The half-lives of many cytoplasmic proteins vary with the identities of their N-terminal residues via the  N-end rule.

a) Proteins with the “destabilizing” N-terminal residues contain Asp, Arg, Leu, Lys, and Phe with their half-lives > 2 to 3 hours

b) Proteins with the “destabilizing” N-terminal residues with their half-lives of only 2 to 3 minutes contain; Asp, Arg, Leu, Lys, and Phe

c) Proteins contain Ala, Gly, Met, Ser, Thr, and Val have half-lives of >10 hours are stabilizing N-terminal residue in prokaryotes

d) Those with the “stabilizing” N-terminal residues Ala, Gly, Met, Ser, Thr, and Val have half-lives of >20 hours in eukaryotes

Which of the following is correct?

#Question id: 389

#Unit 1. Molecules and their Interaction Relevant to Biology

A weak acid HA has a pKa of 5.0.  If 1.0 mol of this acid and 0.1 mol of NaOH were dissolved in one liter of water, what would the final pH be?

#Question id: 390

#Unit 1. Molecules and their Interaction Relevant to Biology

What are the properties arising due to varying concentrations of solute in a given solvent, irrespective of the nature of solute with respect to the solvent?

#Question id: 391

#Unit 1. Molecules and their Interaction Relevant to Biology

In a hospital laboratory, a 10.0 mL sample of gastric juice, obtained several hours after a meal, was titrated with 0.1 M NaOH to neutrality; 7.2 mL of NaOH was required. The patient’s stomach contained no ingested food or drink, thus assume that no buffers were present. What was the pH of the gastric juice?

#Question id: 393

#Unit 1. Molecules and their Interaction Relevant to Biology

Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results?

#Question id: 400

#Unit 1. Molecules and their Interaction Relevant to Biology

Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that ________.

#Question id: 401

#Unit 1. Molecules and their Interaction Relevant to Biology

.Which of the following graphs describes the relationship between [H3O+] and pH?