CHAPTER 3—BIOLOGICAL MOLECULES: THE CARBON COMPOUNDS OF
LIFE
MULTIPLE CHOICE
1. Most life on Earth depends, directly or indirectly, on a process that combines water and carbon dioxide
to make carbon-based compounds. This process is called
a.
aerobic respiration.
b.
decomposition.
c.
photosynthesis.
d.
anaerobic respiration.
e.
fermentation.
2. Which of the following does NOT add carbon dioxide to the atmosphere?
a.
forest fires
b.
decomposers
c.
burning of fossil fuels
d.
photosynthesis
e.
decomposer respiration
3. Carbon has four electrons in its valence shell. It will typically form ____ covalent bonds to fill its
valence shell.
a.
one
b.
two
c.
four
d.
six
e.
eight
4. In general, molecules made mostly of carbon atoms covalently bound to each other and to other atoms
are called ____.
a.
hydrocarbons
b.
carbohydrates
c.
polymers
d.
functional groups
e.
organic molecules
5. In general, molecules consisting only of carbon and hydrogen atoms are called ____.
a.
hydrocarbons
b.
carbohydrates
c.
polymers
d.
functional groups
e.
organic molecules
6. Which of the following is NOT an organic molecule?
a.
cholesterol
b.
ATP
c.
water
d.
glucose
e.
lipid
7. Which of these hydrocarbons has a double bond in its structure?
a.
C3H8
b.
C2H6
c.
CH4
d.
C2H4
e.
C2H2
8. Four of the following elements make up the majority of atoms in living things. Which element is the
exception?
a.
carbon
b.
hydrogen
c.
iron
d.
nitrogen
e.
oxygen
9. Which of the following is NOT found in hydrocarbons?
a.
branching
b.
double bonds
c.
ring formation
d.
triple bonds
e.
quadruple bonds
10. The simplest hydrocarbon, CH4, is called ____.
a.
methane
b.
ethyne
c.
cyclohexane
d.
ethane
e.
benzene
11. Which of the following is an example of a hydrocarbon?
a.
C2H6O
b.
C8H18
c.
C6H12O6
d.
CO2
e.
C2H6S
12. Reactions that use the equivalent of a water molecule to break a molecule into smaller subunits are
called ____ reactions.
a.
equilibrium
b.
hydration
c.
hydrolysis
d.
redox
e.
dehydration synthesis
13. Reactions that remove the equivalent of a water molecule when subunits are joined to make a larger
molecule are called ____ reactions.
a.
equilibrium
b.
hydration
c.
hydrolysis
d.
redox
e.
dehydration synthesis
14. The functional group shown above is ____.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
15. The functional group shown above is ____.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
16. The functional group shown above is ____.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
17. The functional group shown above is ____.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
18. The functional group shown above is ____.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
19. Which functional group is characteristic of organic acids such as acetic acid?
a.
carbonyl group
b.
hydroxyl group
c.
phosphate group
d.
amino group
e.
carboxyl group
20. Which functional group forms the highly reactive part of aldehydes and ketones?
a.
carbonyl group
b.
hydroxyl group
c.
phosphate group
d.
amino group
e.
carboxyl group
21. Which functional group is polar and a key component of alcohols?
a.
carbonyl group
b.
hydroxyl group
c.
phosphate group
d.
amino group
e.
carboxyl group
22. Which functional group acts as an organic base?
a.
carbonyl group
b.
hydroxyl group
c.
phosphate group
d.
amino group
e.
carboxyl group
23. Isomers are two or more molecules with ____ chemical formula and ____ molecular structures.
a.
a different; different
b.
the same; different
c.
a different; the same
d.
the same; the same
e.
a structural; theoretical
24. Structural isomers differ from each other
a.
in the arrangement of their covalent bonds.
b.
in their molecular formulas.
c.
by being mirror images of each other that cannot be superimposed on each other.
d.
by having double covalent bonds instead of single bonds.
e.
by having different atomic isotopes in their molecules.
25. When molecules are referred to as D- or L- (for example D-forms of sugars and L-forms of amino
acids), the D- and L- designations refer to the specific ____.
a.
functional group
b.
structural isomer
c.
covalent bond
d.
secondary structure
e.
stereoisomer
26. What is the general term for a large molecule built up of a long chain of identical or nearly identical
subunits connected by covalent bonds?
a.
lipid
b.
functional group
c.
polymer
d.
carbohydrate
e.
multimer
27. Which organic molecules have a chemical formula that is (or is very nearly) a multiple of (CH2O)?
a.
proteins
b.
lipids
c.
nucleic acids
d.
carbohydrates
e.
amino acids
28. Monosaccharides and disaccharides are types of ____.
a.
proteins
b.
lipids
c.
nucleic acids
d.
carbohydrates
e.
amino acids
29. A monosaccharide with six carbons is called ____.
a.
triose
b.
hexose
c.
pentose
d.
heptose
e.
tetrose
30. The molecule shown above is a(n) ____.
a.
amino acid
b.
monosaccharide
c.
steroid
d.
nucleotide
e.
phospholipid
31. The linkage commonly found between subunits in a chain of monosaccharides is called a ____ bond.
a.
phosphodiester
b.
disulfide
c.
glycosidic
d.
hydrogen
e.
peptide
32. The disaccharide shown above is ____.
a.
sucrose
b.
maltose
c.
lactose
d.
cellulose
e.
fructose
33. The disaccharide shown above is ____.
a.
cellulose
b.
fructose
c.
maltose
d.
sucrose
e.
lactose
34. The disaccharide shown above is ____.
a.
lactose
b.
fructose
c.
maltose
d.
cellulose
e.
sucrose
35. Amylose is a polymer made up of glucose monomers joined by ____.
a.
(1-4) linkages
b.
(1-6) linkages
c.
(1-4) linkages
d.
(1-6) linkages
e.
both (1-4) and (1-6) linkages
36. Probably the most abundant carbohydrate on Earth, this unbranched chain of -glucose subunits is the
primary structural fiber in plant cell walls.
a.
chitin
b.
amylopectin
c.
cellulose
d.
glycogen
e.
amylose
37. This polysaccharide is a chain of glucose units that are modified by having nitrogen-containing groups.
It is the main structural fiber in the external skeletons of arthropods and is also a structural material in
the cell walls of fungi.
a.
chitin
b.
amylopectin
c.
cellulose
d.
glycogen
e.
amylose
38. Animal cells commonly have polysaccharides attached to ____ in their surface membranes.
a.
proteins
b.
nucleic acids
c.
lipids
d.
both nucleic acids and lipids
e.
both proteins and lipids
39. The molecule shown above is glyceraldehyde, an example of a ____ sugar.
a.
triose
b.
hexose
c.
pentose
d.
heptose
e.
tetrose
40. The molecule shown above is ribose, an example of a ____ sugar.
a.
triose
b.
hexose
c.
pentose
d.
heptose
e.
tetrose
41. The molecule shown above is mannose, an example of a ____ sugar.
a.
triose
b.
hexose
c.
pentose
d.
heptose
e.
tetrose
42. Suppose that an equal amount of each of the following polysaccharides was placed in a landfill. Which
of them should last the longest before it is decomposed?
a.
chitin
b.
amylopectin
c.
cellulose
d.
glycogen
e.
amylose
43. In many animals, this polysaccharide is found in large quantities in liver and muscle cells. It is highly
branched, with many (1-4) and (1-6) linkages.
a.
chitin
b.
amylopectin
c.
cellulose
d.
glycogen
e.
amylose
44. Although they have a diversity of structures, all members of this group of organic molecules are
primarily nonpolar and thus water-insoluble.
a.
proteins
b.
lipids
c.
nucleic acids
d.
carbohydrates
e.
amino acids
45. The molecule shown above is ____, having ____.
a.
unsaturated; a carbon-carbon double bond
b.
saturated; a carbon-carbon double bond
c.
unsaturated; no carbon-carbon double bonds
d.
saturated; no carbon-carbon double bonds
e.
saturated; a carbon-carbon triple bond
46. The molecule shown above is ____, having ____.
a.
unsaturated; a carbon-carbon double bond
b.
saturated; a carbon-carbon double bond
c.
unsaturated; no carbon-carbon double bonds
d.
saturated; no carbon-carbon double bonds
e.
saturated; a carbon-carbon triple bond
47. Which of the following is the best explanation for why unsaturated fats tend to be more fluid at
biological temperatures than saturated fats?
a.
Double bonds in saturated fats cause them to be denser and thus more solid than
unsaturated fats.
b.
The presence of extra hydrogen atoms in saturated fats makes them lighter, so they float
away from water and congeal together more easily than unsaturated fats.
c.
The presence of extra hydrogen atoms in saturated fats makes them denser than
unsaturated fats, and denser materials tend to be more solid.
d.
Because unsaturated fats can still be hydrogenated but saturated fats cannot, the
unsaturated fats are more reactive and thus more fluid.
e.
Kinks in the chain of an unsaturated fat create more disorder or irregularity in the structure
of the molecule, making unsaturated fats harder to pack together than saturated fats.
48. A fatty acid has ____ group at the end of a hydrocarbon chain.
a.
a carbonyl group
b.
a hydroxyl group
c.
a phosphate group
d.
an amino group
e.
a carboxyl group
49. Among the following, which number of carbons would be the most likely number of carbons for a
fatty acid from a living organism?
a.
8
b.
13
c.
16
d.
19
e.
26
50. If three molecules of a fatty acid having the formula C16H22O2 are each joined to a molecule of
glycerol (C3H8O3) with a dehydration synthesis reaction, the resulting neutral fat molecule would have
the formula
a.
C48H66O6.
b.
C48H72O8.
c.
C51H68O6.
d.
C51H72O8.
e.
C51H74O9.
51. Glycerol forms the backbone of
a.
triglycerides.
b.
polysaccharides and nucleic acids.
c.
nucleic acids.
d.
polypeptides.
e.
triglycerides and phospholipids.
Use the figure above for the following question(s).
52. The molecule shown above is ____.
a.
a triglyceride
b.
an amino acid
c.
a steroid
d.
a polysaccharide
e.
a phospholipid
53. Which of the following would the molecule shown above be called?
a.
a protein
b.
a lipid
c.
a nucleic acid
d.
a carbohydrate
e.
an amino acid
54. Which of these are the main structural components of biological membranes?
a.
starches
b.
triglycerides
c.
proteins
d.
phospholipids
e.
steroids
55. The molecule shown above is ____.
a.
a triglyceride
b.
an amino acid
c.
a steroid
d.
a polysaccharide
e.
a phospholipid
56. In a phospholipid, glycerol is bound to
a.
three phosphate groups, each of which are bound to fatty acids.
b.
two fatty acid chains and one phosphate group.
c.
two phosphate groups, each of which are bound to hydrogen.
d.
three phosphate groups, two of which are bound to fatty acids.
e.
two phosphate groups on one side and three fatty acids on the other side.
57. The molecule shown above is ____.
a.
a triglyceride
b.
an amino acid
c.
a steroid
d.
a polysaccharide
e.
a phospholipid
58. The molecule shown above is testosterone, a substance that has important regulatory functions in
humans and many other animals. Molecules with regulatory functions like testosterone are called
____.
a.
phytosterols
b.
enzymes
c.
lipoproteins
d.
hormones
e.
receptors
59. Waxy coatings, such as found on skin, hair, and feathers of some animals and the cuticle of some
plants, are commonly used by living organisms for protection against water loss and for lubrication.
Such waxes are considered to be a type of ____.
a.
triglyceride
b.
steroid
c.
neutral lipid
d.
phospholipid
e.
fatty acid
60. The sex hormones of many animals are a specific type of lipid molecule known as
a.
fatty acid.
b.
phospholipid.
c.
carotenoid.
d.
steroid.
e.
lipoprotein.
61. Two types of cholesterol are found in human blood, HDL and LDL. Clinical studies have shown that
the risk of coronary heart disease is greatest for a person with a ____ level of HDL in their blood and a
____ level of LDL in their blood.
a.
high; low
b.
low; low
c.
low; high
d.
low; moderate
e.
moderate; moderate
62. Which of the following is NOT a major function of proteins in living organisms?
a.
speeding up biological reactions
b.
transporting substances across membranes
c.
providing structural support
d.
regulating the activity of other cellular molecules
e.
storing genetic information
63. Proteins are polymers of ____.
a.
amino acids
b.
monosaccharides
c.
steroids
d.
nucleotides
e.
phospholipids
64. The two amino acids depicted above both have side groups (R groups) that are
a.
acidic and polar.
b.
uncharged and nonpolar.
c.
basic and polar.
d.
positively and negatively charged and nonpolar.
e.
uncharged and polar.