TLS Online TPP Program

#Question id: 12220


A female patient has unexplained severe hypernatremia (plasma Na+ = 167 mmol/L) and complains of frequent urination and large urine volumes. A urine specimen reveals that the Na+ concentration is 15mmol/L (very low) and the osmolarity is 155 mOsm/L (very low). Laboratory tests reveal: plasma renin activity = 3 ng angiotensin I/ml/hr (normal = 1.0), plasma antidiuretic hormone (ADH) = 30 pg/ml (normal = 3 pg/ml), and plasma aldosterone = 20 ng/dL (normal = 6 ng/dL). Which of the following is the most likely reason for her hypernatremia?

#Unit 7. System Physiology – Animal
  1. Simple dehydration due to decreased water intake
  2. Nephrogenic diabetes insipidus
  3. Central diabetes insipidus
  4. Syndrome of inappropriate ADH
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TLS Online TPP Program

#Question id: 71

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is not the priority rule for R, S Configuration?

TLS Online TPP Program

#Question id: 72

#Unit 1. Molecules and their Interaction Relevant to Biology

For the reaction catalyzed by the enzyme hexokinase: Glucose + ATP → glucose 6-phosphate + ADP the equilibrium constant, Keq, is 7.8 × 102. In living E. coli cells, [ATP] = 5 mM, [ADP] = 0.5 mM, [glucose] = 2 mM, and [glucose 6-phosphate] = 1 mM. Which of the following conclusions made on the basis of the above calculations is incorrect?

TLS Online TPP Program

#Question id: 73

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the Variation of Reaction Spontaneity (Sign of ΔG) given in Column I with the Signs of ΔH and ΔS given in column II.

COLUMN I

COLUMN II

 

 

 

  ΔH

ΔS

ΔG = ΔH – TΔS

1.

+

a. The reaction is both enthalpically and entropically opposed. It is nonspontaneous (endergonic) at all temperatures.

2.

 −

− 

b. The reaction is enthalpically opposed (endothermic) but entropically favored. It is spontaneous only at temperatures above T = ΔH/ΔS.

3.

+

+

c. The reaction is enthalpically favored but entropically opposed. It is spontaneous only at temperatures below T = ΔH/ΔS.

4.

+

d. The reaction is both enthalpically favored (exothermic) and entropically favored. It is spontaneous (exergonic) at all temperatures.

TLS Online TPP Program

#Question id: 74

#Unit 1. Molecules and their Interaction Relevant to Biology

The enthalpy and entropy of the initial and final states of a reacting system are shown in the table. Calculate the change in free energy for the reaction when the temperature is 4°C.

TLS Online TPP Program

#Question id: 75

#Unit 1. Molecules and their Interaction Relevant to Biology

The experimental approach taken in current biological investigations presumes that ________.

TLS Online TPP Program

#Question id: 76

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following illustrations is not a structural isomer of an organic compound with the molecular formula C6H14? For clarity, only the carbon skeletons are shown; hydrogen atoms that would be attached to the carbons have been omitted.