Question

The area of the gold electrodes on the quartz crystal microbalance at the opening of Chapter 2 is 3.3 mm^2. One gold electrode is covered with DNA at a surface density of 1.2 pmol/cm2. (a) How much mass of the nucleotide cytosine (C) is bound to the surface of the electrode when each bound DNA is elongated by one unit of C

Answer 1

This question is incomplete, the complete question is;

The area of the gold electrodes on the quartz crystal microbalance at the opening of Chapter 2 is 3.3 mm^2. One gold electrode is covered with DNA at a surface density of 1.2 pmol/cm2.

(a) How much mass of the nucleotide cytosine (C) is bound to the surface of the electrode when each bound DNA is elongated by one unit of C. The mass formula mass of the bound nucleotide is cytosine + deoxyribose + phosphate = C9H10N3O6P = 287.2 g/mol

Answer: mass of the nucleotide (c) bound is 11.37 g

Explanation:

Given that the area of gold electrodes = 3.3 mm^2

surface density of one gold electrode = 1.2 pmol/cm^2

that is to that in every 1 cm^2 of area, 1.2 pmol DNA is present

therefore

mass of nucleotide present in 3.3 mm^2 is;

= (1.2/100 * 3.3) pmol

= 0.0396 pmol

we were given that formula mass of the bound nucleotide = 287.2 g/mol

so

mass of the nucleotide (c) bound = ( 287.2 * 0.0396 )g

mass of the nucleotide (c) bound =  11.37 g