Question 1

Micelles,formed by detergents in water,have

Accepted Answer

A) hydrophilic interiors and hydrophobic exteriors. 
B) hydrophobic interiors and hydrophilic exteriors. 
C) hydrophilic interiors and exteriors. 
D) hydrophobic interiors and exteriors. 
E) None of the above. 
A) hydrophilic interiors and hydrophobic exteriors. 
B) hydrophobic interiors and hydrophilic exteriors. 
C) hydrophilic interiors and exteriors. 
D) hydrophobic interiors and exteriors. 
E) None of the above.

Question 2

Pure water has a concentration of

Accepted Answer

A) 18 g/ml. 
B) 1 g/ml. 
C) 1000 g/ml. 
D) 55 M. 
A) 18 g/ml. 
B) 1 g/ml. 
C) 1000 g/ml. 
D) 55 M.

Question 3

Cells keep the osmotic pressure from being too great by

Accepted Answer

A) existing in hypertonic solutions. 
B) making macromolecules from smaller molecules. 
C) existing in a hypotonic solution. 
D) existing in an isotonic solution. 
E) Both B and D. 
A) existing in hypertonic solutions. 
B) making macromolecules from smaller molecules. 
C) existing in a hypotonic solution. 
D) existing in an isotonic solution. 
E) Both B and D.

Question 4

The ratio of the concentration of a ________ over ________ describes the proportions of forms of a weak acid necessary to satisfy the Henderson-Hasselbalch equation.

Accepted Answer

A) conjugate acid;conjugate base 
B) conjugate base;conjugate acid 
C) proton donor;proton acceptor 
D) proton acceptor;proton donor 
E) B and D 
A) conjugate acid;conjugate base 
B) conjugate base;conjugate acid 
C) proton donor;proton acceptor 
D) proton acceptor;proton donor 
E) B and D

Question 5

Enzymes which condense subunits of macromolecules during their synthesis usually

Accepted Answer

A) transfer an acyl or carbonyl group to an electrophile. 
B) exclude water from the active site. 
C) contain inhibitors of hydrolases. 
D) are catalyzing thermodynamically favored reactions. 
E) All of the above. 
A) transfer an acyl or carbonyl group to an electrophile. 
B) exclude water from the active site. 
C) contain inhibitors of hydrolases. 
D) are catalyzing thermodynamically favored reactions. 
E) All of the above.

Question 6

Molecules that are both hydrophobic and hydrophilic are ________.

Accepted Answer

A) amphipathic 
B) amphoteric 
C) bipolar 
D) not possible 
A) amphipathic 
B) amphoteric 
C) bipolar 
D) not possible

Question 7

Which parameter has the greatest correlation to reaction rate?

Accepted Answer

A) Activation energy. 
B) Gibb's free energy. 
C) Enthalpy. 
D) Entropy. 
E) None of the above. 
A) Activation energy. 
B) Gibb's free energy. 
C) Enthalpy. 
D) Entropy. 
E) None of the above.

Question 8

The Henderson-Hasselbalch equation can be used to calculate

Accepted Answer

A) the pH of a solution of an organic acid. 
B) the amount of salt and acid to add to form a specific buffer. 
C) the pKa of a weak acid. 
D) All of the above. 
E) A and C only. 
A) the pH of a solution of an organic acid. 
B) the amount of salt and acid to add to form a specific buffer. 
C) the pKa of a weak acid. 
D) All of the above. 
E) A and C only.

Question 9

The H+ (or H₃O+)in cells is the same concentration as that of undissociated water.

Accepted Answer

A) True 
 B)False

Question 10

The strength of van der Waals forces between two molecules changes as the distance between them changes.

Accepted Answer

A) True 
 B)False

Question 11

The polarity of small molecules is a result of

Accepted Answer

A) the presence of oxygen. 
B) the geometry of the bonds in the molecule. 
C) the polar covalent bonds. 
D) All of the above. 
E) B and C. 
A) the presence of oxygen. 
B) the geometry of the bonds in the molecule. 
C) the polar covalent bonds. 
D) All of the above. 
E) B and C.

Question 12

At the midpoint of a titration curve

Accepted Answer

A) the concentration of a conjugate base is equal to the concentration of a conjugate acid. 
B) the pH equals the pKa. 
C) the ability of the solution to buffer is best. 
D) All of the above. 
E) A and B only. 
A) the concentration of a conjugate base is equal to the concentration of a conjugate acid. 
B) the pH equals the pKa. 
C) the ability of the solution to buffer is best. 
D) All of the above. 
E) A and B only.

Question 13

The water solubility of alcohols with a single hydroxyl group increases as a function of molecular weight.

Accepted Answer

A) True 
 B)False

Question 14

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) H ₃PO₄ and HCl. 
D) None of the above. 
A) H₂PO₄- and HPO₄²-. 
B) HPO₄²- and PO₄³-. 
C) H ₃PO₄ and HCl. 
D) None of the above.

Question 15

For a weak acid with a pKa = 6.5,the effective buffering range is usually considered to be

Accepted Answer

A) pH 6 to pH 7. 
B) pH 6.4 to pH 6.6. 
C) pH 5.5 to pH 7.5. 
D) dependent on the molarity of the acid. 
E) B and C. 
A) pH 6 to pH 7. 
B) pH 6.4 to pH 6.6. 
C) pH 5.5 to pH 7.5. 
D) dependent on the molarity of the acid. 
E) B and C.

Question 16

The ion-product constant for water,Kw,is

Accepted Answer

A) 1 × 10-⁷ M². 
B) 1 × 10-⁷ M. 
C) 1 × 10-14 M². 
D) 1 × 10-14 M. 
A) 1 × 10-⁷ M². 
B) 1 × 10-⁷ M. 
C) 1 × 10-14 M². 
D) 1 × 10-14 M.

Question 17

The self-ionization of water is ________.

Accepted Answer

A) a unimolecular dissociation of a single water molecule to H+ and OH- 
B) a biomolecular reaction between two water molecules to yield H₃O+ and OH- 
C) a result of hydrophobic interactions 
D) a termolecular reaction involving the simultaneous collision of H₂O,H+ and OH- 
A) a unimolecular dissociation of a single water molecule to H+ and OH- 
B) a biomolecular reaction between two water molecules to yield H₃O+ and OH- 
C) a result of hydrophobic interactions 
D) a termolecular reaction involving the simultaneous collision of H₂O,H+ and OH-

Question 18

Which statement explains the cleaning action of soap on greasy dishes?

Accepted Answer

A) The soap changes the water-solubility of the grease so that it is easily dissolved by the water. 
B) The grease is trapped inside the hydrophobic interior of micelles made of soap molecules. 
C) The soap chemically breaks down the grease into smaller,more water-soluble molecules. 
D) The soap hydrates the grease with its polar head groups and holds it in suspension. 
A) The soap changes the water-solubility of the grease so that it is easily dissolved by the water. 
B) The grease is trapped inside the hydrophobic interior of micelles made of soap molecules. 
C) The soap chemically breaks down the grease into smaller,more water-soluble molecules. 
D) The soap hydrates the grease with its polar head groups and holds it in suspension.

Question 19

The buffering capacity of a weak acid and its conjugate base is strongest when the pH = pKa.

Accepted Answer

A) True 
 B)False

Question 20

The abundance of water in the cells and tissues helps to minimize temperature fluctuations.This is due to what property of water?

Accepted Answer

A) Density. 
B) Viscosity. 
C) Specific heat. 
D) Boiling point. 
A) Density. 
B) Viscosity. 
C) Specific heat. 
D) Boiling point.

Exam 2: Water

Micelles,formed by detergents in water,have

Pure water has a concentration of

Cells keep the osmotic pressure from being too great by

The ratio of the concentration of a ________ over ________ describes the proportions of forms of a weak acid necessary to satisfy the Henderson-Hasselbalch equation.

Enzymes which condense subunits of macromolecules during their synthesis usually

Molecules that are both hydrophobic and hydrophilic are ________.

Which parameter has the greatest correlation to reaction rate?

The Henderson-Hasselbalch equation can be used to calculate

The H+ (or H₃O+)in cells is the same concentration as that of undissociated water.

The strength of van der Waals forces between two molecules changes as the distance between them changes.

The polarity of small molecules is a result of

At the midpoint of a titration curve

The water solubility of alcohols with a single hydroxyl group increases as a function of molecular weight.

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

For a weak acid with a pKa = 6.5,the effective buffering range is usually considered to be

The ion-product constant for water,Kw,is

The self-ionization of water is ________.

Which statement explains the cleaning action of soap on greasy dishes?

The buffering capacity of a weak acid and its conjugate base is strongest when the pH = pKa.

The abundance of water in the cells and tissues helps to minimize temperature fluctuations.This is due to what property of water?

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 Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters

The ratio of the concentration of a over describes the proportions of forms of a weak acid necessary to satisfy the Henderson-Hasselbalch equation.

The H⁺ (or H₃O⁺)in cells is the same concentration as that of undissociated water.