FL 2

Which of the following atoms will be expected to have the smallest second ionization energy? A. Na B. C C. O D. Ca

D. Metals have lower ionization energies than non-metals as long as the ionization event involves a valence electron. Since Na is an alkali metal, it has only one valence electron and has a large second ionization energy. Ca is an alkaline earth metal and has two valence electrons. It will therefore have the smallest second ionization energy of the four atoms listed, which include Na and two non-metals.

What expression gives the amount of light energy (in J per photon) that is converted to other forms between the fluorescence excitation and emission events?

E = hf = hc/λ, where h = 6.62 × 10 −34 J ∙ s and c = 3 × 10 8 m/s. Excitation occurs at λe = 360 nm, but fluorescence is observed at λf = 440 nm. This implies that an energy of E = (6.62 × 10 −34) × (3 × 10 8) × [1 / (360 × 10 −9) − 1 / (440 × 10 −9)] J they subtracted the wavelengths

Which statement about the cooperativity of RIα/C activation and RIα protein folding is supported by the data in figures 2 and 3? A. Both activation and folding are cooperative. B. Activation is cooperative, but folding is not. C. Folding is cooperative, but activation is not. D. Neither activation nor folding is cooperative.

The answer to this question is A because both curves have a sigmoidal shape, which is indicative of cooperative processes.

Based on the information in the passage, PDK1 catalyzes the addition of phosphate to what functional group? A. Hydroxyl B. Amine C. Carboxyl D. Phenyl

The answer to this question is A because reactions involving either Ser or Thr would involve the hydroxyl group in the side chain of these amino acids.

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?

A. n-Pentane → 2-butanone → n-butanol → propanoic acid

n [Cu(NH3)4]2+, the subscript 4 indicates which of the following? A. The oxidation number of Cu only B. The coordination number of Cu2+ only C. Both the oxidation number of Cu and the coordination number of Cu2+ D. Neither the oxidation number of Cu nor the coordination number of Cu2+

B. The coordination number of Cu2+ only

It is possible to design a reactor where the SCY conductor and the nitrogen/ammonia electrode operate at different temperatures. Which combination of temperatures is expected to give the best results? A. SCY temperature higher than electrode temperature B. SCY temperature lower than electrode temperature C. SCY temperature the same as electrode temperature D. The temperature of the components does not make a difference.

The answer to this question is A because the proton conductivity of SCY increases with increasing temperature, while the favorability of reaction decreases with overall temperature. It is therefore beneficial to maintain the SCY conductor at a higher temperature. takeaway: raising temp will cause reaction to move to the left (thermodynamically) however we want the electrode temperature to be higher to favor the kinetics

Which amino acid is found in greatest abundance in the active site of a laccase?

The answer to this question is C because the five-membered imidazole rings depicted in Figure 1 are associated with histidine, an amino acid whose side chain is frequently encountered at the active site of metalloenzymes.

Based on the data from Table 1, what effects do acid and chloride have on the enzymatic activity of laccases?

The answer to this question is D. Activity increased at lower pH, which corresponds to a higher acidity of the solution, while introduction of chloride lowered activity dramatically

The lone pair of electrons in ammonia allows the molecule to: A. assume a planar structure. B. act as an oxidizing agent. C. act as a Lewis acid in water. D. act as a Lewis base in water.

Lewis base is a substance that donates an electron pair in forming a covalent interaction.

In the overall electrochemical reaction: A. nitrogen is oxidized at the anode, and hydrogen is reduced at the cathode. B. nitrogen is reduced at the cathode, and hydrogen is oxidized at the anode. C. nitrogen is reduced at the anode, and hydrogen is oxidized at the cathode. D. nitrogen is oxidized at the cathode, and hydrogen is reduced at the anode.

SO N2(g) + 6H+ + 6e- → 2NH3(g) in this equation we can see that nitrogen gains a negative charge, which means that its OXIDIZED and given electrons. we know that because hydrogen is positive with nonmetals (with N is) so we can assume that nitrogen went from 0 to - charge

Compared to the concentration of the proteasome, the concentration of the substrate is larger by what factor? A.5 × 101 B.5 × 102 C.5 × 103 D.5 × 104

2 × 10-9 M, while the substrate was present at 100 × 10-6 M. The ratio of these two numbers is 5 × 104

What atom is the site of covalent attachment of AMC to the model tetrapeptide used in the studies?

The answer to this question is A because AMC is attached to the peptide on the carboxyl side. This suggests that an amide linkage involving the N atom in AMC is used to covalently attach the fluorophore to the peptide.

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?

kcat = Vmax/[E] = (125 nM/s)/5.0 μM = 2.5 × 10-2 s-1

When used in place of spHM, which peptide would be most likely to achieve the same experimental results? A. FLGFAY B. FLGFQY C. FLGFGY D. FLGFEY

phosphorylated threonine would most likely be mimicked by glutamic acid in terms of size and charge.

At 25°C, the formation of [Cu(NH3)4]2+ according to Equation 1 is most likely a: A. spontaneous process with positive ΔG°. B. spontaneous process with negative ΔG°. C. nonspontaneous process with positive ΔG°. D. nonspontaneous process with negative ΔG°.

the answer to this question is B because the equilibrium constant for the reaction is very large (much greater than 1). This necessarily means that ΔG° is negative and the reaction is spontaneous.

What is the total number of sp2-hybridized carbon atoms present in the fluorophore used in the experiments?

There are 10 carbon atoms in AMC. Nine of these carbon atoms are AX3 systems that possess exactly one doubly bonded atom and are therefore sp2-hybridized.

What is the concentration of Ca2+(aq) in a saturated solution of CaCO3? (Note: The solubility product constant Ksp for CaCO3 is 4.9 × 10-9.) A. 2.4 × 10-4 M B. 4.9 × 10-5 M C. 7.0 × 10-5 M D. 4.9 × 10-9 M

the solubility product constant expression for CaCO3 is Ksp = [Ca2+][CO32-]. Since equal quantities of Ca2+(aq) and CO32-(aq) are produced when CaCO3 dissolves, this expression reduces to 4.9 × 10-9 = x2, or 49 × 10-10 = x2.