AP Biology
Organic Molecules Questions
Name ___________________________________
Multiple Choice. Circle the letter of the BEST answer.
1.
a.
b.
c.
d.
2.
a.
b.
c.
d.
3.
Substances that are nonpolar and repelled by water are ________.
hydrolyzed
nonpolar
hydrophilic
hydrophobic
A hydrogen bond is ________.
a sharing of a pair of electrons between a hydrogen nucleus and an oxygen nucleus
a sharing of a pair of electrons between a hydrogen nucleus and either an oxygen or a
nitrogen nucleus
formed when an electronegative atom of a molecule weakly interacts with a hydrogen atom
that is already participating in a separate polar covalent bond
none of these
A nonpolar covalent bond implies that ________.
a.
b.
c.
d.
one negative atom bonds with a hydrogen atom
it is a double bond
there is no difference in charge at the ends (the two poles) of the bond
atoms of different elements do not exert the same pull on shared electrons
4.
This type of chemical bond contributes to the shape of large molecules.
a.
b.
c.
d.
e.
5.
a.
b.
c.
d.
6.
a.
b.
c.
d.
hydrogen
ionic
covalent
inert
single
Which of the following properties of water protects aquatic organisms during a long, cold winter?
cohesion
solvent properties
temperature-stabilizing
none of these
Amino acids are linked by ________ bonds to form the primary structure of a protein.
disulfide
hydrogen
ionic
peptide
7.
a.
b.
c.
d.
e.
8.
a.
b.
c.
d.
e.
9.
a.
b.
c.
d.
10.
a.
b.
c.
d.
e.
11.
a.
b.
c.
d.
12.
a.
b.
c.
d.
e.
Proteins ________.
are weapons against disease-causing bacteria and other invaders
are composed of amino acid subunits
may act as hormones
may function as enzymes
all of these
Which of the following does not belong to the lipid class of organic molecules?
sterols
waxes
phospholipids
glycoproteins
triglycerides
DNA ________.
is one of the adenosine phosphates
is one of the nucleotide coenzymes
contains protein-building instructions
is composed of monosaccharides
Most of the chemical reactions in cells must have ________ present before they proceed.
RNA
salt
enzymes
fats
chitin
Carbon is part of so many different substances because ________.
carbon generally forms two covalent bonds with a variety of other atoms
a carbon atom generally forms four covalent bonds with a variety of atoms
carbon ionizes easily
carbon is a polar compound
Which of the following levels of protein structure is not correctly linked to its description?
primary--the linear sequence of amino acids
secondary--coiling of a polypeptide due to the action of hydrogen bonds
tertiary--interactions between the domains of a protein
quaternary--chemical interactions between multiple polypeptide chains
all of these are correct
13.
________ are molecules used by cells as structural materials, energy transport molecules, or storage
forms of energy.
a.
b.
c.
d.
Lipids
Nucleic acids
Carbohydrates
Proteins
14.
a.
b.
c.
d.
e.
Hydrolysis could be correctly described as the ________.
heating of a compound in order to drive off its excess water and concentrate its volume
breaking of a long-chain compound into its subunits by adding water molecules to its
structure between the subunits
linking of two or more molecules by the removal of one or more water molecules
constant removal of hydrogen atoms from the surface of a carbohydrate
an example of a condensation class of reactions
15.
Genetic instructions are encoded in the base sequence of ________; molecules of ________ function
in processes using genetic instructions to construct proteins.
a.
b.
c.
d.
DNA; DNA
DNA; RNA
RNA; DNA
RNA; RNA
Matching. Place the letter of the BEST answer in the blank
16.
For each of the following, choose the correct class of carbohydrates with which the indicated term is
associated. Answers may be used more than once.
a.
b.
c.
oligosaccharides
polysaccharides
monosaccharides
_____ (1)
_____ (2)
_____ (3)
_____ (4)
_____ (5)
_____ (6)
_____ (7)
_____ (8)
"complex carbohydrates"
chitin
disaccharides
ribose and deoxyribose
lactose, sucrose, and maltose
glucose and fructose
starch and glycogen
cellulose
17.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
Choose the most appropriate answer for each term.
A coiled or extended pattern of protein structure caused by regular intervals of H bonds
Three or more amino acids joined in a linear chain
Proteins with linear or branched oligosaccharides covalently bonded to them; found on
animal cell surfaces, in cell secretion, or on blood proteins
Folding of a protein through interactions among R groups of a polypeptide chain
Form when freely circulating blood proteins encounter and combine with cholesterol, or
phospholipids
The type of covalent bond linking one amino acid to another
HLAs and hemoglobin are examples of this level of protein structure
Breaking weak bonds in large molecules (such as protein) to change their shape so they no
longer function
A self-organized polypeptide chain that functions as a stable unit
Lowest level of protein structure; has a linear, unique sequence of amino acids
A small organic compound having an amino group, an acid group, a hydrogen atom, and an
R group
The most diverse of all the large biological molecules; constructed from pools of only 20
kinds of amino acids
A group of proteins that contribute to cell shape and organization
A chemical bond between polypeptide chains that uses two sulfur atoms
Enzymes typically belong to this group of proteins
_____ (1)
_____ (2)
_____ (3)
_____ (4)
_____ (5)
_____ (6)
_____ (7)
_____ (8)
_____ (9)
_____ (10)
_____ (11)
_____ (12)
_____ (13)
_____ (14)
_____ (15)
amino acid
disulfide bridges
peptide bond
polypeptide chain
primary structure
proteins
secondary structure
tertiary structure
domain
quaternary structure
lipoproteins
glycoproteins
denaturation
fibrous proteins
globular proteins
18.
For each of the following, choose the class of organic molecule to which the item belongs. Choices
may be used more than once.
a.
b.
c.
d.
lipids
nucleic acids
proteins
carbohydrates
_____ (1)
_____ (2)
_____ (3)
_____ (4)
_____ (5)
_____ (6)
_____ (7)
_____ (8)
_____ (9)
_____ (10)
_____ (11)
glycoproteins
phospholipids
glycogen
adenosine triphosphate
sucrose and maltose
triglycerides
DNA and RNA
HLAs and hemoglobin
cholesterol
glycogen and starch
waxes
19.
Study the structural formulas of the two adjacent amino acids. Identify the enzyme action causing
formation of a covalent bond and a water molecule (through a condensation reaction) by circling an H atom
from one amino acid and an -OH group from the other amino acid. Also circle the covalent bond that formed
the dipeptide.
20.
In the following diagram, identify condensation reaction sites between the two glucose molecules by
circling the components of the water removed that allow a covalent bond to form between the glucose
molecules (text Figure 3.8, p.40). Note that the reverse reaction is hydrolysis and that both condensation and
hydrolysis reactions require enzymes in order to proceed efficiently.
21.
In the answer blanks, label the molecules shown as saturated or unsaturated. For the unsaturated
molecules, circle the regions that make them unsaturated.
a.
b.
c.
___________________
___________________
___________________
22.
Using a condensation reaction, combine glycerol with three fatty acids to form a triglyceride. In the
diagram to the left, circle the participating atoms that will identify three covalent bonds. In the diagram to the
right, circle the resulting covalent bonds.
23.
a.
b.
c.
In the model of an amino acid below, label the R group, amino group, and carboxyl group.
__________
__________
__________
24.
In the diagram of a nucleotide below, label the phosphate groups, nitrogenous base, and five-carbon
sugar subunits.
a.
b.
c.
__________
__________
__________
25.
In the diagram of a single-stranded nucleic acid molecule, encircle as many complete nucleotides as
possible. How many complete nucleotides are present?
Organic Molecules Questions
Answer Section
SHORT ANSWER
1. ANS:
d
2. ANS:
c
3. ANS:
c
4. ANS:
a
5. ANS:
c
6. ANS:
d
7. ANS:
e
8. ANS:
d
9. ANS:
c
10. ANS:
c
11. ANS:
b
12. ANS:
e
13. ANS:
c
14. ANS:
b
15. ANS:
b
16. ANS:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
b
b
a
c
a
c
b
b
17.
ANS:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
18. ANS:
k
n
f
b
j
l
a
d
i
g
e
c
h
m
o
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
19. ANS:
20. ANS:
c
a
d
b
d
a
b
c
a
d
a
21.
a.
b.
c.
ANS:
unsaturated
saturated
unsaturated
22. ANS:
23. ANS:
a.
b.
c.
R group
amino group
carboxyl group
24. ANS:
a.
b.
c.
phosphate group
five-carbon sugar
nitrogenous base
25.
ANS:
three