The side chain of histidine has a typical pKa value in the range of 6.5-7.4.
However, when analyzing the pKa values in a particular protein, scientists
determined that one particular His residue has an unusually low pKa value of
4.8. Which of the following statements correctly explains this anomaly?
1) The microenvironment around a residue can impact its pKa value.
2) A positively charged amino acid must be near this residue.
3) A negatively charged amino acid must be near this residue.
4) This residue must be located on the surface of the protein. - ANSWER
Statements 1 and 2
The side chain of ________ has a pKa in the physiological pH range and is
therefore often involved in proton transfer during enzymatic catalysis. -
ANSWER Histidine
All amino acids have a chiral α-carbon EXCEPT ________. - ANSWER
glycine
Which of the following statements regarding Anfinsen's denaturing experiments
with ribonuclease A are valid?
1) Exposing the denatured protein to air oxidation and then dialysis to remove
urea restored the protein to its original functionality.
2) Removing urea by dialysis and then allowing air oxidation of the denatured
protein restored the protein to its original functionality.
3) Denaturing the protein with both urea and β-mercaptoethanol yielded an
inactive protein.
,4) Protein folding is determined by its primary sequence. - ANSWER Only
statements 2, 3, and 4 are valid.
Which of the following statements about protein quaternary structure are
correct?
1) It involves a complex of two or more proteins interacting with each other.
2) The subunits of the structure can be either identical or different.
3) The interactions between subunits can give rise to indefinite growth of
polymeric complexes.
4) Most assemblies of protein subunits have one or more defined axis of
rotation. - ANSWER All statements are correct.
In general, enzymes are what kinds of molecules?
proteins
minerals
carbohydrates
lipids
nucleic acids - ANSWER proteins
The basic building blocks of proteins are _______ - ANSWER amino acids
All amino acids are composed what three things attached to it? - ANSWER
central α-carbon that has an amine group
a carboxylic acid group
and an R group
All amino acids except _______ are chiral with the two isomer forms known as
the L-isomer and the D-isomer. - ANSWER glycine
The ____ is the only isomer known to be incorporated into proteins. -
ANSWER L-isomer
This ionic state, where the carboxylic acid is negative and the amine group is
positive, is known as the __________ state - ANSWER zwitterionic state
What are the N-terminal and C-terminal residues for the following peptide
sequence?
,Peptide sequence: EASY - ANSWER E is the N-terminal residue; Y is the C-
terminal residue.
Ultimate source of energy for life on earth is:
A. Sun
B. Geothermal heat
C. Carbohydrates
D. Fats
E. Other organisms - ANSWER Sun
Which is not a common component of biomolecules?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
E. Chlorine - ANSWER Chlorine
Which is a basic structural unit of living organisms?
A. Nucleus
B. Cell membrane
C. Tissue
D. Cell
E. Cytoskeleton - ANSWER Cell
Which of the following is not an organelle?
A. Mitochondria
B. Chloroplast
C. Nucleus
D. Plasma Membrane
E. Golgi Complex - ANSWER Plasma Membrane
Which of the following is not a role played by carbohydrates in living cells?
A. Energy source
B. Structural support
C. Intercellular communication
D. Both A and B
E. All roles are played - ANSWER All roles are played by carbohydrates in
living cells
, Metabolism is best defined as the...
A. Reactions of living cells
B. Reactions that synthesize large molecules in living cells
C. Reactions that degrade molecules in living cells
D. Conversion of food molecules to energy
E. Reactions that synthesize and degrade molecules in living cells - ANSWER
E. Reactions that synthesize and degrade molecules in living cells
The average life span of a species is about ________years
A) One million
B) Ten million
C) Five hundred thousand
D) Five million
E) One hundred thousand - ANSWER A. One million
Which of the following is not a waste product of living organisms
A) Carbon dioxide
B) Water
C) Urea
D) Ammonia
E) Glycine - ANSWER E. Glycine
Biochemistry is defined as
A) The study of life processes
B) The study of the molecular basis of life
C) The study of living organisms
D) The study of organic compounds in living organisms
E) The study of living compounds - ANSWER B. The study of the molecular
basis of life
One of the principal methods that organisms use to obtain energy from chemical
bonds is by ___________.
A) Substitution reactions
However, when analyzing the pKa values in a particular protein, scientists
determined that one particular His residue has an unusually low pKa value of
4.8. Which of the following statements correctly explains this anomaly?
1) The microenvironment around a residue can impact its pKa value.
2) A positively charged amino acid must be near this residue.
3) A negatively charged amino acid must be near this residue.
4) This residue must be located on the surface of the protein. - ANSWER
Statements 1 and 2
The side chain of ________ has a pKa in the physiological pH range and is
therefore often involved in proton transfer during enzymatic catalysis. -
ANSWER Histidine
All amino acids have a chiral α-carbon EXCEPT ________. - ANSWER
glycine
Which of the following statements regarding Anfinsen's denaturing experiments
with ribonuclease A are valid?
1) Exposing the denatured protein to air oxidation and then dialysis to remove
urea restored the protein to its original functionality.
2) Removing urea by dialysis and then allowing air oxidation of the denatured
protein restored the protein to its original functionality.
3) Denaturing the protein with both urea and β-mercaptoethanol yielded an
inactive protein.
,4) Protein folding is determined by its primary sequence. - ANSWER Only
statements 2, 3, and 4 are valid.
Which of the following statements about protein quaternary structure are
correct?
1) It involves a complex of two or more proteins interacting with each other.
2) The subunits of the structure can be either identical or different.
3) The interactions between subunits can give rise to indefinite growth of
polymeric complexes.
4) Most assemblies of protein subunits have one or more defined axis of
rotation. - ANSWER All statements are correct.
In general, enzymes are what kinds of molecules?
proteins
minerals
carbohydrates
lipids
nucleic acids - ANSWER proteins
The basic building blocks of proteins are _______ - ANSWER amino acids
All amino acids are composed what three things attached to it? - ANSWER
central α-carbon that has an amine group
a carboxylic acid group
and an R group
All amino acids except _______ are chiral with the two isomer forms known as
the L-isomer and the D-isomer. - ANSWER glycine
The ____ is the only isomer known to be incorporated into proteins. -
ANSWER L-isomer
This ionic state, where the carboxylic acid is negative and the amine group is
positive, is known as the __________ state - ANSWER zwitterionic state
What are the N-terminal and C-terminal residues for the following peptide
sequence?
,Peptide sequence: EASY - ANSWER E is the N-terminal residue; Y is the C-
terminal residue.
Ultimate source of energy for life on earth is:
A. Sun
B. Geothermal heat
C. Carbohydrates
D. Fats
E. Other organisms - ANSWER Sun
Which is not a common component of biomolecules?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
E. Chlorine - ANSWER Chlorine
Which is a basic structural unit of living organisms?
A. Nucleus
B. Cell membrane
C. Tissue
D. Cell
E. Cytoskeleton - ANSWER Cell
Which of the following is not an organelle?
A. Mitochondria
B. Chloroplast
C. Nucleus
D. Plasma Membrane
E. Golgi Complex - ANSWER Plasma Membrane
Which of the following is not a role played by carbohydrates in living cells?
A. Energy source
B. Structural support
C. Intercellular communication
D. Both A and B
E. All roles are played - ANSWER All roles are played by carbohydrates in
living cells
, Metabolism is best defined as the...
A. Reactions of living cells
B. Reactions that synthesize large molecules in living cells
C. Reactions that degrade molecules in living cells
D. Conversion of food molecules to energy
E. Reactions that synthesize and degrade molecules in living cells - ANSWER
E. Reactions that synthesize and degrade molecules in living cells
The average life span of a species is about ________years
A) One million
B) Ten million
C) Five hundred thousand
D) Five million
E) One hundred thousand - ANSWER A. One million
Which of the following is not a waste product of living organisms
A) Carbon dioxide
B) Water
C) Urea
D) Ammonia
E) Glycine - ANSWER E. Glycine
Biochemistry is defined as
A) The study of life processes
B) The study of the molecular basis of life
C) The study of living organisms
D) The study of organic compounds in living organisms
E) The study of living compounds - ANSWER B. The study of the molecular
basis of life
One of the principal methods that organisms use to obtain energy from chemical
bonds is by ___________.
A) Substitution reactions
