Question 1

The pKₐs of phosphoric acid are 2.1,7.2,and 12.Which of the following ionic form(s)of phosphoric acid is/are present at pH 7.0?

Accepted Answer

A) HPO4-2 
B) H₂PO4- 
C) HPO4-2 and PO4-3 
D) H₂PO4- and HPO4-2 
A) HPO4-2 
B) H₂PO4- 
C) HPO4-2 and PO4-3 
D) H₂PO4- and HPO4-2

Question 2

Which of the following effects do solutes have on a water solvent?

Accepted Answer

A) They enhance the dynamic interplay among H₂O molecules. 
B) They increase the orientation that neighbouring water molecules can assume. 
C) They have no effect. 
D) They give order to the solvent. 
A) They enhance the dynamic interplay among H₂O molecules. 
B) They increase the orientation that neighbouring water molecules can assume. 
C) They have no effect. 
D) They give order to the solvent.

Question 3

Which of the following is reason for the ionization of water?

Accepted Answer

A) The smaller electronegative oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
B) The larger electronegative oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
C) The smaller electropositive oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
D) The larger electropositive oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
A) The smaller electronegative oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
B) The larger electronegative oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
C) The smaller electropositive oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate. 
D) The larger electropositive oxygen atom strips the electron from one of its hydrogen atoms,leaving the proton to dissociate.

Question 4

Which of the following is a feature of micelles?

Accepted Answer

A) Hydrocarbon tails form hydrophobic interactions with water. 
B) Polar ends form hydrophobic interactions with water. 
C) Hydrocarbon tails are excluded from the water into hydrophobic domains. 
D) Polar ends are hydrophobic,and non-polar ends are hydrophilic. 
A) Hydrocarbon tails form hydrophobic interactions with water. 
B) Polar ends form hydrophobic interactions with water. 
C) Hydrocarbon tails are excluded from the water into hydrophobic domains. 
D) Polar ends are hydrophobic,and non-polar ends are hydrophilic.

Question 5

We are preparing an acetate buffer at pH 4.5 with 0.01 M solutions of acetic acid (pKₐ = 4.8)and sodium acetate.Which of the following should the volume of acetic acid be compared to the volume of sodium acetate solution?

Accepted Answer

A) less than half 
B) exactly half 
C) equal to 
D) about twice 
A) less than half 
B) exactly half 
C) equal to 
D) about twice

Question 6

Which of the following solvents has the highest dielectric constant?

Accepted Answer

A) water 
B) acetic acid 
C) ethanol 
D) hexane 
A) water 
B) acetic acid 
C) ethanol 
D) hexane

Question 7

Which of the following pairs would be the best buffer at pH 10.0?

Accepted Answer

A) acetic acid and sodium acetate (pKa = 4.76) 
B) H₂CO3 and NaHCO₃ (pKas are 3.77 and 10.4) 
C) lactic acid and sodium lactate (pKa = 3.86) 
D) NaH₂PO4 and Na2HPO4 (pKas are 2.1,7.2,12.4) 
A) acetic acid and sodium acetate (pKa = 4.76) 
B) H₂CO3 and NaHCO₃ (pKas are 3.77 and 10.4) 
C) lactic acid and sodium lactate (pKa = 3.86) 
D) NaH₂PO4 and Na2HPO4 (pKas are 2.1,7.2,12.4)

Question 8

Aspirin contains a carboxylic acid with a pKa of 3.5.Which of the following regarding its structure is correct?

Accepted Answer

A) It will be mostly protonated in the bloodstream. 
B) It will be mostly protonated in the stomach. 
C) It will be easily absorbed in the stomach due to its negative charge. 
D) It will be easily transported in the bloodstream due to its neutral charge. 
A) It will be mostly protonated in the bloodstream. 
B) It will be mostly protonated in the stomach. 
C) It will be easily absorbed in the stomach due to its negative charge. 
D) It will be easily transported in the bloodstream due to its neutral charge.

Question 9

Which of the following types of interactions occur between hydrogen bonded water and non-polar solutes?

Accepted Answer

A) hydrophobic 
B) hydrophilic 
C) ionic 
D) van der Waals 
A) hydrophobic 
B) hydrophilic 
C) ionic 
D) van der Waals

Question 10

Which of the following buffer systems primarily maintain intracellular pH?

Accepted Answer

A) HPO42-/H₂PO4-;HCO₃-/H₂CO3 
B) H3PO4/H₂PO4-;histidine 
C) HCO₃-/H₂CO3;H3PO4/H₂PO4- 
D) HPO4-/H₂PO4-;histidine 
A) HPO42-/H₂PO4-;HCO₃-/H₂CO3 
B) H3PO4/H₂PO4-;histidine 
C) HCO₃-/H₂CO3;H3PO4/H₂PO4- 
D) HPO4-/H₂PO4-;histidine

Question 11

Hypoventilation is characterized by inability to excrete CO₂ rapidly enough.Which of the following is NOT a cause of hypoventilation?

Accepted Answer

A) depressant drugs 
B) encephalitis 
C) narcotics 
D) lung diseases 
A) depressant drugs 
B) encephalitis 
C) narcotics 
D) lung diseases

Question 12

Water is particularly suited as a solvent for biosystems.Which of the following is NOT a characteristic of water?

Accepted Answer

A) Water is a medium for ionization,enhancing the variety of chemical species. 
B) Water is innocuous,yet a powerful solvent. 
C) Water is an excellent solvent for non-polar substances. 
D) Water is relatively chemically inert,yet dissolves a variety of solutes. 
A) Water is a medium for ionization,enhancing the variety of chemical species. 
B) Water is innocuous,yet a powerful solvent. 
C) Water is an excellent solvent for non-polar substances. 
D) Water is relatively chemically inert,yet dissolves a variety of solutes.

Question 13

Which of the following is NOT soluble in water?

Accepted Answer

A) salts 
B) sugars 
C) aldehydes 
D) hydrocarbons 
A) salts 
B) sugars 
C) aldehydes 
D) hydrocarbons

Question 14

Which of the following values is the pKa for a weak acid that is 25% deprotonated at pH 4?

Accepted Answer

A) 3.40 
B) 3.52 
C) 4.48 
D) 4.60 
A) 3.40 
B) 3.52 
C) 4.48 
D) 4.60

Question 15

Which of the following is a characteristic of pure liquid H₂O molecules?

Accepted Answer

A) They are held in a rigid 3-dimensional network. 
B) They have local preference for linear geometry. 
C) They have large numbers of strained or broken hydrogen bonds. 
D) They do not switch H bonds readily. 
A) They are held in a rigid 3-dimensional network. 
B) They have local preference for linear geometry. 
C) They have large numbers of strained or broken hydrogen bonds. 
D) They do not switch H bonds readily.

Exam 2: Water: the Medium of Life

The pKₐs of phosphoric acid are 2.1,7.2,and 12.Which of the following ionic form(s)of phosphoric acid is/are present at pH 7.0?

Which of the following effects do solutes have on a water solvent?

Which of the following is reason for the ionization of water?

Which of the following is a feature of micelles?

We are preparing an acetate buffer at pH 4.5 with 0.01 M solutions of acetic acid (pKₐ = 4.8)and sodium acetate.Which of the following should the volume of acetic acid be compared to the volume of sodium acetate solution?

Which of the following solvents has the highest dielectric constant?

Which of the following pairs would be the best buffer at pH 10.0?

Aspirin contains a carboxylic acid with a pKa of 3.5.Which of the following regarding its structure is correct?

Which of the following types of interactions occur between hydrogen bonded water and non-polar solutes?

Which of the following buffer systems primarily maintain intracellular pH?

Hypoventilation is characterized by inability to excrete CO₂ rapidly enough.Which of the following is NOT a cause of hypoventilation?

Water is particularly suited as a solvent for biosystems.Which of the following is NOT a characteristic of water?

Which of the following is NOT soluble in water?

Which of the following values is the pKa for a weak acid that is 25% deprotonated at pH 4?

Which of the following is a characteristic of pure liquid H₂O molecules?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

Filters

Aspirin contains a carboxylic acid with a pK_a of 3.5.Which of the following regarding its structure is correct?