Chapter 13

DNA Structure and Function

The DNA Helix
DNA is composed of two strands of molecules. Each strand consists of subunits called nucleotides that contain a phosphate group and one of four…
DNA Packaging
13.2: DNA Packaging
Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly…
Organization of Genes
13.3: Organization of Genes
Each chromosome contains hundreds or thousands of genes, depending on the chromosome and species in question. Genes are organized into regions called…
Chromosomal Banding
13.4: Chromosomal Banding
It can be useful to visualize chromosomes when studying the genetic basis of traits, such as diseases. To this end, geneticists have taken advantage…
Replication in Prokaryotes
13.5: Replication in Prokaryotes
DNA replication in prokaryotes has three main steps—initiation, elongation, and termination. It begins when initiator proteins bind to the…
Replication in Eukaryotes
13.6: Replication in Eukaryotes
DNA replication in eukaryotes is a highly conserved process which begins with proteins binding at multiple origins of replication on a chromosome.…
Proofreading
13.7: Proofreading
During DNA replication nucleotides are added to the new stand being synthesized in a sequence complementary to the template strand. However, errors…
Mismatch Repair
13.8: Mismatch Repair
Following proofreading, errors which occurred during DNA replication—like pairing adenine with cytosine—may persist, and these can be…
Nucleotide Excision Repair
13.9: Nucleotide Excision Repair
DNA can become damaged by environmental factors such as exposure to UV radiation, or certain chemical carcinogens. When this occurs, bulky lesions…
Mutations
13.10: Mutations
Mutations occur when DNA sequences are altered from their original sequence. This may affect a single base—known as point mutation—all…
Transcription
13.11: Transcription
Transcription is the process of synthesizing RNA from a DNA template and is the first step in producing a protein from a gene sequence. A complex of…
Translation
13.12: Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). The process begins when the small…
DNA Microarrays
13.13: DNA Microarrays
Microarrays are important tools for profiling gene expression, and are based on complementary binding between probes that are attached to glass chips…
Fluorescence in situ Hybridization (FISH)
13.14: Fluorescence in situ Hybridization (FISH)
A chromosome, which is a molecule of DNA and its associated proteins, may be observed under a microscope with the aid of dyes and probes. One…
Bioengineering: Folding and Characterization of a Bio-responsive Robot from DNA Origami
13.15: Bioengineering: Folding and Characterization of a Bio-responsive Robot from DNA Origami
Structural DNA nanotechnology uses nucleic acid as a self-assembling elementary unit for the construction of arbitrary shapes. This protocol…
Genetics: Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast
13.16: Genetics: Targeted in Situ Mutagenesis of Histone Genes in Budding Yeast
Histones play roles in the organization and function of eukaryotic chromosomes, and in budding yeast, each is encoded by two genes. This article…
Biology: The ChIP-exo Method and Identifying Protein-DNA Interactions with Near Base-Pair Precision
13.17: Biology: The ChIP-exo Method and Identifying Protein-DNA Interactions with Near Base-Pair Precision
Chromatin immunoprecipitation is a tool used to isolate specific protein-DNA interactions, however, some protocols provide low mapping precision and…
Immunology: A Simple Chelex Protocol for DNA Extraction from Anopheles spp.
13.18: Immunology: A Simple Chelex Protocol for DNA Extraction from Anopheles spp.
This video describes a rapid and affordable way to extract quality malaria parasite and vector DNA from mosquito specimens. Capitalizing on the…
Genetics: Identifying Transcription Factor Olig2 Genomic Binding Sites in Acutely Purified PDGFRα+ Cells by Low-cell Chromatin Immunoprecipitation Sequencing Analysis
13.19: Genetics: Identifying Transcription Factor Olig2 Genomic Binding Sites in Acutely Purified PDGFRα+ Cells by Low-cell Chromatin Immunoprecipitation Sequencing Analysis
A major goal in genetics is to understand how gene transcription is regulated. The binding of transcription factor proteins to DNA is a major…