文档介绍：CHAPTER 1
DNA, Gene Structure, and DNA
Replication
Chapter Outline
Overview 3
DNA is the Hereditary Material: A Brief History 4
The Central Dogma 6
The “RNA World” Came First? 8
The Molecular Structure of DNA 8
The Molecular Structure of RNA 11
The Double Helix 13
Base Pairing is Fundamental 14
DNA Exists in Several Forms 14
Genes 16
The ic Code for Protein-Coding Genes is a Triplet and is Degenerate 16
anization 18
Efficient DNA Replication is Essential 21
DNA Replication is Semiconservative 21
Replication Begins at Replication Origins 21
DNA Replication Occurs Only in the 5′ to 3′ Direction 22
Replication of DNA Requires an RNA Primer 23
Ligation of Replicated DNA Fragments 23
DNA Replication during Mitosis in Eukaryotes 25
Telomeres at the End: A Solution to the Loss of DNA during Replication 28
DNA Replication Fidelity and DNA Repair 28
Mutations in the Genome 29
ic Terminology 32
Independent Assortment and bination during Sexual Reproduction 33
General References 33
References Cited 34
Overview
Arthropod genes are made of deoxyribonucleic acid (DNA) and are located
in chromosomes that consist of proteins, RNA, and DNA. DNA is a polymer
of nucleotides (nt). Each nucleotide consists of a pentose sugar, one of four
Insect Molecular ics.
DOI: http://dx./-0-12-415874--9
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4 Chapter 1
nitrogenous bases, and a phosphoric ponent. DNA consists of -
plementary strands in a helix form. Pairing of the nitrogenous bases adenine (A)
with thymine (T) and cytosine (C) with guanine (G) on the plementary
strands occurs by hydrogen bonding. A pairs with T by two hydrogen bonds, and
C pairs with G by three hydrogen bonds. DNA has chemically distinct 5′ and 3′
ends, and the two strands are antiparallel, w