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Biochemistry -Structure and Properties of Amino Acids
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1. When the amino acid alanine (R-group is CH3) is added to a solution with a pH of 7.3, alanine becomes
an isotope
a cation
nonpolar
a zwitterions
2. What is the end product of leucine metabolism?
Acetyl-CoA
Pyruvic acid
Oxaloacetic acid
Acetyl carnitine
3. What is the heaviest of the twenty amino acids?
Phenylalanine
Tryptophan
Tyrosine
Histidine
4. Which of the following amino acids can form hydrogen bonds with their side (R) groups?
Asparagine
Aspartic acid
Glutamine
All of these
5. The isoelectric point of an amino acid is defined as the pH
where the molecule carries no electric charge
where the carboxyl group is uncharged
where the amino group is uncharged
of maximum electrolytic mobility
6. Molecules that bear charged groups of opposite polarity are known as
zwitterions
ambions
ion conversion
amphions
7. What is the product of the catabolic breakdown of Arginine?
Alpha-ketoglutarate
Fumarate
Oxaloacetate
Succinate
8. Which amino acids would most likely reside in the membrane-anchoring domain of a membrane embedded protein?
Isoleucine, valine and phenylalanine
Phenylalanine, valine, and aspartate
Leucine, threonine, and lysine
Lysine, arginine and histidine
9. An essential amino acid is one that
is essentially easy to synthesize
is essential to flagella motion
the body cannot synthesize
the body can synthesize under essential conditions
10. D-Alanine and L-Alanine are technically known as
anomers
enantiomers
epimers
polymer
11. Which of the following pairs of amino acids would carry a negative charge on their side chain at pH 8.0?
Asparagine & Glutamine
Leucine & Glycine
Histidine & Lysine
Aspartate & Glutamate
12. In a polypeptide average mass of an amino acid residue is
110 daltons
118 daltons
80 daltons
150 daltons
13. Which pair of amino acids absorbs the most UV light at 280 nm?
Threonine & Histidine
Trp & Tyrosine
Cystein & Asparagine
Phenylalnine & Proline
14. Which of the following is a nonstandard amino acid?
Cysteine
Isoleucine
Hydroxyproline
Histidine
15. Which of the following is an essential amino acid?
Tryptophan
Methionine
Lysine
All of these
16. Protein fluorescence arises primarily from which residue?
Arginine
Tryptophan
Tyrosine
Phenylalanine
17. Which of the following amino acid is known as half-cystine residue?
Cysteine
Isoleucine
Valine
Histidine
18. Which of the following is not an essential amino acid?
Aspartic acid
Glutamic acid
Glycine
All of these
19. Which of the following is not a sensible grouping of amino acids based on their polarity properties?
Ala, Leu, and Val
Arg, His, and Lys
Phe, Trp, and Tyr
Asp, Ile, and Pro
20. Proteins and macromolecular structures take on their higher order structures
by self-assembly
with the help of molecular chaperons
with the help of precursor sequences that are removed from the final structures
all of the above
21. What is the product of the catabolic breakdown of Alanine?
Fumarate
Oxaloacetate
Pyruvate
Malate
22. How many different amino acids are there?
3
20
100
An infinite number
23. Amino acids required in the human diet and not synthesized by the body are called
specialized
trace
essential
accessory
24. Which of the following amino acid contain an imidazolium moiety?
Alanine
Valine
Cysteine
Histidine
25. The sequence of letters 'WYQN' will represent
Tryptophan, tyrosine, glutamic acid, asparagine
Tryptophan, tyrosine, glutamine, asparagine
Tryptophan, glutamine, tryptophan, asparagine
Glutamine, tyrosine, tryptophan, aspartic acid
26. The sulphur containing side chain of cysteine is
ampiphillic, highly reactive and capable of reacting with another cysteine
hydrophillc, highly reactive and capable of reacting with another cysteine
hydrophobic, highly reactive and capable of reacting with another cysteine
none of the above
27. Which of the following is a nonprotein amino acid?
Dopamine
Hydroxylysine
Cystine
none of the these
28. Serine and threonine are polar amino acids due to
reactive hydroxyl group in the side chain
reactive alcoholic group in the side chain
reactive keto group in the side chain
reactive aldehyde group in the side chain
29. Which of the following is not the hydrophobic and aromatic amino acid?
Phenylalanine
Tyrosine
Tryptophan
none of the these
30. Stereo chemical configuration of all a-amino acids derived from proteins is
L
D
L and D
None of these
31. The α-amino acids have a carboxyl group with a pK around __________ , and an amino group with a pK near __________ .
1.1, and 12.1
6.5, and 8.0
3.3, and 10.5
2.2, and 9.4
32. Coomassie Blue stains the proteins by reacting with
arginine residues
free c-termini
peptide bonds
aromatic ring
33. Which amino acid when exposed to ninhydrin produces a brown color?
Asparagine
Proline
Alanine
Valine
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