Chapter 6 The structure of DNA and RNA

Slides:

Advertisements

Similar presentations

Nucleotides and DNA Structure

Advertisements

Introduction to molecular biology. Subjects overview Investigate how cells organize their DNA within the cell nucleus, and replicate it during cell division.

Reminder-four classes of large biomolecules Carbohydrates/polysaccharides Lipids Proteins/polypeptides Nucleic acids/polynucleotides.

DNA STRUCTURE DNA is composed of polynucleotide chains

At the end of this lecture you should be able to: Recognize the structural components of a DNA and a RNA molecule. (LO 5.1) Recognize and apply the.

1. This will cover the following: Genomic organization of prokaryotic and eukaryotic cells. Structure of DNA, RNA and polypeptide. Watson and Crick Model.

Lecture 1 An introduction to DNA Topology  The human cell contains 23 pairs of chromosomes  If we scale the cell nucleus to the size of Basketball.

Section C Properties of Nucleic Acids

Nitrogenous bases Bicyclic purines Monocyclic pyrimidine

NUCLEIC ACIDS BY DR. MARYJANE. Are of two types: DNA RNA.

DNA. Gene Expression - Transcription Genes are expressed as encoded proteins in a 2 step process: transcription + translation Central dogma of biology:

Key Concepts Nucleotides consist of a sugar, phosphate group, and nitrogen-containing base. Ribonucleotides polymerize to form RNA. Deoxyribonucleotides.

Let’s Review! What is a macromolecule?

Structure (chapter 10, pages 266 – 278) and Replication of DNA (chapter 12, pages 318 – 334)

11 September, 2006 Chapter 6 DNA Structure. Overview The classical DNA structure is an antiparallel duplex of polynucleotides. The two strands of DNA.

Ch20 and 21 DNA, Synthesis and Repair 阮雪芬NTU April 29, 2003.

Download Chem 642 ppts from here.

Welcome Each of You to My Molecular Biology Class.

Deoxyribonucleic Acid (DNA). The double helix Nitrogenous Bases and Pentose Sugars.

Section C PROPERTIES OF NUCLEIC ACIDS

DNA Biology Lab 11. Nucleic Acids  DNA and RNA both built of nucleotides containing Sugar (deoxyribose or ribose) Nitrogenous base (ATCG or AUCG) Phosphate.

Welcome to My Molecular Biology Lecture. Molecular Biology of the Gene, 5/E --- Watson et al. (2004) Part I: Chemistry and Genetics Part II: Maintenance.

Supercoiling of DNA Topology

Proteins and Amino Acids

Proteins (aka polypeptides)

The topology of nucleic acids

Molecular Biology (Foundation Block) The central dogma of molecular biology Nucleotide chemistry DNA, RNA and chromosome structure DNA replication Gene.

Genome organization. Nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) store and transfer genetic information in living organisms.

DNA STRUCTURE. NUCLEIC ACIDS Nucleic acids are polymers Nucleic acids are polymers Monomer---nucleotides Monomer---nucleotides Nitrogenous bases Nitrogenous.

Nucleic Acids Nucleic acid: are polymers of Nucleotides linked with 3’, 5’- phosphodiester bonds Nucleotide residues are all oriented in the same direction.

CHAPTER 24 Genes and Chromosomes

Welcome to My Molecular Biology Lecture. Molecular Biology of the Gene, 5/E --- Watson et al. (2004) Part I: Chemistry and Genetics Part II: Maintenance.

1. Let’s Review! What is a macromolecule? What are the four kinds of organic molecules? What are nucleic acids made of? 2 - A large organic molecule (made.

Chapter 1 Genes Are DNA. 1.1 Introduction chromosome – A discrete unit of the genome carrying many genes. –Each chromosome consists of a very long molecule.

CHAPTER 7 THE CHEMISTRY OF CELLS CONTINUED. Proteins are essential to the structures and activities of life Proteins are involved in –cellular structure.

Nucleic Acids Jon Wilson Cell Physiology. Structure of DNA DNA is a double helix made of complimentary antiparallel strands The backbone is constructed.

Molecular Biology I-II The central dogma of molecular biology Nucleotide chemistry DNA, RNA and Chromosome Structure DNA Replication Gene Expression Transcription.

Chapter 24 Genes and Chromosomes

CHAPTER 24 Genes and Chromosomes  Organization of information in chromosomes  DNA supercoiling  Structure of the chromosome Key topics:

Polynucleotides: DNA and RNA

Welcome to My Molecular Biology Lecture

Lecturer: 譚賢明助理教授 Office: 醫學大樓十樓生科系 B 區 Phone: 5067 Textbook: Stryer’s Biochemistry (6 th ed.) (Chapters 4, 5, 28-31) Lewin’s Cells (Chapters 5 & 6) 分子細胞生物學.

DNA Structure DNA is usually a double-helix and has two strands running in opposite directions. (There are some examples of viral DNA which are single-stranded).

(CHAPTER 9- Brooker Text) Molecular Structure of DNA & RNA Sept 9 & 11, 2008 BIO 184 Dr. Tom Peavy.

Chapter 4 Nucleic Acids and the RNA World. Key Concepts Nucleotides consist of a sugar, a phosphate group, and a nitrogen-containing base. Ribonucleotides.

DNA structure and function

DNA supercoiling. Jerome Vinograd, 1965 sedimentation equilibrium experiments with viral DNA circular DNAs can exist in two distinct forms differing in.

NUCLEIC ACIDS Genetic material of all known organisms DNA: deoxyribonucleic acid RNA: ribonucleic acid (e.g., some viruses) Consist of chemically.

Nucleic Acids: How Structure Conveys Information Feb 23, 2016 CHEM 281.

Genes Are DNA Chapter 2. Genes Are DNA Aala A. Abulfaraj.

Chemical nature of hereditary material. Discovery of Nuclein “Nuclein.”……………??????????? In 1868, Johann Friedrich Miescher, a young Swiss medical student.

1 Advanced Biochemistry 高等生化學 Nucleotides and Nucleic Acids 陳威戎.

Molecular Biology - I Dr. Sumbul Fatma Clinical Chemistry Unit Department of Pathology.

Chapter 4. Structure of DNA

Structure of Nucleic Acids

Let’s Review! What is a macromolecule?

Chapter 3 Nucleic Acid Structure

Sect. 9.2: “The Struct. Of DNA” Sect. 9.3: “DNA Replication”

10.2 DNA and RNA are polymers of nucleotides

The Chemical Building Blocks of Life

Key Concepts Nucleotides consist of a sugar, phosphate group, and nitrogen-containing base. Ribonucleotides polymerize to form RNA. Deoxyribonucleotides.

Lec2 م. م مياسه مثنى.

DNA: The Molecule of Heredity

Determination of the double-helical structure of DNA has illuminated molecular biology for more than half a century. Fig. 9-CO, p.215.

DNA is the Hereditary Material

Key Concepts Nucleotides consist of a sugar, phosphate group, and nitrogen-containing base. Ribonucleotides polymerize to form RNA. Deoxyribonucleotides.

The Replication of DNA.

Presentation transcript:

Chapter 6 The structure of DNA and RNA

DNA is composed of polynucleotide chain: the helical structure of DNA

Purines and pyrimidines

Base tautomers

The two chains of the double helix have complementary sequences

DNA is usually a right-handed double helix

The major groove is rich in chemical information

DNA strands can separate (denature) and reassociate

Dependence of DNA denaturation on G+C content and on salt concentration Low salt high

Topological states of covalently closed, circular (ccc) DNA LK=Tw+ Wr Linking number is composed of twist and writhe

Two forms of writhe of supercoiled DNA toroidal writhe interwound

Lko is the linking Number of fully relaxed cccDNA under Physiological conditions Lko for such a molecule is the number of base pairs divided by 10.5. For a cccDNA of 10500 base pairs, Lk = +1,000 (DNA is right-handed) DNA in cells is negatively supercoiled Linking difference △Lk = Lk- Lko

Relaxing DNA with DNAse I

Relaxed DNA

Supertwisted DNA: DNA in cells is negatively supercoiled

Topoisomerases can relax supercoiled DNA Schematic for changing the linking number in DNA with topoisomerase II

Schematic mechanism of action for topoisomerase I

DNA topoisomers can be separated by electrophoresis

Intercalation of ethidium inot DNA

RNA contains ribose and uracil and is usually single-stranded

Double helical characteristics of RNA Hairpin bulge loop

RNA can fold up into complex tertiary structures

Some RNAs are enzymes, known as ribozymes The hammerhead ribozyme cleaves RNA by the formation of a 2’, 3’ cyclic phosphate