring in place of the 4 kg4 kilograms mass? (Assume that the elastic limit is not reached.) (ques 29)

According to Hooke's law, the displacement of the spring from its equilibrium position depends linearly upon the stretching force. Thus increasing the force on the spring by a factor of three will increase the stretch of the spring by a factor of three. 9 cm

2 H2O(l) → 2 H2(g) + O2(g) If 9 g of H2O decomposes according to the reaction shown above, how many moles of hydrogen gas are produced?

According to the balanced equation, 2 moles of H2O decompose to give 2 moles of H2. Since 9 g H2O × (1 mol H2O/18 g H2O) = 0.5 mol H2O, then 0.5 mol H2O× (2 mol H2/2 mol H2O) = 0.5 moles of hydrogen gas produced 0.5 mol

The number of sunspots on the surface of the Sun increases and decreases over an 11-year period called the solar cycle. The graph above shows how the number of sunspots varied over 50 years. When will the next minimum and the next maximum in the number of sunspots most likely occur? (question 11)

According to the graph, there was a minimum number of sunspots in 1996 and a maximum in 2000. Adding 11, the number of years in the solar cycle, to those years would approximate when the next minimum and maximum would be most likely to occur, in 2007 and 2011, respectively Min: 2007 Max: 2011

The four diagrams above represent a cylinder with a movable, frictionless piston as seen during four different experiments. The external pressure, shown by the arrows, is the same in all four experiments. Contained in each cylinder is a sample of an ideal gas. The small spheres represent the relative number of molecules present in the cylinder during the different experiments. Which of the cylinders contains the gas with the lowest absolute temperature? (ques 50)

According to the ideal gas law, T = PV/nRT equals, where T is the temperature, P is the pressure, V is the volume of gas, n is the number of moles of gas, and R is the ideal gas constant. Since P and R are constants, the relative temperatures can be compared using the ratio of V/nV over n. Cylinder IV has the smallest volume of gas and the greatest relative number of molecules, therefore it has the lowest absolute temperature. IV

When a log burns in a fireplace, producing ash and smoke, which of the following is true?

According to the law of conservation of matter, the total mass of the products is equal to the total mass of the reactants consumed in the reaction. The law of conservation of energy states that the total energy of an isolated system remains constant. During the burning of a log, some chemical energy is converted to thermal energy and light energy and the total energy of the system is constant Energy and matter are both conserved

In eukaryotic cells, which of the following provides energy for the active transport of ions across the plasma membrane?

Active transport refers to moving a substance such as an ion against its gradient (often a concentration gradient), from lower to higher. This requires a source of energy. In eukaryotic cells, as ATP is hydrolyzed to ADP + Pi energy is released. Cells obtain the energy to initially synthesize ATP through metabolism of foods such as sugar. ATP is formed through the pathways of glycolysis and the Krebs cycle but especially as a consequence of energy transfers during redox reactions along electron transport chains in the mitochondria. Mitochondria use the energy in sugars to synthesize ATP

In a chain of islands, closely related bird species occupy different islands. The species share a common ancestor that inhabits the mainland. Which of the following was the most likely mechanism of speciation?

Adaptive radiation is the process by which a population from an ancestral species relocates to a new environment, occupying a variety of niches. Each niche has different selective pressures, leading to the emergence of new species. Adaptive radiation

An alkaline battery converts which of the following forms of energy into electrical energy?

An alkaline battery consists of two electrodes (the anode and the cathode) separated by an alkaline electrolyte, such as KOHK O H. Oxidation and reduction reactions occur at the anode and cathode, respectively, producing a current. Thus, chemical energy is converted into electrical energy. Chemical

On the basis of the phase diagram for carbon dioxide above, which of the following will happen if a sample of carbon dioxide (dry ice) at 5 atm and -100ºC is put into a chamber that is at 1 atm and -15°C? (ques 59)

At 1 atm and -15°C, the most stable state of carbon dioxide is a gas. A line drawn from the initial conditions of 5 atm and-100°C to the final conditions at 1 atm and -15°C does not pass through the region of the phase diagram corresponding to the liquid phase. Therefore, the sample of solid CO2 vaporizes (sublimates) without melting. It will immediately begin to vaporize.

ΔG = ΔH − TΔS The change in Gibbs energy for a reaction at constant temperature is given by the equation above. For an endothermic reaction with ΔH = +20,000 J (change in enthalpy equals positive 20,000 joules) and ΔS = +100 J/K (change in entropy equals positive 100 joules per kelvin), which of the following is true about the reaction?

At temperatures greater than 200 K (T > 200 K) TΔS > 20,000 J and ΔG < 0. If ΔG < is less than zero, a reaction is spontaneous. It is spontaneous at temperatures above 200 K200 kelvins only

Based on positions of elements in the periodic table, which of the following compounds is most likely to exist?

BaCl2 is most likely to exist based on periodic trends in chemical reactivity. Barium is in group 2 in the periodic table and loses its two valence electrons to form Ba2+ions. Chlorine is in group 17 in the periodic table and gains an electron to form Cl- ions. BaCl2 is an ionic compound composed of Ba2+ and Cl- ions BaCl2

10 kg10 kilogram cart is rolling along the surface shown in the figure above. What is the minimum kinetic energy of the cart at the base of the hill if it is going to be able to roll to the top of the upper level (assume g = 10 m/s2)> (ques 35)

By energy conservation, the sum of the cart's kinetic energy and potential energy is a constant (assuming negligible energy loss due to friction and air resistance). As the cart moves up the hill, its kinetic energy will decrease and its potential energy will increase. If the cart just reaches the top of the hill, then the cart will be at rest at the top of the hill and will have only potential energy at that point; that is, its initial kinetic energy at the base of the hill will have been converted entirely into potential energy at the top of the hill. Thus the minimum kinetic energy of the cart is equal to 10 kg × 10 m/s2 × 4.0 m = 400 joules 400J

Under which of the following circumstances would a population of animal species be expected to increase at the greatest rate?

Carrying capacity is defined as the maximum population size that a particular environment can support based on available resources, including food, shelter, and sites in which to nest or hide from predators. If the population is at one-half the carrying capacity of the habitat, the population will most likely continue to increase in size The population size equals one-half the carrying capacity of the habitat

Which TWO of the following are types of chemical weathering?

Chemical weathering occurs when water, gas, and acid interact with minerals in rocks, leading to various chemical reactions that change the rocks' composition. Dissolution occurs when atmospheric carbon dioxide dissolves in rainwater, producing a weak acid known as carbonic acid. Carbonic acid is effective at dissolving rocks, especially those containing calcite, such as limestone and marble. Oxidation occurs when atmospheric oxygen reacts with various metals in minerals to create a new oxide mineral. Rusting is the better-known term for this process. 1. Dissolution 2. Oxidation

Which of the following is a safe laboratory procedure?

Concentrated acid should be added to water. (B) is unsafe because alcohol is flammable, and (C) is a poor procedure because the volatile liquids will evaporate. (D) is not a safe practice, since many chemicals will contaminate waste water, no matter how much water is added, and because some chemicals that may become mixed can react with each other and produce harmful products, including gases that can disperse into the laboratory. Preparing a dilute acid solution by adding a small amount of concentrated acid to water in a flask

24 0 NA-> X + β 11 -1 Which of the following is formed when a beta particle is emitted from sodium-24, as shown above?

During the β (beta) -emission process, a neutron in sodium-24, is transformed into a proton and a β-particle (electron), thus increasing the atomic number by 1 to 12. The resulting isotope is 24Mg12. The answer can also be found by looking at the balanced equation 24 z 0 NA-> X + β 11 y -1 in which y is the atomic number and z is the mass number. In the balanced reaction y - 1 = 11 and z + 0 = 24. Hence y = 12 and z = 24y equals 12 and z equals 24. 24 Mg 12

If a wire carries a steady current of 0.1 amp for 20 seconds, which of the following gives the total charge passing through the wire during this time interval?

Electric current is defined as the charge per unit time passing a given point. A current of 1 ampere is equal to 1 coulomb per second Thus a steady current of 0.1 amp in 20 seconds corresponds to a total charge of 2 coulombs 2 coulombs

In order for endothermic animals to maintain homeostasis of body temperature, the body will prevent above-normal body temperatures by

Endothermic animals are those animals that are warmed by heat generated by their own metabolism. They can also lose heat by several mechanisms, one of which is the dilation of blood vessels of the skin. Dilation permits greater blood flow through the vessels and facilitates cooling of heated blood as heat is lost to the environment. directing blood vessels of the skin to dilate

When a substance undergoes a phase change from a gas to liquid at its boiling point, which of the following properties of the substance always decreases?

Entropy always decreases when a substance undergoes a phase change from a gas to a liquid. Mass and temperature are unchanged, and density generally increases, with a few exceptions. entropy

Experimental evidence supports the fact that most of the mass of an atom is contained in which of the following?

Ernest Rutherford published results of his gold foil experiment in 1911. A beam of alpha particles was directed at a thin sheet of gold foil. Most of the particles passed through the foil, but some were reflected or deflected, providing experimental evidence that the atom has a relatively small nucleus that contains most of the mass of the atom. the nucleus

Four experiments were done with a metal wire. In each experiment, the resistance of the wire at a low and a high temperature was measured more than once. Which experiment gives the strongest evidence that resistance increases as temperature increases? (question 13)

Experiment 3 provides the strongest evidence that resistance increases as temperature increases. The four pairs of resistance measurements at low and high temperature correctly demonstrate the relationship between resistance and temperature with good precision. Experiment 3

Of the following substances, which is most strongly attracted to a magnet?

Ferromagnetic substances will be most strongly attracted to a magnet. Of the four elements listed, only iron is ferromagnetic Iron

If a flat object is placed 3 meters in front of a plane mirror, the image will be formed

For a plane mirror, the image distance is equal to the object distance. That is, the image formed by the mirror is located the same distance behind the mirror as the object is located in front of the mirror. 3 meters behind the surface of the mirror

A thermometer inserted into a solution has a mercury level of just a bit less than halfway between the markings for 22.4ºC22 point 4 degrees Celsius and 22.5ºC22 point 5 degrees Celsius. To represent the correct number of significant figures, the temperature of the solution should be recorded as

For any marked measuring device, one place beyond the numerical place of the marking is estimated, and this determines the correct number of significant figures. If the thermometer is marked to 0.1°Czero point one degrees Celsius, the hundredth place should be estimated and the temperature recorded as 22.44°C 22.44

Which of the following combinations of identical resistors produces the smallest total resistance? (ques 42)

For resistors in series, the equivalent (total) resistance is equal to the sum of the individual resistances, while for resistors in parallel the reciprocal of the equivalent resistance is equal to the sum of the reciprocals of the individual resistances. By applying these rules, one obtains the following values for the total equivalent resistance.

The height to which a ball bounces is compared to the height from which it is dropped. The ball is dropped from five different heights, and the results are plotted above. On the basis of these data, it should be concluded that the (question 9)

Four of the data points fall along a straight line with a positive slope, suggesting that the height of the bounce is directly proportional to the height of the drop. However, the data point for the 6-foot drop is not close to the line, and the drop must be repeated to support or contradict this conclusion. data point for the 6-foot drop does not seem to fit the pattern and the drop should be repeated

When the bones of the human arm and the bones of a bat wing are compared, many similarities are observed. These similarities are examples of

Homologous structures are structures of different species that have some similarity because they are derived from a common ancestor. A bat and a human share a common vertebrate ancestor homologous structures

Of the following, which has the lowest normal boiling point?

Hydrogen is a nonpolar molecule. Because each hydrogen atom in the molecule has only one electron shell, it is less polarizable than other diatomic molecules. As a result, it has relatively weak London dispersion forces only and therefore a low boiling point. H2

A sample contains 8 g grams of a radioisotope that has a half-life of 10 years. How much time is required for the sample to decay until approximately 1 g of the isotope remains in the sample?

If the half-life of the substance is 10 years, then every 10 years the amount of the isotope is decreased by half. Thus, it requires three half-lives, or 30 years, for the isotope to decay until approximately 1 g remains in the sample 30years

Johannes Kepler's greatest contribution to science was that he

In 1609, Johannes Kepler published what is now known as Kepler's first law of planetary motion. Kepler, a mathematician, asserted that observations of the movements of Mars were consistent with the planet having an elliptical orbit with the Sun as one of the focal points. Kepler's law refined the Copernican model of the solar system described the orbits of the planets as ellipses

Which of the following guidelines should be used when collecting data during an experiment?

In an experiment, only one factor at a time should be varied. This factor is called the manipulated or independent variable. The responding or dependent variable will be measured and recorded. Vary only one factor at a time when studying how a system responds.

One similarity between the Bohr and quantum mechanical models of the atom is that electrons

In both the Bohr and quantum mechanical models, electrons are only in certain allowed energy states are only in certain allowed energy states

A student placed 20 radish seeds on a damp paper towel in a petri dish and placed the dish under a fluorescent light. After 48 hours, all the seeds had germinated. In order for the student to draw a valid conclusion about the effect of water on seed germination, which of the following should also have been included in the investigation?

In order to draw a valid conclusion about the effect of water on seed germination, the student should have included a control experiment, a second dish with a dry paper towel, in the investigation. The only experimental variable should be the presence or absence of water. The control variables, light and temperature, should be the same for both dishes. A second dish with a dry, rather than damp, paper towel should have been used

A ball is thrown in a horizontal direction. The ball is released at a vertical height of 6 feet and with an initial speed along the horizontal direction only, as shown in figure I. At the same time, an identical ball is dropped from rest from a vertical height of 6 feet, as shown in figure II. Which of the following best describes what happens subsequently? (Assume that air friction is negligible) (question 33)

In the absence of air resistance, both balls fall vertically with the same gravitational acceleration and will hit the ground at the same time. Both balls will hit the ground at the same time

Which of the following categories used to classify biological organisms includes the other three categories?

In the hierarchy of organism classification, phyla (the plural of phylum) include classes, which include orders, which include families. Phylum

Which TWO of the following are true about insulin?

Insulin is a peptide hormone secreted by beta cells of the pancreas. It plays a role in regulating blood sugar levels and the rate of fat metabolism 1.it is secreted by cells of the pancreas. 2.it plays a role in regulating blood sugar levels.

Of the following animal classes, which includes the greatest number of species?

It is estimated that at least 75 percent of all living species are insects. The number of insect species alive today is estimated to be at least two million and may be many times greater. More than 750,000 of the species have been described. Insects may be found in all environments, although very few are found in the oceans. Insects probably have the largest biomass of all terrestrial animals. Insecta

Which of the following statements best summarizes Hutton's geological principle of uniformitarianism?

James Hutton's concept of uniformitarianism states that all natural processes that affect the Earth's crust, such as erosion, deposition, volcanic eruptions, faulting, and glaciation, operate with the same intensity and under the same set of constraints now as in the geologic past. Hutton's concept is often rephrased as "The present is the key to the past." Present physical laws are the key to the past

Which of the following is a line on a weather map that connects points of equal pressure?

Lines on a weather map connecting points of equal air pressure are referred to as isobars. The word isobar means equal (iso-) weight (-bar). Distribution of isobars is closely related to wind magnitude and direction and can be used to predict future weather patterns. Isobar

Which of the following types of biological molecules contain the most energy per gram?

Lipids have more energy content per gram than nucleic acids, carbohydrates, and proteins have. As lipids are metabolized, they undergo exothermic chemical reactions in which energy is required to break bonds in the lipids, but a larger amount of energy is released as new bonds are formed in the products. lipids

Which of the following properties of matter refers to the ability to be hammered into thin sheets?

Malleability is the ability of a substance to be hammered into thin sheets and is a physical property that characterizes metals Malleability

Which of the following diagrams best represents a cell with a diploid number (2N) of 4 that produces diploid, genetically identical daughter cells when it is done dividing? (ques 84)

Mitosis results in the production of genetically identical diploid daughter cells, whereas meiosis results in genetically unique haploid daughter cells. (A) is the only option that illustrates mitosis, specifically the metaphase stage. The four chromosomes, each composed of a pair of identical chromatids, are independently aligned on the spindle apparatus at the equator of the cell.

The solubility of KCl at 40°C 39 g in 100 g of water.If 82 g of KCl is added to 200g of water at 40°C which of the following is true at equilibrium?

Most, but not all, of the KClK C l is dissolved, and the solution is saturated

A tractor is pulling a wagon full of hay. The mass of the wagon and hay is two times the mass of the tractor. When the tractor accelerates forward, the force that the wagon exerts on the tractor is

Newton's third law states that for every action, there is a reaction force that is equal in magnitude but opposite in direction to the action force. Thus the force that the wagon exerts on the tractor must be equal in magnitude to the force that the tractor exerts on the wagon. equal in magnitude to the force that the tractor exerts on the wagon

Of the following elements, which is the most metallic? A

Of the elements listed, only Bi is a metal. Metallic character decreases across the rows (periods) and increases down the columns (groups) of the periodic table. Bi

In which of the following are the types of electromagnetic radiation listed in order of increasing energy?

Of the four types of electromagnetic radiation listed, the most energetic photons are found in gamma rays, the least energetic photons are found in infrared radiation, and ultraviolet photons are more energetic than visible light photons. Infrared < visible < ultraviolet < gamma rays

Which of the following is equivalent to 1 × 10-3g (grams)?

One gram is equal to 1,000 milligrams, so 1 × 10-3 g × (1,000 mg/g) = 1 milligram (0.001 gram) 1 milligram

In the root system of a vascular plant, the movement of water from the soil into the plant's root cells occurs by

Osmosis refers to the passive movement of water into a region of higher solute concentration from a region of lower solute concentration. The concentration of dissolved minerals inside the root hairs is much higher than the concentration outside the root hairs, in the soil, and similarly the concentration of water is higher in the soil than in the root hairs, so water enters the large surface area of the root hairs by osmosis osmosis

Zn + CuCl2 → Cu + ZnCl2 Which of the following species is oxidized in the reaction shown above?

Oxidation is the loss of electrons. In this reaction, Zn loses two electrons to form Zn2+ and therefore is oxidized. Zn

A phagocytic white blood cell will most likely have more of which of the following organelles than a muscle cell will?

Phagocytic cells engulf and digest large particulate materials (e.g., destruction of bacteria by macrophages or neutrophils). Lysosomes are organelles that contain hydrolytic enzymes and function in intracellular digestion. Lysosomes

One way in which stars differ from planets is that stars

Planets are bodies that orbit stars, however they do not give off their own light. Stars generate their own light and energy via a process known as nuclear fusion, when fast-moving hydrogen nuclei are smashed together to form helium. This fusion process produces enough energy for stars to shine. Planets are visible only because of the sunlight they reflect. produce their own light

Of the following organisms, which are primary consumers in an ecosystem?

Primary consumers eat producers, which are autotrophs such as plants, algae, and cyanobacteria. Hence, grasshoppers that eat plants are primary consumers. grasshoppers

Which of the following substances is highly soluble in water?

Propanol can form hydrogen bonds with water, and therefore is completely miscible (soluble in all proportions) with water Propanol, CH3CH2CH2OH

In cold weather, it is more difficult to make people comfortable in a room with a high ceiling than in a room with a low ceiling primarily because

Since cold air is more dense than warm air, convection currents will develop, with warmer air rising to the ceiling and cooler air dropping toward the floor. When the ceiling is high, there will be a greater temperature difference between ceiling and floor, thus making it more difficult to make people comfortable. .cold air is more dense than warm air

If a beaker and a bathtub are each filled with pure boiling water, which of the following indicates the relative temperatures and heat content of the water in each?

Since the water is boiling, the water is at the same temperature in both the beaker and the bathtub. The heat content of a sample of a substance depends on the amount of the substance in the sample and the temperature. Since the bathtub holds more water than the beaker holds and the temperature is the same in both, the sample of boiling water in the bathtub has greater heat content than the sample in the beaker has. Temp: same in both Heat content: greater in bathtub

Trout automatically swim or orient themselves in an upstream direction that keeps them from being swept away. This behavior is an example of

Taxis is a response toward or away from a stimulus. The swimming of trout into a water current is referred to as positive rheotaxis. The behavior points the fish in the direction from which most food appears and keeps the fish from being swept away. The fish detect the current and respond to it through the lateral line system, a mechanosensory system distributed superficially on the skin surface and in fluid-filled canals just under the skin on the head and body of the fish. taxis

Which of the following is a product of the Calvin cycle of photosynthesis?

The Calvin cycle fixes CO2 to organic molecules to synthesize the 3-carbon sugar glyceraldehyde 3-phosphate. The products of the light reactions, ATP and NADPH , are used during the Calvin cycle as a source of energy and electrons, respectively sugar

Which of the following will decrease the likelihood of mass wasting occurring on a hillside?

The addition of water from rainfall adds weight to a slope and reduces friction, making the slope more susceptible to failure. Building houses at the top of a slope can add weight to slope materials, which leads to a greater driving force. Steeper slopes also have more potential for slope failure. Planting vegetation helps to stabilize slopes because roots hold soil and loose rock together. Also, plants reduce ground moisture by absorbing water from the soil. Planting vegetation on the hillside

An equation is shown as follows: __ C 6 H 12 O 6 +___ O , -> ___C O 2 + ___H 2 O If the equation for the combustion of glucose above is balanced using the smallest whole-number coefficients possible, what is the coefficient for O2O 2 ?

The balanced equation is C6H12O6 + 6 O2 → 6 CO2 + 6 H2O 6

During a chemical process, a system absorbs 4.8 kJ of heat while doing 1.2 kJ of work on the surroundings. The change in internal energy of the system is

The change in internal energy of the system is equal to the energy absorbed by the system minus the energy used by the system to do work on the surroundings, or (4.8 kJ- 1.2 kJ= +3.6 kJ) +3.6 kJ

The elements in the first column in the periodic table have similar chemical properties because they have

The chemical properties of the elements in the first column are largely determined by their electron configurations. Elements in group 1 have one electron in their valence shell and have similar chemical properties. the same number of outer electrons

Which of the following will result in a solution of 0.50 M HCl?

The concentration of the solution that results from adding 250 mL of 2.0 M HCl to 750 mL of water is 0.50 M. In 250 mL of 2.0 M HCl there is 0.50 mol of HCl. The total volume after mixing is 1,000 mL or 1.0 L. The concentration of the solution is 0.50 mol HCl of solution which is 0.50 M HCl. 250 mL of 2.0 M HCl added to 750 mL H2O

Which of the following parts of a compound microscope would be used to regulate the amount of light transmitted through the specimen on a slide?

The diaphragm is a rotating disk under the stage that is used to control the intensity and size of the cone of light directed upward to the slide the diaphragm

An emergency vehicle, blowing its siren, approaches a stationary observer and then passes and moves away. Which of the following is true of the frequency of the sound of the siren heard by the stationary observer as compared with that heard by the driver?

The frequency heard by the stationary observer depends on whether the vehicle is approaching the observer or moving away from the observer, a phenomenon known as the Doppler effect. When the vehicle is approaching the observer, the frequency heard by the observer is higher than the frequency heard by the driver. When the vehicle is moving away from the observer, the frequency heard by the observer is lower than the frequency heard by the driver. Approaching: higher Moving Away: lower

The primary reason that stripping the outer and inner bark from the circumference of a tree will eventually kill the tree is that removal of the bark

The inner bark contains the phloem, which is living vascular tissue that carries sugar and other organic nutrients from the leaves to other parts of the plant, including the roots. Removing the bark will prevent the flow of sugar to the roots and eventually kill the tree. prevents the transport of sugar to the roots

The number of moles of atoms in 48.6 g of Mg is

The molar mass of Mg is 24.3 g/mol therefore, 48.6 g of Mg contain 2 moles of Mg atoms 2

Which of the following is the most likely cause of Down syndrome?

The most common cause of Down syndrome is trisomy 21, or three copies of chromosome 21 in every cell. A gamete should contain only one copy of every chromosome, so that a zygote contains two copies of every chromosome. If the homologous pairs of chromosome 21 do not separate during meiosis I or if the chromosome 21 chromatids do not separate during meiosis II, gametes will form with two copies of chromosome 21. When such a gamete fuses with a gamete containing the normal one copy of chromosome 21, the zygote will contain three copies of the chromosome. The consequent overproduction of chromosome 21-encoded proteins causes Down syndrome. The nondisjunction of chromosome 21 during meiosis

An equation is shown as follows: AgNO3(aq) + NaC l (aq) -> AgCl (s) + NaNO3 (aq) For the precipitation reaction shown above, the net ionic reaction is

The net ionic reaction shows only the ions that react to form the precipitate AgCl. Ag+ (aq) + Cl- (aq) -> AgCl (s)

A respiratory control center is located in which of the following structures?

The neurons primarily responsible for regulating breathing are located in the medulla oblongata, near the base of the brain stem. Neural circuits in the respiratory control center detect stretching of the lungs and regulate the degree of lung expansion during inhalation. Neurons in the medulla also use the pH of the blood as an indicator of the necessary depth and rate of breathing. Increased metabolic activity causes an increase in blood CO2, which dissociates into HCO3- and H. This causes a decrease in the pH of the blood and of the cerebrospinal fluid that bathes the central nervous system. Medulla oblongata

A woman with blood type B (genotype IBIB or IBi) has four children with a man whose blood type is unknown. Two of the children have blood type B, one has blood type O, and one has blood type AB. What must the blood types of the parents be?

The only way the couple could have a child with blood type O is for each parent to have at least one i allele; i is recessive to IA and IB. The child must receive one i allele each parent, as blood type O requires that the individual has genotype ii. The woman is blood type B, so her genotype must be Ibi. The only way this couple could have a child with blood type AB is if the man has the genotype IAi. The two children with blood type B must have the genotype Ibi. Mom: IBi Dad: IAi

The graph above shows the relative population sizes of three animal species in a particular habitat over a period of time. These data best support which of the following hypotheses? (ques 79)

The peaks and valleys of the population I graph follow shortly after the peaks and valleys of the population II graph, suggesting that fluctuations in the size of population II influence the size of population I. There are also relatively fewer members of population I than of population II. Both of these facts suggest that population I preys on population II. The fluctuations in size of population III are relatively small and are independent of the fluctuations in population I, strongly suggesting that population I does not prey on population III. I is a predator of II but not of III

If the length of a simple pendulum is doubled, the period of the pendulum will

The period T of a simple pendulum of length L is given by the equation T=2π√L/g where g is the acceleration due to gravity. If the length of the pendulum is doubled, then the period of the pendulum will increase by a factor of √2 increase of a factor by by √2

Which of the following is the correct name for Cu(NO3)2C ?

The polyatomic anion nitrate (NO3-) ion has a charge of -1. Therefore, copper has a charge of +2, designated by the Roman numeral II. Copper(II) nitrate

Since the lungs in many adult amphibians are small or even absent, upon which of the following do they mainly depend for gas exchange?

The skin of some amphibians is thin and membranous, which allows the free diffusion of the gases O2 and CO2 down the concentration gradients between the blood vessels under the skin and the surroundings. When completely submerged in water, all of the gas exchange of some amphibians occurs through the skin. When out of the water, mucus glands keep the skin moist, which facilitates gas exchange with the air. Skin

Which TWO of the following increase the solubility of carbon dioxide in water?

The solubility of a gas in a liquid is affected by the temperature of the liquid and the pressure of the gas above the liquid. Decreasing the temperature of the water and increasing the pressure of carbon dioxide above the water increases the solubility of the carbon dioxide in the water. 1. Decreasing the temperature of the water 2. Increasing the pressure of carbon dioxide above the water

If when a certain compound is dissolved in water, the temperature of the water decreases, the process is called

The solution process of the compound is endothermic. The thermal energy required for the process is transferred from the water, so the temperature of the water decreases. an endothermic process

Plants that reproduce by making flowers and seeds are classified as

The term "angiosperm" refers to a plant that produces seeds within an enclosure (the fruit) and is commonly called a flowering plant. Conifers are a type of gymnosperm, a group that reproduces by making "naked" unenclosed seeds but does not flower. Bryophytes, a collective term for nonvascular plants, reproduce by producing spores. Similarly, ferns reproduce only through the production of spores. angiosperm

Two astronauts, of masses 60 kg60 kilograms and 80 kg80 kilograms, are initially at rest in outer space. They push each other apart. If the speed of the lighter astronaut is 12 m/s12 meters per second, what is the speed of the heavier astronaut?

The two astronauts are initially at rest, which means that the initial total momentum of the two astronauts is equal to zero. In the absence of any net external forces, linear momentum is conserved. Thus the total momentum of the two astronauts after they push each other apart must be equal to zero. That means that the two astronauts will move apart in opposite directions and that the speed of the heavier astronaut can be found using the equation mheavy*vheavy=mlight*vlight which gives vheavy = (60 kg × 12 m/s)/80 kg = 9 m/s 9.0m/s

sample of liquid water of a certain mass at 20°C and 1 atm has a volume of 1,000 mL. Which of the following is the most likely volume of a water sample with the same mass at 80°C and 1 atm?

The volume of liquid water generally increases in very small increments with increasing temperatures. Since the water is in the liquid state and not in the gaseous state, the volume of the sample at 80°Cis most likely 1,027 mL, only slightly larger than the volume of the sample at 20°C. 1,027 mL

The gravity on the Moon is 1/6one sixth as strong as the gravity on Earth. With respect to the weight (W) and mass (M) of two identical bricks that are placed on the surfaces of Earth and the Moon, which of the following is true?

The weight of an object is equal to the force of gravity acting on the object; thus for identical objects, the weight on the Moon will be less than the weight on Earth. The mass of an object does not depend on the location of the object, which means that the masses of identical objects will be equal. MEarth=MMoon

The process of translation uses the genetic code in messenger RNA in the synthesis of which of the following?

Translation refers to the synthesis of proteins based on codons, or sequential ribonucleotide triplets, present in an mRNA. A ribosome binds to an initiation codon of an mRNA, and tRNAs, carrying individual amino acids as dictated by the codon sequence, bind to sequential codons in the mRNA. The ribosome forms peptide bonds between the amino acids, and the amino acids are released from the tRNAs, which then dissociate from the mRNA and the ribosome. Proteins

Upwelling currents along the west coast of South America are characterized by

Upwelling currents occur when winds blowing across the ocean surface push water away from an area. When this occurs, water rises from beneath the surface to replace the diverging surface water. Subsurface water that rises to the surface as a result of upwelling is typically colder, rich in nutrients, and biologically productive. Therefore, good fishing grounds are found where upwelling is common. The west coast of South America is one such area. cold, nutrient-rich water

Which of the following best accounts for the fact that metals are good conductors of electricity?

Valence electrons of metals are delocalized and held loosely in a crystal lattice of positive ions. The mobility of the electrons accounts for the electrical conductivity of metals. Valence electrons are delocalized in a crystal lattice of positive ions

As shown above, a ray of light, L, passes from medium 1 through a boundary into medium 2. What will be the path of the light in medium 2 ? (n is refractive index.) (ques 44)

When light passes from a medium with a higher index of refraction into a medium with a lower index of refraction, the light will be refracted away from the normal to the interface (the dashed line in the figure), in accordance with Snell's law.

Which of the following best describes the effect on the tides when the Sun, Earth, and Moon are in alignment?

When the Sun, Earth, and Moon are in alignment (a condition known as syzygy), the tidal force due to the Sun is increased, which reinforces the tidal force produced by the Moon. The tide's range is then at its maximum range, called spring tide. The difference between high and low tides is relatively large.

Which of the following characteristics is most important in demonstrating that a hypothesis should be called a theory?

hypothesis is a tentative explanation for a set of observations. Further experiments are conducted to test the validity of the hypothesis. If the hypothesis proves valid following many experimental tests over an extended period of time, it may be referred to as a theory. It provides an explanation for the results of many experiments.

DNA synthesis occurs by semiconservative replication in which each strand serves as the template for synthesis of a new strand. Which of the following characteristics of DNA is most important to this mechanism?

molecule of DNA is composed of two antiparallel strands of nucleotides; the strands are held together by hydrogen bonds between complementary base pairs on the two strands. During DNA replication, the two strands separate and a new strand complementary to each template strand is synthesized by DNA polymerases. Because nucleotides containing adenine (A) must pair with nucleotides containing thymine (T) and nucleotides containing cytosine (C) must pair with nucleotides containing guanine (G), only one possible nucleotide can be added opposite the nucleotide present on the template strand. Thus each template strand dictates the sequence of the new strand with which it will bind. The two strands of a DNA molecule exhibit complementary base pairing

Which of the following is the ground state electron configuration for Ti?

the atomic number for Ti, titanium, is 22; therefore a neutral atom of Ti has 22 electrons and, using the Aufbau principle, the ground state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d2. 1s2 2s2 2p6 3s2 3p6 4s2 3d2

Bean plants lower their leaves in the evening and raise them to a horizontal position in the morning. The movements will continue even if the plant is kept in constant light or darkness. Such movements are referred to as

the daily change in the position of the bean plant's leaves dependent on the time of day but independent of light is an example of circadian rhythm. The plants undergo genetically programmed physiological changes that affect the position of the leaves in a cyclic fashion over an approximately 24-hour period. circadian rhythms

The device shown above has an input voltage of 25.0 V25 point zero volts and an output voltage of 50.0 V50 point zero volts. The device is which of the following? (question 38)

transformer is a device which inductively couples two AC circuits and can be used to step up voltage or step down voltage. transformer