BIOC0001 EXAM QUESTIONS AND ANSWERS WIT
COMPLETE SOLUTIONS VERIFIED 100% GUARANTEED
PASS
Two amino acids of the standard 20 contain sulfur atoms. They are:
A) cysteine and serine.
B) cysteine and threonine.
C) methionine and cysteine
D) methionine and serine
E) threonine and serine.
C) methionine and cysteine
Which amino acid does not have a charged side chain?
Select one:
A) K (Lysine)
B) R (Arginine)
C) P (Proline)
D) D (Aspartic Acid)
C) P (Proline)
,Which amino acid is not polar?
Select one:
A) A (Alanine)
B) S (Serine)
C) N (Asparagine)
D) Q (Glutamine)
A) A (Alanine)
Which of the following is not a sensible grouping of amino acids based on their
properties?
Select one:
A) Arg, His, Lys
B) Phe, Trp, Tyr
C) Glu, Gly, Val
D) Asn, Gln, Ser
C) Glu, Gly, Val
Alanine is similar to serine in the same way that:
Select one:
A) Val is similar to Thr.
B) Phe is similar to Tyr.
C) Phe is similar to Trp.
,D) Ser is similar to Thr.
E) Trp is similar to Pro.
B) Phe is similar to Tyr
- the structure of serine is similar to alanine, with the only difference being the addition
of a hydroxyl group on serine's side chain
- likewise, tyrosine is similar to phenylalanine, with the only difference being the addition
of a hydroxyl group on tyrosine's side chain
Which pair of amino acids absorb the most UV light at 280 nm?
Select one:
A) Thr and His
B) Cys and Asp
C) Trp and Tyr
D) Phe and Pro
C) Trp and Tyr
- Trp and Tyr, and to a much lesser extent Phe, absorb UV light due to the presence of
electrons in delocalised aromatic systems
- this accounts for the characteristic strong absorbance of light by most proteins at a
wavelength of 280 nm
How to figure out if the amino acid is L or D:
, 1. orient the molecule with the alpha-carboxylic group on top and the side chain on the
bottom
2. if the alpha-amine group is located on the left side of the carbon chain, the molecule
is L. If the alpha-amine group is on the right side, the compound is D
Which of the following statements about cystine is correct?
A) Cystine forms when the -CH2-SH R-group is oxidised to form a -CH2-S-S-CH2-
disulphide bridge between two cysteines
B) Cystine is formed by the oxidation of the carboxylic acid group on cysteine
C) Cystine is formed through a peptide linkage between two cysteines
D) Two cystines are released when a -CH2-S-S-CH2- disulphide bridge is reduced
to -CH2-SH
A) Cystine forms when the -CH2-SH R-group is oxidised to form a -CH2-S-S-CH2-
disulphide bridge between two cysteines
The isoelectric point of an amino acid is defined as...
Select one:
A) The pH where the amino group is uncharged
B) The pH where the molecule carries no net electric charge
C) The pH where the carboxyl group is uncharged
D) pH 7.0, a neutral pH
B) The pH where the molecule carries no net electric charge
COMPLETE SOLUTIONS VERIFIED 100% GUARANTEED
PASS
Two amino acids of the standard 20 contain sulfur atoms. They are:
A) cysteine and serine.
B) cysteine and threonine.
C) methionine and cysteine
D) methionine and serine
E) threonine and serine.
C) methionine and cysteine
Which amino acid does not have a charged side chain?
Select one:
A) K (Lysine)
B) R (Arginine)
C) P (Proline)
D) D (Aspartic Acid)
C) P (Proline)
,Which amino acid is not polar?
Select one:
A) A (Alanine)
B) S (Serine)
C) N (Asparagine)
D) Q (Glutamine)
A) A (Alanine)
Which of the following is not a sensible grouping of amino acids based on their
properties?
Select one:
A) Arg, His, Lys
B) Phe, Trp, Tyr
C) Glu, Gly, Val
D) Asn, Gln, Ser
C) Glu, Gly, Val
Alanine is similar to serine in the same way that:
Select one:
A) Val is similar to Thr.
B) Phe is similar to Tyr.
C) Phe is similar to Trp.
,D) Ser is similar to Thr.
E) Trp is similar to Pro.
B) Phe is similar to Tyr
- the structure of serine is similar to alanine, with the only difference being the addition
of a hydroxyl group on serine's side chain
- likewise, tyrosine is similar to phenylalanine, with the only difference being the addition
of a hydroxyl group on tyrosine's side chain
Which pair of amino acids absorb the most UV light at 280 nm?
Select one:
A) Thr and His
B) Cys and Asp
C) Trp and Tyr
D) Phe and Pro
C) Trp and Tyr
- Trp and Tyr, and to a much lesser extent Phe, absorb UV light due to the presence of
electrons in delocalised aromatic systems
- this accounts for the characteristic strong absorbance of light by most proteins at a
wavelength of 280 nm
How to figure out if the amino acid is L or D:
, 1. orient the molecule with the alpha-carboxylic group on top and the side chain on the
bottom
2. if the alpha-amine group is located on the left side of the carbon chain, the molecule
is L. If the alpha-amine group is on the right side, the compound is D
Which of the following statements about cystine is correct?
A) Cystine forms when the -CH2-SH R-group is oxidised to form a -CH2-S-S-CH2-
disulphide bridge between two cysteines
B) Cystine is formed by the oxidation of the carboxylic acid group on cysteine
C) Cystine is formed through a peptide linkage between two cysteines
D) Two cystines are released when a -CH2-S-S-CH2- disulphide bridge is reduced
to -CH2-SH
A) Cystine forms when the -CH2-SH R-group is oxidised to form a -CH2-S-S-CH2-
disulphide bridge between two cysteines
The isoelectric point of an amino acid is defined as...
Select one:
A) The pH where the amino group is uncharged
B) The pH where the molecule carries no net electric charge
C) The pH where the carboxyl group is uncharged
D) pH 7.0, a neutral pH
B) The pH where the molecule carries no net electric charge
