CH16_Answers

CH16_Answers - Raven/Johnson Biology 8e Chapter 16 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 16 Answers 1. Control of gene expression can occur at which of the following steps? a. Splicing of pre-mRNA into mature mRNA b. Initiation of translation c. Initiation of transcription d. All of the above The correct answer is d— A. Answer a is incorrect. Because alternative splicing can produce different gene products, it can be considered a possible mechanism of control. It is not the only possibility. The correct answer is d— B. Answer b is incorrect. Although not the most common form of control, the initiation of translation is controlled. It is not the only possibility. The correct answer is d— C. Answer c is incorrect. Control of the initiation of transcription is a common form of control in all cell types. It is not the only possibility. The correct answer is d—All of the above D. Answer d is correct. All of the options listed are potential modes of control of gene expression. 2. Regulatory proteins interact with DNA by— a. unwinding the helix and changing the pattern of base-pairing b. the sugar–phosphate backbone of the double helix c. unwinding the helix and disrupting-base pairing d. binding to the major groove of the double helix interacting with base-pairs The correct answer is d— A. Answer a is incorrect. Regulatory proteins can bind without unwinding the DNA strands, and they never change the pattern of base-pairing. The correct answer is d— B. Answer b is incorrect. The sugar–phosphate backbone does not participate in the binding of regulator proteins. This region of the DNA is always the same, independent of the sequence of nucleotides. The correct answer is d— C. Answer c is incorrect. Regulatory proteins bind without unwinding the helix. The correct answer is d—binding to the major groove of the double helix interacting with base- pairs D. Answer d is correct. The major groove accommodates a number of regulatory proteins. The base pairs are accessible within the major groove. 3. The two protein subunits of a leucine zipper are held together - a. by β-sheet domains b. by the interactions of hydrophobic amino acids c. by two α-helical domains separated by a turn
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 16 Answers d. the interaction of atoms of zinc The correct answer is b— A. Answer a is incorrect. Beta-sheet domains are associated with zinc-finger motifs. The correct answer is b—by the interactions of hydrophobic amino acids B. Answer b is correct. Hydrophobic leucine amino acids interact to “zip” the two proteins together. The correct answer is b— C. Answer c is incorrect. Alpha-helical domains are common to many DNA-binding motifs. This is a description of the helix-turn-helix motif. 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 / 8

CH16_Answers - Raven/Johnson Biology 8e Chapter 16 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