TLS Online TPP Program

#Question id: 72


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?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. The reaction is therefore far from equilibrium.

  2. The cellular concentrations of the products are much lower and those of the reactants are much higher.

  3. The reaction therefore tends strongly to go to the right.

  4. The cellular concentrations of the products are much higher and those of the reactants are much lower.

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TLS Online TPP Program

#Question id: 49

#Unit 1. Molecules and their Interaction Relevant to Biology

The equilibrium constant, Keq, for the following reaction is 2 × 105 M: If the measured cellular concentrations are [ATP] = 5 mM, [ADP] = 0.5 mM, and [Pi] = 5 mM, on the basis of the above information calculate the Keq in living cells?

TLS Online TPP Program

#Question id: 50

#Unit 1. Molecules and their Interaction Relevant to Biology

The enzyme fumarase catalyzes the reverse hydration of fumaric acid to l-malate, but it will not catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of:

TLS Online TPP Program

#Question id: 51

#Unit 1. Molecules and their Interaction Relevant to Biology

 If the equilibrium constant, Keq, for the reaction ATP → ADP + Pi is 2.22 × 105 M, calculate the standard free-energy change, ΔG°, for the synthesis of ATP from ADP and Pi at 25 °C.

TLS Online TPP Program

#Question id: 52

#Unit 1. Molecules and their Interaction Relevant to Biology

Choose the incorrect option regarding Isomerism.

TLS Online TPP Program

#Question id: 53

#Unit 1. Molecules and their Interaction Relevant to Biology

Calculate the number of times the DNA of a modern E. coli cell has been copied accurately since its earliest bacterial precursor cell arose about 3.5 billion years ago. Assume for simplicity that over this time period, E. coli has undergone, on average, one cell division every 12 hours (this is an overestimate for modern bacteria, but probably an underestimate for ancient bacteria).

TLS Online TPP Program

#Question id: 54

#Unit 1. Molecules and their Interaction Relevant to Biology

About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?