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Chapter 14
The Molecular Basis of Inheritance
CHAPTER OUTLINE
Chromosomes carry genetic information in eukaryotes
DNA is composed of nucleotides
The two nucleotide chains of DNA form a double helix
DNA replicates semiconservatively
Most genes carry information for making proteins
The genetic code is read as a series of triplets
CHAPTER OBJECTIVES
1. Distinguish between a chromosome and a gene.
2. Name the units that compose the DNA molecule and identify the three parts of each
unit.
3. Describe base pairing in DNA molecules. Given the base sequence of one strand of
DNA, predict that of a complementary strand of DNA.
LECTURE OUTLINE
I. How is the genetic information organized in eukaryotic cells?
A. What are chromosomes?
II. What is the structure of DNA?
A. What are nucleotides? What are the three units of nucleotides?
B. What nucleotide bases are in DNA?
complimentary but not identical?
III. How does the cell make copies of its DNA?
A. What is DNA polymerase and what does it do?
B. Why is DNA replication said to be “semiconservative”?
C. Why does this method of replication practically guarantee that the two daughter
DNA molecules will be identical to the original?
D. How do cells fix errors in DNA replication?
IV. The genetic code converts the blueprint of information in DNA into proteins.
V. What are the two steps in protein synthesis (also called gene expression)?
A. What is transcription? Where does it take place?
B. What are the three kinds of RNA?
1. What does mRNA do?
2. What does rRNA do? Where is it found?
4. Describe the sequence of events that occur at the ribosome during translation.
a. What is the role of the AUG sequence?
VI. What is important about the fact that the genetic code is shared by virtually all organisms?
VII. What are mutations?
A. What are the effects of mutations on protein synthesis?
B. Why are mutations important for evolution?
C. What are transposons and why are they important?
KEY TERMS
anticodon, p. 285
chromatin, p. 276
genetic code, p. 282
messenger RNA (mRNA), p. 283
semiconservative replication, p. 279
totipotency, p. 274
TEACHING TIPS
1. Purchase or make a three-dimensional model of the DNA double helix. There are kits available,
from paper cutouts to pop-together models that can be used to demonstrate DNA structure. These
2. Protein synthesis is difficult for many students. Models and kits are available. There are also some
3. Ask students to translate a sequence of bases in mRNA using a copy of the genetic code. Have
4. To help students understand the players in protein synthesis, the following analogy to the
construction of a house is useful. DNA in the nucleus is like the set of master drawings in the