Practice test 3 flashcards
When determining ratio of protease to substrate, what value goes on top of division symbol? Below division symbol?
Substrate concentration goes on top and proteasome concentration would go on bottom of division line
The concentration of enzyme for each experiment was 5.0 μM. What is kcat for the reaction at pH 4.5 with NO chloride added when Compound 3 is the substrate? (hint: use eqn Kcat = Vmax/{E}
2.5*10^-2.
Four organic compounds: 2-butanone, n-pentane, propanoic acid, and n-butanol, present as a mixture, are separated by column chromatography using silica gel with benzene as the eluent. What is the expected order of elution of these four organic compounds from first to last?
n-Pentane → 2-butanone → n-butanol → propanoic acid. Since silica gel serves as the stationary phase for the experiment, increasing the polarity of the eluting molecule will increase its affinity for the stationary phase and increase the elution time (decreased Rf).
What is the definition of half-life?
the time it takes for half of all the radioactive nuclei to decay into their daughter nuclei.
What is the net charge of an amino acid at pH 7?
A typical uncharged amino acid will have a pos. charged N-terminus and a neg. charged C terminus equaling a net neutral charge of 0
What are the structural features possessed by storage lipids? (aka TAGs)
Three fatty acids ester-linked to a single glycerol. Didn’t know exact structure of a TAG
The lone pair of electrons in ammonia allows the molecule to act as a lewis….in water. How?
act as a Lewis base in water. By definition, a Lewis base is a substance that donates an electron pair
What is ionization energy determined by?
Ionization energy is determined by valence e- and whether or not a molecule is a metal. Metals have lower ionization nrgies than non-metals
A glass rod is rubbed with a silk scarf producing a charge of +3.2 × 10–9 C on the rod. (Recall that the magnitude of the proton and electron charges is 1.6 × 10–19 C.) The glass rod has what charge?
the number of charges in excess can be computed as +3.2 × 10 –9 C/1.6 × 10 –19 C = +2.0 × 10 10.
What is the resistance equation for parallel circuits? Circuits in series?
Parallel = 1/R1 + 1/R2 Series = R1 + R2
Which DNA amino acids are purines? How can you tell?
Purines: Adenine & Guanine (bi-cyclic)
Which DNA amino acids are pyrimidines? How can you tell?
Pyrimidines: cytosine, thymine and uracil (mono-cyclic)
What are the differences between the Krebs cycle and glycolysis?
TCA cycle: oxidation of acetyl CoA into CO2 and H2O.
Glycolysis: chain of rxns. converting glucose into pyruvate thus producing ATP.
What does the isoelectric point mean? What does it mean if “a protein has an isoelectric point of 10 at physiological pH”?
Isoelectric point: the point at which the protein carries a net 0 charge.
If a protein has an isoelectric point of 10 at physiological pH then it carries a positive charge at homeostatic conditions.
What is the purpose of a northern blot? Southern blot? Western blot?
N. Blot: RNA isolation
S. Blot: DNA extraction
W. Blot: Protein extraction
