Molecular Biology of the Cell, Chapter 4 PDF

Chapter 4 DNA, Chromosomes, and Genomes Copyright © 2022 W. W. Norton & Company, Inc. Chapter Contents The Structure and Function of DNA Chromosomal DNA and Its Packaging in the Chromatin Fiber The Effect of Chromatin Structure on DNA Function The Global Structure of Chromosomes THE STRUCTURE AND FU...

Chapter 4 DNA, Chromosomes, and Genomes Copyright © 2022 W. W. Norton & Company, Inc. Chapter Contents The Structure and Function of DNA Chromosomal DNA and Its Packaging in the Chromatin Fiber The Effect of Chromatin Structure on DNA Function The Global Structure of Chromosomes THE STRUCTURE AND FUNCTION OF DNA A DNA Molecule Consists of Two Complementary Chains of Nucleotides The Structure of DNA Provides a Mechanism for Heredity In Eukaryotes, DNA Is Enclosed in a Cell Nucleus THE STRUCTURE AND FUNCTION OF DNA https://sites.google.com/a/wrps.net/cns-ontl/cns-2nd-semester-weblinks/unit-7/biomolecules---nucleic-acids DNA Consists of Two Complementary Chains of Nucleotides DNA strands are held together by a phosphodiester bond DNA double helix are held together by hydrogen bonds between complementary base pairs The Structure of DNA Provides a Mechanism for Heredity Most genes contain information to make proteins In Eukaryotes, DNA Is Enclosed in a Cell Nucleus CHROMOSOMAL DNA AND ITS PACKAGING IN THE CHROMATIN FIBER Eukaryotic DNA Is Packaged into a Set of Chromosomes Chromosomes Contain Long Strings of Genes The Nucleotide Sequence of the Human Genome Shows How Our Genes Are Arranged Each DNA Molecule That Forms a Linear Chromosome Must Contain a Centromere, Two Telomeres, and Replication Origins DNA Molecules Are Highly Condensed in Chromosomes Nucleosomes Are a Basic Unit of Eukaryotic Chromosome Structure Eukaryotic DNA Is Packaged into a Set of Chromosomes G banding or Giemsa banding Adenine and thymine (AT-rich) DNA and relatively gene-poor, stain more darkly in G-banding. In contrast, less condensed chromatin (Euchromatin) which tends to be rich with guanine and cytosine (GC-rich) and more transcriptionally active incorporates less stain, and these regions appear as light bands in G-banding. Chromosomes Contain Long Strings of Genes The Nucleotide Sequence of the Human Genome Shows How Our Genes Are Arranged Each DNA Molecule That Forms a Linear Chromosome Must Contain : a Centromere Two Telomeres Replication Origins DNA Molecules Are Highly Condensed in Chromosomes Nucleosomes Are a Basic Unit of Eukaryotic Chromosome Structure CHROMOSOMAL DNA AND ITS PACKAGING IN THE CHROMATIN FIBER The Structure of the Nucleosome Core Particle Reveals How DNA Is Packaged Nucleosomes Have a Dynamic Structure and Are Frequently Subjected to Changes Catalyzed by ATP-dependent Chromatinremodeling Complexes Attractions Between Nucleosomes Compact the Chromatin Fiber The Structure of the Nucleosome Core Particle Reveals How DNA Is Packaged Handshake CHROMOSOMAL DNA AND ITS PACKAGING IN THE CHROMATIN FIBER Nucleosomes Have a Dynamic Structure and Are Frequently Subjected to Changes Catalyzed by ATP-dependent Chromatin-remodeling Complexes Attractions Between Nucleosomes Compact the Chromatin Fiber THE EFFECT OF CHROMATIN STRUCTURE ON DNA FUNCTION Different Regions of the Human Genome Are Packaged Very Differently in Chromatin Heterochromatin Is Highly Condensed and Restricts Gene Expression The Core Histones Are Covalently Modified at Many Different Sites Covalent Modifications and Histone Variants Can Act in Concert to Control Chromosome Functions Different regions of the human genome are packaged very differently in chromatin Heterochromatin is highly condensed, gene-poor and restricts gene expression Euchromatin is less condensed, gene-rich, and more accessible to transcription. The Core Histones Are Covalently Modified at Many Different Sites Covalent Modifications and Histone Variants Can Act in Concert to Control Chromosome Functions Copyright © 2022 W. W. Norton & Company, Inc. THE EFFECT OF CHROMATIN STRUCTURE ON DNA FUNCTION The Heterochromatic State Can Spread Along a Chromosome and Be Inherited from One Cell Generation to the Next. Centromeres Have a Special, Inherited Chromatin Structure The structure of a simple centromere THE GLOBAL STRUCTURE OF CHROMOSOMES Chromosomes Are Folded into Large Loops of Chromatin Polytene Chromosomes Are Uniquely Useful for Visualizing Chromatin Structures Chromosome Loops Decondense When the Genes Within Them Are Expressed Mammalian Interphase Chromosomes Occupy Discrete Territories in the Nucleus, with Their Heterochromatin and Euchromatin Distributed Differently THE GLOBAL STRUCTURE OF CHROMOSOMES Chromosomal DNA Is Organized into Loops by Large Protein Rings Euchromatin and Heterochromatin Separate Spatially in the Nucleus Mitotic Chromosomes Are Highly Condensed THE GLOBAL STRUCTURE OF CHROMOSOMES Chromosomes Are Folded into Large Loops of Chromatin Lampbrush chromosome THE GLOBAL STRUCTURE OF CHROMOSOMES Polytene Chromosomes Are Uniquely Useful for Visualizing Chromatin Structures THE GLOBAL STRUCTURE OF CHROMOSOMES Polytene Chromosomes Are Uniquely Useful for Visualizing Chromatin Structures THE GLOBAL STRUCTURE OF CHROMOSOMES Chromosome Loops Decondense When the Genes Within Them Are Expressed RNA synthesis in polytene chromosome puffs. THE GLOBAL STRUCTURE OF CHROMOSOMES Mammalian Interphase Chromosomes Occupy Discrete Territories in the Nucleus, with Their Heterochromatin and Euchromatin Distributed Differently THE GLOBAL STRUCTURE OF CHROMOSOMES Chromosomal DNA Is Organized into Loops by Large Protein Rings Structural maintenance of chromosomes (SMC)