Chapter 13, Problem 3STP

Summary Introduction

Introduction:

Gel electrophoresis is a technique used to separate the DNA fragments according to the size of the fragments. The fragments are loaded on the negatively charged end of a gel. When electric current is applied, the DNA fragments move to positive end of the gel. The smaller fragments move farther and faster than the larger ones.

Answer to Problem 3STP

Correct answer:

The correct answer is option B. the fingerprint of a person’s DNA

Explanation of Solution

Explanation/justification for the correct answer:

Option B. the fingerprint of a person’s DNA−After the restriction enzymes make cuts in the DNA and form fragments, gel electrophoresis is done to separate the fragments of DNA. A unique pattern is created based on the size of the DNA fragments. This pattern can be compared to the known DNA fragments for identification. Hence the pattern on of gel electrophoresis reveals a person’s DNA fingerprint.Hence this is the correct option.

Explanation for incorrect answer:

Option A. the amount of noncoding DNA present−Gel electrophoresis reveals the unique banding pattern that is different for each individual. This is called DNA fingerprinting and it involves long stretches of noncoding DNA that is unique to each individual. It does not give information about the amount of noncoding DNA present.Hence this is not the correct option.

Option C. the number of genes in a piece of DNA- Gel electrophoresis reveals the unique banding pattern that is different for each individual. This is called DNA fingerprinting and it involves long stretches of noncoding DNA that is unique to each individual. It does not give information about the number of genes present in a piece of DNA.Hence this is not the correct option.

Option D. the random patterns of DNA−Gel electrophoresis reveals the unique banding pattern that is different for each individual. This is called DNA fingerprinting and it involves long stretches of noncoding DNA that is unique to each individual. It does not tell about the random patterns of DNA.Hence this is not the correct option.