Principles of Biochemistry, 5e (Moran/Horton/Scrimgeour) - Test Bank - Chapter 3

Principles of Biochemistry, 5/E



Laurence A. Moran, University of Toronto
Robert A Horton, North Carolina State University
Gray Scrimgeour, University of Toronto
Marc Perry, University of Toronto

ISBN-10: 0321707338
ISBN-13:  9780321707338
Publisher:  Prentice Hall
Copyright:  2012

Principles of Biochemistry, 5e (Moran/Horton/Scrimgeour/Perry/Rawn)
Chapter 3   Amino Acids and the Primary Structures of Proteins


1) Amino acids are named that because each one
A) is a unique carboxylic acid.
B) has a standard configuration.
C) is a carboxyl derivative of an amide acid.
D) is an amino derivative of a carboxylic acid.
Answer:  D
Page Ref: Section 3-1

2) Amino acids found in meteorites and near stars are
A) D isomers only.
B) L isomers only.
C) Both D and L isomers.
D) not isomers.
Answer:  C
Page Ref: Section 3-1

3) The last common ancestor of modern organisms must have used
A) D amino acids.
B) L amino acids.
C) both D and L amino acids.
D) either D or L amino acids.
Answer:  B
Page Ref: Section 3-1

4) If the R group of an amino acid is -CH3, then the name of this compound is
A) methyl amino acid.
B) 2-aminopropanoic acid.
C) alanine.
D) All of the above.
E) B and C.
Answer:  E
Page Ref: Section 3-1

5) Amino acids with non-ionizable side chains are zwitterions when they are ________.
A) in any solution
B) at physiological pH, pH = 7.4
C) in acidic solutions only
D) in alkaline solutions only
E) All of the above
Answer:  B
Page Ref: Section 3-1
 
6) Glycine is not a stereoisomer because
A) it has no chiral carbon.
B) it does not form enantiomers.
C) it does not exist in two non-superimposable mirror-image forms.
D) All of the above.
E) A and B only.
Answer:  D
Page Ref: Section 3-1

7) An amino acid with two chiral carbon atoms
A) is unstable.
B) can exist in 4 forms, all of which are superimposable.
C) can form three possible stereoisomers.
D) can form four possible stereoisomers.
E) can form five possible stereoisomers.
Answer:  D
Page Ref: Section 3-1

8) The number of commonly found amino acids with only one chiral carbon is
A) 17.
B) 18.
C) 19.
D) 20.
Answer:  A
Page Ref: Section 3-1

9) At neutral pH, the net charge of serine is
A) positive.
B) negative.
C) zero.
D) None of the above.
Answer:  C
Page Ref: Section 3-1

10) Fossil dating by amino acid racemization measured
A) the amount of a D-amino acid present.
B) the amount of an L-amino acid present.
C) the amounts of both D and L forms of an amino acid present.
D) the total of all amino acids present.
Answer:  C
Page Ref: Section 3-1

 
11) The RS system of nomenclature describes
A) the relative sizes of molecules.
B) the way the amino acid side chains are arranged.
C) the absolute configuration about chiral carbon centers .
D) the strength of the chemical groups in amino acids.
Answer:  C
Page Ref: Section 3-1
12) The R group of an amino acid determines if it is
A) hydrophilic or hydrophobic.
B) polar or nonpolar.
C) charged or uncharged.
D) an acid or a base.
E) All of the above.
Answer:  E
Page Ref: Section 3-1

13) Proline is distinct among the 20 commonly found amino acids because
A) it is a ring compound.
B) it is hydrophilic and ionic.
C) the nitrogen of the amino group is in a ring.
D) the carbon of the carboxyl group is in a ring.
E) it has little effect on protein structure.
Answer:  C
Page Ref: Section 3-2

14) Tyrosine and tryptophan are less hydrophobic than phenylalanine because
A) phenylalanine has an indole group.
B) phenylalanine has no polar group in the side chain.
C) phenylalanine is a phenol.
D) tyrosine and tryptophan have smaller R groups.
E) All of the above.
Answer:  B
Page Ref: Section 3-2

15) Alanine, valine, leucine and isoleucine are important in three dimensional structure because they
A) are branched.
B) are highly hydrophobic.
C) are highly hydrophilic.
D) attract water molecules.
Answer:  B
Page Ref: Section 3-2

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