Midterm 1 Old Exams/Study Questions Flashcards
- Which of the following amino acids would you find in a “turn” of the polypeptide backbone?
a. Tryptophan
b. Proline
c. Phenylalanine
d. Histidine
e. glycine
f. b and e
f. b and e (proline and glycine)
What kind of noncovalent interaction is typified by interactions between two molecules that
are so close together that they can experience weak attractive forces bonding them together?
van der Waals forces
- A disulfide bond in a protein usually exists:
outside the cell because the environment outside the cell is oxidizing
- Which of the following is not a macromolecule formed by polymerization?
a. proteins
b. lipids
c. polynucleotides
d. polysaccharides
e. DNA
b. lipids
- Monomeric proteins do not contain a:
a. primary structure.
b. secondary structure.
c. tertiary structure.
d. quaternary structure.
d. quarternary structure
- Which amino acid is most likely to be found in the core of a protein?
a. methionine
b. asparagines
c. serine
d. threonine
e. glutamic acid
methionine
- The α-helix is characterized by orientation of ______ the molecular axis.
a. H bonds parallel to
b. H bonds perpendicular to
c. ionic bonds parallel to
d. ionic bonds perpendicular to
e. peptide bonds perpendicular to
H bond parallel to
- Which amino acid is most likely located on the surface of a native protein in aqueous solution?
a. Phenylalanine
b. Isoleucine
c. Asparagine
d. Tryptophan
e. None of the above
c. Asparagine
- Which of the following is not a model organism?
a. Mice
b. Fruit fly
c. Roundworm
d. Yeast
e. Human
f. Bacteria
e. human
- When two atoms differing in electronegativity are joined in a covalent bond, then the
a. electrons are shared equally between the atoms.
b. bond is nonpolar.
c. resulting compound is devoid of any dipole moment.
d. atom with the greater electronegativity attracts the bonded electrons more.
d. atom with greater electronegativity attracts the bonded electrons more
- Which of the following is a mechanism for regulating protein activity?
a. proteolytic processing
b. phosphorylation/dephosphorylation
c. ligand binding
d. b and c
e. all of the above
e. all of the above
- Which are amino acids used in the kinase/phosphatase switch?
a. serine
b. threonine
c. tyrosine
d. a and b
e. a, b and c
e. serine, threonine, and tyrosine
14. What kind of enzyme adds phosphate groups to enzymes for the purpose of activating or deactivating them? a. phosphatases b. protein kinases c. flippases d. glycosyltransferases
protein kinases
– are mirror images. They have similar chemical properties but different
biological properties.
Stereoisomers
What kind of enzyme adds phosphate groups to proteins for the purpose of activating or deactivating them?
protein kinases
- Following amino acids are used in a kinase/phosphatase switch except:
a. serine
b. threonine
c. tyrosine
d. glycine
e. none of these above
d. glycine
- Which of the following can activate a GTPase?
a. GDI
b. GDP
c. GAP
d. GEF
e. GTPase
d. GEF
- All of the following are pyrimidines except:
a. adenine
b. cytosine
c. thymine
d. uracil
e. none of these above
a. adenine
- Which of the following is a mechanism for regulating protein activity?
a. proteolytic processing
b. phosphorylation/dephosphorylation
c. ligand binding
d. all of the above
d. all of the above
- Which of the following is/are required for the release of a folded protein from a chaperonin?
a. assistance of GroES
b. hydrolysis of ATP
c. GroEL in a tight conformation
d. GroES in a relaxed conformation
e. a and b
e. a and b
- Which of the following is a building block of DNA?
a. Tryptophan
b. Proline
c. Phenylalanine
d. Uracil
e. none of these above
e. none of these
- Which of the following has the weakest bond strength?
a. phosphoanhydride bond
b. phosphodiester bond
c. peptide bond
d. covalent bond
e. ionic bond
ionic bond
- A(n) cell has membrane-bound organelles.
Eukaryotic
is the smallest particle of an element.
Atom
- Which of the following statements are correct?
I. An atomic nucleus typically contains proton(s) and neutron(s)
II. An atom by itself has more electrons than protons.
III. The number of neutrons determines whether an atom is stable or reactive
IV. Hydrogen bonds are weak and can be broken by heat, yet they contribute significantly to the
specificity of interactions between macromolecules.
V. Atom is the smallest particle of an element.
a. I and II
b. II and III
c. I, III, and IV
d. I, IV, and V
e. I, II, IV, and V
d. I, IV, and V
- Which of the following statements are correct?
I. The hereditary information of a cell is passed on by its proteins.
II. Bacterial DNA is found in the nucleus.
III. All cells of the same organism have the same number of chromosome (with the exception of
egg and sperm cells).
IV. The cytosol of a eukaryotic cell contains membrane-enclosed organelles.
a. I and II
b. II and III
c. III and IV
d. II and IV
e. II, III, and IV
c. III. All cells of the same organism have the same number of chromosome (with the exception of
egg and sperm cells).
IV. The cytosol of a eukaryotic cell contains membrane-enclosed organelles.
Tryptophan repressor is inactive when it is bound to a molecule of tryptophan.
A. True
B. False
false
The active site of an enzyme usually occupies only a – of the enzyme surface.
small fraction
- Which of the following amino acid would you expect to find more often near the center of a
folded globular protein in the cell cytoplasm?
a. serine
b. lysine
c. histidine
d. valine
e. tyrosine
valine
- Which DNA pyrimidine forms two H bonds with its partner in the other DNA strand?
a. adenine
b. cytosine
c. guanine
d. uracil
e. none of these above
none of these
- Disulfide bonds help to stabilize the three-dimensional structure of proteins. Which amino
acid is involved in the formation of disulfide bonds?
a. lysine
b. aspartic acid
c. asparagine
d. proline
e. None of these above
none of these
- What kind of enzymes remove phosphate groups on the surface of their substrate proteins for
the purpose of activating or deactivating the substrates?
A. carboxypeptidase
B. protein kinases
C. flippases
D. glycosyltransferases
E. None of these above
none of these
An amphipathic molecule has
a. both positive and negative components.
b. both hydrophilic and hydrophobic properties.
c. only nonpolar covalent bonds.
d. a and b
e. b and c
both hydrophilic and hydrophobic
- Following amino acid is used in a kinase/phosphatase switch:
a. alanine
b. threonine
c. proline
d. glycine
e. none of these above
threonine
Which of the following can inactivate a small GTPase?
a. GTP
b. GDP
c. GAP
d. GEF
e. DnaK
GAP
Which of the following is purine?
a. adenine
b. cytosine
c. thymine
d. uracil
e. none of these above
adenine
- Which of the following is a mechanism for regulating protein activity?
a. proteolytic processing
b. phosphorylation/dephosphorylation
c. translation
d. all of the above
e. a and b
proteolytic processing
phosphorylation/dephosphorylation