If natural selection in a particular environment favored genetic systems that permitted the production of daughter ʺcellsʺ that were genetically dissimilar from the mother ʺcells,ʺ then one should expect selection for

I. polynucleotide polymerase with low mismatch error rates.

II. polynucleotide polymerases without proofreading capability.

III. batteries of efficient polynucleotide repair enzymes.

IV. polynucleotide polymerases with proofreading capability.

V. polynucleotide polymerases with high mismatch error rates.

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#Question id: 20246

#XL - P Chemistry

Which one of the following compound has sp² hybridization ?

TLS Online TPP Program

#Question id: 20247

#XL - P Chemistry

C₂H₆ (g) + 3.5 O₂ (g) →2CO₂ (g) + 3H₂O (g)

ΔSvap (H₂O, l) = x1 cal K^–1 (boiling point + T₁)

ΔHf (H₂O, l) = x₂

ΔHf (CO2) = x₃

ΔHf (C2H6) = x₄

Hence ΔH for the reaction is –

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#Question id: 20248

#XL - P Chemistry

C (s) + O2 (g) →CO2, (g); DH = –94.3 kcal/mol

CO (g) + O2(g) → CO2 (g); DH = – 67.4 kcal/mol

O2(g) → 2O (g); ΔH = 117.4 kcal/mol

CO (g) → C (g) + O(g) ; ΔH = 230.6 kcal/mol

Calculate ΔH for C (s) → C (g) in kcal/mol.

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#Question id: 20249

#XL - P Chemistry

The difference between ΔH and ΔE on a molar basis for the combustion of n–octane at 25°C would be : 25ºC

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#Question id: 20250

#XL - P Chemistry

What is the work done against the atmosphere when 25 grams of water vaporizes at 373 K against a constant external pressure of 1 atm ? Assume that steam obeys perfect gas laws. Given that the molar enthalpy of vaporization is 9.72 kcal/mole, what is the change of internal energy in the above process ?

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#Question id: 20251

#XL - P Chemistry

In the reaction CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g) ΔH = –265 kcal

The enthalpies of formation of CO2 and SO2 are both negative and are in the ratio 4 : 3. The enthalpy of formation of CS2 is + 26 kcal/mol. Calculate the enthalpy of formation of SO2.