EXAM I Flashcards
A solution is made of 0.5 M K_2 HPO_4 and 0.25 M KH_2 PO_4 (pK = 6.82). The pH of the solution would be __________.
a) 1.0
b) 3.0
c) 6.52
d) 7.12
e) 9.34
b) 7.12
Which of the following DNA sequences is (are) palindromic in double stranded form?
a) AGCT
b) AAGCTT
c) AGGA
d) A and B
e) A, B, and C
d) A and B
Which one of these characteristics is NOT true for the alpha helix?
a) It is represented in ribbon diagrams as a cylinder.
b) There is a requirement for glycine every third amino acid residue.
c) A hydrogen bond forms between the carbonyl oxygen of the nth amino acid residue and the NH group of the (n+4)th amino acid residue.
d) Proline is typically not found in the alpha helix.
e) All of the above are true of the alpha helix.
b) There is a requirement for glycine every third amino acid residue.
A fast and common method for determining the concentration of protein in aqueous solution is:
a) tandem mass spectrometry
b) “salting in” with ammonium sulfate
c) drying a portion and weighing the solid
d) measuring light adsorption at 280 nm
e) Edman degradation
d) measuring light adsorption at 280 nm
Amphiphilics molecules:
a) have both oxidizing and reducing groups
b) are micelles
c) have chromophores in two different wavelengths regions
d) have both acidic and basic groups
e) have both hydrophilic and hydrophobic groups
e) have both hydrophilic and hydrophobic groups
Nucleotides contain phosphate groups bonded to the:
a) C3’ or C5’ atoms
b) C3 or C3’ atoms
c) C5 or N9 atoms
d) C3 or N9 atoms
e) none of the above
a) C3’ or C5’ atoms
The disulfide bond between two cysteine molecules:
a) is a peptide bond
b) is an ionic bond that is stable at physiological pH
c) is a covalent bond formed by oxidation
d) is a hydrogen bond between the two sulfhydryl groups
e) is a weak ion-induced dipole attraction
c) is a covalent bond formed by oxidation
Highly active muscle generates lactic acid by respiration so fast that the blood passing through the muscle experiences a drop in pH from about 7.4 to 7.2. Under these conditions, hemoglobin releases about 10% more O_2 than it does at pH 7.4. This is because of:
a) allostery
b) the Bohr effect
c) heme protonation
d) structural similarities with myoglobin
e) presence of carbon monoxide at higher acidity
b) the Bohr effect
Either dansyl chloride or Edman’s reagent can be used to identify the __________ of a protein.
a) amino acid sequence
b) N-terminal amino acid
c) C-terminal amino acid
d) quaternary structure
e) none of the above
b) N-terminal amino acid
The theory of evolution includes the following principles:
a) evolution is not directed towards a specific goal
b) evolution is ongoing, and is constrained by its past
c) evolution requires some sloppiness for adaptation to changes
d) A and B
e) A, B, and C
e) A, B, and C
The most important intermolecular interaction involved in stabilizing protein structure is:
a) amino acid
b) water molecule
c) purine base
d) peptide bond
e) pyrimidine base
d) peptide bond
Nucleotides are linked together in nucleic acids by a __________ bond.
a) peptide
b) phosphodiester
c) glycosidic
d) ester
e) disulfide
b) phosphodiester
Treatment of a protein with a reducing agent such as β-mercaptoethanol along with a detergent such as SDS (sodium dodecyl sulfate) disrupts all of the following interactions except:
a) ionic interactions
b) hydrogen bonds
c) disulfide bonds
d) peptide bonds
e) hydrophobic interactions
d) peptide bonds
In the tetrapeptide: Serine-Lysine-Arginine Glutamate
a) Serine is the N-terminal amino acid, Glutamate is the C-terminal amino acid
b) Serine is the C-terminal amino acid, Glutamate is the N-terminal amino acid
c) Serine and Glutamate are both C-terminal amino acids
d) Serine and Glutamate are both N-terminal amino acids
e) Not enough information to tell
a) Serine is the N-terminal amino acid, Glutamate is the C-terminal amino acid
