Chapter 23, Problem 7STP

Interpretation Introduction

Interpretation:

The number of molecules of adenine in one molecule of Sample II needs to be determined.

Concept introduction:

DNA stands for deoxyribonucleic acid and RNA stands for ribonucleic acid. DNA includes four bases such as adenine (A), guanine (G), cytosine (C), and thymine (T). RNA consists of four bases: adenine, cytosine, uracil, and guanine.

Answer to Problem 7STP

Option C is the correct option.

Explanation of Solution

We know that 32.5% of bases is equal to 402. So, one can calculate the total number of bases by using the following formula,

$\frac{\text{402}}{\text{32}\text{.5\%}}\text{×100=}\text{1237}\text{bases}$

Hence, the total number of bases is $\text{1237}$

If C = G, then percentage is equal to 32.5% and total percentage after adding is 65%. The percentage left over is 32.5% composed of A and T. By this it can be concluded that 17.5% is A and 17.5% is T.

The number of molecules of adenine is determined as follows,

$\begin{array}{c}\text{Number}\text{of}\text{adenine}\text{=}\text{17}\text{.5\%×1237}\text{bases}\\ \text{=}\text{216}\end{array}$

Conclusion

216 molecules of adenine are there in one molecule of Sample II.