Molecular Biology Final Exam UPDATED
Questions and CORRECT Answers
Why can humans digest starch but not cellulose?
A) Starch is softer than cellulose.
B) Starch monomers are joined by covalent bonds, and cellulose monomers are joined by ionic
bonds.
C) The monomer of starch is glucose, while the monomer of cellulose is galactose.
D) Humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-
glycosidic linkages of cellulose. - CORRECT ANSWER -D
The term insoluble fiber on food packages refers to which of the following molecules?
A) starch
B) amylopectin
C) cellulose
D) polypeptides - CORRECT ANSWER -C
How many molecules of water are released during polymerization of a 22 monomer-long
cellulose molecule?
A) 21
B) 44
C) 11
D) 22 - CORRECT ANSWER -A
Which of the following statements describes the interaction of water molecules with
phospholipids?
A) Phospholipids dissolve in water.
B) Phospholipids do not interact with water because water is polar and lipids are nonpolar.
C) The polar heads avoid water; the nonpolar tails attract water (because water is polar and
opposites attract).
,D) The polar heads interact with water; the nonpolar tails do not. - CORRECT ANSWER -
D
An amino acid is to a protein as a glucose molecule is to ________.
A) nucleic acid
B) glycogen
C) a lipid
D) a tripeptide - CORRECT ANSWER -B
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are
associated with an accumulation of misfolded polypeptides?
A) Diabetes mellitus
B) Alzheimer's and Parkinson's
C) Parkinson's only
D) Alzheimer's only - CORRECT ANSWER -B
Ovalbumin, the egg white protein is denatured in scrambled egg. Which of the following is not
affected?
A) primary structure of ovalbumin
B) secondary structure of ovalbumin
C) tertiary structure of ovalbumin
D) quaternary structure of ovalbumin - CORRECT ANSWER -A
Which of the following ratios of nucleotides is constant for DNA?
A) A + U = G + C
B) A + C = U + G
C) A + G = T + C
D) A + T = G + C - CORRECT ANSWER -C
,Which molecule has both hydrophilic and hydrophobic properties and is found in plasma
membranes? - CORRECT ANSWER - Phospholipids- 5
How many amino acids and peptide bonds does a tetrapeptide have?
A) three amino acids and four peptide bonds
B) four amino acids and two peptide bonds
C) four amino acids and four peptide bonds
D) four amino acids and three peptide bonds - CORRECT ANSWER -D
When nucleotides polymerize to form a nucleic acid, ________.
A) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
B) a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second
C) covalent bonds form between the bases of two nucleotides
D) hydrogen bonds form between the bases of two nucleotides - CORRECT ANSWER -A
"The native structure of hemoglobin (HB) comprises of two α and two β subunits, each of which
carries a heme group. There appear to be no previous studies that report the in-vitro folding and
assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that
has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding.
This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J
Am Soc Mass Spectrum 2007, 18, 8-16)Hemoglobin, when subjected to 40% acetonitrile at pH
10.0, loses its quaternary structure, which means the ________.
A) four α and β polypeptides dissociate, peptide bonds between amino acids, and α and β
polypeptides lose their 3-D structure
B) peptide bonds between amino acids break
C) four α and β polypeptides dissociate
D) α and β polypeptides lose their 3-D structure - CORRECT ANSWER -C
What is the role of hydrogen in the synthesis of "hardened fats" from vegetable oil?
A) Hydrogen causes cross-linking between chains.
B) Hydrogen increases the carbon chain length.
, C) Hydrogen causes hydrolysis to occur.
D) Hydrogen reduces the number of carbon-carbon double bond. - CORRECT ANSWER -
D
Which of the following best describes glycogen?
A) is formed by the hydrolysis of glucose molecules.
B) has alpha 1-6 glyosidic bonds.
C) a fibrous protein that helps in maintaining cellular structure
D) a storage polysaccharide found in plants - CORRECT ANSWER -B
Which part of an amino acid gives it its unique identity?
A) the components of its side chain
B) the glycerol molecule that forms the backbone of the amino acid
C) the long carbon-hydrogen tails of the molecule
D) the carboxyl and amino groups - CORRECT ANSWER -A
Which of the following are possible base compositions for double-stranded DNA?
A) 5, 45, 45, 5, 0
B) 20, 20, 20, 20, 20
C) 35, 15, 35, 15, 0
D) All of these - CORRECT ANSWER -A
Which of the following molecules is a Disaccharide? - CORRECT ANSWER - 15
If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be
labeled?
A) DNA
B) RNA
Questions and CORRECT Answers
Why can humans digest starch but not cellulose?
A) Starch is softer than cellulose.
B) Starch monomers are joined by covalent bonds, and cellulose monomers are joined by ionic
bonds.
C) The monomer of starch is glucose, while the monomer of cellulose is galactose.
D) Humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-
glycosidic linkages of cellulose. - CORRECT ANSWER -D
The term insoluble fiber on food packages refers to which of the following molecules?
A) starch
B) amylopectin
C) cellulose
D) polypeptides - CORRECT ANSWER -C
How many molecules of water are released during polymerization of a 22 monomer-long
cellulose molecule?
A) 21
B) 44
C) 11
D) 22 - CORRECT ANSWER -A
Which of the following statements describes the interaction of water molecules with
phospholipids?
A) Phospholipids dissolve in water.
B) Phospholipids do not interact with water because water is polar and lipids are nonpolar.
C) The polar heads avoid water; the nonpolar tails attract water (because water is polar and
opposites attract).
,D) The polar heads interact with water; the nonpolar tails do not. - CORRECT ANSWER -
D
An amino acid is to a protein as a glucose molecule is to ________.
A) nucleic acid
B) glycogen
C) a lipid
D) a tripeptide - CORRECT ANSWER -B
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are
associated with an accumulation of misfolded polypeptides?
A) Diabetes mellitus
B) Alzheimer's and Parkinson's
C) Parkinson's only
D) Alzheimer's only - CORRECT ANSWER -B
Ovalbumin, the egg white protein is denatured in scrambled egg. Which of the following is not
affected?
A) primary structure of ovalbumin
B) secondary structure of ovalbumin
C) tertiary structure of ovalbumin
D) quaternary structure of ovalbumin - CORRECT ANSWER -A
Which of the following ratios of nucleotides is constant for DNA?
A) A + U = G + C
B) A + C = U + G
C) A + G = T + C
D) A + T = G + C - CORRECT ANSWER -C
,Which molecule has both hydrophilic and hydrophobic properties and is found in plasma
membranes? - CORRECT ANSWER - Phospholipids- 5
How many amino acids and peptide bonds does a tetrapeptide have?
A) three amino acids and four peptide bonds
B) four amino acids and two peptide bonds
C) four amino acids and four peptide bonds
D) four amino acids and three peptide bonds - CORRECT ANSWER -D
When nucleotides polymerize to form a nucleic acid, ________.
A) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
B) a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second
C) covalent bonds form between the bases of two nucleotides
D) hydrogen bonds form between the bases of two nucleotides - CORRECT ANSWER -A
"The native structure of hemoglobin (HB) comprises of two α and two β subunits, each of which
carries a heme group. There appear to be no previous studies that report the in-vitro folding and
assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that
has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding.
This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J
Am Soc Mass Spectrum 2007, 18, 8-16)Hemoglobin, when subjected to 40% acetonitrile at pH
10.0, loses its quaternary structure, which means the ________.
A) four α and β polypeptides dissociate, peptide bonds between amino acids, and α and β
polypeptides lose their 3-D structure
B) peptide bonds between amino acids break
C) four α and β polypeptides dissociate
D) α and β polypeptides lose their 3-D structure - CORRECT ANSWER -C
What is the role of hydrogen in the synthesis of "hardened fats" from vegetable oil?
A) Hydrogen causes cross-linking between chains.
B) Hydrogen increases the carbon chain length.
, C) Hydrogen causes hydrolysis to occur.
D) Hydrogen reduces the number of carbon-carbon double bond. - CORRECT ANSWER -
D
Which of the following best describes glycogen?
A) is formed by the hydrolysis of glucose molecules.
B) has alpha 1-6 glyosidic bonds.
C) a fibrous protein that helps in maintaining cellular structure
D) a storage polysaccharide found in plants - CORRECT ANSWER -B
Which part of an amino acid gives it its unique identity?
A) the components of its side chain
B) the glycerol molecule that forms the backbone of the amino acid
C) the long carbon-hydrogen tails of the molecule
D) the carboxyl and amino groups - CORRECT ANSWER -A
Which of the following are possible base compositions for double-stranded DNA?
A) 5, 45, 45, 5, 0
B) 20, 20, 20, 20, 20
C) 35, 15, 35, 15, 0
D) All of these - CORRECT ANSWER -A
Which of the following molecules is a Disaccharide? - CORRECT ANSWER - 15
If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be
labeled?
A) DNA
B) RNA
