16.Globular proteins fold up into compact, spherical structures that have uneven surfaces. They tend to form
multisubunit complexes, which also have a rounded shape. Fibrous proteins, in contrast, span relatively large
distances within the cell and in the extracellular space. Which protein is not classified as a fibrous protein?
(a)elastase (b)collagen (c)keratin (d)elastin
17.You have two purified samples of protein Y: the wild-type (nonmutated) protein and a mutant version with a
single amino acid substitution. When washed through the same gel-filtration column, mutant protein Y runs through
the column more slowly than the normal protein. Which of the following changes in the mutant protein is most likely
to explain this result?
(a)the loss of a binding site on the mutant protein surface through which protein Y normally forms dimers
(b)a change that results in the mutant proteinâs acquiring an overall positive instead of a negative charge
(c)a change that results in the mutant proteinâs being larger than the wild-type protein
(d)a change that results in the mutant proteinâs having a slightly different shape from the wild-type protein
18.Which of the following statements is true?
(a)Disulfide bonds are formed by the cross-linking of methionine residues.
(b)Disulfide bonds are formed mainly in proteins that are retained within the cytosol.
(c)Disulfide bonds stabilize but do not change a proteinâs final conformation.
(d)Agents such as mercaptoethanol can break disulfide bonds through oxidation.
19.Proteins bind selectively to small molecule targets called ligands. The selection of one ligand out of a mixture of
possible ligands depends on the number of weak, noncovalent interactions in the proteinâs ligand-binding site. Where
is the binding site typically located in the protein structure?
(a)on the surface of the protein (b)inside a cavity on the protein surface
(c)buried in the interior of the protein (d)forms on the surface of the protein in the presence of ligand
thanks
16.Globular proteins fold up into compact, spherical structures that have uneven surfaces. They tend to form
multisubunit complexes, which also have a rounded shape. Fibrous proteins, in contrast, span relatively large
distances within the cell and in the extracellular space. Which protein is not classified as a fibrous protein?
(a)elastase (b)collagen (c)keratin (d)elastin
17.You have two purified samples of protein Y: the wild-type (nonmutated) protein and a mutant version with a
single amino acid substitution. When washed through the same gel-filtration column, mutant protein Y runs through
the column more slowly than the normal protein. Which of the following changes in the mutant protein is most likely
to explain this result?
(a)the loss of a binding site on the mutant protein surface through which protein Y normally forms dimers
(b)a change that results in the mutant proteinâs acquiring an overall positive instead of a negative charge
(c)a change that results in the mutant proteinâs being larger than the wild-type protein
(d)a change that results in the mutant proteinâs having a slightly different shape from the wild-type protein
18.Which of the following statements is true?
(a)Disulfide bonds are formed by the cross-linking of methionine residues.
(b)Disulfide bonds are formed mainly in proteins that are retained within the cytosol.
(c)Disulfide bonds stabilize but do not change a proteinâs final conformation.
(d)Agents such as mercaptoethanol can break disulfide bonds through oxidation.
19.Proteins bind selectively to small molecule targets called ligands. The selection of one ligand out of a mixture of
possible ligands depends on the number of weak, noncovalent interactions in the proteinâs ligand-binding site. Where
is the binding site typically located in the protein structure?
(a)on the surface of the protein (b)inside a cavity on the protein surface
(c)buried in the interior of the protein (d)forms on the surface of the protein in the presence of ligand
thanks
