Chapter 13, Problem 7Q

Although it is well known that X-rays cause mutations, they are routinely used to diagnose medical problems, including potential tumors, broken bones, and dental cavities. Why is this done? What precautions need to be taken?

Which of the following best describes the process of DNA sequencing? a. DNA is separated on a gel, and the different bands are labeled with fluorescent nucleotides and scanned with a laser. b. A laser is used to fluorescently label the nucleotides present within the DNA, the DNA is run on a gel, and then the DNA is broken into fragments. c. Nucleotides are scanned with a laser and incorporated into the DNA that has been separated on a gel, and then the DNA is amplified with PCR. d. Fragments of DNA are produced in a reaction that labels them with any of four different fluorescent dyes, and the fragments then are run on a gel and scanned with a laser. e. DNA is broken down into its constituent nucleotides, and the nucleotides are then run on a gel and purified with a laser.