Part 1 Chapters 1-18 PDF

Chapter 1 Introduction: Themes in the Study of Life The introduction to the study of biology in Chapter 1 highlights seven book -wide themes, with special emphasis on the core theme of evolution. How scientists use inductive reasoning to draw general conclusions and deductive reasoning to test hypotheses is emphasized. Questions in this chapter are designed to help assess a student’s understanding of the content of Chapter 1 based on the three key concepts. Multiple-Choice Questions 1) Which of the following properties or processes do we associate with living things? A) evolutionary adaptations B) energy processing C) responding to the environment D) growth and reproduction E) all of the above 2) Which of the following is not a theme that unifies biology? A) interaction with the environment B) emergent properties C) evolution D) reductionism E) structure and function 3) Which of the following sequences represents the hierarchy of biological organization from the least to the most complex level? A) organelle, tissue, biosphere, ecosystem, population, organism B) cell, community, population, organ system, molecule, organelle C) organism, community, biosphere, molecule, tissue, organ D) ecosystem, cell, population, tissue, organism, organ system E) molecule, cell, organ system, population, ecosystem, biosphere 4) A localized group of organisms that belong to the same species is called a A) biosystem. B) community. C) population. D) ecosystem. E) family. 5) Which of the following is a false statement regarding DNA? A) Each chromosome has one very long DNA molecule with hundreds of thousands of genes. B) Every cell is enclosed by a membrane. C) Every cell uses DNA as its genetic information. D) All forms of life are composed of cells that have a membrane-enclosed nucleus. E) DNA is the unit of inheritance that is transmitted from parent to offspring. 6) In terms of the hierarchical organization of life, a bacterium is at the level of organization, whereas a human is at the level of organization. A) single-celled organism; multicellular organism B) single organelle; organism C) organelle; organ system D) single tissue; multicellular organism E) tissue; organism 7) Which of these is a correct representation of the hierarchy of biological organization from least to most complex? A) organelle of a stomach cell, digestive system, large intestine, small intestine, intestinal tissue, organism B) organelle of an intestinal cell, digestive system, small intestine, large intestine, intestinal tissue, organism C) molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism D) molecule, small intestine, large intestine, intestinal tissue, digestive system, organism E) molecule, digestive system, digestive cell organelle, small intestine, large intestine, intestinal cell, organism 8) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into A) the energy of motion. B) carbon dioxide and water. C) the potential energy of chemical bonds. D) oxygen. E) kinetic energy. 9) The main source of energy for producers in an ecosystem is A) light energy. B) kinetic energy. C) thermal energy. D) chemical energy. E) ATP. 10) The dynamics of any ecosystem include the following major processes: A) the flow of energy from sunlight to producers B) the flow of energy from sunlight to producers and then to consumers C) the recycling of chemical nutrients D) the flow of energy to producers and the recycling of nutrients E) the flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients. 11) For most ecosystems is (are) the ultimate source of energy, and energy leaves the ecosystem in the form of. A) sunlight; heat B) heat; light C) plants; animals D) plants; heat E) producers; consumers 12) The illustration above represents A) a computer simulation of the structure of a eukaryotic cell. B) a map of a network of protein interactions within a eukaryotic cell. C) an inventory of all the genes in a fruit fly. D) an X-ray diffraction image of the nucleus and cytoplasm of a eukaryotic cell. E) a computer generated map of the interaction of genes and cytoplasm in a prokaryotic cell. 13) The lowest level of biological organization that can perform all the activities required for life is the A) organelle–for example, a chloroplast. B) cell–for example, a skin cell. C) tissue–for example, nervous tissue. D) organ system–for example, the reproductive system. E) organism–for example, an amoeba, dog, human, or maple tree. 14) Which of the following is a false statement regarding deoxyribonucleic acid (DNA)? A) Each deoxyribonucleic acid molecule is composed of two long chains of nucleotides arranged in a double helix. B) Genes are composed of deoxyribonucleic acid. C) DNA is composed of chemical building blocks called nucleotides. D) DNA is a code for the sequence of amino acids in a protein. E) DNA is an enzyme that puts together amino acids to make a protein. 15) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? A) animal B) plant C) archaea D) fungi E) protists 16) Which of the following statements concerning prokaryotic and eukaryotic cells is not correct? A) Prokaryotic cells lack a membrane-bound nucleus. B) Prokaryotic cells contain small membrane-enclosed organelles. C) Eukaryotic cells contain a membrane-bound nucleus. D) DNA, or deoxyribonucleic acid, is present in both prokaryotic cells and eukaryotic cells. E) DNA or deoxyribonucleic acid is present in the nucleus of eukaryotic cells. 17) Which of the following is reflective of the phrase "the whole is greater than the sum of its parts"? A) high-throughput technology B) emergent properties C) natural selection D) reductionism E) feedback regulations 18) In order to understand the chemical basis of inheritance, one must understand the molecular structure of DNA. This is an example of the application of to the study of biology. A) evolution B) emergent properties C) reductionism D) the cell theory E) feedback regulation 19) A type of protein critical to all cells is organic catalysts called A) feedback activators. B) feedback inhibitors. C) enzymes. D) metabolites. E) nutrients. 20) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of A) a bioinformatic system. B) positive feedback. C) negative feedback. D) feedback inhibition. E) enzymatic catalysis. 21) When blood glucose level rises, the pancreas secretes insulin, and as a result blood glucose level declines. When blood glucose level is low, the pancreas secretes glucagon, and as a result blood glucose level rises. Such regulation of blood glucose level is the result of A) catalytic feedback. B) positive feedback. C) negative feedback. D) bioinformatic regulation. E) protein-protein interactions. 22) Life is diverse. How many species are estimated to be presently on the earth? A) 1,800 B) 180,000 C) 1,800,000 D) 18,000,000 E) 180,000,000 23) Which branch of biology is concerned with the naming and classifying of organisms? A) informatics B) schematic biology C) taxonomy D) genomics E) evolution 24) Prokaryotic and eukaryotic cells generally have which of the following features in common? A) a membrane-bounded nucleus B) a cell wall made of cellulose C) ribosomes D) flagella or cilia that contain microtubules E) linear chromosomes made of DNA and protein 25) Prokaryotes are classified as belonging to two different domains. What are the domains? A) Bacteria and Eukarya B) Archaea and Monera C) Eukarya and Monera D) Bacteria and Protista E) Bacteria and Archaea 26) Species that are in the same are more closely related than species that are only in the same. A) phylum; class B) family; order C) class; order D) family; genus E) kingdom; phylum 27) Two species that belong to the same genus must also belong to the same A) kingdom. B) phylum. C) class. D) order. E) all of the above 28) Which of these is reflective of the hierarchical organization of life from most to least inclusive? A) kingdom, order, family, phylum, class, genus, species B) phylum, class, order, kingdom, family, genus, species C) kingdom, phylum, class, order, family, genus, species D) genus, species, kingdom, phylum, class, order, family E) class, order, kingdom, phylum, family, genus, species 29) A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification? A) Eukarya B) Archaea C) Animalia D) Protista E) Fungi 30) A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism? A) domain Bacteria, kingdom Prokaryota B) domain Archaea, kingdom Bacteria C) domain Eukarya, kingdom Plantae D) domain Eukarya, kingdom Protista E) domain Eukarya, kingdom Fungi 31) Which of these provides evidence of the common ancestry of all life? A) the ubiquitous use of catalysts by living systems B) the universality of the genetic code C) the structure of the nucleus D) the structure of cilia E) the structure of chloroplasts 32) Which of the following is (are) true of natural selection? A) requires genetic variation B) results in descent with modification C) involves differential reproductive success D) B and C only E) A, B, and C 33) Charles Darwin proposed a mechanism for descent with modification which stated that organisms of a particular species are adapted to their environment when they possess A) non-inheritable traits that enhance their survival in the local environment. B) non-inheritable traits that enhance their reproductive success in the local environment. C) non-inheritable traits that enhance their survival and reproductive success in the local environment. D) inheritable traits that enhance their survival and reproductive success in the local environment. E) inheritable traits that decrease their survival and reproductive success in the local environment. 34) All of the following statements are part of Charles Darwin's concept of natural selection except A) Slight inheritable variations within a population may make an individual significantly more or less likely to survive in its environment, and thus to reproduce. B) Every organism has the potential to produce more offspring than the local environment can support. C) Characteristics of organisms are inherited as genes on chromosomes. D) Better adapted members of a species will survive and reproduce more successfully. E) Most individuals in a species do not survive to reproduce. 35) Which of these individuals is most likely to be successful in an evolutionary sense? A) a reproductively sterile individual who never falls ill B) an organism that dies after 5 days of life but leaves 10 offspring, all of whom survive to reproduce C) a male who mates with 20 females and fathers 1 offspring D) an organism that lives 100 years and leaves 2 offspring, both of whom survive to reproduce E) a female who mates with 20 males and produces 1 offspring 36) In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will A) remain unchanged. B) gradually decline. C) rapidly decline. D) gradually increase. E) rapidly increase. 37) Through time, the lineage that led to modern whales shows a change from four -limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by A) natural philosophy. B) creationism. C) the hierarchy of the biological organization of life. D) natural selection. E) feedback inhibition. 38) Evolution is biology's core theme that ties together all the other themes. This is because evolution explains A) the unity and diversity of life. B) how organisms become adapted to their environment through the differential reproductive success of varying individuals. C) why distantly related organisms sometimes resemble each other. D) explains why some organisms have traits in common. E) all of the above 39) The method of scientific inquiry that describes natural structures and processes as accurately as possible through careful observation and the analysis of data is known as A) hypothesis-based science. B) discovery science. C) experimental science. D) quantitative science. E) qualitative science. 40) Collecting data based on observation is an example of ; analyzing this data to reach a conclusion is an example of reasoning. A) hypothesis-based science; inductive B) the process of science; deductive C) discovery science; inductive D) descriptive science; deductive E) hypothesis-based science; deductive 41) What is a hypothesis? A) the same thing as an unproven theory B) a tentative explanation that can be tested and is falsifiable C) a verifiable observation sensed directly, or sensed indirectly with the aid of scientific instrumentation D) a fact based on qualitative data that is testable E) a fact based on quantitative data that is falsifiable 42) Which of these is based on a deduction? A) My car won't start. B) My car's battery is dead. C) My car is out of gas. D) I lost my car key. E) If I turn the key in the ignition while stepping on the gas pedal, then my car will start. 43) When applying the process of science, which of these is tested? A) a question B) a result C) an observation D) a prediction E) a hypothesis 44) A controlled experiment is one in which A) the experiment is repeated many times to ensure that the results are accurate. B) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data. C) there are at least two groups, one of which does not receive the experimental treatment. D) there are at least two groups, one differing from the other by two or more variables. E) there is one group for which the scientist controls all variables. 45) Why is it important that an experiment include a control group? A) The control group is the group that the researcher is in control of; it is the group in which the researcher predetermines the nature of the results. B) The control group provides a reserve of experimental subjects. C) A control group is required for the development of an "if, then" statement. D) A control group assures that an experiment will be repeatable. E) Without a control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor. 46) The application of scientific knowledge for some specific purpose is known as A) technology. B) deductive science. C) inductive science. D) anthropologic science. E) pure science. True/False Questions 47) A common form of regulation in which accumulation of an end product of a process slows that process is called positive feedback. 48) Charles Darwin presented verifiable evidence that supported the view that life can arise by spontaneous generation. 49) Recent evidence points to the conclusion that the ancestral finches of the Galapagos originated in the islands of the Caribbean. 50) Discovery science uses inductive reasoning to derive generalizations from a large number of specific observations. 51) In hypothesis-based science, deductive reasoning is used to predict a result that would be found if a particular hypothesis is correct. 52) Discovery science has contributed much to our understanding of nature without most of the steps of the so-called scientific method. 53) Science requires that hypothesis be testable and falsifiable and that observations be repeatable. 54) A theory in science is equivalent in scope to a well-structured hypothesis. 55) The goal of systems biology is to construct models to predict the emergent properties of cells. Self-Quiz Questions The following questions are from the end-of-chapter-review Self-Quiz questions in Chapter 1 of the textbook. 1) All the organisms on your campus make up A) an ecosystem. B) a community. C) a population. D) an experimental group. E) a taxonomic domain. 2) Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal? A) brain, organ system, nerve cell, nervous tissue B) organ system, nervous tissue, brain C) organism, organ system, tissue, cell, organ D) nervous system, brain, nervous tissue, nerve cell E) organ system, tissue, molecule, cell 3) Which of the following is not an observation or inference on which Darwin's theory of natural selection is based? A) Poorly adapted individuals never produce offspring. B) There is heritable variation among individuals. C) Because of overproduction of offspring, there is competition for limited resources. D) Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring. E) A population can become adapted to its environment. 4) Systems biology is mainly an attempt to A) understand the integration of all levels of biological organization from molecules to the biosphere. B) simplify complex problems by reducing the system into smaller, less complex units. C) construct models of the behavior of entire biological systems. D) build high-throughput machines for the rapid acquisition of biological data. E) speed up the technological application of scientific knowledge. 5) Protists and bacteria are grouped into different domains because A) protists eat bacteria. B) bacteria are not made of cells. C) protists have a membrane-bounded nucleus, which bacterial cells lack. D) bacteria decompose protists. E) protists are photosynthetic. 6) Which of the following best demonstrates the unity among all organisms? A) matching DNA nucleotide sequences B) descent with modification C) the structure and function of DNA D) natural selection E) emergent properties 7) Which of the following is an example of qualitative data? A) The temperature decreased from 20°C to 15°C. B) The plant's height is 25 centimeters (cm). C) The fish swam in a zig-zag motion. D) The six pairs of robins hatched an average of three chicks. E) The contents of the stomach are mixed every 20 seconds. 8) Which of the following best describes the logic of hypothesis-based science? A) If I generate a testable hypothesis, tests and observations will support it. B) If my prediction is correct, it will lead to a testable hypothesis. C) If my observations are accurate, they will support my hypothesis. D) If my hypothesis is correct, I can expect certain test results. E) If my experiments are set up right, they will lead to a testable hypothesis. 9) A controlled experiment is one that A) proceeds slowly enough that a scientist can make careful records of the results. B) may include experimental groups and control groups tested in parallel. C) is repeated many times to make sure the results are accurate. D) keeps all environmental variables constant. E) is supervised by an experienced scientist. 10) Which of the following statements best distinguishes hypotheses from theories in science? A) Theories are hypotheses that have been proved. B) Hypotheses are guesses; theories are correct answers. C) Hypotheses usually are relatively narrow in scope; theories have broad explanatory power. D) Hypotheses and theories are essentially the same thing. E) Theories are proved true in all cases; hypotheses are usually falsified by tests. 11) With rough sketches, draw a biological hierarchy similar to the one in Figure 1.4 in the text but using a coral reef as the ecosystem, a fish as the organism, its stomach as the organ, and DNA as the molecule. Include all levels in the hierarchy. Chapter 2 The Chemical Context of Life Information in this chapter establishes a foundation for later discussion and elaboration of molecular-level events and processes in biological systems. Ensuring that students possess the technical vocabulary (terms and definitions) to understand descriptions in later chapters is a major focus. Test Bank questions emphasize understanding and application of technical vocabulary, as well as comprehension of atomic structure and processes such as electron orbitals, bond formation, ionization, etc. Questions near the end of this Test Bank set emphasize ability to relate terminology and word descriptions to pictorial or symbolic representations of atomic structures and processes. Most students will probably find these later questions most difficult. Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? A) carbon, sodium, chlorine, nitrogen B) carbon, sulfur, phosphorus, hydrogen C) oxygen, hydrogen, calcium, sodium D) carbon, hydrogen, nitrogen, oxygen E) carbon, oxygen, sulfur, calcium 2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates? A) nitrogen B) calcium C) iodine D) sodium E) phosphorus 3) Three or four of the following statements are true and correct. Which one, if any, is false? If all the statements are true, choose answer E. A) Carbon, hydrogen, oxygen, and nitrogen make up approximately 96% of living matter. B) The trace element iodine is required only in very small quantities by vertebrates. C) Virtually all organisms require the same elements in the same quantities. D) Iron is an example of an element needed by all organisms. E) All of the other statements are true and correct. 17 4) Which of the following statements is false? A) Atoms of the various elements differ in their number of subatomic particles. B) All atoms of a particular element have the same number of protons in their nuclei. C) The neutrons and protons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton. D) An atom is the smallest unit of an element that still retains the properties of the element. E) Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge. 5) Each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. Which of the following indicates the number of protons in an atom's nucleus? A) atomic mass B) atomic weight C) atomic number D) mass weight E) mass number 6) The mass number of an element can be easily approximated by adding together the number of in an atom of that element. A) protons and neutrons B) energy levels C) protons and electrons D) neutrons and electrons E) isotopes 7) What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons? A) 15 daltons B) 16 daltons C) 30 daltons D) 31 daltons E) 46 daltons 8) Oxygen has an atomic number of 8 and a mass number of 16. Thus, the atomic mass of an oxygen atom is A) exactly 8 grams. B) exactly 8 daltons. C) approximately 16 grams. D) approximately 16 daltons. E) 24 amu (atomic mass units). 9) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen? A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14. B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7. C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams. D) The nitrogen atom has a mass number of 7 grams and an atomic number of 14. E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons. 10) Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have A) 20 protons. B) 40 electrons. C) 40 neutrons. D) A and B only E) A, B, and C 11) An atom with an atomic number of 9 and a mass number of 19 would have an atomic mass of approximately A) 9 daltons. B) 9 grams. C) 10 daltons. D) 20 grams. E) 19 daltons. 12) Different atomic forms of an element contain the same number of protons but a different number of neutrons. What are these different atomic forms called? A) ions B) isotopes C) neutronic atoms D) isomers E) radioactive atoms 13) How do isotopes of the same element differ from each other? A) number of protons B) number of electrons C) number of neutrons D) valence electron distribution E) amount of radioactivity 14) Which of the following best describes the relationship between the atoms described below? Atom 1 Atom 2 1H 3H 1 1 A) They are isomers. B) They are polymers. C) They are isotopes. D) They contain 1 and 3 protons, respectively. E) They each contain 1 neutron. 15) Which of the following best describes the relationship between the atoms described below? Atom 1 Atom 2 31 P 32 P 15 15 A) They contain 31 and 32 electrons, respectively. B) They are both phosphorus cations. C) They are both phosphorus anions. D) They are both isotopes of phosphorus. E) They contain 31 and 32 protons, respectively. 16) One difference between carbon-12 ( 12 C) and carbon-14 ( 14 C) is that carbon-14 has 6 6 A) two more protons than carbon-12. B) two more electrons than carbon-12. C) two more neutrons than carbon-12. D) A and C only E) B and C only 17) 3 H is a radioactive isotope of hydrogen. One difference between hydrogen-1 ( 1 H) and 1 hydrogen-3 ( 3 H) is that hydrogen-3 has 1 A) one more neutron and one more proton than hydrogen-1. B) one more proton and one more electron than hydrogen -1. C) one more electron and one more neutron than hydrogen-1. D) two more neutrons than hydrogen-1. E) two more protons than hydrogen-1. 18) The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon-14 contains neutrons. A) 6 B) 7 C) 8 D) 12 E) 14 19) Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that A) an electron may move to an electron shell farther out from the nucleus. B) an electron may move to an electron shell closer to the nucleus. C) the atom may become a radioactive isotope. D) the atom would become a positively charged ion, or cation. E) the atom would become a negatively charged ion, or anion. 20) The atomic number of neon is 10. Therefore, which of the following is correct about an atom of neon? A) It has 8 electrons in its outer electron shell. B) It is inert. C) It has an atomic mass of 10 daltons. D) A and B only E) A, B, and C are correct. 21) From its atomic number of 15, it is possible to predict that the phosphorus atom has A) 15 neutrons. B) 15 protons. C) 15 electrons. D) 8 electrons in its outermost electron shell. E) B and C only Please refer to Figure 2.1 to answer the following questions. Figure 2.1 22) Which drawing depicts the electron configuration of neon ( 20 Ne)? 10 23) Which drawing depicts the electron configuration of oxygen ( 16 O)? 8 24) Which drawing depicts the electron configuration of nitrogen ( 14 N)? 7 25) Which drawing is of an atom with the atomic number of 6? 26) Which drawing depicts an atom that is inert or chemically unreactive? 27) Which drawing depicts an atom with a valence of 3? 28) Which drawing depicts an atom with a valence of 2? 29) Atoms whose outer electron shells contain eight electrons tend to A) form ionic bonds in aqueous solutions. B) form covalent bonds in aqueous solutions. C) be stable and chemically nonreactive, or inert. D) be unstable and chemically very reactive. E) be isotopes and very radioactive. Use the information extracted from the periodic table in Figure 2.2 to answer the following questions. Figure 2.2 30) How many electrons does nitrogen have in its valence shell? A) 2 B) 5 C) 7 D) 8 E) 14 31) How many electrons does phosphorus have in its valence shell? A) 1 B) 2 C) 3 D) 4 E) 5 32) How many neutrons are present in the nucleus of a phosphorus atom? A) 8 B) 15 C) 16 D) 31 E) 46 33) How many electrons does an atom of sulfur have in its valence shell? A) 4 B) 6 C) 8 D) 16 E) 32 34) Based on electron configuration, which of these elements would exhibit chemical behavior most like that of oxygen? A) carbon B) hydrogen C) nitrogen D) sulfur E) phosphorus 35) How many electrons would be expected in the outermost electron shell of an atom with atomic number 12? A) 1 B) 2 C) 4 D) 6 E) 8 36) The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon ( 12 C)? 6 A) 7nitrogen B) 9flourine C) 10neon D) 12magnesium E) 14silicon 37) What is the valence of an atom with six electrons in its outer electron shell? A) 1 B) 2 C) 3 D) 4 E) 5 38) Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom? A) 1 B) 3 C) 5 D) 7 E) 9 39) What is the maximum number of electrons in the 1s orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5 40) What is the maximum number of electrons in a 2p orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5 41) A covalent chemical bond is one in which A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. D) outer-shell electrons of one atom are transferred to the inner electron shells of another atom. E) the inner-shell electrons of one atom are transferred to the outer shell of another atom. 42) If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed? A) S-H B) H-S-H C) H- S-H | H D) H | H- S-H | H E) H=S=H 43) What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen? A) 1 B) 2 C) 3 D) 4 E) 6 44) A molecule of carbon dioxide (CO2) is formed when one atom of carbon (atomic number 6) is covalently bonded with two atoms of oxygen (atomic number 8). What is the total number of electrons that must be shared between the carbon atom and the oxygen atoms in order to complete the outer electron shell of all three atoms? A) 1 B) 2 C) 3 D) 4 E) 5 45) Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)? A) Each hydrogen atom has a partial positive charge. B) The nitrogen atom has a strong positive charge. C) Each hydrogen atom has a slight negative charge. D) The nitrogen atom has a partial positive charge. E) There are covalent bonds between the hydrogen atoms. 46) When two atoms are equally electronegative, they will interact to form A) equal numbers of isotopes. B) ions. C) polar covalent bonds. D) nonpolar covalent bonds. E) ionic bonds. 47) What results from an unequal sharing of electrons between atoms? A) a nonpolar covalent bond B) a polar covalent bond C) an ionic bond D) a hydrogen bond E) a hydrophobic interaction 48) A covalent bond is likely to be polar when A) one of the atoms sharing electrons is much more electronegative than the other atom. B) the two atoms sharing electrons are equally electronegative. C) the two atoms sharing electrons are of the same element. D) it is between two atoms that are both very strong electron acceptors. E) the two atoms sharing electrons are different elements. 49) Which of the following molecules contains the strongest polar covalent bond? A) H2 B) O2 C) CO2 D) H2O E) CH4 The following questions refer to Figure 2.3. Figure 2.3 50) What results from the chemical reaction illustrated in Figure 2.3? A) a cation with a net charge of +1 B) a cation with a net charge of -1 C) an anion with a net charge of +1 D) an anion with a net charge of -1 E) A and D 51) What is the atomic number of the cation formed in the reaction illustrated in Figure 2.3? A) 1 B) 8 C) 10 D) 11 E) 16 52) The ionic bond of sodium chloride is formed when A) chlorine gains an electron from sodium. B) sodium and chlorine share an electron pair. C) sodium and chlorine both lose electrons from their outer valence shells. D) sodium gains an electron from chlorine. E) chlorine gains a proton from sodium. 53) What is the difference between covalent bonds and ionic bonds? A) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of electrons between atoms. B) Covalent bonds involve the sharing of neutrons between atoms, and ionic bonds involve the sharing of electrons between atoms. C) Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms. D) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of neutrons between atoms. E) Covalent bonds involve the transfer of electrons between atoms, and ionic bonds involve the sharing of neutrons between atoms. - 54) In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl. What is the cation of NH4Cl? A) N, with a charge of +3 B) H, with a charge of +1 C) H2 with a charge of +4 D) NH4 with a charge of +1 E) NH4 with a charge of +4 55) The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? A) MgCl B) MgCl2 C) Mg2Cl D) Mg2Cl2 E) MgCl3 56) Which of the following results from a transfer of electron(s) between atoms? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction 57) Which of the following explains most specifically the attraction of water molecules to one another? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction 58) Van der Waals interactions result when A) hybrid orbitals overlap. B) electrons are not symmetrically distributed in a molecule. C) molecules held by ionic bonds react with water. D) two polar covalent bonds react. E) a hydrogen atom loses an electron. 59) A van der Waals interaction is the weak attraction between A) the electrons of one molecule and the electrons of a nearby molecule. B) the nucleus of one molecule and the electrons of a nearby molecule. C) a polar molecule and a nearby nonpolar molecule. D) a polar molecule and a nearby molecule that is also polar. E) a nonpolar molecule and a nearby molecule that is also nonpolar. 60) Which of the following is not considered to be a weak molecular interaction? A) a covalent bond B) a van der Waals interaction C) an ionic bond in the presence of water D) a hydrogen bond E) A and B only 61) Which of the following would be regarded as compounds? A) H2 B) H2O C) O2 D) CH4 E) B and D, but not A and C 62) Sometimes atoms form molecules by sharing two pairs of valence electrons. When this occurs, the atoms are said to be joined by A) a double covalent bond. B) an electronegative bond. C) a hydrogen bond. D) a protonic bond. E) a complex bond. Refer to the following figure to answer the following questions. 63) The molecule shown here could be described in chemical symbols as A) CH4. B) H2O. C) C2H3. D) C4H4. E) CH2O. 64) The molecule shown here is the simplest of organic compounds. It is called A) a carbohydrate. B) carbon dioxide. C) methane. D) carbonic hydrate. E) methyl carbonate. Refer to the following figure to answer the following questions. 65) In the methane molecule shown here, bonds have formed that include both the s orbital valence electrons of the hydrogen atoms and the p orbital valence electrons of the carbon. The electrons in these bonds are said to have A) double orbitals. B) tetrahedral orbitals. C) complex orbitals. D) hybrid orbitals. E) reduced orbitals. 66) Which one of the atoms shown would be most likely to form a cation with a charge of +1? A) B) C) D) E) 67) Which one of the atoms shown would be most likely to form an anion with a charge of -1? A) B) C) D) E) 68) Which of the following pairs of atoms would be most likely to form a covalent bond? A) B) C) D) E) 69) Which of the following pairs of atoms would be most likely to form an ionic bond? A) B) C) D) E) 70) The hybrid orbitals in a molecule of methane are oriented A) toward the corners of a tetrahedron centered on the carbon atom. B) toward the corners of a cube centered on the carbon atom. C) toward the corners of a triangle centered on the carbon atom. D) toward the corners of a rectangle centered on the carbon atom. E) toward the edges of an oval centered on the carbon atom. 71) Which of the following is true for this reaction? 3 H2 + N2 ↔ 2 NH3 A) The reaction is nonreversible. B) Hydrogen and nitrogen are the reactants of the reverse reaction. C) Hydrogen and nitrogen are the products of the forward reaction. D) Ammonia is being formed and decomposed. E) Hydrogen and nitrogen are being decomposed. 72) Which of the following best describes chemical equilibrium? A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. D) Reactions stop only when all reactants have been converted to products. E) There are equal concentrations of reactants and products, and the reactions have stopped. 73) Which of the following describes any reaction that has reached chemical equilibrium? A) The concentration of the reactants equals the concentration of the products. B) The rate of the forward reaction is equal to the rate of the reverse reaction. C) All of the reactants have been converted to the products of the reaction. D) All of the products have been converted to the reactants of the reaction. E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products. 74) A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone? A) a compound with the same number of carbon atoms as the hormone B) a compound with the same molecular mass (measured in daltons) as the hormone C) a compound with the same three-dimensional shape as part of the hormone D) a compound with the same number of orbital electrons as the hormone E) a compound with the same number of hydrogen and nitrogen atoms as the hormone Self-Quiz Questions The following questions are from the end-of-chapter-review Self-Quiz questions in Chapter 2 of the textbook. 1) In the term trace element, the modifier trace means A) the element is required in very small amounts. B) the element can be used as a label to trace atoms through an organism's metabolism. C) the element is very rare on Earth. D) the element enhances health but is not essential for the organism's long-term survival. E) the element passes rapidly through the organism. 2) Compared with 31P, the radioactive isotope 32P has A) a different atomic number. B) one more neutron. C) one more proton. D) one more electron. E) a different charge. 3) Atoms can be represented by simply listing the number of protons, neutrons, and electrons -for example, 2p+; 2n0; 2e- for helium. Which one of the following lists represents the 18O isotope of oxygen? A) 6p+; 8n0; 6e- B) 8p+; 10n0; 8e- C) 9p+; 9n0; 9e- D) 7p+; 2n0; 9e- E) 10p+; 8n0; 9e- 4) The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound: A) HS B) HS2 C) H2S D) H3S2 E) H4S 5) The reactivity of an atom arises from A) the average distance of the outermost electron shell from the nucleus. B) the existence of unpaired electrons in the valence shell. C) the sum of the potential energies of all the electron shells. D) the potential energy of the valence shell. E) the energy difference between the s and p orbitals. 6) Which statement is true of all atoms that are anions? A) The atom has more electrons than protons. B) The atom has more protons than electrons. C) The atom has fewer protons than does a neutral atom of the same element. D) The atom has more neutrons than protons. E) The net charge is 12. 7) What coefficients must be placed in the following blanks so that all atoms are accounted for in the products? C6H12O6 C2H6O + CO2 A) 1; 2 B) 2; 2 C) 1; 3 D) 1; 1 E) 3; 1 8) Which of the following statements correctly describes any chemical reaction that has reached equilibrium? A) The concentrations of products and reactants are equal. B) The rate of the forward reaction equals the rate of the reverse reaction. C) Both forward and reverse reactions have halted. D) The reaction is now irreversible. E) No reactants remain. 9) Draw Lewis structures for each hypothetical molecule shown below, using the correct number of valence electrons for each atom. Determine which molecule makes sense because each atom has a complete valence shell and each bond has the correct number of electrons. Explain what makes the other molecules nonsensical, considering the number of bonds each type of atom can make. Chapter 3 Water and the Fitness of the Environment As far as we know, life depends on water. Chemical and physical properties of water determine many of the features and processes that are fundamental to life. This chapter describes the structure of the water molecule and explores the many ways that polar covalent bonds and hydrogen bonds among water molecules affect organisms and their interactions with their environments. In addition, this chapter discusses topics including concentrations of solutions, hydrogen ion concentration (pH), and buffer solutions. Material in this chapter lends itself to high-level questions involving Application/Analysis and Synthesis/Evaluation of information. In this edition, we have added a number of questions that require interpretation of graphs or translation of information from one format to another (data table to graph, graph to narrative, etc.). Multiple-Choice Questions 1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by A) hydrogen bonds. B) nonpolar covalent bonds. C) polar covalent bonds. D) ionic bonds. E) van der Waals interactions. 2) The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A) a covalent bond B) a hydrogen bond C) an ionic bond D) a hydrophilic bond E) a hydrophobic bond 3) An example of a hydrogen bond is the bond between A) C and H in methane (CH4). B) the H of one water molecule and the O of another water molecule. C) Na+and Cl- in salt. D) the two hydrogen atoms in a molecule of hydrogen gas (H 2). E) Mg+and Cl- in MgCl2. 41 4) Water is able to form hydrogen bonds because A) oxygen has a valence of 2. B) the water molecule is shaped like a tetrahedron. C) the bonds that hold together the atoms in a water molecule are polar covalent bonds. D) the oxygen atom in a water molecule has a weak positive charge. E) each of the hydrogen atoms in a water molecule is weakly negative in charge. 5) What gives rise to the cohesiveness of water molecules? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) both A and C 6) Which of the following effects is produced by the high surface tension of water? A) Lakes don't freeze solid in winter, despite low temperatures. B) A water strider can walk across the surface of a small pond. C) Organisms resist temperature changes, although they give off heat due to chemical reactions. D) Water can act as a solvent. E) The pH of water remains exactly neutral. 7) Which of the following takes place as an ice cube cools a drink? A) Molecular collisions in the drink increase. B) Kinetic energy in the drink decreases. C) A calorie of heat energy is transferred from the ice to the water of the drink. D) The specific heat of the water in the drink decreases. E) Evaporation of the water in the drink increases. 8) Which of the following statements correctly defines a kilocalorie? A) the amount of heat required to raise the temperature of 1 g of water by 1°F B) the amount of heat required to raise the temperature of 1 g of water by 1°C C) the amount of heat required to raise the temperature of 1 kg of water by 1°F D) the amount of heat required to raise the temperature of 1 kg of water by 1°C E) the amount of heat required to raise the temperature of 1,000 g of water by 1°F 9) The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? A) 0.2°C B) 1.0°C C) 2.0°C D) 10.0°C E) 20.0°C 10) Water's high specific heat is mainly a consequence of the A) small size of the water molecules. B) high specific heat of oxygen and hydrogen atoms. C) absorption and release of heat when hydrogen bonds break and form. D) fact that water is a poor heat conductor. E) inability of water to dissipate heat into dry air. 11) Which type of bond must be broken for water to vaporize? A) ionic bonds B) nonpolar covalent bonds C) polar covalent bonds D) hydrogen bonds E) covalent bonds 12) Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon? A) the change in density when it condenses to form a liquid or solid B) reactions with other atmospheric compounds C) the release of heat by the formation of hydrogen bonds D) the release of heat by the breaking of hydrogen bonds E) the high surface tension of water 13) At what temperature is water at its densest? A) 0°C B) 4°C C) 32°C D) 100°C E) 212°C 14) Why does ice float in liquid water? A) The liquid water molecules have more kinetic energy and thus support the ice. B) The ionic bonds between the molecules in ice prevent the ice from sinking. C) Ice always has air bubbles that keep it afloat. D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. E) The crystalline lattice of ice causes it to be denser than liquid water. The following question is based on Figure 3.1: solute molecule surrounded by a hydration shell of water. Figure 3.1 15) Based on your knowledge of the polarity of water molecules, the solute molecule is most likely A) positively charged. B) negatively charged. C) without charge. D) hydrophobic. E) nonpolar. 16) Hydrophobic substances such as vegetable oil are A) nonpolar substances that repel water molecules. B) nonpolar substances that have an attraction for water molecules. C) polar substances that repel water molecules. D) polar substances that have an affinity for water. E) charged molecules that hydrogen-bond with water molecules. 17) One mole (mol) of a substance is A) 6.02 × 1023 molecules of the substance. B) 1 g of the substance dissolved in 1 L of solution. C) the largest amount of the substance that can be dissolved in 1 L of solution. D) the molecular mass of the substance expressed in grams. E) A and D only 18) How many molecules of glucose (C6H2O6 molecular mass =180 daltons) would be present in one mole of glucose? A) 24 B) 342 C) 23 × 1014 D) 180 × 1014 E) 6.02 × 1023 19) How many molecules of glycerol (C3H8O3) would be present in 1 L of a 1 M glycerol solution? A) 1 B) 14 C) 92 D) 1 × 107 E) 6.02 × 1023 20) When an ionic compound such as sodium chloride (NaCl) is placed in water the component atoms of the NaCl crystal dissociate into individual sodium ions (Na +) and chloride ions (Cl- ). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of particles (molecules or ions)? A) 1 L of 0.5 M NaCl B) 1 L of 0.5 M glucose C) 1 L of 1.0 M NaCl D) 1 L of 1.0 M glucose E) C and D will contain equal numbers of particles. 21) The molecular mass of glucose is 180 g. Which of the following procedures should you carry out to make a 1 M solution of glucose? A) Dissolve 1 g of glucose in 1 L of water. B) Dissolve 180 g of glucose in 1 L of water. C) Dissolve 180 g of glucose in 100 g of water. D) Dissolve 180 mg (milligrams) of glucose in 1 L of water. E) Dissolve 180 g of glucose in water, and then add more water until the total volume of the solution is 1 L. 22) The molecular mass of glucose (C6H12O6) is 180 g. Which of the following procedures should you carry out to make a 0.5 M solution of glucose? A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L. B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. D) Dissolve 0.5 g of glucose in 1 L of water. E) Dissolve 180 g of glucose in 1 L of water. Figure 3.2 23) How many grams of the molecule in Figure 3.2 would be equal to 1 mol of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 24) How many grams of the molecule in Figure 3.2 would be required to make 1 L of a 0.5 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 25) How many grams of the molecule in Figure 3.2 would be required to make 2.5 L of a 1 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 26) A small birthday candle is weighed, then lighted and placed beneath a metal can containing 100 mL of water. Careful records are kept as the temperature of the water rises. Data from this experiment are shown on the graph. What amount of heat energy is released in the burning of candle wax? A) 0.5 kilocalories per gram of wax burned B) 5 kilocalories per gram of wax burned C) 10 kilocalories per gram of wax burned D) 20 kilocalories per gram of wax burned E) 50 kilocalories per gram of wax burned 27) Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are non-polar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol? A) B) C) D) E) 28) You have a freshly-prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022 29) The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? A) 55.6M B) 18M C) 37M D) 0.66M E) 1.0M 30) You have a freshly-prepared 1M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022 31) Which of the following ionizes completely in solution and is considered to be a strong acid? A) NaOH B) HCl C) NH3 D) H2CO3 E) CH3COOH 32) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)? A) NaCl B) HCl C) NH3 D) H2CO3 E) NaOH 33) Which of the following statements is completely correct? A) H2CO3 is a weak acid, and NaOH is a weak base (alkali). B) H2CO3 is a strong acid, and NaOH is a strong base (alkali). C) NH3 is a weak base (alkali), and H2CO3 is a strong acid. D) NH3 is a weak base (alkali), and HCl is a strong acid. E) NH3 is a strong base (alkali), and HCl is a weak acid. 34) A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral 35) A solution contains 0.0000001(10-7) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral 36) What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M? A) pH 2 B) pH 4 C) pH 10 D) pH 12 E) pH 14 37) What is the pH of a solution with a hydrogen ion [H +] concentration of 10-8 M? A) pH 2 B) pH 4 C) pH 6 D) pH 8 E) pH 10 38) Which of the following solutions has the greatest concentration of hydrogen ions [H +]? A) gastric juice at pH 2 B) vinegar at pH 3 C) tomato juice at pH 4 D) black coffee at pH 5 E) household bleach at pH 12 39) Which of the following solutions has the greatest concentration of hydroxyl ions [OH-]? A) lemon juice at pH 2 B) vinegar at pH 3 C) tomato juice at pH 4 D) urine at pH 6 E) seawater at pH 8 40) If the pH of a solution is decreased from 9 to 8, it means that the A) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9. B) concentration of H+ has increased 10-fold (10X) compared to what it was at pH 9. C) concentration of OH- has increased 10-fold (10X) compared to what it was at pH 9. D) concentration of OH- has decreased to one-tenth (1/10) what it was at pH 9. E) Both B and D are correct. 41) If the pH of a solution is increased from pH 5 to pH 7, it means that the A) concentration of H+ is twice (2X) what it was at pH 5. B) concentration of H+ is half (1/2) what it was at pH 5. C) concentration of OH- is 100 times greater than what it was at pH 5. D) concentration of OH- is one-hundredth (0.01X) what it was at pH 5. E) concentration of H+ is 100 times greater and the concentration of OH- is one-hundredth what they were at pH 5. 42) One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH 6? A) 4 times more B) 400 times more C) 4,000 times more D) 10,000 times more E) 100,000 times more 43) One liter of a solution pH 9 has how many more hydroxyl ions (OH -) than 1 L of a solution of pH 4? A) 5 times more B) 100 times more C) 1,000 times more D) 10,000 times more E) 100,000 times more 44) Which of the following statements is true about buffer solutions? A) They maintain a constant pH when bases are added to them but not when acids are added to them. B) They maintain a constant pH when acids are added to them but not when bases are added to them. C) They maintain a constant pH of exactly 7 in all living cells and biological fluids. D) They maintain a relatively constant pH when either acids or bases are added to them. E) They are found only in living systems and biological fluids. 45) Buffers are substances that help resist shifts in pH by A) releasing H+ in acidic solutions. B) donating H+ to a solution when they have been depleted. C) releasing OH- in basic solutions. D) accepting H+ when the are in excess. E) Both B and D are correct. 46) One of the buffers that contribute to pH stability in human blood is carbonic acid (H 2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO 3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood drops, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. B) the concentration of hydroxide ion (OH-) to increase. C) the concentration of bicarbonate ion (HCO3-) to increase. D) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3. E) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3. 47) One of the buffers that contribute to pH stability in human blood is carbonic acid H2CO3. Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood increases, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of H2O. B) an increase in the concentration of H2CO3 and a decrease in the concentration of H2O. C) a decrease in the concentration of HCO3- and an increase in the concentration of H2O. D) an increase in the concentration of HCO3- and a decrease in the concentration of H2O. E) a decrease in the concentration of HCO3- and an increase in the concentration of both H2CO3 and H2O. 48) Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake? A) 1 × 10-10 mol of hydroxyl ion per liter of lake water B) 1 × 10-4 mol of hydroxyl ion per liter of lake water C) 10.0 M with regard to hydroxyl ion concentration D) 4.0 M with regard to hydroxyl ion concentration E) both B and D 49) Research indicates that acid precipitation can damage living organisms by A) buffering aquatic systems such as lakes and streams. B) decreasing the H+ concentration of lakes and streams. C) increasing the OH- concentration of lakes and streams. D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth. E) both B and C 50) Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that A) solution Y has no free hydrogen ions (H+). B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y. C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X. D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. E) None of the other answer choices correctly describes these solutions. 51) Pure, freshly-distilled water has a pH of 7. This means that A) there are no H+ ions in the water. B) there are no OH- ions in the water. C) the concentration of H+ ions in the water equals the concentration of OH - ions in the water. D) the concentration of H+ ions in the water is 7 times the concentration of OH- ions in the water. E) The concentration of OH- ions in the water is 7 times the concentration of H+ ions in the water. 52) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly-distilled water, which of the following graphs correctly describes the results? A) B) C) D) E) 53) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O H2CO3. Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2. What prediction can we make about the pH of blood as that blood first comes in contact with respiring cells? A) Blood pH will decrease slightly. B) Blood pH will increase slightly. C) Blood pH will remain unchanged. D) Blood pH will first increase, then decrease as CO2 combines with hemoglobin. E) Blood pH will first decrease, then increase sharply as CO2 combines with hemoglobin. 54) A 100 mL beaker contains 10 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker, 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing? A) The concentration of Na+ ion rises. B) The concentration of Cl- ion falls. C) The concentration of undissociated H2O molecules remains unchanged. D) The pH of the beaker's contents rises. E) The pH of the beaker's contents falls. 55) Equal volumes of vinegar from a freshly-opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH? A) 100 mL of pure water B) 100 mL of freshly-brewed coffee C) 100 mL of household cleanser containing 0.5M ammonia D) 100 mL of freshly-squeezed orange juice E) 100 mL of tomato juice 56) You have two beakers; one contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. A) Equal amounts of NaCl crystals will dissolve in both water and methanol. B) NaCl crystals will NOT dissolve in either water or methanol. C) NaCl crystals will dissolve readily in water but will not dissolve in methanol. D) NaCl crystals will dissolve readily in methanol but will not dissolve in water. E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster. 57) You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCL and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be A) 2.0. B) 12.0. C) 7.0. D) 5.0. E) 9.0. Self-Quiz Questions The following questions are from the end-of-chapter-review Self-Quiz questions in Chapter 3 of the textbook. 1) Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? A) water's change in density when it condenses B) water's ability to dissolve molecules in the air C) the release of heat by the formation of hydrogen bonds D) the absorption of heat by the breaking of hydrogen bonds E) water's high surface tension 2) A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50 -L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) A) 50°C B) 5°C C) 10°C D) 100°C E) 1°C 3) The bonds that are broken when water vaporizes are A) ionic bonds. B) hydrogen bonds between water molecules. C) covalent bonds between atoms within water molecules. D) polar covalent bonds. E) nonpolar covalent bonds 4) Which of the following is a hydrophobic material? A) paper B) table salt C) wax D) sugar E) pasta 5) We can be sure that a mole of table sugar and a mole of vitamin C are equal in their A) mass in daltons. B) mass in grams. C) number of molecules. D) number of atoms. E) volume. 6) How many grams of acetic acid (C2H4O2) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) A) 10.0 g B) 0.1 g C) 6.0 g D) 60.0 g E) 0.6 g 7) Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? A) 4.0 M B) 10-10 M C) 10-4 M D) 104 M E) 4% 8) What is the hydroxide ion concentration of the lake described in question 7? A) 10-7 M B) 10-4 M C) 10-10 M D) 10-14 M E) 10 M 9) Draw three water molecules and label the atoms. Draw solid lines to indicate covalent bonds and dotted lines for hydrogen bonds. Add partial charge labels as appropriate. Chapter 4 Carbon and the Molecular Diversity of Life All organisms are composed mostly of chemical structures based on the element carbon. This chapter builds upon information and concepts introduced in Chapters 2 and 3 and extends the descriptions and analysis to more detailed consideration of the carbon atom. Of all the elements, carbon is unparalleled in its ability to form molecules that are large, complex, and diverse. Student understanding of this complexity and diversity is aided by naming and describing typical groups of atoms (functional groups) that are mixed and matched to construct larger carbon-based molecules. Much of the material in this chapter lends itself to questions that emphasize recall and application; and many such questions are presented. But other topics in this chapter require synthesis and interpretation, as well as visualization of three-dimensional arrangements of atoms, and so we have added several questions that will be more challenging for most students. This chapter lays the foundation for later elaboration of roles of molecular structure in various life processes. Several form/function questions assess student understanding of these concepts. Multiple-Choice Questions 1) Organic chemistry is a science based on the study of A) functional groups. B) vital forces interacting with matter. C) carbon compounds. D) water and its interaction with other kinds of molecules. E) inorganic compounds. 2) Early 19th-century scientists believed that living organisms differed from nonliving things as a result of possessing a "life force" that could create organic molecules from inorganic matter. The term given to this belief is A) organic synthesis. B) vitalism. C) mechanism. D) organic evolution. E) inorganic synthesis. 61 3) The experimental approach taken in current biological investigations presumes that A) simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms. B) a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods. C) although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods. D) living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products. E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena. 4) One of the following people set up a closed system to mimic Earth's early atmosphere and discharged electrical sparks through it. A variety of organic compounds common in organisms were formed. Who did this? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 5) Which of the following people used this apparatus to study formation of organic compounds? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 6) Which of the following people was the first to synthesize an organic compound, urea, from inorganic starting materials? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 7) Which of the following people's synthesis of this compound from inorganic starting materials provided evidence against vitalism? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 8) Which of the following people synthesized an organic compound, acetic acid, from inorganic substances that had been prepared directly from pure elements? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 9) Which of the following people's synthesis of this compound from inorganic starting materials provided evidence against vitalism? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 10) One of the following people was the first to suggest that organic compounds, those found in living organisms, were distinctly different from inorganic compounds found in the nonliving world. Though this suggestion is now known to be incorrect, it stimulated important research into organic compounds. Who suggested this? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé 11) How many electron pairs does carbon share in order to complete its valence shell? A) 1 B) 2 C) 3 D) 4 E) 8 12) A carbon atom is most likely to form what kind of bond(s) with other atoms? A) ionic B) hydrogen C) covalent D) A and B only E) A, B, and C 13) Which of the following statements best describes the carbon atoms present in all organic molecules? A) They were incorporated into organic molecules by plants. B) They were processed into sugars through photosynthesis. C) They are ultimately derived from carbon dioxide. D) Only A and C are correct. E) A, B, and C are correct. 14) Why are hydrocarbons insoluble in water? A) The majority of their bonds are polar covalent carbon-to-hydrogen linkages. B) The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. C) They are hydrophilic. D) They exhibit considerable molecular complexity and diversity. E) They are lighter than water. 15) How many structural isomers are possible for a substance having the molecular formula C4H10? A) 1 B) 2 C) 4 D) 3 E) 11 Figure 4.1 16) The two molecules shown in Figure 4.1 are best described as A) optical isomers. B) radioactive isotopes. C) structural isomers. D) nonradioactive isotopes. E) geometric isomers. Figure 4.2 17) Shown here in Figure 4.2 are the structures of glucose and fructose. These two molecules differ in the A) number of carbon, hydrogen, and oxygen atoms. B) types of carbon, hydrogen, and oxygen atoms. C) arrangement of carbon, hydrogen, and oxygen atoms. D) number of oxygen atoms joined to carbon atoms by double covalent bonds. E) answers A, B, and C 18) Shown here in Figure 4.2 are the structures of glucose and fructose. These two molecules are A) geometric isotopes. B) enantiomers. C) geometric isomers. D) structural isomers. E) nonisotopic isomers. 19) Which of the following statements correctly describes geometric isomers? A) They have variations in arrangement around a double bond. B) They have an asymmetric carbon that makes them mirror images. C) They have the same chemical properties. D) They have different molecular formulas. E) Their atoms and bonds are arranged in different sequences. Figure 4.3 20) The two molecules shown in Figure 4.3 are best described as A) enantiomers. B) radioactive isotopes. C) structural isomers. D) nonisotopic isomers. E) geometric isomers. 21) Research indicates that Ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that A) have identical three-dimensional shapes. B) are mirror images of one another. C) lack an asymmetric carbon. D) differ in the location of their double bonds. E) differ in their electrical charge. 22) Research indicates that Albuterol, a drug used to relax bronchial muscles, improving airflow and thus offering relief from asthma, consists only of one enantiomer, the R-form. Why is it important for this drug to consist of only one enantiomeric form, rather than a mixture of enantiomers? A) Different enantiomers may have different or opposite physiological effects. B) It is impossible to synthesize mixtures of enantiomers. C) It is much less expensive to synthesize one enantiomer at a time. D) Albuterol is an example of a compound for which only one enantiomer exists. E) Only the R-form of Albuterol has been studied; until more information is available, physicians prefer to use the pure R-form. 23) Three or four of the following illustrations depict different structural isomers of the organic compound with molecular formula C6H14. For clarity, only the carbon skeletons are shown; hydrogen atoms that would be attached to the carbons have been omitted. Which one, if any, is NOT a structural isomer of this compound? A) B) C) D) E) Each of the illustrations in the other answer choices depicts a structural isomer of the compound with molecular formula C6H14. 24) Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric forms) of the same molecule? A) B) C) D) E) 25) Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule? A) B) C) D) E) 26) Three or four of the pairs of structures shown below depict enantiomers (enantiomeric forms) of the same molecule. Which pair, if any, are NOT enantiomers of a single molecule? If each of the pairs depicts enantiomers, choose answer F. A) B) C) D) E) F) Both illustrations in each of the other answer choices depict enantiomers of the same molecule. 27) Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that A) have identical three-dimensional shapes. B) are mirror images of one another. C) lack an asymmetric carbon. D) differ in the location of their double bonds. E) differ in their electrical charge. 28) A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound? A) It lacks an asymmetric carbon, and it is probably a fat or lipid. B) It should dissolve in water. C) It should dissolve in a nonpolar solvent. D) It won't form hydrogen bonds with water. E) It is hydrophobic. 29) Which is the best description of a carbonyl group? A) an oxygen joined to a carbon by a single covalent bond B) a nitrogen and two hydrogens joined to a carbon by covalent bonds C) a carbon joined to two hydrogens by single covalent bonds D) a sulfur and a hydrogen joined to a carbon by covalent bonds E) a carbon atom joined to an oxygen by a double covalent bond Figure 4.4 30) What is the name of the functional group shown in Figure 4.4? A) carbonyl B) ketone C) aldehyde D) carboxyl E) hydroxyl 31) Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen? A) an alcohol such as ethanol B) a monosaccharide such as glucose C) a steroid such as testosterone D) an amino acid such as glycine E) a hydrocarbon such as benzene 32) Which of the following is a false statement concerning amino groups? A) They are basic in pH. B) They are found in amino acids. C) They contain nitrogen. D) They are nonpolar. E) They are components of urea. 33) Which two functional groups are always found in amino acids? A) ketone and aldehyde B) carbonyl and carboxyl C) carboxyl and amino D) phosphate and sulfhydryl E) hydroxyl and aldehyde 34) Amino acids are acids because they always possess which functional group? A) amino B) carbonyl C) carboxyl D) sulfhydryl E) aldehyde 35) A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it A) would function only as an acid because of the carboxyl group. B) would function only as a base because of the amino group. C) would function as neither an acid nor a base. D) would function as both an acid and a base. E) is impossible to determine how it would function. 36) A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so? A) carboxyl B) sulfhydryl C) hydroxyl D) amino E) phosphate 37) Which functional groups can act as acids? A) amine and sulfhydryl B) carbonyl and carboxyl C) carboxyl and phosphate D) hydroxyl and aldehyde E) ketone and amino The following questions refer to the structures shown in Figure 4.5. Figure 4.5 38) Which of the structures is an impossible covalently bonded molecule? A) A B) B C) C D) D E) E 39) Which of the structures contain(s) a carboxyl functional group? A) A B) B C) C D) C and E E) none of the structures 40) In which of the structures are the atoms bonded by ionic bonds? A) A B) B C) C D) C, D, and E only E) none of the structures The following questions refer to the functional groups shown in Figure 4.6. Figure 4.6 41) Which is a hydroxyl functional group? 42) Which is an amino functional group? 43) Which is a carbonyl functional group? 44) Which is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules? 45) Which is a carboxyl functional group? 46) Which is an acidic functional group that can dissociate and release H+ into a solution? 47) Which is a basic functional group that can accept H+ and become positively charged? The following questions refer to the molecules shown in Figure 4.7. Figure 4.7 48) Which molecule is water soluble because it has a hydroxyl functional group? 49) Which molecule is an alcohol? 50) Which molecules contain a carbonyl group? A) A and B B) B and C C) C and D D) D and E E) E and A 51) Which molecule has a carbonyl functional group in the form of a ketone? 52) Which molecule has a carbonyl functional group in the form of an aldehyde? 53) Which molecule contains a carboxyl group? 54) Which molecule can increase the concentration of hydrogen ions in a solution and is therefore an organic acid? The following questions refer to the molecules shown in Figure 4.8. Figure 4.8 55) Which molecule contains a sulfhydryl functional group? 56) Which molecule functions to transfer energy between organic molecules? 57) Which molecule contains an amino functional group, but is not an amino acid? 58) Which molecule is a thiol? 59) Which molecule is an organic phosphate? 60) Which molecule can function as a base? 61) Testosterone and estradiol are A) nucleic acids. B) carbohydrates. C) proteins. D) phospholipids. E) steroids. 62) Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? A) Testosterone and estradiol are structural isomers but have the same molecular formula. B) Testosterone and estradiol are geometric isomers but have the same molecular formula. C) Testosterone and estradiol have different functional groups attached to the same carbon skeleton. D) Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, while the other has three rings. E) Testosterone and estradiol are enantiomers of the same organic molecule. Self-Quiz Questions The following questions are from the end-of-chapter-review Self-Quiz questions in Chapter 4 of the textbook. 1) Organic chemistry is currently defined as A) the study of compounds made only by living cells. B) the study of carbon compounds. C) the study of vital forces. D) the study of natural (as opposed to synthetic) compounds. E) the study of hydrocarbons. 2) Which of the following hydrocarbons has a double bond in its carbon skeleton? A) C3H8 B) C2H6 C) CH4 D) C2H4 E) C2H2 3) Choose the term that correctly describes the relationship between these two sugar molecules: A) structural isomers B) geometric isomers C) enantiomers D) isotopes 4) Identify the asymmetric carbon in this molecule: 5) Which functional group is not present in this molecule? A) carboxyl B) sulfhydryl C) hydroxyl D) amino 6) Which action could produce a carbonyl group? A) the replacement of the -OH of a carboxyl group with hydrogen B) the addition of a thiol to a hydroxyl C) the addition of a hydroxyl to a phosphate D) the replacement of the nitrogen of an amine with oxygen E) the addition of a sulfhydryl to a carboxyl 7) Which chemical group is most likely to be responsible for an organic molecule behaving as a base? A) hydroxyl B) carbonyl C) carboxyl D) amino E) phosphate Chapter 5 The Structure and Function of Large Biological Molecules Most of the new and revised questions in Chapter 5 are based on the concept of macromolecules as polymers. Questions require the student to recognize the structure, formation, properties, and function of carbohydrates, lipids, proteins, and nucleic acids. Most questions are at the Knowledge/Comprehension level, but wherever possible, Application/Analysis questions are utilized. Multiple-Choice Questions 1) For this pair of items, choose the option that best describes their relationship. (A) The number of alpha glucose 1-4 linkages in cellulose (B) The number of alpha glucose 1 -4 linkages in starch A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). 2) For this pair of items, choose the option that best describes their relationship. (A) The probability of finding chitin in fungal cell walls (B) The probability of finding chitin in arthropod exoskeletons A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). 3) For this pair of items, choose the option that best describes their relationship. (A) The number of cis double bonds in saturated fatty acids (B) The number of cis double bonds in unsaturated fatty acids A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). 4) For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with nonpolar side chains are hydrophobic. (B) The probability that amino acids with side chains containing a carboxyl group are hydrophobic. A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). 5) For this pair of items, choose the option that best describes their relationship. (A) The number of purines in the DNA strand 5'-AAGAGGAGAAA-3' (B) The number of pyrimidines in the DNA strand 5'-AAGAGGAGAAA-3' A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B). 6) Which of the following is not a polymer? A) glucose B) starch C) cellulose D) chitin E) DNA 7) What is the chemical mechanism by which cells make polymers from monomers? A) phosphodiester linkages B) hydrolysis C) dehydration reactions D) ionic bonding of monomers E) the formation of disulfide bridges between monomers 8) How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? A) 12 B) 11 C) 10 D) 9 E) 8 9) Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) A and B are correct. 10) Which of the following polymers contain nitrogen? A) starch B) glycogen C) cellulose D) chitin E) amylopectin 11) The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? A) C18H36O18 B) C18H30O15 C) C6H10O5 D) C18H10O15 E) C3H6O3 12) The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the a form. Which of the following could amylase break down? A) glycogen B) cellulose C) chitin D) A and B only E) A, B, and C 13) On food packages, to what does the term "insoluble fiber" refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin 14) A molecule with the chemical formula C6H12O6 is probably a A) carbohydrate. B) lipid. C) monosaccharide D) A and B only. E) A, B, and C. Figure 5.1 15) If 2 molecules of the general type shown in Figure 5.1 were linked together, carbon 1 of one molecule to carbon 4 of the other, the single molecule that would result would be A) maltose. B) fructose. C) glucose. D) galactose. E) sucrose. 16) Which of the following descriptors is true of the molecule shown in Figure 5.1? A) hexose B) fructose C) glucose D) A and B only E) A and C only 17) Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide 18) All of the following are polysaccharides except A) glycogen B) starch C) chitin D) cellulose E) amylopectin 19) Which of the following is true of both starch and cellulose? A) They are both polymers of glucose. B) They are geometric isomers of each other. C) They can both be digested by humans. D) They are both used for energy storage in plants. E) They are both structural components of the plant cell wall. 20) Which of the following is true of cellulose? A) It is a polymer composed of sucrose monomers. B) It is a storage polysaccharide for energy in plant cells. C) It is a storage polysaccharide for energy in animal cells. D) It is a major structural component of plant cell walls. E) It is a major structural component of animal cell plasma membranes. 21) Humans can digest starch but not cellulose because A) the monomer of starch is glucose, while the monomer of cellulose is galactose. B) humans have enzymes that can hydrolyze the beta ( ) glycosidic linkages of starch but not the alpha (a) glycosidic linkages of cellulose. C) humans have enzymes that can hydrolyze the alpha (a) glycosidic linkages of starch

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