chapter 4 carbon and the molecular diversity of life · pdf filechapter 4 carbon and the...

Chapter 4 Carbon and the Molecular Diversity of LifeAll organisms are composed mostly of chemical structures based on the element carbon. This chapterbuilds upon information and concepts introduced in Chapters 2 and 3 and extends the descriptions andanalysis to more detailed consideration of the carbon atom. Of all the elements, carbon is unparalleled inits ability to form molecules that are large, complex, and diverse. Student understanding of thiscomplexity 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 thischapter lends itself to questions that emphasize recall and application; and many such questions arepresented. But other topics in this chapter require synthesis and interpretation, as well as visualization ofthree-dimensional arrangements of atoms, and so we have added several questions that will be morechallenging for most students. This chapter lays the foundation for later elaboration of roles of molecularstructure in various life processes. Several form/function questions assess student understanding of theseconcepts.

Multiple-Choice Questions

1) Organic chemistry is a science based on the study ofA) functional groups.B) vital forces interacting with matter.C) carbon compounds.D) water and its interaction with other kinds of molecules.E) inorganic compounds.

Answer: CTopic: Concept 4.1Skill: Knowledge/Comprehension

2) Early 19th-century scientists believed that living organisms differed from nonliving thingsas a result of possessing a ʺlife forceʺ that could create organic molecules from inorganicmatter. The term given to this belief is

A) organic synthesis.B) vitalism.C) mechanism.D) organic evolution.E) inorganic synthesis.

Answer: BTopic: Concept 4.1Skill: Knowledge/Comprehension

61

3) The experimental approach taken in current biological investigations presumes thatA) simple organic compounds can be synthesized in the laboratory from inorganic

precursors, but complex organic compounds like carbohydrates and proteins can onlybe synthesized by living organisms.

B) a life force ultimately controls the activities of living organisms and this life forcecannot be studied by physical or chemical methods.

C) although a life force, or vitalism, exists in living organisms, this life force cannot bestudied by physical or chemical methods.

D) living organisms are composed of the same elements present in nonliving things, plusa 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 lawsthat can be used to explain all natural phenomena.

Answer: ETopic: Concept 4.1Skill: Knowledge/Comprehension

4) One of the following people set up a closed system to mimic Earthʹs early atmosphere anddischarged electrical sparks through it. A variety of organic compounds common inorganisms were formed. Who did this?

A) Stanley MillerB) Jakob BerzeliusC) Friedrich WohlerD) Hermann KolbeE) August Kekulé

Answer: ATopic: Concept 4.1Skill: Knowledge/Comprehension

62 Chapter 4, Carbon and the Molecular Diversity of Life

5) Which of the following people used this apparatus to study formation of organiccompounds?



6) Which of the following people was the first to synthesize an organic compound, urea, frominorganic starting materials?



Chapter 4, Carbon and the Molecular Diversity of Life 63

7) Which of the following peopleʹs synthesis of this compound from inorganic startingmaterials provided evidence against vitalism?



8) Which of the following people synthesized an organic compound, acetic acid, frominorganic substances that had been prepared directly from pure elements?


Answer: DTopic: Concept 4.1Skill: Knowledge/Comprehension

9) Which of the following peopleʹs synthesis of this compound from inorganic startingmaterials provided evidence against vitalism?




10) One of the following people was the first to suggest that organic compounds, those foundin living organisms, were distinctly different from inorganic compounds found in thenonliving world. Though this suggestion is now known to be incorrect, it stimulatedimportant research into organic compounds. Who suggested this?



11) How many electron pairs does carbon share in order to complete its valence shell?A) 1B) 2C) 3D) 4E) 8


12) A carbon atom is most likely to form what kind of bond(s) with other atoms?A) ionicB) hydrogenC) covalentD) A and B onlyE) A, B, and C


13) Which of the following statements best describes the carbon atoms present in all organicmolecules?

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 formulaC4H10?

A) 1B) 2C) 4D) 3E) 11

Answer: BTopic: Concept 4.2Skill: Application/Analysis

Figure 4.1

16) The two molecules shown in Figure 4.1 are best described asA) 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 moleculesdiffer 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 moleculesare

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 asA) 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 amixture 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, improvingairflow 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 amixture 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.Answer: ATopic: Concept 4.2Skill: Knowledge/Comprehension


23) Three or four of the following illustrations depict different structural isomers of the organiccompound with molecular formula C6H14. For clarity, only the carbon skeletons areshown; hydrogen atoms that would be attached to the carbons have been omitted. Whichone, 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 thecompound with molecular formula C6H14.



24) Which of the pairs of molecular structures shown below depict enantiomers (enantiomericforms) of the same molecule?

A)

B)

C)

D)

E)

Answer: DTopic: Concept 4.2Skill: Synthesis/Evaluation


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)

Answer: CTopic: Concept 4.2Skill: Synthesis/Evaluation

26) Three or four of the pairs of structures shown below depict enantiomers (enantiomericforms) 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 samemolecule.

Answer: BTopic: Concept 4.2Skill: Synthesis/Evaluation

27) Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occuras 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 thefollowing 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 wonʹt 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 bondB) a nitrogen and two hydrogens joined to a carbon by covalent bondsC) a carbon joined to two hydrogens by single covalent bondsD) a sulfur and a hydrogen joined to a carbon by covalent bondsE) 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) carbonylB) ketoneC) aldehydeD) carboxylE) hydroxyl


31) Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen?A) an alcohol such as ethanolB) a monosaccharide such as glucoseC) a steroid such as testosteroneD) an amino acid such as glycineE) 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 aldehydeB) carbonyl and carboxylC) carboxyl and aminoD) phosphate and sulfhydrylE) hydroxyl and aldehyde


34) Amino acids are acids because they always possess which functional group?A) aminoB) carbonylC) carboxylD) sulfhydrylE) 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.

Answer: DTopic: Concept 4.3Skill: Application/Analysis

36) A chemist wishes to make an organic molecule less acidic. Which of the followingfunctional groups should be added to the molecule in order to do so?

A) carboxylB) sulfhydrylC) hydroxylD) aminoE) phosphate

Answer: DTopic: Concept 4.3Skill: Application/Analysis


37) Which functional groups can act as acids?A) amine and sulfhydrylB) carbonyl and carboxylC) carboxyl and phosphateD) hydroxyl and aldehydeE) 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) AB) BC) CD) DE) E


39) Which of the structures contain(s) a carboxyl functional group?A) AB) BC) CD) C and EE) none of the structures



40) In which of the structures are the atoms bonded by ionic bonds?A) AB) BC) CD) C, D, and E onlyE) 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?Answer: ATopic: Concept 4.3Skill: Knowledge/Comprehension

42) Which is an amino functional group?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

43) Which is a carbonyl functional group?Answer: BTopic: Concept 4.3Skill: Knowledge/Comprehension

44) Which is a functional group that helps stabilize proteins by forming covalent cross-linkswithin or between protein molecules?Answer: ETopic: Concept 4.3Skill: Knowledge/Comprehension

45) Which is a carboxyl functional group?Answer: CTopic: Concept 4.3Skill: Knowledge/Comprehension


46) Which is an acidic functional group that can dissociate and release H+ into a solution?Answer: CTopic: Concept 4.3Skill: Knowledge/Comprehension

47) Which is a basic functional group that can accept H+ and become positively charged?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

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?Answer: ATopic: Concept 4.3Skill: Knowledge/Comprehension

49) Which molecule is an alcohol?Answer: ATopic: Concept 4.3Skill: Knowledge/Comprehension

50) Which molecules contain a carbonyl group?A) A and BB) B and CC) C and DD) D and EE) E and A


51) Which molecule has a carbonyl functional group in the form of a ketone?Answer: CTopic: Concept 4.3Skill: Knowledge/Comprehension


52) Which molecule has a carbonyl functional group in the form of an aldehyde?Answer: BTopic: Concept 4.3Skill: Knowledge/Comprehension

53) Which molecule contains a carboxyl group?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

54) Which molecule can increase the concentration of hydrogen ions in a solution and istherefore an organic acid?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

The following questions refer to the molecules shown in Figure 4.8.

Figure 4.8

55) Which molecule contains a sulfhydryl functional group?Answer: BTopic: Concept 4.3Skill: Knowledge/Comprehension

56) Which molecule functions to transfer energy between organic molecules?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

57) Which molecule contains an amino functional group, but is not an amino acid?Answer: ATopic: Concept 4.3Skill: Knowledge/Comprehension

58) Which molecule is a thiol?Answer: BTopic: Concept 4.3Skill: Knowledge/Comprehension


59) Which molecule is an organic phosphate?Answer: DTopic: Concept 4.3Skill: Knowledge/Comprehension

60) Which molecule can function as a base?Answer: ATopic: Concept 4.3Skill: Knowledge/Comprehension

61) Testosterone and estradiol areA) nucleic acids.B) carbohydrates.C) proteins.D) phospholipids.E) steroids.


62) Testosterone and estradiol are male and female sex hormones, respectively, in manyvertebrates. In what way(s) do these molecules differ from each other?

A) Testosterone and estradiol are structural isomers but have the same molecularformula.

B) Testosterone and estradiol are geometric isomers but have the same molecularformula.

C) Testosterone and estradiol have different functional groups attached to the samecarbon skeleton.

D) Testosterone and estradiol have distinctly different chemical structures, with oneincluding four fused rings of carbon atoms, while the other has three rings.

E) Testosterone and estradiol are enantiomers of the same organic molecule.Answer: CTopic: Concept 4.3Skill: Knowledge/Comprehension


Self-Quiz Questions

The following questions are from the end-of-chapter-review Self-Quiz questions in Chapter 4 of thetextbook.

1) Organic chemistry is currently defined asA) 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.

Answer: B

2) Which of the following hydrocarbons has a double bond in its carbon skeleton?A) C3H8B) C2H6C) CH4D) C2H4E) C2H2

Answer: D

3) Choose the term that correctly describes the relationship between these two sugarmolecules:

A) structural isomersB) geometric isomersC) enantiomersD) isotopes

Answer: A

4) Identify the asymmetric carbon in this molecule:

Answer: B


5) Which functional group is not present in this molecule?

A) carboxylB) sulfhydrylC) hydroxylD) amino

Answer: B

6) Which action could produce a carbonyl group?A) the replacement of the OH of a carboxyl group with hydrogenB) the addition of a thiol to a hydroxylC) the addition of a hydroxyl to a phosphateD) the replacement of the nitrogen of an amine with oxygenE) the addition of a sulfhydryl to a carboxyl

Answer: A

7) Which chemical group is most likely to be responsible for an organic molecule behaving asa base?

A) hydroxylB) carbonylC) carboxylD) aminoE) phosphate

Answer: D


chapter 4 carbon and the molecular diversity of life · pdf filechapter 4 carbon and the...

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