Question 1

The pH of human blood is maintained at 7.4 by

Accepted Answer

A)  buffering proteins. 
B)  carbon dioxide-carbonic acid buffer systems. 
C)  a bicarbonate buffer system. 
D)  B and C 
E)  A, B and C 
A)  buffering proteins. 
B)  carbon dioxide-carbonic acid buffer systems. 
C)  a bicarbonate buffer system. 
D)  B and C 
E)  A, B and C D

Question 2

The osmotic pressure of a 0.010 M sucrose C12H22O11) solution at 25 °C is 0.24 atm. How does the osmotic pressure of a 0.010 M glucose C6H12O6) solution at 25 °C compare to this? Note that neither solute is volatile or ionizable.

Accepted Answer

A)  The glucose solution has a lower osmotic pressure because its molar mass is lower than sucrose. 
B)  The glucose solution has a higher osmotic pressure because its molar mass is lower than sucrose. 
C)  The osmotic pressures are equal because the solutions have the same molar concentration. 
D)  Nothing can be said about the osmotic pressure of the glucose solution without more information. 
A)  The glucose solution has a lower osmotic pressure because its molar mass is lower than sucrose. 
B)  The glucose solution has a higher osmotic pressure because its molar mass is lower than sucrose. 
C)  The osmotic pressures are equal because the solutions have the same molar concentration. 
D)  Nothing can be said about the osmotic pressure of the glucose solution without more information. C

Question 3

In the detergent, sodium dodecyl sulfate, the sulfate groups are very hydrophobic.

Accepted Answer

A) True 
 B)False  False

Question 4

Which statement best characterizes the distribution of charge in the hydronium ion, H3O+?

Accepted Answer

A)  The positive charge is distributed over all of the atoms in the ion. 
B)  The positive charge is localized only on the oxygen atom. 
C)  The positive charge is distributed between the three hydrogen atoms only. 
D)  The positive charge is localized on only one of the hydrogen atoms. 
A)  The positive charge is distributed over all of the atoms in the ion. 
B)  The positive charge is localized only on the oxygen atom. 
C)  The positive charge is distributed between the three hydrogen atoms only. 
D)  The positive charge is localized on only one of the hydrogen atoms.

Question 5

The imidazolium ion has a pKa = 7.0. Imidazolium buffers can be prepared for pH values of

Accepted Answer

A)  6.5 to 7.5. 
B)  6.1 to 7.1. 
C)  5.5 to 8.5. 
D)  6.0 to 8.0. 
E)  6.0 to 7.5. 
A)  6.5 to 7.5. 
B)  6.1 to 7.1. 
C)  5.5 to 8.5. 
D)  6.0 to 8.0. 
E)  6.0 to 7.5.

Question 6

Compare solution A with pH = 4 to solution B with pH = 6.

Accepted Answer

A)  The concentration of hydronium ion in solution A is twice that in solution B. 
B)  Solution A has greater buffering capacity than solution B. 
C)  The concentration of hydronium ion in solution A is 100 times that in solution B. 
D)  The hydroxide concentrations are equal in the two solutions since pH only measures the concentration of H+. 
A)  The concentration of hydronium ion in solution A is twice that in solution B. 
B)  Solution A has greater buffering capacity than solution B. 
C)  The concentration of hydronium ion in solution A is 100 times that in solution B. 
D)  The hydroxide concentrations are equal in the two solutions since pH only measures the concentration of H+.

Question 7

If human blood is not maintained at close to pH = 7.4, a person can develop

Accepted Answer

A)  acidosis. 
B)  alkalosis. 
C)  diabetes. 
D)  Both A and B 
E)  None of the above 
A)  acidosis. 
B)  alkalosis. 
C)  diabetes. 
D)  Both A and B 
E)  None of the above

Question 8

The three dimensional structure of most proteins is largely determined by

Accepted Answer

A)  other proteins which fold them. 
B)  weak noncovalent interactions. 
C)  denaturation. 
D)  hydrogen bonds. 
E)  All of the above 
A)  other proteins which fold them. 
B)  weak noncovalent interactions. 
C)  denaturation. 
D)  hydrogen bonds. 
E)  All of the above

Question 9

pKa values of phosphoric acid are 2.2, 7.2 and 12.7. A phosphate buffer of pH = 7.4 can be prepared using

Accepted Answer

A)  H2PO4- and HPO42-. 
B)  HPO42- and PO43-. 
C)  H3PO4 and HCl. 
D)  None of the above 
A)  H2PO4- and HPO42-. 
B)  HPO42- and PO43-. 
C)  H3PO4 and HCl. 
D)  None of the above

Question 10

Van der Waals forces are very strongly repulsive at short nuclear distances and very weak at long internuclear distances.

Accepted Answer

A) True 
 B)False

Question 11

The solubility rule ʺlike dissolves likeʺ refers primarily to similarities in amphipathic nature between the solute and solvent.

Accepted Answer

A) True 
 B)False

Question 12

Histidine contains an imidazole group which is titratable. A histidine buffer can be prepared using

Accepted Answer

A)  NaOH and histidine. 
B)  NaOH and imidazolium ion. 
C)  imidazolium ion and imidazole conjugate base). 
D)  HCl and imidazole. 
E)  All of the above 
A)  NaOH and histidine. 
B)  NaOH and imidazolium ion. 
C)  imidazolium ion and imidazole conjugate base). 
D)  HCl and imidazole. 
E)  All of the above

Question 13

Since HCl is a strong acid its value of Ka is .

Accepted Answer

A)  effectively equal to infinity 
B)  equal to Kw 
C)  zero 
D)  dependent on the concentration of HCl 
A)  effectively equal to infinity 
B)  equal to Kw 
C)  zero 
D)  dependent on the concentration of HCl

Question 14

Which of these noncovalent forces in biological systems is usually the strongest?

Accepted Answer

A)  hydrogen bonds 
B)  London dispersion forces 
C)  hydrophobic interactions 
D)  van der Waals forces 
A)  hydrogen bonds 
B)  London dispersion forces 
C)  hydrophobic interactions 
D)  van der Waals forces

Question 15

The pressure is the pressure required to prevent the flow of solvent through a solvent-permeable membrane that separates two solutions of different solute concentration.

Accepted Answer

A)  hydrostatic 
B)  electromotive 
C)  osmotic 
D)  partial 
A)  hydrostatic 
B)  electromotive 
C)  osmotic 
D)  partial

Question 16

The pH of a 10-4 M solution of HCl is

Accepted Answer

A)  3. 
B)  3.5. 
C)  4. 
D)  4.5. 
E)  greater than 4.5. 
A)  3. 
B)  3.5. 
C)  4. 
D)  4.5. 
E)  greater than 4.5.

Question 17

Acetic acid has a pKa of 4.8. How many milliliters of 0.2 M acetic acid and 0.1 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8?

Accepted Answer

A)  500 ml acetic acid and 500 ml sodium acetate 
B)  250 ml acetic acid and 250 ml sodium acetate, then 500 ml water 
C)  250 ml acetic acid and 500 ml sodium acetate, then 250 ml water 
D)  500 ml acetic acid and 250 ml sodium acetate, then 250 ml water 
A)  500 ml acetic acid and 500 ml sodium acetate 
B)  250 ml acetic acid and 250 ml sodium acetate, then 500 ml water 
C)  250 ml acetic acid and 500 ml sodium acetate, then 250 ml water 
D)  500 ml acetic acid and 250 ml sodium acetate, then 250 ml water

Question 18

Salt bridges are often found on the surfaces of proteins where they are stabilized by water.

Accepted Answer

A) True 
 B)False

Question 19

When acid is added to pure water, Kw, the ion-product constant of water, changes.

Accepted Answer

A) True 
 B)False

Question 20

Water clustered about nonpolar molecules contribute to hydrophobic interactions because

Accepted Answer

A)  Their number is minimized to increase the total entropy of water. 
B)  Nonpolar molecules are more highly organized than polar molecules. 
C)  Water molecules in the cell are more organized in the regions away from the nonpolar molecule. 
D)  All of the above 
E)  B and C 
A)  Their number is minimized to increase the total entropy of water. 
B)  Nonpolar molecules are more highly organized than polar molecules. 
C)  Water molecules in the cell are more organized in the regions away from the nonpolar molecule. 
D)  All of the above 
E)  B and C

Exam 2: Water

The pH of human blood is maintained at 7.4 by

The osmotic pressure of a 0.010 M sucrose C12H22O11) solution at 25 °C is 0.24 atm. How does the osmotic pressure of a 0.010 M glucose C6H12O6) solution at 25 °C compare to this? Note that neither solute is volatile or ionizable.

In the detergent, sodium dodecyl sulfate, the sulfate groups are very hydrophobic.

Which statement best characterizes the distribution of charge in the hydronium ion, H3O+?

The imidazolium ion has a pKa = 7.0. Imidazolium buffers can be prepared for pH values of

Compare solution A with pH = 4 to solution B with pH = 6.

If human blood is not maintained at close to pH = 7.4, a person can develop

The three dimensional structure of most proteins is largely determined by

pKa values of phosphoric acid are 2.2, 7.2 and 12.7. A phosphate buffer of pH = 7.4 can be prepared using

Van der Waals forces are very strongly repulsive at short nuclear distances and very weak at long internuclear distances.

The solubility rule ʺlike dissolves likeʺ refers primarily to similarities in amphipathic nature between the solute and solvent.

Histidine contains an imidazole group which is titratable. A histidine buffer can be prepared using

Since HCl is a strong acid its value of Ka is .

Which of these noncovalent forces in biological systems is usually the strongest?

The pressure is the pressure required to prevent the flow of solvent through a solvent-permeable membrane that separates two solutions of different solute concentration.

The pH of a 10-4 M solution of HCl is

Acetic acid has a pKa of 4.8. How many milliliters of 0.2 M acetic acid and 0.1 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8?

Salt bridges are often found on the surfaces of proteins where they are stabilized by water.

When acid is added to pure water, Kw, the ion-product constant of water, changes.

Water clustered about nonpolar molecules contribute to hydrophobic interactions because

Introduction to Biochemistry

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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The osmotic pressure of a 0.010 M sucrose C₁₂H₂₂O₁₁) solution at 25 °C is 0.24 atm. How does the osmotic pressure of a 0.010 M glucose C₆H₁₂O₆) solution at 25 °C compare to this? Note that neither solute is volatile or ionizable.

Which statement best characterizes the distribution of charge in the hydronium ion, H₃O⁺?

The imidazolium ion has a pK_a= 7.0. Imidazolium buffers can be prepared for pH values of

pK_avalues of phosphoric acid are 2.2, 7.2 and 12.7. A phosphate buffer of pH = 7.4 can be prepared using

Since HCl is a strong acid its value of K_ais .

The pH of a 10^-⁴M solution of HCl is

Acetic acid has a pK_aof 4.8. How many milliliters of 0.2 M acetic acid and 0.1 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8?

When acid is added to pure water, K_w, the ion-product constant of water, changes.