Microbiology: A Systems Approach 4th Edition by Marjorie Kelly Cowan

Exercise 50

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles and, in most cases, they do not have a single correct answer.
Sketch a molecule of double-stranded DNA, and explain each of the following:
a. proper nitrogenous base-pairing between the strands
b. proper orientation of the strands
c. proper positioning of the sugar-phosphate backbone