Lipids and Proteins by fjwuxn

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									Lipids and Proteins
1. Most naturally occurring
monounsaturated fatty acids can
be classified as which of the
following?
A   D
B   L
C   cis
D   trans
E   none of the above
2. Which molecule is a fatty acid?


A   CH3COOH
B   CH2=CHCOOH
C   (CH3)2CH(CH2)7COOH
D   CH3(CH2)7CH=CH(CH2)7COOH
E   None of the above
3. Which molecule is a saturated
fatty acid?

A   CH3 (CH2)14COOH
B   CH2=CHCOOH
C   (CH3)2CH(CH2)5COOH
D   CH3(CH2)7CH=CH(CH2)7COOH
E   None of the above
4. Triglycerides belong to which
general class of organic
molecules?
A   esters
B   alcohols
C   carboxylic acids
D   ketones
E   ethers
5. Fats are generally___ at room
temperature and are obtained
from____.

A   liquids; plants
B   liquids; animals
C   solids; plants
D   solids; animals
E   none of the above
6. The chemical makeup of oils is

A simple esters of long chain alcohols and
  fatty acids
B esters of glycerol with three identical
  unsaturated fatty acids
C esters of glycerol with three
  predominantly unsaturated fatty acids
D none of the above
7. Saturated triacylglycerols are
usually ___ because _____.
A liquids; they have relatively short fatty acid
  chains
B liquids; their rigid fatty acid chains do not
  fit together closely
C solids; they have relatively long fatty acid
  chains
D solids; their flexible fatty acid chains allow
  the molecules to fit together closely
8. Which reaction can be used to
convert oils into fats?

A hydrogenation
B hydrolysis
C esterification
D saponification
E dehydration
9. The saponification reaction used
to form soaps can be described as

A   acid-catalyzed hydrolysis
B   base-catalyzed hydrolysis
C   hydrogenation
D   dehydrogenation
E   dehydration
10. In chemical terms, soaps can
be described as

A   simple esters of fatty acids
B   mixed esters of fatty acids
C   salts of carboxylic acids
D   long chain acids
E   bases formed from glycerol
11. The hydrocarbon end of a soap
molecule is

A   hydrophilic and attracted to grease
B   hydrophobic and attracted to grease
C   hydrophilic and attracted to water
D   hydrophobic and attracted to water
E   neither hydrophilic nor hydrophobic
12. Members of which class of
biomolecules are the building
blocks of proteins?
A   glycerols
B   monosaccharides
C   fatty acids
D   amino acids
E   nucleic acids
13. The peptide bond joining amino
acids into proteins is a specific
example of the ___ bond.

A amide
B carbonyl
C ester
D glycosidic
E hydrogen
14. Which category of amino acid
contains side groups that are
hydrophobic?

A   polar
B   non-polar
C   basic
D   acidic
E   basic and acidic
15. Non-polar side groups on
amino acids are said to be ___
because they are not attracted to
water molecules.
A hydrophilic
B hydrophobic
C ionized
D unreactive
E none of these
16. Which amino acid is classifed
as neutral and non-polar?

A aspartic acid
B histidine
C phenylalanine
D lysine
E tyrosine
17. Which amino acid is classified
as basic?

A valine
B threonine
C phenylalanine
D lysine
E glutamic acid
18. Amino acids found in proteins
all have the following features.

A   all are α-amino acids
B   all are L-amino acids
C   all are cis-amino acids
D   all are correct
E   none are correct
19.
1 Circle the carboxyl group
2 Underline the amine group
3 Label the alpha carbon
4  Draw a box around the side group
5  Draw the structure at a pH lower than the
   isoelectric point
6 Draw the structure at a pH higher than
   the isoelectric point
20. The isoelectric point of an
amino acid is

A the pH at which it exists in the basic form
B the pH at which it exists in the acid form
C the pH at which it exists in the zwitterion
  form
D the pH equal to its pKa
E the pH equal to its pKb
21. Proteins are least soluble in
water _____.

A   at their isoelectric point
B   at low pH
C   at neutral pH
D   at high pH
E   at both high and low pH
22. The amino acid sequence of a
protein is known as its

A   primary structure
B   secondary structure
C   tertiary structure
D   quaternary structure
E   none of the above
23. The N-terminal amino acid in
the peptide ala-leu-gly-his-pro is

A   alanine
B   leucine
C   glycine
D   histidine
E   proline
    24. The C-terminal amino acid in
    the peptide ala-leu-gly-his-pro is

A   alanine
B   leucine
C   glycine
D   histidine
E   proline
25. How many different tripeptides
can be formed from one molecule
each of the amino acids tyrosine,
valine and alanine?
A3
B6
C9
D 12
E 24
26. Which pair of amino acids can
have hydrophobic interactions?

A arginine and glutamic acid
B aspartic acid and lysine
C leucine and alanine
D glutamic acid and serine
E glycine and asparagine
27. Which pair of amino acids can
have ionic interactions?

A asparagine and glutamic acid
B aspartic acid and lysine
C leucine and alanine
D glutamic acid and serine
E glycine and asparagine
28. Which pair of amino acids can
form hydrogen bonds between their
side groups?

A arginine and glutamic acid
B aspartic acid and lysine
C leucine and alanine
D glutamine and serine
E glycine and asparagine
29. The beta-pleated sheet is an
example of

A   primary structure
B   secondary structure
C   tertiary structure
D   quaternary structure
E   none of the above
30. The type of bond that is most
important in maintaining secondary
structure of a protein is
A   disulfide bridges
B   hydrogen bonding within the backbone
C   hydrogen bonding between side groups
D   salt bridges
E   hydrophobic interactions
31. Proteins that consist of two or
more chains assembled into a large
3-dimensional structure are said to
display
A   primary structure
B   secondary structure
C   tertiary structure
D   quaternary structure
E   none of the above
32. When a protein is _____, its
primary structure is destroyed, thus
destroying the other aspects of its
structure.
A   denatured
B   hydrolyzed
C   ionized
D   polymerized
E   esterified
33. All of the following can
denature proteins without
destroying the primary structure
except
A heat
B agitation
C enzyme treatment (digestion)
D lowering pH
E heavy metal ions
                Answers
1. C    2. D     3. A    4. A    5. D
6. C    7. D     8. A    9. B    10. C
11. B   12. D    13. A   14. B   15. B
16. C   17. D    18. A   19.     20. C
21. A   22. A    23. A   24. E   25. B
26. C   27. B    28. D   29. B   30. B
31. D   32. B    33. C

								
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