BIOCHEM ICS ?’S + BRS FALL24 EXAM QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
B. X-C-H
Which of the following hydrogens CANNOT participate in hydrogen bonding?
- A. X-F-H
- B. X-C-H
- C. X-N-H
- D. X-O-H
B. Water forms more hydrogen bonds.
Why does water have higher surface tension than ethanol?
- A. Ethanol does not form hydrogen bonds.
- B. Water forms more hydrogen bonds.
- C. Both have equal surface tension.
- D. None of them has a significant surface tension.
A. Heat of evaporation
Sweating reduces body heat through evaporative cooling. This happens because water
has a very high:
- A. Heat of evaporation
,- B. Viscosity
- C. Surface tension
- D. Dielectric constant
A. 4.0
Based on the pKa values below, the strongest acid is the one with pKa:
- A. 4.0
- B. 6.0
- C. 8.0
- D. 10.0
- E. 12.0
C. 100:1 or 100
If the pKa of lactic acid is approximately 4.0, what is the ratio of conjugate base to acid
at pH 3.0?
- A. 1:1 or 1
- B. 1:1000 or 0.0001
- C. 100:1 or 100
- D. 1:10 or 0.1
- E. 1:100 or 0.001
D. The majority of this compound is in the conjugate base of a weak acid at
physiological pH
A 47-year-old male arrives unresponsive at the ER in a state of coma. His wife indicates
that he has lately been complaining of fatigue as well as showing signs of polyphagia
(frequent hunger), polydipsia (constant thirst), and polyuria (increased volume of
, urination). His breath has a fruity odor. Laboratory tests of this patient revealed the
presence of acetoacetate (CH3COCH2COO-, pKa=3.4), a ketone body, in his urine.
Which of the following is TRUE about this compound?
- A. 50% of this compound is present in the protonated form at physiological pH (pH 7)
- B. The majority of this compound is in its deprotonated form at pH 3.4
- C. It is produced by carbonic anhydrase
- D. The majority of this compound is in the conjugate base of a weak acid at
physiological pH
- E. It is a component of the blood buffer system
A. Increase
Based on the reactions above, hyperventilation will (fill in the blank) blood pH:
- A. Increase
- B. Decrease
- C. Not affect
A. Chronic obstructive pulmonary disease
A patient was admitted to the hospital with increased breathlessness. Arterial blood gas
measurements revealed pO2 of 6 kPa (normal = 10.5 - 13.5 kPa), pCO2 of 8.4 kPa
(normal = 4.6 - 6.0 kPa), a blood pH of 7.28 (normal = 7.35-7.45), and bicarbonate
concentration of 35 mmol/L (normal = 23-30 mmol/L). What is the most likely diagnosis
of this patient?
- A. Chronic obstructive pulmonary disease
- B. Diabetic ketoacidosis
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED
B. X-C-H
Which of the following hydrogens CANNOT participate in hydrogen bonding?
- A. X-F-H
- B. X-C-H
- C. X-N-H
- D. X-O-H
B. Water forms more hydrogen bonds.
Why does water have higher surface tension than ethanol?
- A. Ethanol does not form hydrogen bonds.
- B. Water forms more hydrogen bonds.
- C. Both have equal surface tension.
- D. None of them has a significant surface tension.
A. Heat of evaporation
Sweating reduces body heat through evaporative cooling. This happens because water
has a very high:
- A. Heat of evaporation
,- B. Viscosity
- C. Surface tension
- D. Dielectric constant
A. 4.0
Based on the pKa values below, the strongest acid is the one with pKa:
- A. 4.0
- B. 6.0
- C. 8.0
- D. 10.0
- E. 12.0
C. 100:1 or 100
If the pKa of lactic acid is approximately 4.0, what is the ratio of conjugate base to acid
at pH 3.0?
- A. 1:1 or 1
- B. 1:1000 or 0.0001
- C. 100:1 or 100
- D. 1:10 or 0.1
- E. 1:100 or 0.001
D. The majority of this compound is in the conjugate base of a weak acid at
physiological pH
A 47-year-old male arrives unresponsive at the ER in a state of coma. His wife indicates
that he has lately been complaining of fatigue as well as showing signs of polyphagia
(frequent hunger), polydipsia (constant thirst), and polyuria (increased volume of
, urination). His breath has a fruity odor. Laboratory tests of this patient revealed the
presence of acetoacetate (CH3COCH2COO-, pKa=3.4), a ketone body, in his urine.
Which of the following is TRUE about this compound?
- A. 50% of this compound is present in the protonated form at physiological pH (pH 7)
- B. The majority of this compound is in its deprotonated form at pH 3.4
- C. It is produced by carbonic anhydrase
- D. The majority of this compound is in the conjugate base of a weak acid at
physiological pH
- E. It is a component of the blood buffer system
A. Increase
Based on the reactions above, hyperventilation will (fill in the blank) blood pH:
- A. Increase
- B. Decrease
- C. Not affect
A. Chronic obstructive pulmonary disease
A patient was admitted to the hospital with increased breathlessness. Arterial blood gas
measurements revealed pO2 of 6 kPa (normal = 10.5 - 13.5 kPa), pCO2 of 8.4 kPa
(normal = 4.6 - 6.0 kPa), a blood pH of 7.28 (normal = 7.35-7.45), and bicarbonate
concentration of 35 mmol/L (normal = 23-30 mmol/L). What is the most likely diagnosis
of this patient?
- A. Chronic obstructive pulmonary disease
- B. Diabetic ketoacidosis
