Answer Key For The NY State Lab Test: Making Connections

Transcription

1 Answer Key For The NY State Lab Test: Making Connections Sm-Makingconnections Version W Version X Version Y Version Z Q No. Answer Q No. Answer Q No. Answer Q No. Answer

2 Questions with Explanations For The Entire Test: Sm-Makingconnections Teacher Answer Key **NO VERSION/RANDOM** 4 1. Base your answer on the information below and accompanying graph and on your knowledge of biology. Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph shown. Students in a different science class carried out the same experiment. The data they obtained did notsupport the hypothesis that increased exercise results in increased heart rate. The most scientifically sound way to deal with this situation is to 1. write a new hypothesis 2. read about pulse rate in a biology textbook. have the students in both classes vote to decide which hypothesis is correct 4. ask students in a third class to do the experiment and see if their results support the hypothesis 4 The most scientifically sound way to deal with this situation is to ask students in a third class to do the experiment and see if their results support the hypothesis. Repeatability of experimental results is an essential component of sound science. If an experiment cannot be repeated multiple times with the same results by independent researchers, it is likely that the original experiment was flawed in some way and its results invalid. (1), () It is not true that the most scientifically sound way to deal with this situation is to write a new hypothesis or have the students in both classes vote to decide which hypothesis is correct. Either of these actions would introduce bias into the experiment and invalidate its results. (2) It is not true that the most scientifically sound way to deal with this situation is to read about pulse rate in a biology textbook. This is an action that should be taken by the researcher as an initial part of the experimental method, not as an action to validate experimental results.

3 4 2. Base your answer on the information below, on the accompanying data table, and on your knowledge of biology. A group of students obtained the following data while trying to determine the effect of exercise on pulse rate. Which statement is an example of an observation the students could have made? 1. Pulse rates in beats per minute decrease. The pulse rate of student C was for all people after exercise. dangerously low. 4. The pulse rate of student F increased by 2. Student A most likely exercises regularly. 0 beats per minute. 4 The pulse rate of student F increased by 0 beats per minute is the statement that is an example of an observation the students could have made. This direct observation can be made by examining the data from the table that indicate that the pulse rate of person F before exercise was 68 beats per minute and after exercise was 98 beats per minute, a difference of 0 beats per minute. (1) Pulse rates in beats per minute decrease for all people after exercise is not the statement that is an example of an observation the students could have made. No data are provided in the table that indicate what happens to students' pulse rates after the completion of exercise. So this observation cannot be made based on the data provided. (2) Student A most likely exercises regularly is not the statement that is an example of an observation the students could have made. No data are provided in the table that indicate what exercise habits each subject maintains. So this observation cannot be made based on the data provided. () The pulse rate of student C was dangerously low is not the statement that is an example of an observation the students could have made. No data are provided in the table concerning the normal range of human pulse rate. So this observation cannot be made based on the data provided. 1. A student hypothesized that watching sports on television would cause viewers' pulse rates to increase. She designed an experiment to determine the effect of watching sports on pulse rate. A group of 200 volunteers took their pulse rates and then watched their

4 favorite sports on television. After the games, they immediately took their pulse rates again. The data collected showed that the pulse rates of some people increased, but the pulse rates of an equal number of people did not change. Although the hypothesis was not supported by the data, the hypothesis is still valuable because it 1. may lead to further investigation. is the opinion of the experimenter 2. can be changed to fit the data 4. is based on beliefs of the volunteers 1 Although the hypothesis was not supported by the data, the hypothesis is still valuable because itmay lead to further investigation. Sound science uses situations such as unsupported hypotheses as opportunities to conduct deeper or redirected research. Such opportunities often result in information that can lead to the development of new scientific theories. (2), (), (4) It is not true that although the hypothesis was not supported by the data, the hypothesis is still valuable because it can be changed to fit the data, because it is the opinion of the experimenter, or because it is based on beliefs of the volunteers. Any of these actions would introduce bias into the experiment and invalidate its results. Sound science requires that experimental hypotheses be tested against collected data and analyzed objectively for accuracy. Hypotheses must not be manipulated to fit the data or to support any particular opinion or belief. 4. Students were asked to determine if they could squeeze a clothespin more times in a minute after resting than after exercising. An experiment that accurately tests this question should include all of the following except 1. a hypothesis on which to base the design. two sets of clothespins, one that is easy to of the experiment open and one that is more difficult to open 4. a control group and an experimental 2. a large number of students group with equal numbers of students of approximately the same age An experiment that accurately tests this question should include all of the following except two sets of clothespins, one that is easy to open and one that is more difficult to open. Using two sets of clothespins that differ in strength introduces an additional variable to the experiment that will invalidate the results. Instead, all clothespins should be the same strength in this experiment. (1) An experiment that accurately tests this question should include a hypothesis on which to base the design of the experiment. A good experiment always begins with a hypothesis (an "educated guess") as to the researcher's prediction about its results. (2) An experiment that accurately tests this question should include a large number of students. A good experiment includes a significant number of experimental subjects as a means of avoiding statistical bias in the experiment. (4) An experiment that accurately tests this question should include a control group and an experimental group with equal numbers of students of approximately the same age. A

5 good experiment always includes a control group that mirrors the experimental group in all respects except the independent variable (controlled by the experimenter). 5. Base your answer on the information given and on your knowledge of biology. In an investigation, 28 students in a class determined their pulse rates after performing each of three different activities. Each activity was performed three times during equal time intervals. The average results are shown in the accompanying graph. Before constructing the graph it would have been most helpful to organize the results of the investigation in 1. a research plan. a data table 2. an equation 4. a generalization Before constructing the graph it would have been most helpful to organize the results of the investigation in a data table. Data tables assist the researcher by providing a means of organizing data during the course of an experiment. Properly designed, a data table facilitates efficient analysis of experimental results. (1) Before constructing the graph it would not have been most helpful to organize the results of the investigation in a research plan. A research plan is an outline of the steps that must be taken to run an experiment, collect and analyze data, and draw inferences and conclusions. A research plan is drawn up well before data is collected and organized into a data table. (2) Before constructing the graph it would not have been most helpful to organize the results of the investigation in an equation. An equation is a mathematical model that assists scientists in describing a natural phenomenon and in better understanding it. An equation is developed as an aspect of data analysis after data is collected. (4) Before constructing the graph it would not have been most helpful to organize the results of the investigation in a generalization. A generalization is a statement of inference or conclusion that is developed as a result of considerable data collection, analysis, and modeling. Generalizations are the last component of a research plan to be developed. 1

6 6. Although the digestive system is primarily responsible for the breakdown of food, this process can be disrupted if the circulatory system malfunctions because the nutrients cannot be delivered to the cells that need them. The best explanation for this disruption is that 1. Human body systems interact with each. the digestive system and the circulatory other to perform life functions system the same organs 2. the circulatory system is the control center of the body 4. the circulatory system is responsible for the the breakdown of food 1 The best explanation for this disruption is that human body systems interact with each other to perform life functions. In humans, these systems are cooperative in their operation and allow for coordination and homeostatic balance of the body. (2), (4) The best explanation for this disruption is not that the circulatory system is the control center of the body or that the circulatory system is responsible for the coordination of life functions, including the breakdown of food. In humans, control and coordination are functions provided by the nervous system, not the circulatory system. () The best explanation for this disruption is not that the digestive system and the circulatory system have many organs in common. In humans, these systems are separate and distinct. They are cooperative in their operation and allow for coordination and homeostatic balance of the body Base your answer on the accompanying information and on your knowledge of biology. An experiment was designed to test whether students could squeeze a clothespin more times in one minute after resting or after exercise. The dependent variable for this experiment is the 1. time the student was squeezing the clothespin. strength of the student 2. number of times the student was able to squeeze the clothespin 4. length of the clothespin 2 The dependent variable for this experiment is the number of times the student was able to squeeze the clothespin. The dependent variable in an experiment is the factor that is being measured and that changes in response to the experimental conditions controlled by the researcher. In this case, the researcher is measuring the number of times the students could squeeze a clothespin within a given time period (one minute) under two different conditions (after rest or after exercise). In this experiment, the number of times the clothespin is squeezed is the dependent variable. : (1), (4) The dependent variable for this experiment is not the time the student was squeezing the clothespin or the length of the clothespin. These factors represent constant,

7 not variable, conditions of the experiment. They are established by the researcher as a part of the experimental method. () The dependent variable for this experiment is not the strength of the student. Because the student subjects tested in this experiment are individuals whose strength may vary greatly, a large number of students should be tested to ensure that the experimental results are not biased. This variable is neither dependent nor independent. It is an experimental subject variable that should be factored into the experimental design. 8. In an experiment to test the effect of exercise on the number of times a clothespin can be squeezed in 1 minute, the dependent variable would be the 1. test subject. number of squeezes 2. amount of exercise 4. clothespin In an experiment to test the effect of exercise on the number of times a clothespin can be squeezed in 1 minute, the dependent variable would be the number of squeezes. The dependent variable in any experiment is the factor being tested, a factor that varies in response to researcher-manipulated changes in the independent variable. In this case, the number of squeezes in 1 minute is the variable dependent on the researcher-manipulated variable, which is the amount of exercise done by the test subjects prior to the experiment. (1) In an experiment to test the effect of exercise on the number of times a clothespin can be squeezed in 1 minute, the dependent variable would not be the test subject. The test subject is the student whose responses to the independent variable are being tested and recorded. (2) In an experiment to test the effect of exercise on the number of times a clothespin can be squeezed in 1 minute, the dependent variable would not be the amount of exercise. The amount of exercise is the independent variable manipulated by the researcher. (4) In an experiment to test the effect of exercise on the number of times a clothespin can be squeezed in 1 minute, the dependent variable would not be the clothespin. The clothespin is the equipment used to measure the dependent variable, not the variable itself. 9. Base your answer on the accompanying diagram illustrating one type of cellular communication and on your knowledge of biology. If a stimulus is received by the cells at A, the cells at E will most likely use energy obtained from a reaction between

8 1. DNA and RNA. glucose and oxygen 2. ecosystems and biospheres 4. populations and communities The cells at E will most likely use energy obtained from a reaction between glucose and oxygen if a stimulus is received by the cells at A. The diagram illustrates a reflex arc involving a receptor organ (represented by the skin cells labeled A), a nerve connection (represented by the nerve cells labeled B, C, and D), and an effector organ (represented by the muscle cells labeled E). When a stimulus is received at A, the appropriate motor response at E is typically muscle contraction. This motor response requires ATP energy released during aerobic respiration involving a chemical reaction between oxygen and glucose. (1) The cells at E will not use energy obtained directly from a reaction between fats and enzymes. Fats are complex foods that must be broken down (digested) into simpler substances (fatty acids and glycerol) before they can be oxidized to release energy for cell processes. Enzymes are organic catalysts that can speed up or slow down reactions, including fat digestion, but do not react with other substances in these reactions. (2) The cells at E will not use energy obtained directly from a reaction between ATP and pathogens. ATP (adenosine triphosphate) is a chemical that temporarily stores energy for cell processes. A pathogen is a disease-causing organism such as a virus or bacterium. There is no known reaction that occurs between ATP and pathogens. (4) The cells at E will not use energy obtained directly from a reaction between water and carbon dioxide. Water and carbon dioxide are reactants in the biochemical process of photosynthesis. Photosynthesis reactions store light energy in the chemical bonds of glucose molecules. Although this reaction may ultimately result in the energy used at E, it is not the most direct source of this energy Which organ system in humans is most directly involved in the transport of oxygen to different tissues and cells in the body? 1. digestive. excretory 2. nervous 4. circulatory 4 The circulatory system in humans is most directly involved in the transport of oxygen. Molecular oxygen is absorbed from the air into the moist lung tissues, where it diffuses

9 through capillary walls and into red blood cells. Red blood cells contain the protein hemoglobin that links chemically with oxygen molecules. The absorbed oxygen is then carried throughout the body within the circulatory system until it is released to tissues for use in the process of cellular respiration. (1) The digestive system in humans is not most directly involved in the transport of oxygen. The digestive system is responsible for the breakdown and absorption of food materials, not for carrying oxygen. (2) The nervous system in humans is not most directly involved in the transport of oxygen. The nervous system is responsible for regulating the body's activities by receiving and interpreting environmental stimuli and by carrying nerve impulses from the central nervous system to effectors such as muscles and glands. () The excretory system in humans is not most directly involved in the transport of oxygen. The excretory system is responsible for eliminating waste materials (e.g., carbon dioxide, urea) from the body, not for carrying oxygen An experiment was designed to test whether students could squeeze a clothespin more times in 1 minute after resting or after exercising. What would be a hypothesis for the experiment? 1. Do students squeeze clothespins more often in 1 minute after exercising? 2. Can most students squeeze a clothespin more times after they rest?. Ten students who exercise before squeezing a clothespin squeezed it more times in 1 minute than ten students who rested first. 4. Students who rest before squeezing a clothespin will squeeze it fewer times in 1 minute than students who exercise beforehand. 4 An hypothesis for this experiment would be students who rest before squeezing a clothespin will squeeze it fewer times in 1 minute than students who exercise beforehand. The hypothesis in an experiment is the researcher's best guess about the outcome of the experiment. In this case, the researcher is measuring the number of times the students could squeeze a clothespin within a given time period (1 minute) under two different conditions (after rest or after exercise). This hypothesis projects that students who exercise beforehand will be able to squeeze the clothespin more often than students who do not. (1), (2) A hypothesis for this experiment would not be do students squeeze clothespins more often in 1 minute after exercising? or can most students squeeze a clothespin more times after they rest?these are possible experimental questions that might be posed by the researcher in preparation for setting up an experiment, not hypotheses. () A hypothesis for this experiment would not be Ten students who exercised before squeezing a clothespin squeezed it more times in 1 minute than ten students who rested first. This is a possible observation that might be made by the researcher in analyzing and

10 representing the data collected during this experiment, not a hypothesis Which statement best describes a change that usually takes place in the human body when the heart rate increases as a result of exercise? 1. More oxygen is delivered to muscle cells.. The rate of digestion increases. 2. Blood cells are excreted at a faster rate. 4. No hormones are produced. 1 More oxygen is delivered to muscle cells is the statement that best describes a change that usually takes place in the human body when the heart rate increases as a result of exercise. When the body exercises, muscle cells use oxygen in the process of cellular respiration to release energy from glucose. In order to sustain activity, muscle tissue must receive more oxygen and glucose, which is delivered to it by the bloodstream. (2) Blood cells are excreted at a faster rate is not the statement that best describes a change that usually takes place in the human body when the heart rate increases as a result of exercise. The process of excretion is one in which toxic wastes such as carbon dioxide and urea are removed from tissues. Blood cells are not excreted from the body unless they are first broken down into nitrogenous wastes in the liver. () The rate of digestion increases is not the statement that best describes a change that usually takes place in the human body when the heart rate increases as a result of exercise. During vigorous exercise, the body normally suspends all nonessential life activities in order to ensure that sufficient resources are delivered to muscle cells. In this case, the rate of digestion would decrease, not increase, during exercise. (4) No hormones are produced is not the statement that best describes a change that usually takes place in the human body when the heart rate increases as a result of exercise. Hormones are produced as needed to meet the body's demands for the control of metabolic activities in its tissues In the cells of the human body, oxygen and glucose molecules are used directly in a process that 1. releases energy. builds red blood cells 2. digests foods 4. alters the DNA of the cell 1 In the cells of the human body, oxygen molecules are used directly in a process that releases energy. The life process described is known as aerobic respiration. In this process, molecules of glucose are broken down into molecules of carbon dioxide and water, with the resulting production of ATP molecules. ATP stores the chemical bond energy released in aerobic respiration. (2) It is not true that in the cells of the human body, oxygen molecules are used directly in a process that digests fats. Fats are digested by a cellular chemical process, known as hydrolysis, that breaks up larger organic molecules into smaller subunit molecules. The process of fat digestion begins in the small intestine, where bile from the gallbladder enters and emulsifies complex fat into globules for easier digestion in the small intestine.

11 () It is not true that in the cells of the human body, oxygen molecules are used directly in a process that synthesizes carbohydrate molecules. The synthesis of carbohydrate molecules (i.e., glycogen) occurs in the liver and does not require the presence of oxygen. (4) It is not true that in the cells of the human body, oxygen molecules are used directly in a process that alters the genetic traits of the cell. Alterations of the genetic traits of a cell are known as mutations. Mutations do not require the presence of oxygen in order to occur What is an advantage of a change in pulse rate after exercising? 1. The heart needs to produce more energy to supply the active muscle cells and maintain homeostasis. 2. An increased blood flow carries excess waste products (like lactic acid) away from the active muscle cells.. The blood is removing oxygen from muscle cells that were not active and carrying it to muscle cells that are active. 4. The blood is supplying the active muscle cells with carbon dioxide to neutralize wastes in those cells. 2 An increased blood flow carries excess waste products away from the active muscle cells is an advantage of a change in pulse rate after exercising. As the blood passes through capillaries in muscle tissues, it absorbs carbon dioxide and other wastes from these cells for excretion via the lungs, kidneys, and skin to the outside environment. Increasing blood flow through muscle tissues accelerates the removal of these wastes. (1) The heart needs to produce more energy to supply the active muscle cells and maintain homeostasis is not an advantage of a change in pulse rate after exercising. The heart does not produce energy. Rather, the heart circulates dissolved glucose and hemoglobin-bound oxygen to active muscle cells. The mitochondria in muscle cells can then convert the chemical bond energy of glucose into ATP energy, thereby maintaining homeostasis. () The blood is removing oxygen from muscle cells that were not active and carrying it to muscle cells that are active is not an advantage of a change in pulse rate after exercising. Once oxygen is released to muscle cells from the blood, the oxygen is not then removed from those cells for transport elsewhere. Instead, the oxygen is used in the cells to which it was first delivered. (4) The blood is supplying the active muscle cells with carbon dioxide to neutralize wastes in those cells is not an advantage of a change in pulse rate after exercising. Carbon dioxide is a by-product (waste) of the respiratory reactions. Carbon dioxide is removed from, not supplied to, muscle cells by the blood. 15. A student lifted weights after school and found that his muscles started to burn. He couldn't continue to lift the weights after prolonged exercising. This muscle fatigue is most likely due to. lack of oxygen in the muscles and build 1. the heart beating too fast and tiring out up of lactic acid waste

12 2. the lungs accumulating oxygen 4. lack of carbon dioxide in the muscles This muscle fatigue is most likely due to lack of oxygen and build up of waste in the muscles. During periods of strenuous exercise, muscle cells quickly use up available dissolved oxygen required for aerobic respiration. As a result, the cells resort instead to a less-efficient form of anaerobic respiration known as lactic acid fermentation or glycolysis. This process results in the production of a small amount of ATP energy and the metabolic waste lactic acid. Lactic acid stimulates a pain response in the muscles where it forms. This combination of factors is what we describe as muscle fatigue. (1) This muscle fatigue is not most likely due to the heart beating too fast and tiring out. Although an increased heart rate is typical during exercise, it is not the cause of muscle fatigue. (2) This muscle fatigue is not most likely due to the lungs accumulating oxygen. The lungs function to absorb oxygen from the air and transfer the oxygen to the blood. This activity is not the cause of muscle fatigue. (4) This muscle fatigue is not most likely due to lack of carbon dioxide in the muscles. Carbon dioxide is a waste product of aerobic respiration but not of lactic acid fermentation. Carbon dioxide is not the cause of muscle fatigue A marathon runner frequently experiences muscle cramps and burning while running. If he stops running and rests, the cramps eventually go away. The cramping and burning in the muscles most likely results from 1. lack of adequate oxygen supply to the. the runner stretching before running muscle 2. the runner running too slowly 4. breathing too much 1 The cramping of the muscles most likely results from lack of adequate oxygen supply to the muscle. During periods of oxygen deprivation, muscle cells revert to an anaerobic respiratory process known as lactic acid fermentation. During this process, lactic acid builds up in the muscle cells, causing them to cramp. The lactic acid is also detected by nerves in the muscle, sending a sensation of pain to the brain and thus alerting it to the need to reestablish a proper oxygen level in the muscles. (2) The cramping of the muscles does not most likely result from the runner running too slowly. Usually running too fast for the body's capabilities, not too slowly, results in muscle cramping. () The cramping of the muscles does not most likely result from the runner warming up before running. Warm-up techniques, in which the muscles are stretched and blood flow increased, generally reduce the incidence of muscle cramping. (4) The cramping of the muscles does not most likely result from increased glucose production in the muscle. Glucose is produced in the muscles from the breakdown of glycogen stored in the muscle cells and in the liver. Its increased production would have little or no effect on the incidence of muscle cramping.

13 17. Base your answer on the information below and accompanying graph and on your knowledge of biology. Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph shown. Which statement is best supported by the graph? 1. Before exercising, the average pulse rate was 65; four minutes after exercising, the average pulse rate was After four minutes of exercising, the average pulse rate was 120; two minutes after exercising, the average pulse rate was While exercising, the highest average pulse rate was 150; before exercising, the average pulse rate was Two minutes before exercising, the average pulse rate was 80; after two minutes of exercise, the average pulse rate was 140. While exercising, the highest average pulse rate was 150; before exercising, the average pulse rate was 65 is the statement best supported by the graph. An examination of the graph shows that for the five minutes prior to the start of the exercise period, the average pulse rate was uniformly at 65 beats per minute. During the first three minutes of the exercise period, the average pulse rate rose quickly to 120. Then it more gradually rose to 150 over the next seven minutes. Finally, the graph shows that the average pulse rate began to decline as soon as the exercise period ended and reached 80 beats per minute by five minutes past this period. (1) Before exercising, the average pulse rate was 65; four minutes after exercising, the average pulse rate was 65 is not the statement best supported by the graph. The graph indicates that four minutes after exercising, the average pulse rate was approximately 85 beats per minute, not 65. (2) After four minutes of exercising, the average pulse rate was 120; two minutes after exercising, the average pulse rate was 120 is not the statement best supported by the graph. The graph indicates that after four minutes of exercising, the average pulse rate was approximately 15 beats per minute, not 120. (4) Two minutes before exercising, the average pulse rate was 80; after two minutes of exercise, the average pulse rate was 140 is not the statement best supported by the graph.

14 The graph indicates that two minutes before exercising, the average pulse rate was approximately 65 beats per minute, not 85. After two minutes of exercise, the average pulse rate was approximately 90 beats per minute, not Which statement accurately compares cells in the human circulatory system to cells in the human nervous system? 1. Cells in the circulatory system carry out the same exact function as cells in the nervous system. 2. Cells in the circulatory system are identical in structure to cells in the nervous system.. Cells in the nervous system are different in structure from cells in the circulatory system, and they carry out different specialized functions. 4. Cells in the nervous system carry out the same exact function as cells in the circulatory system. Cells in the nervous system are different in structure from cells in the circulatory system, and they carry out different specialized functions is the statement that accurately compares cells that make up the circulatory and nervous systems of humans. Neurons, a specific cell type found in the human nervous system, have a branched structure and are specialized to conduct nerve impulses. By contrast, red blood cells and white blood cells typically found in the human circulatory system are small cells whose principal functions are to carry respiratory oxygen to body tissues and to destroy foreign antigens, respectively. (1) Cells in the circulatory system carry out the same life function for the organism as cells in the nervous system is not a statement that accurately compares cells that make up the circulatory and nervous systems of humans. The primary function of the red blood cells of the human circulatory system is the transport of materials such as oxygen and dissolved food around the body; that of white blood cells is the immune response. By contrast, the primary function of the neuron is the regulation of bodily functions by means of nerve impulse transmission. (2) Cells in the circulatory system are identical in structure to cells in the nervous system is not a statement that accurately compares cells that make up the circulatory and nervous systems of humans. Cells of the human circulatory system are of several different types (including red blood cells, white blood cells, lymphocytes, and platelets); these cells tend to be small, discrete units. Human neurons also are of several types (including sensory neurons, motor neurons, and interneurons) but differ from blood tissues in that they are generally long and/or highly branched cells that cluster together in nerves. (4) Cells in the nervous system act independently, but cells in the circulatory system function together is not a statement that accurately compares cells that make up the circulatory and nervous systems of humans. Scientific research increasingly indicates that the cells of all body systems act together in a coordinated fashion even though they may not be physically connected. 19. Base your answer on the information below, on the accompanying data table, and on

15 your knowledge of biology. A group of students obtained the following data while trying to determine the effect of exercise on pulse rate. Which two body systems were most actively involved in this experiment? 1. respiratory and immune. respiratory and circulatory 2. digestive and endocrine 4. immune and circulatory Respiratory and circulatory are the two body systems that were most actively involved in this experiment. Data provided in the table give information about pulse rate, which directly involves the circulatory system. The student's general knowledge of biology is needed to understand that the respiratory system functions to provide oxygen needed for cellular respiration as well as to remove carbon dioxide and other metabolic wastes from muscles involved in the exercise regimen. (1), (4) Respiratory and immune and immune and circulatory are not the two body systems that were most actively involved in this experiment. The immune system provides the body with protection from foreign invaders and potentially dangerous antigens. This system was not directly involved with this experiment. (2) Digestive and endocrine are not the two body systems that were most actively involved in this experiment. The digestive system functions to break down complex foods into soluble molecules. The endocrine system manufactures hormones that function to direct the activities of specific target tissues. These systems were not directly involved with this experiment Base your answer on the accompanying information and on your knowledge of biology. An experiment was designed to test whether students could squeeze a clothespin more times in one minute after resting or after exercise. The experimental results could be made more valid by 1. increasing the number of students. using safety precautions 2. using a plastic clothespin 4. making a bar graph of the data

16 1 The experimental results could be made more valid by increasing the number of students. Because the student subjects tested in this experiment are individuals whose strength may vary greatly, a large number should be tested to ensure that the experimental results are not based on too small a number of subjects. Instead, the results should be based on an average representing the strengths and abilities of a large, typical group of students. Using a large number of experimental subjects makes the experimental results more valid by helping the researcher to avoid statistical error introduced when a too-small subject group is used. : (2) The experimental results could not be made more valid by using a plastic clothespin. This factor should represent a constant condition of the experiment established by the researcher as a part of the experimental method. Using a plastic clothespin does not make the experimental results more valid. () The experimental results could not be made more valid by using safety precautions. Safety precautions should always be considered when conducting scientific research. This factor should represent a constant condition of the experiment established by the researcher as a part of the experimental method. However, using safety precautions does not make the experimental results more valid. (4) The experimental results could not be made more valid by making a bar graph of the data. Graphical representations of raw data help the researcher to analyze the results of the experiment, but they do not make the experimental results more valid. 21. An experiment was carried out to determine whether drinking caffeinated soda increases pulse rate. The pulse rates of two groups of people at rest were measured. Group A was then given caffeinated soda and group B was given caffeine-free soda. One hour after drinking the soda, the pulse rates were measured. The participants in the experiment were all the same age, and they were all given the same amount of soda. The dependent variable in this experiment is the 1. type of soda given to each group. pulse rate of each group 2. amount of soda given to each group 4. age of participants in each group The dependent variable in this experiment is the pulse rate of each group. A dependent variable is what is measured in an experiment and what is affected by other conditions present in the experiment. The dependent variable responds to the independent variable. It is called dependent because it depends on the independent variable. This researcher is testing the effect of caffeinated/caffeine-free soda (independent variable) on pulse rate (dependent variable). [Note: This experimental design is flawed in that it does not contain a true control group, which might be a third group who drink only water.] (1) The dependent variable in this experiment is not the type of soda given each group. The type of soda given each group is the independent variable of this experiment. An independent variable is the condition in the experiment manipulated by the researcher.

17 (2), (4) The dependent variable in this experiment is not the amount of soda given to each group or the age of participants in each group. These conditions of the experiment are constants that are consciously controlled by the researcher so they do not vary from group to group. The use of constants in an experiment helps to ensure that the independent variable (type of soda), and not some other condition, affects the dependent variable (pulse rate). 22. A student conducted an experiment to determine if listening to different types of music would affect pulse rate. She thought that pulse rate would change with different types of music. Each person participating in her experiment listened to seven different selections of music for 0 seconds each. The pulse rates were taken after each 0-second interval of music. Based on her experiment, the student concluded that a person's pulse rate changed when listening to different types of music. The component missing from this experiment is a 1. prediction. control group 2. hypothesis 4. research plan The component missing from this experiment is a control group. A control group is a second group that is subjected to all of the conditions of the experiment with the exception of the independent variable being studied (music). The control group helps the researcher to determine the validity of the experiment by eliminating the possibility that the dependent variable (pulse rate) is being affected by unrecognized stimuli. This student's control group might have been a second group of people who sat next to members of the experimental group and who experienced all the same stimuli except the music selections heard by the experimental group. (1), (2) The component missing from this experiment is not a prediction or a hypothesis. A hypothesis is a scientific term referring to a researcher's educated guess about the results of an experiment. In this case, the hypothesis is about the effect of an independent variable (music) on a dependent variable (pulse rate). The term prediction has essentially the same meaning in general language. The student's hypothesis/prediction is captured in the sentence "she thought that pulse rate would change with different types of music." (4) The component missing from this experiment is not a research plan. A research plan is a set of tasks needed to test the effect of an independent variable (music) on a dependent variable (pulse rate). The student's research plan is captured in the following sentences, "Each person participating in her experiment listened to seven different selections of music for 0 seconds each. The pulse rates were taken after each 0-second interval of music." 2 2. A student squeezes a clothespin as rapidly as possible for one minute. Without stopping to rest, the student continues to squeeze the clothespin for a second minute. At the end of the second minute, the student's fingers and hand feel very cramped and tired. The physical tiredness and cramping in the muscles in the student's hand were most likely due to the increased production of

18 1. energy (ATP). oxygen 2. waste products (lactic acid) 4. glucose (sugar) 2 The physical tiredness and cramping in the muscles in the student's hand were most likely due to the increased production of waste products. When muscles are exercised strenuously, muscle tissues quickly use up available oxygen needed for the process of aerobic respiration. At this point the cells begin to carry on a type of anaerobic respiration known as lactic acid fermentation. Lactic acid is the waste product of this process that builds up in muscle cells and causes the feelings of cramping and tiredness in the muscle. (1) The physical tiredness and cramping in the muscles in the student's hand were not most likely due to the increased production of ATP. ATP (adenosine triphosphate) is an energy-rich compound that is produced as a result of the respiratory reactions. The presence of ATP in the muscles would decrease, not increase, feelings of cramping and tiredness in the muscles. () The physical tiredness and cramping in the muscles in the student's hand were not most likely due to the increased production of oxygen. Oxygen is used, not produced, in muscle cells. (4) The physical tiredness and cramping in the muscles in the student's hand were not most likely due to the increased production of glucose. Glucose is used, not produced, in muscle cells. 24. Base your answer on information below and accompanying graph and on your knowledge of biology. Students were asked to design a lab that investigated the relationship between exercise and heart rate. Heart rate was determined by recording the pulse rate in beats per minute. The students hypothesized that increased exercise results in an increased heart rate. The class results for the experiment are shown in the graph shown. The change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation that 1. reduces the rate at which oxygen is. results in the production of more energy carried to the muscle cells (ATP) in muscle cells 2. increases the rate at which carbon dioxide 4. slows the destruction of bacon involved

19 is carried to the muscle cells in breathing of muscle cells The change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation thatresults in the production of more ATP in muscle cells. Red blood cells in the bloodstream absorb and carry oxygen for use by cells throughout the body. During exercise, an elevated heart rate increases blood flow to the muscles. Oxygen is released into muscle cells from the blood and transported in the cytoplasm to the mitochondria. Respiratory enzymes in the mitochondria use this oxygen to release energy from the chemical bonds of glucose and to store that energy temporarily in molecules of ATP. Finally, ATP supplies the muscle cell with the energy needed for continued exercise. (1) It is not true that the change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation that reduces the rate at which oxygen is carried to the muscle cells. The rate at which oxygen is carried to the muscle cells is increased by this change in heart rate, not reduced. (2) It is not true that the change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation that increases the rate at which carbon dioxide is carried to the muscle cells. Carbon dioxide, a waste product of respiration, is removed from muscle cells, not carried to them, by the blood. (4) It is not true that the change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation that slows the destruction of enzymes involved in respiration of muscle cells. Enzymes have a finite number of reactions they can catalyze before they are recycled. Elevated heart rate neither speeds up nor slows down their destruction. 25. In an experiment to determine the effect of exercise on pulse rate, a student checks his pulse rate before and after exercising for several minutes. The purpose of checking his pulse rate before exercising is that it 1. serves as the conclusion for the. serves as a control for the experiment experiment 2. is needed to justify the sample size 4. is needed to formulate a hypothesis The purpose of checking his pulse rate before exercising is that it serves as a control for the experiment. A control is an element of an experiment. A control is identical to the experimental group in all respects except for the independent variable, which is the variable controlled by the experimenter. If the student seeks to test the effect of exercise on his pulse rate (dependent variable), then measuring his resting pulse rate establishes a baseline. Then the student can compare his resting pulse rate (control) with his pulse rate after exercising for several minutes. (1) The purpose of checking his pulse rate before exercising is not that it serves as the conclusion for the experiment. A conclusion is a statement by the experimenter concerning the knowledge gained after conducting a scientific experiment. Checking the student's resting pulse rate does not constitute an experimental conclusion. (2) The purpose of checking his pulse rate before exercising is not that it is needed to

20 justify the sample size. The sample size for this experiment is one subject, the experimenter himself, and cannot be justified by this means. This is a nonsense distracter. (4) The purpose of checking his pulse rate before exercising is not that it is needed to formulate a hypothesis. A hypothesis is a statement of the probable outcome of a scientific experiment. Hypotheses are typically developed from the experimenter's prior research into an area of inquiry. Checking the student's resting pulse rate does not constitute an experimental hypothesis The list below includes three organ systems that are DIRECTLY used when a human runs. circulatory system muscular system skeletal system Which one of the following systems should also be included in the list? 1. immune system. digestive system 2. reproductive system 4. nervous system 4 The nervous system is the system that should also be included in the list. When a person engages in a physical activity such as running, the nervous system is fully involved in such neural activities as conscious decision making, motor coordination, reflex, and autonomic control of the rates of breathing and heartbeat. This neural control allows the body to maintain homeostasis even while under the stress of the physical activity. (1) The immune system is not the system that should also be included in the list. Although the immune system is constantly at work protecting the body from infectious disease, this action is not directly related to the physical activity of running. (2) The reproductive system is not the system that should also be included in the list. Although the reproductive system is constantly at work preparing the body for the production of offspring, this action is not directly related to the physical activity of running. () The digestive system is not the system that should also be included in the list. Although the digestive system is constantly at work processing foods that provide the body with materials and energy, this action is not directly related to the physical activity of running A student measures his pulse rate while he is watching television and records it. Next, he walks to a friend's house nearby and when he arrives, measures and records his pulse rate again. He and his friend then decide to run to the mall a few blocks away. On arriving at the mall, the student measures and records his pulse rate once again. Finally, after sitting and talking for a half hour, the student measures and records his pulse rate for the last time. Which graph best illustrates the expected changes in his pulse rate according to the