Lesson 2: Large Biological Molecules

Question 1

Which of the following is true of both starch and cellulose?

A. They are cis-trans isomers of each other.
B. They are both used for energy storage in plants.
C. They are both structural components of the plant
cell wall.
D. They are both polymers of glucose.
E. They can both be digested by humans.

Answer 1

D. They are both polymers of glucose.

Question 2

Which of the following statements is true for the class of biological molecules known as lipids?

A. They are insoluble in water.
B. They contain less energy than proteins and
carbohydrates.
C. They are made from glycerol, fatty acids, and
phosphate.
D. They contain nitrogen.
E. They are made by dehydration reactions.

Answer 2

A. They are insoluble in water.

Question 3

Which of the following is true of cellulose?

A. It is a polymer composed of enantiomers of glucose.
B. It is a storage polysaccharide for energy in plant cells.
C. It is a major structural component of plant cell walls.
D. It’s a polymer composed of enantiomers of glucose,
it’s a storage polysaccharide for energy in plant
cells, it’s digestible by bacteria in the human gut,
and it’s a major structural component of plant cell
walls.
E. It is digestible by bacteria in the human gut.

Answer 3

C. It is a major structural component of plant cell walls.

Question 4

What is the structural feature that allows DNA to replicate?

A. disulphide bonding (bridging) of the two helixes
B. sugar-phosphate backbone
C. three-component structure of the nucleotides
D. complementary pairing of the nitrogenous bases
E. twisting of the molecule to form an α helix

Answer 4

D. complementary pairing of the nitrogenous bases

Question 5

What maintains the secondary structure of a protein?

A. hydrogen bonds between the R groups
B. hydrogen bonds between the amino group of one
peptide bond and the carboxyl group of another
peptide bond
C. peptide bonds
D. hydrophobic interactions
E. disulphide bonds

Answer 5

B. hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Question 6

Which of the following is true regarding saturated fatty acids?

A. They are the principal molecules in lard and butter.
B. They are usually liquid at room temperature.
C. They are usually produced by plants.
D. They are the predominant fatty acid in corn oil.
E. They have double bonds between carbon atoms of
the fatty acids.

Answer 6

A. They are the principal molecules in lard and butter.

Question 7

A molecule with the chemical formula C6H12O6 is probably a

A. carbohydrate and lipid only.
B. carbohydrate.
C. carbohydrate and monosaccharide only.
D. lipid.
E. monosaccharide

Answer 7

C. carbohydrate and monosaccharide only.

Question 8

Molecules with which functional groups may form polymers via dehydration reactions?

A. carbonyl groups
B. carboxyl groups
C. hydroxyl groups
D. either hydroxyl or carboxyl groups
E. either carbonyl or carboxyl groups

Answer 8

D. either hydroxyl or carboxyl groups

Question 9

The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?

A. Both serine and leucine would be on the exterior of
the globular protein.
B. Leucine would be in the interior, and serine would
be on the exterior of the globular protein.
C. Serine would be in the interior, and leucine would be
on the exterior of the globular protein.
D. Both serine and leucine would be in the interior and
on the exterior of the globular protein.
E. Both serine and leucine would be in the interior of
the globular protein.

Answer 9

B. Leucine would be in the interior, and serine would be on the exterior of the globular protein.

Question 10

Which of the following polymers contain nitrogen?

A. starch
B. amylopectin
C. chitin
D. glycogen
E. cellulose

Answer 10

C. chitin

Question 11

Humans can digest starch but not cellulose because

A. humans have enzymes that can hydrolyze the α
glycosidic linkages of starch but not the β glycosidic
linkages of cellulose.
B. the monomer of starch is glucose, while the
monomer of cellulose is glucose with a nitrogen-
containing group.
C. humans have enzymes that can hydrolyze the β
glycosidic linkages of starch but not the α glycosidic
linkages of cellulose.
D. humans harbour starch-digesting bacteria in the
digestive tract.
E. the monomer of starch is glucose, while the
monomer of cellulose is galactose.

Answer 11

A. humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.

Question 12

Which of the following descriptions best fits the class of molecules known as nucleotides?

A. a nitrogenous base and a pentose sugar
B. a pentose sugar and a purine or pyrimidine
C. a nitrogenous base, a phosphate group, and a
pentose sugar
D. a phosphate group and an adenine or uracil
E. a nitrogenous base and a phosphate group

Answer 12

C. a nitrogenous base, a phosphate group, and a pentose sugar

Question 13

Which of the following is an example of hydrolysis?

A. the synthesis of two amino acids, forming a peptide
with the release of water
B. the reaction of a fat, forming glycerol and fatty acids
with the release of water
C. the synthesis of a nucleotide from a phosphate, a
pentose sugar, and a nitrogenous base with the
production of a molecule of water
D. the reaction of two monosaccharides, forming a
disaccharide with the release of water
E. the reaction of a fat, forming glycerol and fatty acids
with the consumption of water

Answer 13

E. the reaction of a fat, forming glycerol and fatty acids with the consumption of water

Question 14

Which of the following is not a monomer/polymer pairing?

A. amino acid/protein
B. triglyceride/phospholipid bilayer
C. ribonucleotide/RNA
D. deoxyribonucleotide/DNA
E. monosaccharide/polysaccharide

Answer 14

B. triglyceride/phospholipid bilayer

Question 15

A molecule with the formula C18H36O2 is probably a

A. fatty acid.
B. carbohydrate.
C. hydrocarbon.
D. nucleic acid.
E. protein.

Answer 15

A. fatty acid.

Question 16

Use the following information to answer the questions below.

You have just had a breakfast of toast (high-fibre bread) with butter and jam (no added sugar) along with a glass of milk.
What are the two major polysaccharides you have consumed?

A. cellulose and fructose
B. glucose and fructose
C. starch and fructose
D. cellulose and starch
E. fatty acids and pectin

Answer 16

D. cellulose and starch

Question 17

Polysaccharides, triacylglycerides, and proteins are similar in that they

A. are decomposed into their subunits by dehydration
reactions.
B. are synthesized from subunits by dehydration
reactions.
C. are synthesized from monomers by the process of
hydrolysis.
D. are synthesized as a result of peptide bond
formation between monomers.
E. all contain nitrogen in their monomer building blocks.

Answer 17

B. are synthesized from subunits by dehydration reactions.

Question 18

If 14C-labelled uridine triphosphate is added to the growth medium of cells, what macromolecules will be labelled?

A. both DNA and RNA
B. DNA
C. proteins
D. phospholipids
E. RNA

Answer 18

E. RNA

Question 19

The tertiary structure of a protein is the

A. bonding together of several polypeptide chains by
weak bonds.
B. overall protein structure resulting from the
aggregation of two or more polypeptide subunits.
C. unique three-dimensional shape of the fully folded
polypeptide.
D. organization of a polypeptide chain into an α helix or
β pleated sheet.
E. order in which amino acids are joined in a
polypeptide chain.

Answer 19

C. unique three-dimensional shape of the fully folded polypeptide

Question 20

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?

A. 12
B. 11
C. 9
D. 8
E. 10

Answer 20

E. 10

Question 21

If cells are grown in a medium containing radioactive 32P-labelled phosphate, which of these molecules will be labelled?

A. nucleic acids
B. proteins
C. amylose
D. phospholipids
E. both phospholipids and nucleic acids

Answer 21

E. both phospholipids and nucleic acids

Question 22

Which class of biological molecules are grouped together because their monomers are amino acids?

A. carbohydrates
B. lipids
C. proteins
D. nucleic acids
E. This is not a criterion for grouping molecules.

Answer 22

C. proteins

Question 23

Which of the following statements about the 5’ end of a polynucleotide strand of DNA is correct?

A. The 5’ end has a phosphate group attached to the
number 5 carbon of ribose.
B. The 5’ end is the fifth position on one of the
nitrogenous bases.
C. The 5’ end has a carboxyl group attached to the
number 5 carbon of ribose.
D. The 5’ end has a hydroxyl group attached to the
number 5 carbon of ribose.
E. The 5’ end has phosphate attached to the number 5
carbon of the nitrogenous base.

Answer 23

A. The 5’ end has a phosphate group attached to the number 5 carbon of ribose.

Question 24

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

A. as a disaccharide
B. as a hexose
C. as a polysaccharide
D. as a pentose
E. as a monosaccharide

Answer 24

A. as a disaccharide

Question 25

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?

A. disulphide bonds
B. peptide bonds
C. ionic bonds
D. hydrogen bonds
E. hydrophobic interactions

Answer 25

D. hydrogen bonds

Question 26

On food packages, to what does the term insoluble fibre refer?

A. starch
B. cellulose
C. chitin
D. polypeptides
E. amylopectin

Answer 26

B. cellulose

Question 27

Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibres. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits

A. altered tertiary structure.
B. altered quaternary structure.
C. altered secondary structure.
D. altered primary structure and altered quaternary
structure; the secondary and tertiary structures may
or may not be altered.
E. altered primary structure.

Answer 27

D. altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

Question 28

The bonding of two amino acid molecules to form a larger molecule requires

A. the release of a nitrous oxide molecule.
B. the release of a water molecule.
C. the addition of a water molecule.
D. the addition of a nitrogen atom.
E. the release of a carbon dioxide molecule.

Answer 28

B. the release of a water molecule.

Question 29

In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?

A. in the interior of the folded protein, away from water,
or in a transmembrane portion interacting with lipid
fatty acid chains
B. in the interior of the folded protein, away from water
C. in the transmembrane portion interacting with lipid
fatty acid chains
D. anywhere in the protein, with equal probability
E. on the exterior surface of the protein, interacting
with water

Answer 29

A. in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains

Question 30

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

A. glycogen and chitin only
B. glycogen
C. glycogen, cellulose, and chitin
D. cellulose
E. chitin

Answer 30

B. glycogen

Question 31

All of the following contain amino acids except

A. insulin.
B. cholesterol.
C. antibodies.
D. enzymes.
E. hemoglobin.

Answer 31

B. cholesterol.

Question 32

What is the chemical reaction mechanism by which cells make polymers from monomers?

A. phosphodiester linkages
B. the formation of disulphide bridges between 
     monomers
C. ionic bonding of monomers
D. hydrolysis
E. dehydration reactions

Answer 32

E. dehydration reactions