Question 1

Which of the following classes of compounds is hydrophobic?

Accepted Answer

A)  Table Salt 
B)  Cholesterol 
C)  Phosphate esters 
D)  Cholesterol and phosphate esters. 
E)  All of these are hydrophobic. 
A)  Table Salt 
B)  Cholesterol 
C)  Phosphate esters 
D)  Cholesterol and phosphate esters. 
E)  All of these are hydrophobic.

Question 2

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM.The pKa of acetic acid is 4.76.

Accepted Answer

A)  5.76 
B)  10.6 
C)  12.6 
D)  8.8 
A)  5.76 
B)  10.6 
C)  12.6 
D)  8.8

Question 3

Exhibit 2A   The structure of ATP with various groups labeled.
Group III is the entire phosphate group.
Refer to Exhibit 2A.Which of the functional groups cannot function as a hydrogen donor to water?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  All can donate a hydrogen to water. 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  All can donate a hydrogen to water.

Question 4

Which will dissociate most in water,a weak acid or a strong acid?

Accepted Answer

A)  A weak acid. 
B)  A strong acid 
C)  They should dissociate about the same. 
D)  It's impossible to predict. 
A)  A weak acid. 
B)  A strong acid 
C)  They should dissociate about the same. 
D)  It's impossible to predict.

Question 5

Is water an acid or a base?

Accepted Answer

A)  Water is an acid. 
B)  Water is a base. 
C)  Water is both an acid and a base. 
D)  Water is neither an acid nor a base. 
A)  Water is an acid. 
B)  Water is a base. 
C)  Water is both an acid and a base. 
D)  Water is neither an acid nor a base.

Question 6

If a solution has a pH = 9.6,the [H+] is

Accepted Answer

A)  2.5 × 1010 
B)  9.6 M 
C)  2.5 M 
D)  2.5 × 10-10 M 
E)  9.6 × 10-10 M 
A)  2.5 × 1010 
B)  9.6 M 
C)  2.5 M 
D)  2.5 × 10-10 M 
E)  9.6 × 10-10 M

Question 7

The main intracellular buffer system is

Accepted Answer

A)  H3PO4/H2PO4- 
B)  H2PO4-/ HPO42- 
C)  HPO42-/PO43- 
D)  H3PO4/PO43- 
A)  H3PO4/H2PO4- 
B)  H2PO4-/ HPO42- 
C)  HPO42-/PO43- 
D)  H3PO4/PO43-

Question 8

How does the strength of hydrogen bonds compare with covalent bonds?

Accepted Answer

A)  Hydrogen bonds are much stronger than covalent bonds. 
B)  Hydrogen bonds are much weaker than covalent bonds. 
C)  Hydrogen bonds and covalent bonds have similar strengths. 
D)  The question cannot be answered without knowing which covalent bonds are being referred to 
A)  Hydrogen bonds are much stronger than covalent bonds. 
B)  Hydrogen bonds are much weaker than covalent bonds. 
C)  Hydrogen bonds and covalent bonds have similar strengths. 
D)  The question cannot be answered without knowing which covalent bonds are being referred to

Question 9

How do hydrogen bonds tend to affect the melting and boiling points of substances?

Accepted Answer

A)  They tend to increase both melting and boiling points. 
B)  They tend to decrease both melting and boiling points. 
C)  They tend to increase melting points and decrease boiling points. 
D)  They tend to decrease melting points and increase boiling points. 
E)  They do not have any affect on either melting or boiling points. 
A)  They tend to increase both melting and boiling points. 
B)  They tend to decrease both melting and boiling points. 
C)  They tend to increase melting points and decrease boiling points. 
D)  They tend to decrease melting points and increase boiling points. 
E)  They do not have any affect on either melting or boiling points.

Question 10

Buffering capacity refers to

Accepted Answer

A)  the effectiveness of commercial antacids 
B)  the extent to which a buffer solution can counteract the effect of added acid or base 
C)  the pH of a buffer solution 
D)  the molecular weight of the substance used as a buffer 
A)  the effectiveness of commercial antacids 
B)  the extent to which a buffer solution can counteract the effect of added acid or base 
C)  the pH of a buffer solution 
D)  the molecular weight of the substance used as a buffer

Question 11

True hydrogen bonds can NOT form between hydrogen and this element:

Accepted Answer

A)  N 
B)  F 
C)  C 
D)  O 
E)  All of these elements can form hydrogen bonds. 
A)  N 
B)  F 
C)  C 
D)  O 
E)  All of these elements can form hydrogen bonds.

Question 12

Which of the following molecules is amphipathic?

Accepted Answer

A)  sodium chloride 
B)  acetic acid 
C)  benzene 
D)  palmitic acid 
A)  sodium chloride 
B)  acetic acid 
C)  benzene 
D)  palmitic acid

Question 13

The dissociation constant for an acid is 1 × 10-6.What is its pKa?

Accepted Answer

A)  -6 
B)  6 
C)  0.6 
D)  -0.6 
A)  -6 
B)  6 
C)  0.6 
D)  -0.6

Question 14

Which substance would be the best buffer at pH 8 if it had to be able to buffer against either acid or base?

Accepted Answer

A)  one with a pKa of 7 
B)  one with a pKa of 8 
C)  one with a pKa of 9 
D)  The pKa of a substance doesn't tell you whether it would be a good buffer at this pH. 
A)  one with a pKa of 7 
B)  one with a pKa of 8 
C)  one with a pKa of 9 
D)  The pKa of a substance doesn't tell you whether it would be a good buffer at this pH.

Question 15

What is the pH of a solution with [H+] = 10 mM?

Accepted Answer

A)  10 
B)  1 
C)  2 
D)  -2 
A)  10 
B)  1 
C)  2 
D)  -2

Question 16

The non-covalent interaction below associated with the strongest force in aqueous solution is

Accepted Answer

A)  dipole-induced dipole 
B)  hydrophobic interactions 
C)  hydrogen bonding 
D)  van der Waals forces 
A)  dipole-induced dipole 
B)  hydrophobic interactions 
C)  hydrogen bonding 
D)  van der Waals forces

Question 17

Which of the following is a true statement?

Accepted Answer

A)  most substances contract when they freeze. 
B)  water expands when it freezes. 
C)  hydrogen bonding is related to water's tendency to expand as it freezes. 
D)  all of these are true 
A)  most substances contract when they freeze. 
B)  water expands when it freezes. 
C)  hydrogen bonding is related to water's tendency to expand as it freezes. 
D)  all of these are true

Question 18

Exhibit 2B Contains information on the pK's of some common buffers.
  Refer to Exhibit 2B.A phosphate buffer would work well at this pH:

Accepted Answer

A)  5.0 
B)  7.0 
C)  8.0 
D)  10.0 
E)  7.0 and 8.0 
A)  5.0 
B)  7.0 
C)  8.0 
D)  10.0 
E)  7.0 and 8.0

Question 19

Consider a reaction that produces a significant amount of hydrogen ion and is to be carried out a pH 7.Only two acids are available for making the buffer solution.The pKa values for acids A and B are 6.3 and 7.3,respectively.Which acid would serve as the optimum buffer for this reaction? Or would carrying out the reaction in water simply serve as well?

Accepted Answer

A)  acid A 
B)  acid B 
C)  water 
D)  both acids would be equally effective 
A)  acid A 
B)  acid B 
C)  water 
D)  both acids would be equally effective

Question 20

Which of the following is true regarding hydrogen bonds.

Accepted Answer

A)  They can only form between two different molecules 
B)  They are important in protein folding but not DNA structure 
C)  They are important in DNA structure but not protein folding 
D)  They can be found within a single molecule 
A)  They can only form between two different molecules 
B)  They are important in protein folding but not DNA structure 
C)  They are important in DNA structure but not protein folding 
D)  They can be found within a single molecule

Exam 2: Water: The Solvent for Biochemical Reactions

Which of the following classes of compounds is hydrophobic?

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM.The pKa of acetic acid is 4.76.

Exhibit 2A The structure of ATP with various groups labeled. Group III is the entire phosphate group. Refer to Exhibit 2A.Which of the functional groups cannot function as a hydrogen donor to water?

Which will dissociate most in water,a weak acid or a strong acid?

Is water an acid or a base?

If a solution has a pH = 9.6,the [H+] is

The main intracellular buffer system is

How does the strength of hydrogen bonds compare with covalent bonds?

How do hydrogen bonds tend to affect the melting and boiling points of substances?

Buffering capacity refers to

True hydrogen bonds can NOT form between hydrogen and this element:

Which of the following molecules is amphipathic?

The dissociation constant for an acid is 1 × 10-6.What is its pKa?

Which substance would be the best buffer at pH 8 if it had to be able to buffer against either acid or base?

What is the pH of a solution with [H+] = 10 mM?

The non-covalent interaction below associated with the strongest force in aqueous solution is

Which of the following is a true statement?

Exhibit 2B Contains information on the pK's of some common buffers. Refer to Exhibit 2B.A phosphate buffer would work well at this pH:

Which of the following is true regarding hydrogen bonds.

Biochemistry and the Organization of Cells

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of Rna

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

Filters

What is the pH of an acetic acid solution where the concentration of acetic acid is 2 mM and the concentration of sodium acetate is 20 mM.The pK_a of acetic acid is 4.76.

If a solution has a pH = 9.6,the [H⁺] is

The dissociation constant for an acid is 1 × 10^-6.What is its pK_a?

What is the pH of a solution with [H⁺] = 10 mM?