CH17_Answers

CH17_Answers - Raven/Johnson Biology 8e Chapter 17 Answers...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Raven/Johnson Biology 8e Chapter 17 Answers 1. A recombinant DNA molecules is one that is— a. produced through the process of crossing over that occurs in meiosis b. constructed from DNA from different sources c. constructed from novel combinations of DNA from the same source d. produced through mitotic cell division The correct answer is b— A. Answer a is incorrect. Crossing over produces novel combinations of DNA from a single individual. The offspring are called recombinants. The correct answer is b—constructed from DNA from different sources B. Answer b is correct. Recombinant DNA is constructed in a laboratory and manipulated for a specific purpose. The correct answer is b— C. Answer c is incorrect. New genetic combinations from the same individual occur as a product of crossing over during meiosis. Recombinant DNA is an artificial construct that uses DNA from different sources. The correct answer is b— D. Answer d is incorrect. Mitosis is the asexual form of cell division that produces genetically identical daughter cells. There is no recombination of DNA during mitosis. 2. Type II restriction endonucleases are useful because— a. they degrade DNA from the 5′ end b. they cleave the DNA at random locations c. they cleave the DNA at specific sequences d. they only cleave modified DNA The correct answer is c— A. Answer a is incorrect. The ability to cleave DNA from an end is a property of an exonuclease. Endonucleases work by breaking bonds within the DNA molecule. The correct answer is c— B. Answer b is incorrect. Type II enzymes recognize and cut a specific site, not at random sites. The correct answer is c—they cleave the DNA at specific sequences C. Answer c is correct. A type II restriction endonuclease works by cleaving the DNA at specific sequences. This property is used in many experimental techniques that involve the manipulation of DNA. The correct answer is c— D. Answer d is incorrect. The cells that produce these enzymes protect their own DNA because they do not work on modified DNA. 3. What is the basis of separation of DNA fragments by gel electrophoresis? a. The negative charge on DNA b. The size of the DNA fragments
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Raven/Johnson Biology 8e Chapter 17 Answers c. The sequence of the fragments d. The presence of a dye The correct answer is b— A. Answer a is incorrect. The negative charge is necessary to cause the movement of the DNA fragments through the gel. The correct answer is b—The size of the DNA fragments B. Answer b is correct. Different size fragments move at different speeds with small fragments moving more quickly than larger fragments. The correct answer is b— C. Answer c is incorrect. The sequence of the fragments does not contribute to the separation. The correct answer is b—
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/07/2009 for the course BIO 5 taught by Professor Martins-green during the Spring '09 term at UC Riverside.

Page1 / 7

CH17_Answers - Raven/Johnson Biology 8e Chapter 17 Answers...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online