Download Chapter 4 Carbon and the Molecular Diversity of Life

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.
Answer: C
Topic: Concept 4.1
Skill: Knowledge/Comprehension
2) Early 19th-century scientists believed that living organisms differed from nonliving things
as a result of possessing a ʺlife forceʺ 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.
Answer: B
Topic: Concept 4.1
Skill: Knowledge/Comprehension
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.
Answer: E
Topic: Concept 4.1
Skill: Knowledge/Comprehension
4) One of the following people set up a closed system to mimic Earthʹs 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
Answer: A
Topic: Concept 4.1
Skill: 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 organic
compounds?
A) Stanley Miller
B) Jakob Berzelius
C) Friedrich Wohler
D) Hermann Kolbe
E) August Kekulé
Answer: A
Topic: Concept 4.1
Skill: Knowledge/Comprehension
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
Answer: C
Topic: Concept 4.1
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 63
7) Which of the following peopleʹs 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
Answer: C
Topic: Concept 4.1
Skill: Knowledge/Comprehension
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
Answer: D
Topic: Concept 4.1
Skill: Knowledge/Comprehension
9) Which of the following peopleʹs 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
Answer: D
Topic: Concept 4.1
Skill: Knowledge/Comprehension
64 Chapter 4, Carbon and the Molecular Diversity of Life
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
Answer: B
Topic: Concept 4.1
Skill: Knowledge/Comprehension
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
Answer: D
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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
Answer: C
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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.
Answer: E
Topic: Concept 4.2
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 65
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.
Answer: B
Topic: Concept 4.2
Skill: Knowledge/Comprehension
15) How many structural isomers are possible for a substance having the molecular formula
C4 H10?
A) 1
B) 2
C) 4
D) 3
E) 11
Answer: B
Topic: Concept 4.2
Skill: Application/Analysis
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.
Answer: C
Topic: Concept 4.2
Skill: Knowledge/Comprehension
66 Chapter 4, Carbon and the Molecular Diversity of Life
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
Answer: C
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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.
Answer: D
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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.
Answer: A
Topic: Concept 4.2
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 67
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.
Answer: E
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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.
Answer: B
Topic: Concept 4.2
Skill: Knowledge/Comprehension
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.
Answer: A
Topic: Concept 4.2
Skill: Knowledge/Comprehension
68 Chapter 4, Carbon and the Molecular Diversity of Life
23) Three or four of the following illustrations depict different structural isomers of the organic
compound with molecular formula C 6 H14. 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 C 6 H14.
Answer: C
Topic: Concept 4.2
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 69
24) Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric
forms) of the same molecule?
A)
B)
C)
D)
E)
Answer: D
Topic: Concept 4.2
Skill: Synthesis/Evaluation
70 Chapter 4, Carbon and the Molecular Diversity of Life
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: C
Topic: Concept 4.2
Skill: Synthesis/Evaluation
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)
Chapter 4, Carbon and the Molecular Diversity of Life 71
B)
C)
D)
E)
F) Both illustrations in each of the other answer choices depict enantiomers of the same
molecule.
Answer: B
Topic: Concept 4.2
Skill: Synthesis/Evaluation
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.
Answer: B
Topic: Concept 4.2
Skill: Knowledge/Comprehension
72 Chapter 4, Carbon and the Molecular Diversity of Life
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 wonʹt form hydrogen bonds with water.
E) It is hydrophobic.
Answer: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: E
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 73
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.
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
34) Amino acids are acids because they always possess which functional group?
A) amino
B) carbonyl
C) carboxyl
D) sulfhydryl
E) aldehyde
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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: D
Topic: Concept 4.3
Skill: Application/Analysis
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
Answer: D
Topic: Concept 4.3
Skill: Application/Analysis
74 Chapter 4, Carbon and the Molecular Diversity of Life
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
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: E
Topic: Concept 4.3
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 75
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
Answer: E
Topic: Concept 4.3
Skill: Knowledge/Comprehension
The following questions refer to the functional groups shown in Figure 4.6.
Figure 4.6
41) Which is a hydroxyl functional group?
Answer: A
Topic: Concept 4.3
Skill: Knowledge/Comprehension
42) Which is an amino functional group?
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
43) Which is a carbonyl functional group?
Answer: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
44) Which is a functional group that helps stabilize proteins by forming covalent cross-links
within or between protein molecules?
Answer: E
Topic: Concept 4.3
Skill: Knowledge/Comprehension
45) Which is a carboxyl functional group?
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
76 Chapter 4, Carbon and the Molecular Diversity of Life
46) Which is an acidic functional group that can dissociate and release H + into a solution?
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
47) Which is a basic functional group that can accept H + and become positively charged?
Answer: D
Topic: Concept 4.3
Skill: 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: A
Topic: Concept 4.3
Skill: Knowledge/Comprehension
49) Which molecule is an alcohol?
Answer: A
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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
Answer: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
51) Which molecule has a carbonyl functional group in the form of a ketone?
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 77
52) Which molecule has a carbonyl functional group in the form of an aldehyde?
Answer: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
53) Which molecule contains a carboxyl group?
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
54) Which molecule can increase the concentration of hydrogen ions in a solution and is
therefore an organic acid?
Answer: D
Topic: Concept 4.3
Skill: 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: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
56) Which molecule functions to transfer energy between organic molecules?
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
57) Which molecule contains an amino functional group, but is not an amino acid?
Answer: A
Topic: Concept 4.3
Skill: Knowledge/Comprehension
58) Which molecule is a thiol?
Answer: B
Topic: Concept 4.3
Skill: Knowledge/Comprehension
78 Chapter 4, Carbon and the Molecular Diversity of Life
59) Which molecule is an organic phosphate?
Answer: D
Topic: Concept 4.3
Skill: Knowledge/Comprehension
60) Which molecule can function as a base?
Answer: A
Topic: Concept 4.3
Skill: Knowledge/Comprehension
61) Testosterone and estradiol are
A) nucleic acids.
B) carbohydrates.
C) proteins.
D) phospholipids.
E) steroids.
Answer: E
Topic: Concept 4.3
Skill: Knowledge/Comprehension
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.
Answer: C
Topic: Concept 4.3
Skill: Knowledge/Comprehension
Chapter 4, Carbon and the Molecular Diversity of Life 79
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.
Answer: B
2) Which of the following hydrocarbons has a double bond in its carbon skeleton?
A) C3 H8
B) C2 H6
C) CH4
D) C2 H4
E) C2 H2
Answer: D
3) Choose the term that correctly describes the relationship between these two sugar
molecules:
A) structural isomers
B) geometric isomers
C) enantiomers
D) isotopes
Answer: A
4) Identify the asymmetric carbon in this molecule:
Answer: B
80 Chapter 4, Carbon and the Molecular Diversity of Life
5) Which functional group is not present in this molecule?
A) carboxyl
B) sulfhydryl
C) hydroxyl
D) amino
Answer: B
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
Answer: A
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
Answer: D
Chapter 4, Carbon and the Molecular Diversity of Life 81