Question 1

Buffer systems are effective when the pH values are within ____ pH unit(s) of the pKa value.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 2

Hydrogen bonds in ice are all EXCEPT:

Accepted Answer

A)  directional. 
B)  straight. 
C)  weak. 
D)  responsible for the lower density of ice over liquid water. 
E)  holding water molecules in ice apart. 
A)  directional. 
B)  straight. 
C)  weak. 
D)  responsible for the lower density of ice over liquid water. 
E)  holding water molecules in ice apart.

Question 3

The H-bonded water around an ionic substance tends to ____; and the H-bonded water around nonpolar solutes tends to ____.

Accepted Answer

A)  inhibit ionization, promote hydrophobic interactions 
B)  inhibit ionization, inhibit hydrophobic interactions 
C)  not impact ionization, inhibit hydrophobic interactions 
D)  promote ionization, not impact hydrophobic interactions 
E)  promote ionization, promote hydrophobic interactions 
A)  inhibit ionization, promote hydrophobic interactions 
B)  inhibit ionization, inhibit hydrophobic interactions 
C)  not impact ionization, inhibit hydrophobic interactions 
D)  promote ionization, not impact hydrophobic interactions 
E)  promote ionization, promote hydrophobic interactions

Question 4

If 0.1 moles of Na2HPO4 and 0.1 moles of NaH2PO4 are mixed in water, what is the resulting pH? The pKa values for phosphoric acid are 2.1, 7.2, 12.4.

Accepted Answer

A)  2.1 
B)  4.65 
C)  7.2 
D)  9.8 
E)  12.4 
A)  2.1 
B)  4.65 
C)  7.2 
D)  9.8 
E)  12.4

Question 5

Aspirin contains a carboxylic acid with a pKa of 3.5. Which of the following is true?

Accepted Answer

A)  Aspirin will be mostly protonated in the stomach 
B)  Aspirin will be mostly protonated in the bloodstream 
C)  Aspirin will be easily absorbed in the stomach due to its negative charge 
D)  Aspirin will be easily transported in the bloodstream due to its negative charge 
E)  both a and d are correct 
A)  Aspirin will be mostly protonated in the stomach 
B)  Aspirin will be mostly protonated in the bloodstream 
C)  Aspirin will be easily absorbed in the stomach due to its negative charge 
D)  Aspirin will be easily transported in the bloodstream due to its negative charge 
E)  both a and d are correct

Question 6

Hyperventilation is a physiological mechanism to:

Accepted Answer

A)  lower [CO2 (g)] in the blood and increase blood pH. 
B)  raise [CO2 (g)] in the blood and increase blood pH. 
C)  lower [CO2 (g)] in the blood and decrease blood pH. 
D)  raise [CO2 (g)] in the blood and decrease blood pH. 
E)  lower [CO2 (g)] in the blood and increase [HCO3−]. 
A)  lower [CO2 (g)] in the blood and increase blood pH. 
B)  raise [CO2 (g)] in the blood and increase blood pH. 
C)  lower [CO2 (g)] in the blood and decrease blood pH. 
D)  raise [CO2 (g)] in the blood and decrease blood pH. 
E)  lower [CO2 (g)] in the blood and increase [HCO3−].

Question 7

To ____ the osmotic pressure created by the contents of their cytosol, cells tend to store substances such as amino acids and sugars in ____ form.

Accepted Answer

A)  increase, monomeric 
B)  minimize, polymeric 
C)  minimize, monomeric 
D)  maximize, polymeric 
E)  increase, polymeric 
A)  increase, monomeric 
B)  minimize, polymeric 
C)  minimize, monomeric 
D)  maximize, polymeric 
E)  increase, polymeric

Question 8

A plasma pH of 6.8 doesn't seem too far away from a normal pH of 7.4, but at pH 6.8 the H+ concentration is ____ times greater than at pH 7.4 and results in severe acidosis.

Accepted Answer

A)  0.1 
B)  0.6 
C)  4 
D)  10 
E)  20 
A)  0.1 
B)  0.6 
C)  4 
D)  10 
E)  20

Question 9

Amphiphilic (amphipathic) molecules include:

Accepted Answer

A)  sugars. 
B)  acidic amino acids. 
C)  inorganic salts. 
D)  water. 
E)  salts of fatty acids. 
A)  sugars. 
B)  acidic amino acids. 
C)  inorganic salts. 
D)  water. 
E)  salts of fatty acids.

Question 10

Estimate the pH of the resulting solution prepared by mixing 1.0 mole of solid disodium phosphate (Na2HPO4) and 1.25 mole of hydrochloric acid. The pKa values for phosphoric acid are 2.1, 7.2, 12.4.

Accepted Answer

A)  pH < 2.1 
B)  pH = 2.1 
C)  2.1 < pH < 7.2 
D)  pH = 7.2 
E)  7.2 < pH < 12.4 
A)  pH < 2.1 
B)  pH = 2.1 
C)  2.1 < pH < 7.2 
D)  pH = 7.2 
E)  7.2 < pH < 12.4

Question 11

The average lifetime of a hydrogen bond connection in water is on the order of 10:

Accepted Answer

A)  picoseconds. 
B)  microseconds. 
C)  milliseconds. 
D)  seconds. 
E)  nanoseconds. 
A)  picoseconds. 
B)  microseconds. 
C)  milliseconds. 
D)  seconds. 
E)  nanoseconds.

Question 12

Properties of water that render it so suited to its role as a medium of life include all EXCEPT:

Accepted Answer

A)  Unrivaled ability to form hydrogen bonds. 
B)  Unusually high dielectric constant of water explains water's ability to surround ions and increase the ions' attraction for one another. 
C)  Unparalleled ability to orient around nonpolar solutes to promote hydrophobic interactions. 
D)  The small, but significant, tendency to form H+ and OH− ions. 
E)  None, all are true. 
A)  Unrivaled ability to form hydrogen bonds. 
B)  Unusually high dielectric constant of water explains water's ability to surround ions and increase the ions' attraction for one another. 
C)  Unparalleled ability to orient around nonpolar solutes to promote hydrophobic interactions. 
D)  The small, but significant, tendency to form H+ and OH− ions. 
E)  None, all are true.

Question 13

Buffers have all of the following characteristics EXCEPT:

Accepted Answer

A)  they have relatively flat titration curves at the pH(s) where they buffer. 
B)  they resist changes in their pH as acid or base is added. 
C)  they are typically composed of a weak acid and its conjugate base. 
D)  they buffer best for polyprotic acids half-way between the two pKa values. 
E)  buffer where the amounts of conjugate base are nearly equivalent to the amounts of weak acid. 
A)  they have relatively flat titration curves at the pH(s) where they buffer. 
B)  they resist changes in their pH as acid or base is added. 
C)  they are typically composed of a weak acid and its conjugate base. 
D)  they buffer best for polyprotic acids half-way between the two pKa values. 
E)  buffer where the amounts of conjugate base are nearly equivalent to the amounts of weak acid.

Question 14

Which of the following would be the conjugate acid of hydrogen phosphate, HPO4-2?

Accepted Answer

A)  H2PO4- 
B)  H3PO4. 
C)  H2PO4-2 
D)  H2PO4-. 
E)  none of the above 
A)  H2PO4- 
B)  H3PO4. 
C)  H2PO4-2 
D)  H2PO4-. 
E)  none of the above

Question 15

A weak acid is 33% dissociated at pH 5.0. What is the pKa for this acid?

Accepted Answer

A)  4.5 
B)  4.7 
C)  5.3 
D)  5.5 
E)  cannot be determined from the information provided 
A)  4.5 
B)  4.7 
C)  5.3 
D)  5.5 
E)  cannot be determined from the information provided

Question 16

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 (pKa values are 3.77 and 10.4) 
C)  Lactic acid and sodium lactate (pKa = 3.86) 
D)  NaH2PO4 and Na2HPO4 (pKa values are 2.1, 7.2, 12.4) 
E)  Sodium succinate and succinic acid (pKa = 4.21) 
A)  Acetic acid and sodium acetate (pKa = 4.76) 
B)  H2CO3 and NaHCO3 (pKa values are 3.77 and 10.4) 
C)  Lactic acid and sodium lactate (pKa = 3.86) 
D)  NaH2PO4 and Na2HPO4 (pKa values are 2.1, 7.2, 12.4) 
E)  Sodium succinate and succinic acid (pKa = 4.21)

Question 17

Discuss the Phosphate Buffer System in living systems.​

Accepted Answer

The intracellular pH of most cells is ma

Question 18

In micelles:

Accepted Answer

A)  polar ends form hydrophobic interactions with water. 
B)  nonpolar ends form hydrophilic interactions with water. 
C)  hydrocarbon tails form hydrophobic interactions with water. 
D)  polar ends are hydrophobic and nonpolar ends are hydrophilic. 
E)  hydrocarbon tails are excluded from the water into hydrophobic domains. 
A)  polar ends form hydrophobic interactions with water. 
B)  nonpolar ends form hydrophilic interactions with water. 
C)  hydrocarbon tails form hydrophobic interactions with water. 
D)  polar ends are hydrophobic and nonpolar ends are hydrophilic. 
E)  hydrocarbon tails are excluded from the water into hydrophobic domains.

Question 19

If a weak acid is 25% deprotonated at pH 4, what would the pKa be?

Accepted Answer

A)  3.40 
B)  3.52 
C)  4.48 
D)  4.60 
E)  cannot determine from given information 
A)  3.40 
B)  3.52 
C)  4.48 
D)  4.60 
E)  cannot determine from given information

Question 20

Hypoventilation is characterized by inability to excrete CO2 rapidly enough and can be caused by all EXCEPT:

Accepted Answer

A)  anesthetics. 
B)  depressant drugs. 
C)  narcotics. 
D)  lung diseases. 
E)  encephalitis. 
A)  anesthetics. 
B)  depressant drugs. 
C)  narcotics. 
D)  lung diseases. 
E)  encephalitis.

Exam 2: Water: the Medium of Life

Buffer systems are effective when the pH values are within ____ pH unit(s) of the pKa value.

Hydrogen bonds in ice are all EXCEPT:

The H-bonded water around an ionic substance tends to ____; and the H-bonded water around nonpolar solutes tends to ____.

If 0.1 moles of Na2HPO4 and 0.1 moles of NaH2PO4 are mixed in water, what is the resulting pH? The pKa values for phosphoric acid are 2.1, 7.2, 12.4.

Aspirin contains a carboxylic acid with a pKa of 3.5. Which of the following is true?

Hyperventilation is a physiological mechanism to:

To ____ the osmotic pressure created by the contents of their cytosol, cells tend to store substances such as amino acids and sugars in ____ form.

A plasma pH of 6.8 doesn't seem too far away from a normal pH of 7.4, but at pH 6.8 the H+ concentration is ____ times greater than at pH 7.4 and results in severe acidosis.

Amphiphilic (amphipathic) molecules include:

Estimate the pH of the resulting solution prepared by mixing 1.0 mole of solid disodium phosphate (Na2HPO4) and 1.25 mole of hydrochloric acid. The pKa values for phosphoric acid are 2.1, 7.2, 12.4.

The average lifetime of a hydrogen bond connection in water is on the order of 10:

Properties of water that render it so suited to its role as a medium of life include all EXCEPT:

Buffers have all of the following characteristics EXCEPT:

Which of the following would be the conjugate acid of hydrogen phosphate, HPO4-2?

A weak acid is 33% dissociated at pH 5.0. What is the pKa for this acid?

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

Discuss the Phosphate Buffer System in living systems.​

In micelles:

If a weak acid is 25% deprotonated at pH 4, what would the pKa be?

Hypoventilation is characterized by inability to excrete CO2 rapidly enough and can be caused by all EXCEPT:

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

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

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

The Reception and Transmission of Extracellular Information

Filters

Buffer systems are effective when the pH values are within ____ pH unit(s) of the pK_a value.

The H-bonded water around an ionic substance tends to ; and the H-bonded water around nonpolar solutes tends to .

If 0.1 moles of Na₂HPO₄ and 0.1 moles of NaH₂PO₄ are mixed in water, what is the resulting pH? The pK_a values for phosphoric acid are 2.1, 7.2, 12.4.

Aspirin contains a carboxylic acid with a pK_a of 3.5. Which of the following is true?

To the osmotic pressure created by the contents of their cytosol, cells tend to store substances such as amino acids and sugars in form.

A plasma pH of 6.8 doesn't seem too far away from a normal pH of 7.4, but at pH 6.8 the H⁺ concentration is ____ times greater than at pH 7.4 and results in severe acidosis.

Estimate the pH of the resulting solution prepared by mixing 1.0 mole of solid disodium phosphate (Na₂HPO₄) and 1.25 mole of hydrochloric acid. The pK_a values for phosphoric acid are 2.1, 7.2, 12.4.

Which of the following would be the conjugate acid of hydrogen phosphate, HPO₄^-2?

A weak acid is 33% dissociated at pH 5.0. What is the pK_a for this acid?

Discuss the Phosphate Buffer System in living systems.

If a weak acid is 25% deprotonated at pH 4, what would the pK_a be?

Hypoventilation is characterized by inability to excrete CO₂ rapidly enough and can be caused by all EXCEPT: