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Biology Study Guide 1


1) Which of the following sequences represents the hierarchy of biological organization from the  ...
7) What is a hypothesis?                                                                                  7) _______
     ...
A) atomic weight
      B) mass weight
      C) atomic mass
      D) mass number
      E) atomic number

14) The mass numbe...
21) Atoms whose outer electron shells contain eight electrons tend to                                      21) ______
    ...
29) The ionic bond of sodium chloride is formed when                                                    29) ______
       ...
36) What would be the pH of a solution with a hydrogen ion [       ] concentration of        M?             36) ______
   ...
43) Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which   43) ______
    process?
 ...
48) Upon chemical analysis, a particular protein was found to contain 556 amino acids. How many        48) ______
    pept...
56) Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and                     56) ___...
66) Which of the following are capable of converting light energy to chemical energy?                     66) ______
     ...
73) Which of the following is correct about integral membrane proteins?                               73) ______
     A) T...
79) A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, 79) ______
    d...
85) According to the first law of thermodynamics,                                                    85) ______
      A) s...
92) Which of the following statements regarding enzymes is true?                                      92) ______
     A) E...
99) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the   99) ______
     pathwa...
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Biology Study Guide 1

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Biology Study Guide 1

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Biology Study Guide 1

  1. 1. Biology Study Guide 1 1) Which of the following sequences represents the hierarchy of biological organization from the 1) _______ least to the most complex level? A) cell, community, population, organ system, molecule, organelle B) ecosystem, cell, population, tissue, organism, organ system C) molecule, cell, organ system, population, ecosystem, biosphere D) organism, community, biosphere, molecule, tissue, organ E) organelle, tissue, biosphere, ecosystem, population, organism 2) Which of these is an example of an organelle? 2) _______ A) epidermis B) intestine C) muscle D) chloroplast E) maple leaf 3) Which of these is a correct representation of the hierarchy of biological organization from least to 3) _______ most complex? A) hydrogen, water, muscle cell nucleus, heart muscle cell, heart, heart muscle tissue, human B) heart muscle cell nucleus, hydrogen, water, heart muscle cell, heart, heart muscle tissue, human C) hydrogen, water, heart muscle cell, heart muscle cell nucleus, heart muscle tissue, heart, human D) hydrogen, water, heart muscle cell nucleus, heart muscle cell, heart muscle tissue, heart, human E) water, hydrogen, heart muscle cell nucleus, heart muscle cell, heart muscle tissue, heart, human 4) Which of the following statements concerning prokaryotic and eukaryotic cells is not correct? 4) _______ A) Prokaryotic cells contain small membrane-enclosed organelles. B) Eukaryotic cells contain a membrane-bound nucleus. C) DNA or deoxyribonucleic acid is present in the nucleus of eukaryotic cells. D) DNA, or deoxyribonucleic acid, is present in both prokaryotic cells and eukaryotic cells. E) Prokaryotic cells lack a membrane-bound nucleus. 5) The chemical reactions within cells are regulated by organic catalysts called 5) _______ A) feedback activators. B) metabolites. C) enzymes. D) feedback inhibitors. E) nutrients. 6) Prokaryotic and eukaryotic cells generally have which of the following features in common? 6) _______ A) a cell wall made of cellulose B) linear chromosomes made of DNA and protein C) flagella or cilia that contain microtubules D) ribosomes E) a membrane-bounded nucleus
  2. 2. 7) What is a hypothesis? 7) _______ A) the same thing as an unproven theory B) a verifiable observation sensed directly, or sensed indirectly with the aid of scientific instrumentation C) a fact based on quantitative data that is falsifiable D) a tentative explanation that can be tested and is falsifiable E) a fact based on qualitative data that is testable 8) A controlled experiment is one in which 8) _______ A) there are at least two groups, one differing from the other by two or more variables. B) the experiment is repeated many times to ensure that the results are accurate. C) there is one group for which the scientist controls all variables. D) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data. E) there are at least two groups, one of which does not receive the experimental treatment. 9) Why is it important that an experiment include a control group? 9) _______ A) A control group assures that an experiment will be repeatable. B) 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. C) The control group provides a reserve of experimental subjects. D) The control group is the group that the reseacher is in control of; it is the group in which the researcher predetermines the nature of the results. E) A control group is required for the development of an "if; then" statement. 10) What is the primary reason for including a control group within the design of an experiment? 10) _____ A) To ensure that the results obtained are due to a difference in only one variable B) To test the effect of more than one variable C) To accumulate additional facts that can be reported to other scientists D) To ensure that the experimenter can perform a more complete statistical analysis E) To demonstrate in what way the experiment was performed incorrectly 11) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 11) ______ elements make up approximately 96% of living matter? A) carbon, sulfur, phosphorus, hydrogen B) carbon, oxygen, sulfur, calcium C) carbon, hydrogen, nitrogen, oxygen D) oxygen, hydrogen, calcium, sodium E) carbon, sodium, chlorine, nitrogen 12) Which of the following statements is false? 12) ______ A) An atom is the smallest unit of an element that still retains the properties of the element. B) Atoms of the various elements differ in their number of subatomic particles. C) Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge. D) All atoms of a particular element have the same number of protons in their nuclei. E) The neutrons and protons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton. 13) Each element is unique and different from other elements because of the number of protons in the 13) ______ nuclei of its atoms. Which of the following indicates the number of protons in an atom's nucleus?
  3. 3. A) atomic weight B) mass weight C) atomic mass D) mass number E) atomic number 14) The mass number of an element can be easily approximated by adding together the number of 14) ______ ________ in an atom of that element. A) protons and neutrons B) isotopes C) protons and electrons D) neutrons and electrons E) energy levels 15) What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons? 15) ______ A) 16 daltons B) 30 daltons C) 31 daltons D) 15 daltons E) 46 daltons 16) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a 16) ______ correct statement concerning nitrogen? A) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons. B) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams. C) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7. 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 approximately 7 daltons and an atomic mass of 14. 17) Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must 17) ______ have A) 40 electrons. B) 20 protons. C) 40 neutrons. D) A and B only E) A, B, and C 18) How do isotopes of the same element differ from each other? 18) ______ A) number of neutrons B) amount of radioactivity C) number of electrons D) number of protons E) valence electron distribution 19) The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic 19) ______ nucleus of carbon-14 contains _____ neutrons. A) 12 B) 14 C) 6 D) 8 E) 7 20) The atomic number of neon is 10. Therefore, which of the following is correct about an atom of 20) ______ neon? A) It is inert. B) It has 8 electrons in its outer electron shell. C) It has an atomic mass of 10 daltons. D) A and B only E) A, B, and C are correct.
  4. 4. 21) Atoms whose outer electron shells contain eight electrons tend to 21) ______ A) form ionic bonds in aqueous solutions. B) be isotopes and very radioactive. C) be unstable and chemically very reactive. D) form covalent bonds in aqueous solutions. E) be stable and chemically nonreactive, or inert. Use the information extracted f rom the periodic table in Figure 2.2 to answer the following questions. Figure 2.2 22) How many electrons does nitrogen have in its valence shell? 22) ______ A) 2 B) 5 C) 8 D) 14 E) 7 23) How many electrons does phosphorus have in its valence shell? 23) ______ A) 2 B) 3 C) 4 D) 5 E) 1 24) How many neutrons are present in the nucleus of a phosphorus atom? 24) ______ A) 8 B) 46 C) 31 D) 15 E) 16 25) How many electrons would be expected in the outermost electron shell of an atom with atomic 25) ______ number 12? A) 8 B) 2 C) 6 D) 1 E) 4 26) A covalent chemical bond is one in which 26) ______ A) outer-shell electrons of one atom are transferred to the inner electron shells of another atom. B) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. C) the inner-shell electrons of one atom are transferred to the outer shell of another atom. D) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. E) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. 27) What do atoms form when they share electron pairs? 27) ______ A) aggregates B) elements C) molecules D) ions E) isotopes 28) What results from an unequal sharing of electrons between atoms? 28) ______ A) a hydrogen bond B) a nonpolar covalent bond C) a hydrophobic interaction D) a polar covalent bond E) an ionic bond
  5. 5. 29) The ionic bond of sodium chloride is formed when 29) ______ A) sodium gains an electron from chlorine. B) sodium and chlorine share an electron pair. C) chlorine gains a proton from sodium. D) chlorine gains an electron from sodium. E) sodium and chlorine both lose electrons from their outer valence shells. 30) What is the difference between covalent bonds and ionic bonds? 30) ______ A) Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms. B) Covalent bonds involve the transfer of electrons between atoms, and ionic bonds involve the sharing of neutrons between atoms. C) Covalent bonds involve the sharing of neutrons between atoms, and ionic bonds involve the sharing of electrons between atoms. D) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of electrons between atoms. E) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of neutrons between atoms. Use these choices to answer the following questions. A. nonpolar covalent bond B. polar covalent bond C. ionic bond D. hydrogen bond E. hydrophobic interaction 31) Results from a transfer of electron(s) between atoms. C. ionic bond 31) _____________ 32) Explains most specifically the attraction of water molecules to one another. D. hydrogen 32) _____________ bond 33) In a single molecule of water, the two hydrogen atoms are bonded to a single oxygen atom by 33) ______ A) hydrogen bonds. B) nonpolar covalent bonds. C) ionic bonds. D) van der Waals interactions. E) polar covalent bonds. 34) The slight negative charge at one end of one water molecule is attracted to the slight positive 34) ______ charge of another water molecule. What is this attraction called? A) an ionic bond B) a hydrophobic bond C) a hydrogen bond D) a hydrophilic bond E) a covalent bond 35) Hydrophobic substances such as vegetable oil are 35) ______ A) nonpolar substances that have an attraction for water molecules. B) nonpolar substances that repel 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.
  6. 6. 36) What would be the pH of a solution with a hydrogen ion [ ] concentration of M? 36) ______ A) pH 4 B) pH 2 C) pH 10 D) pH 8 E) pH 6 37) Which of the following solutions has the greatest concentration of hydrogen ions 37) ______ A) gastric juice at pH 2 B) tomato juice at pH 4 C) vinegar at pH 3 D) household bleach at pH 12 E) black coffee at pH 5 38) Which of the following solutions has the greatest concentration of hydroxide ions 38) ______ A) lemon juice at pH 2 B) urine at pH 6 C) vinegar at pH 3 D) seawater at pH 8 E) tomato juice at pH 4 39) If the pH of a solution is decreased from 9 to 8, it means that the 39) ______ A) concentration of has decreased 10 times what it was at pH 9. B) concentration of has increased 10 times what it was at pH 9. C) concentration of has increased 10 times what it was at pH 9. D) concentration of has decreased 10 times what it was at pH 9. E) B and D are correct. 40) One liter of a solution of pH 2 has how many more hydrogen ions ( ) than 1 L of a solution of 40) ______ pH 6 ? A) 10,000 times more B) 100,000 times more C) 4 times more D) 400 times more E) 4,000 times more 41) Which two functional groups are always found in amino acids? 41) ______ A) hydroxyl and aldehyde B) phosphate and sulfhydryl C) carboxyl and amino D) carbonyl and carboxyl E) ketone and aldehyde 42) Which of the following is not on e of the four major groups of macromolecules found in living 42) ______ organisms? A) lipids B) glucose C) carbohydrates D) proteins E) nucleic acids
  7. 7. 43) Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which 43) ______ process? A) the formation of disulfide bridges between monomers B) the addition of water to each monomer (hydrolysis) C) the removal of water (dehydration reactions) D) ionic bonding of the monomers E) connecting monosaccharides together (condensation reactions) 44) Which of the following is true of both starch and cellulose? 44) ______ A) They are both structural components of the plant cell wall. B) They are both polymers of glucose. C) They are both used for energy storage in plants. D) They can both be digested by humans. E) They are geometric isomers of each other. Figure 5.3 45) The molecule shown in Figure 5.3 is a 45) ______ A) saturated fatty acid. B) polypeptide. C) polysaccharide. D) unsaturated fatty acid. E) triacylglycerol. 46) A polypeptide can best be described as a 46) ______ A) polymer containing 20 peptide bonds. B) monomer of a protein polymer. C) polymer containing 20 amino acid molecules. D) polymer containing 19 peptide bonds. E) polymer of amino acids. Figure 5.5 47) The chemical reaction illustrated in Figure 5.5 results in the formation of a (an) 47) ______ A) ester linkage. B) peptide bond. C) ionic bond. D) glycosidic linkage. E) phosphodiester linkage.
  8. 8. 48) Upon chemical analysis, a particular protein was found to contain 556 amino acids. How many 48) ______ peptide bonds are present in this protein? A) 558 B) 139 C) 556 D) 554 E) 555 49) Which of the following descriptions best fits the class of molecules known as nucleotides? 49) ______ A) a pentose sugar and a purine or pyrimidine B) a nitrogenous base and a phosphate group C) a nitrogenous base, a phosphate group, and a pentose sugar D) a nitrogenous base and a pentose sugar E) a phosphate group and an adenine or uracil 50) Which of the following are nitrogenous bases of the pyrimidine type? 50) ______ A) thymine and guanine B) guanine and adenine C) ribose and deoxyribose D) adenine and thymine E) cytosine and uracil 51) Which of the following are nitrogenous bases of the purine type? 51) ______ A) uracil and cytosine B) thymine and uracil C) guanine and adenine D) adenine and thymine E) cytosine and guanine 52) All of the following nitrogenous bases are found in DNA except 52) ______ A) guanine. B) thymine. C) adenine. D) uracil. E) cytosine. 53) Which of the following is an example of hydrolysis? 53) ______ A) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water B) the synthesis of two amino acids, forming a peptide with the release of water C) the reaction of two monosaccharides, forming a disaccharide with the release of water D) the reaction of a fat, forming glycerol and fatty acids with the utilization of water E) the reaction of a fat, forming glycerol and fatty acids with the release of water 54) The element nitrogen is present in all of the following except 54) ______ A) nucleic acids. B) monosaccharides. C) amino acids. D) DNA. E) proteins. 55) Large numbers of ribosomes are present in cells that specialize in producing which of the 55) ______ following molecules? A) lipids B) starches C) glucose D) proteins E) steroids
  9. 9. 56) Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and 56) ______ steroids? A) smooth endoplasmic reticulum B) ribosome C) contractile vacuole D) mitochondrion E) lysosome 57) Which structure is the site of the synthesis of proteins that may be exported from the cell? 57) ______ A) rough ER B) tight junctions C) plasmodesmata D) Golgi vesicles E) lysosomes 58) Which of the following cell components is not directly involved in synthesis or secretion? 58) ______ A) ribosome B) lysosome C) rough endoplasmic reticulum D) Golgi body E) smooth endoplasmic reticulum Refer to the following five terms to answer the following questions. Choose the most appropriate term for each ph rase. Each term may be used once, more than once, or not at all. A. lysosome B. vacuole C. mitochondrion D. Golgi apparatus E. peroxisome 59) produces and modifies polysaccharides that will be secreted D) Golgi apparatus 59) _____________ 60) contains hydrolytic enzymes A) lysosome 60) _____________ 61) helps to recycle the cell's organic material A) lysosome 61) _____________ 62) one of the main energy transformers of cells C) mitochondrion 62) _____________ 63) contains its own DNA and ribosomes C) mitochondrion 63) _____________ 64) a compartment that often takes up much of the volume of a plant cell B) vacuole 64) _____________ 65) Grana, thylakoids, and stroma are all components found in 65) ______ A) mitochondria. B) nuclei. C) lysosomes. D) chloroplasts. E) vacuoles.
  10. 10. 66) Which of the following are capable of converting light energy to chemical energy? 66) ______ A) peroxisomes B) mitochondria C) chloroplasts D) Golgi bodies E) leucoplasts 67) Motor proteins provide for molecular motion in cells by interacting with what types of cellular 67) ______ structures? A) membrane proteins B) cytoskeletons C) ribosomes D) sites of energy production in cellular respiration E) cellulose fibers in the cell wall 68) Which of the following pairs is mismatched? 68) ______ A) Lysosome - protein synthesis B) cell membrane - lipid bilayer C) Nucleus - DNA replication D) Cytoskeleton - microtubules E) Nucleolus - ribosomal RNA 69) Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell 69) ______ through A) desmosomes. B) plasmodesmata. C) tight junctions. D) gap junctions. E) intermediate filaments. 70) Which of the following types of molecules are the major structural components of the cell 70) ______ membrane? A) proteins and cellulose B) phospholipids and proteins C) nucleic acids and proteins D) phospholipids and cellulose E) glycoproteins and cholesterol 71) The presence of cholesterol in the plasma membranes of some animals 71) ______ A) enables the animal to remove hydrogen atoms from saturated phospholipids. B) makes the animal more susceptible to circulatory disorders. C) makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. D) enables the membrane to stay fluid more easily when cell temperature drops. E) enables the animal to add hydrogen atoms to unsaturated phospholipids. 72) All of the following are functions of integral membrane proteins except 72) ______ A) cytoskeleton attachment. B) protein synthesis. C) active transport. D) cell adhesion. E) hormone reception.
  11. 11. 73) Which of the following is correct about integral membrane proteins? 73) ______ A) They are not mobile within the bilayer. B) They are loosely bound to the surface of the bilayer. C) They serve only a structural role in membranes. D) They lack tertiary structure. E) They are usually transmembrane proteins. 74) What is one of the functions of cholesterol in animal cell membranes? 74) ______ A) stores energy B) maintains membrane fluidity C) facilitates transport of ions D) phosphorylates ADP E) speeds diffusion 75) What membrane-surface molecules are thought to be most important as cells recognize each 75) ______ other? A) integral proteins B) glycoproteins C) peripheral proteins D) phospholipids E) cholesterol 76) What kinds of molecules pass through a cell membrane most easily? 76) ______ A) large and hydrophobic B) small and hydrophobic C) monosaccharides such as glucose D) ionic E) large polar 77) Which of the following would likely move through the lipid bilayer of a plasma membrane most 77) ______ rapidly? A) glucose B) K+ C) an amino acid D) starch E) CO2 78) Which of the following statements is correct about diffusion? 78) ______ A) It requires integral proteins in the cell membrane. B) It requires an expenditure of energy by the cell. C) It is very rapid over long distances. D) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. E) It is an active process in which molecules move from a region of lower concentration to one of higher concentration.
  12. 12. 79) A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, 79) ______ distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion? A) The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. B) It will have no unfavorable effect as long as the water is free of viruses and bacteria. C) The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells. D) The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells. E) The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. 80) A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water 80) ______ containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell? A) hypertonic B) isotonic C) hypotonic D) turgid E) flaccid 81) All of the following membrane activities require energy from ATP hydrolysis except 81) ______ A) ions moving out of the cell. B) facilitated diffusion. C) translocation of potassium into a cell. D) active transport. E) proton pumps. 82) What are the membrane structures that function in active transport? 82) ______ A) carbohydrates B) cholesterol C) integral proteins D) peripheral proteins E) cytoskeleton filaments 83) The movement of a substance across a biological membrane against its concentration gradient 83) ______ with the help of energy input is A) active transport. B) osmosis. C) facilitated diffusion. D) diffusion. E) exocytosis. 84) White blood cells engulf bacteria through what process? 84) ______ A) pinocytosis B) receptor-mediated exocytosis C) osmosis D) phagocytosis E) exocytosis
  13. 13. 85) According to the first law of thermodynamics, 85) ______ A) systems rich in energy are intrinsically unstable and will give up energy with time. B) energy can be neither created nor destroyed. C) the universe loses energy because of heat production. D) A and B only E) A, B, and C 86) Which of the following is true for all exergonic reactions? 86) ______ A) The reactions are nonspontaneous. B) The products have more total energy than the reactants. C) Some reactants will be converted to products. D) A net input of en ergy from the surroundings is required for the reactions to proceed. E) The reaction proceeds with a net release of free en ergy. 87) Why is ATP an important molecule in metabolism? 87) ______ A) Its terminal phosphate group contains a strong covalent bond that when hydrolyzed releases free energy. B) It provides energy coupling between exergonic and endergonic reactions. C) Its hydrolysis provides an input of free en ergy for exergonic reactions. D) A and B only E) A, B and C 88) What term is used to describe the transfer of free energy from catabolic pathways to anabolic 88) ______ pathways? A) feedback regulation B) entropy C) bioenergetics D) cooperativity E) energy coupling 89) Which of the following statements is true concerning catabolic pathways? 89) ______ A) They build up complex molecules such as protein from simpler compounds. B) They combine molecules into more energy-rich molecules. C) They are usually coupled with anabolic pathways to which they supply energy in the form of ATP. D) They are endergonic. E) They are spontaneous and do not need enzyme catalysis. 90) How can one increase the rate of a chemical reaction? 90) ______ A) Add a catalyst. B) Decrease the concentration of the reactants. C) Cool the reactants. D) Increase the entropy of the reactants. E) Increase the activation energy needed. 91) Reactants capable of interacting to form products in a chemical reaction must first overcome a 91) ______ thermodynamic barrier known as the reaction's A) endothermic level. B) activation energy. C) free-energy content. D) heat content. E) entropy.
  14. 14. 92) Which of the following statements regarding enzymes is true? 92) ______ A) Enzymes prevent changes in substrate concentrations. B) Enzymes increase the rate of a reaction. C) Enzymes are permanently altered by the reactions they catalyze. D) Enzymes decrease the free en ergy change of a reaction. E) Enzymes change the direction of chemical reactions. 93) An enzyme catalyzes a reaction by 93) ______ A) supplying the energy to speed up a reaction. B) lowering the ∆G of a reaction. C) lowering the energy of activation of a reaction. D) increasing the amount of free energy of a reaction. E) changing the equilibrium of a spontaneous reaction. 94) Which of these statements regarding enzymes is false? 94) ______ A) An enzyme may be used many times over for a specific reaction. B) Enzymes are proteins that function as catalysts. C) Enzymes provide activation energy for the reactions they catalyze. D) The activity of enzymes can be regulated by other molecules. E) Enzymes display specificity for certain molecules with which they interact. 95) The active site of an enzyme is the region that 95) ______ A) is involved in the catalytic reaction of the enzyme. B) binds the products of the catalytic reaction. C) is inhibited by the presence of a coenzyme or a cofactor. D) binds allosteric regulators of the enzyme. E) both A and B 96) According to the induced fit hypothesis of enzyme catalysis, which of the following is correct? 96) ______ A) The binding of the substrate changes the shape of the enzyme's active site. B) The active site creates a microenvironment ideal for the reaction. C) Some enzymes change their structure when activators bind to the enzyme. D) A competitive inhibitor can outcompete the substrate for the active site. E) The binding of the substrate depends on the shape of the active site. 97) Increasing the substrate concentration in an enzymatic reaction could overcome which of the 97) ______ following? A) insufficient cofactors B) allosteric inhibition C) saturation of the enzyme activity D) competitive inhibition E) denaturization of the enzyme 98) Which of the following is true of enzymes? 98) ______ A) Enzyme function is reduced if the three-dimensional structure or conformation of an enzyme is altered. B) Enzymes may require a nonprotein cofactor or ion for catalysis to take place. C) Enzymes increase the rate of chemical reaction by lowering activation energy barriers. D) Enzyme function is influenced by physical and chemical environmental factors such as pH and temperature. E) All of the above are true of enzymes.
  15. 15. 99) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the 99) ______ pathway is known as A) reversible inhibition. B) metabolic inhibition. C) feedback inhibition. D) allosteric inhibition. E) noncooperative inhibition. 100) How does a non-competitive inhibitor decrease the rate of an enzyme reaction? 100) _____ A) by changing the structure of the enzyme B) by changing the free energy change of the reaction C) by binding at the active site of the enzyme D) by decreasing the activation energy of the reaction E) by acting as a coenzyme for the reaction ANSWER KEY: Answers are highlighted

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