DNA: The Genetic Material Chapter 14. Frederick Griffith – 1928 Studied Streptococcus pneumoniae, a pathogenic bacterium causing pneumonia 2 strains of.

Slides:



Advertisements
Similar presentations
CHAPTER 14 LECTURE SLIDES
Advertisements

CHAPTER 14 LECTURE SLIDES
DNA: The Genetic Material
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Evidence that DNA can transform bacteria Frederick Griffith (1928) – Streptococcus.
DNA: The Genetic Material Chapter The Genetic Material Frederick Griffith, 1928 studied Streptococcus pneumoniae, a pathogenic bacterium causing.
The Molecular Basis of Inheritance
DNA: The Genetic Material Chapter The Genetic Material Griffith’s conclusion: - information specifying virulence passed from the dead S strain.
Ch. 16 Warm-Up 1.Draw and label a nucleotide. Why is DNA a double helix? 2.What was the contribution made to science by these people: A.Morgan B.Griffith.
DNA and Replication.
1 DNA: The Genetic Material Chapter The Genetic Material Frederick Griffith, 1928 studied Streptococcus pneumoniae, a pathogenic bacterium causing.
DNA: The Genetic Material Chapter
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 14.
Deoxyribonucleic Acid
DNA Timeline to the discovery of DNA: 1928 – Fredrick Griffith discovers non-virulent bacteria (Streptococcus pneumoniae) become virulent when in contact.
Mice live + Mice die a.b.c.d. Live Virulent Strain of S. pneumoniae Live Nonvirulent Strain of S. pneumoniae Heat-killed Virulent Strain of S. pneumoniae.
DNA: The Genetic Material
The MOLECULAR BASIS OF INHERITANCE
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. See separate PowerPoint slides for all figures and tables.
DNA: The Genetic Material Chapter DNA Structure DNA is a nucleic acid. The building blocks of DNA are nucleotides, each composed of: –a 5-carbon.
DNA: The Genetic Material Chapter 14. Griffith’s experiment with Streptococcus pneumoniae ◦ Live S strain cells killed the mice ◦ Live R strain cells.
THE MOLECULAR BASIS OF INHERITANCE
DNA: The Genetic Material Chapter The Genetic Material Griffith’s results: - live S strain cells killed the mice - live R strain cells did not kill.
DNA Replication Packet #43 Chapter #16 Tuesday, October 13,
Chapter 16 Molecular Basis of Inheritance. Deciphering DNA.
THE MOLECULAR BASIS OF INHERITANCE Chapter 16. THE SEARCH FOR GENETIC MATERIAL Frederick Griffith (1928) – something changed normal cells into pneumonia.
CHAPTER 16 The Molecular Basis of Inheritance. What is DNA? DNA stands for deoxyribonucleic acid. DNA is what makes our genes, and along with protein,
Who are these two famous characters of science?. Mendel (1865): Inheritance.
Chapter 16: DNA Structure and Function n The history of early research leading to discovery of DNA as the genetic material, the structure of DNA, and its.
DNA and Replication 1. History of DNA 2  Early scientists thought protein was the cell’s hereditary material because it was more complex than DNA 
DNA: The Genetic Material Chapter Discovery of DNA Griffith Avery, MacLeod, McCarthy Hershey and Chase 2.
Chromosomes Chromosome Supercoils Coils Nucleosome Histones DNA double helix.
DNA Replication Lecture 11 Fall Read pgs
CHAPTER 16 The Molecular Basis of Inheritance. What is DNA? DNA stands for deoxyribonucleic acid. DNA is what makes our genes, and along with protein,
1 DNA Structure The building blocks of nucleic acids are nucleotides, each composed of: –a 5-carbon sugar called deoxyribose –a phosphate group (PO 4 )
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 14 LECTURE SLIDES.
Question 1 Are viruses alive?. Study of viral DNA helped unravel the key to the inheritable chemical. Protein – vs- nucleic acid Virus has both and.
THE MOLECULAR BASIS OF INHERITANCE Chapter 16. Frederick Griffith (1928)
DNA replication Chapter 16. Summary of history Griffith Mice & Strep Transformation External DNA taken in by cell.
DNA: The Genetic Material 1. 2 DNA Structure DNA is a nucleic acid Composed of nucleotides –5-carbon sugar called deoxyribose –Phosphate group (PO 4 )
DNA: The Molecule of Heredity Chemical nature of DNA –Chromosomes are composed of protein and deoxyribonucleic acid –Gene – functional segment of DNA located.
Ch. 16 Warm-Up 1.Draw and label a nucleotide. 2.Why is DNA a double helix? 3.What is the complementary DNA strand to: DNA: A T C C G T A T G A A C.
Chapter 14 DNA: The Genetic Material The Genetic Material 1. Frederick Griffith worked with pathogenic bacteria Took a virulent strain of.
Molecular Basis of Inheritance Chapter 16 Figure 16.7a, c C T A A T C G GC A C G A T A T AT T A C T A 0.34 nm 3.4 nm (a) Key features of DNA structure.
DNA: Deoxyribonucleic Acid The Carrier of Genetic Information ESSENTIAL QUESTIONS: 1. Which experiments led to the discovery of DNA as the genetic material?
Molecular Biology. The study of DNA and how it serves as a chemical basis of heredity.
DNA: Deoxyribonucleic Acid The Carrier of Genetic Information ESSENTIAL QUESTIONS: 1. Which experiments led to the discovery of DNA as the genetic material?
The Molecular Basis of Inheritance DNA-the Genetic Material DNA-Replication and Repair.
DNA Structure Review. The Griffith Experiment: Hereditary Information Can Pass Between Organisms Frederick Griffith Non-pathogenic S. pneumoniae was transformed.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. See separate PowerPoint slides for all figures and tables.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 14 LECTURE SLIDES To run the animations you must be.
Deoxyribonucleic Acid
The Molecular Basis of Inheritance
THE MOLECULAR BASIS OF INHERITANCE
DNA and Replication.
Overview: Life’s Operating Instructions
Chapter 14: DNA.
DNA Replication Packet #
Deoxyribonucleic Acid
CHAPTER 14 LECTURE SLIDES
The Molecular Basis of Inheritance
Deoxyribonucleic Acid
Cellular Metabolism Chapter 4
Unit 6 – Meiosis, Replication, and Protein Synthesis
DNA Part 1.
DNA: The Genetic Material
DNA: The Molecule of Heredity
DNA replication Chapter 16.
DNA Replication Chapter 12 Section 2
Deoxyribonucleic Acid
Presentation transcript:

DNA: The Genetic Material Chapter 14

Frederick Griffith – 1928 Studied Streptococcus pneumoniae, a pathogenic bacterium causing pneumonia 2 strains of Streptococcus –S strain is virulent –R strain is nonvirulent Griffith infected mice with these strains hoping to understand the difference between the strains 2

3

4

5 Transformation –Information specifying virulence passed from the dead S strain cells into the live R strain cells Our modern interpretation is that genetic material was actually transferred between the cells

6 Avery, MacLeod, & McCarty – 1944 Repeated Griffith’s experiment using purified cell extracts Removal of all protein from the transforming material did not destroy its ability to transform R strain cells DNA-digesting enzymes destroyed all transforming ability Supported DNA as the genetic material

7 Hershey & Chase –1952 Investigated bacteriophages –Viruses that infect bacteria Bacteriophage was composed of only DNA and protein Wanted to determine which of these molecules is the genetic material that is injected into the bacteria

8

9 DNA Structure DNA is a nucleic acid Composed of nucleotides –5-carbon sugar called deoxyribose –Phosphate group (PO 4 ) Attached to 5′ carbon of sugar –Nitrogenous base Adenine, thymine, cytosine, guanine –Free hydroxyl group (—OH) Attached at the 3′ carbon of sugar

10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Purines Pyrimidines Adenine Guanine NH 2 C C N N N C H N C CH O H H OC NC H N C H C H O O C N C H N C H3CH3C C H H O O C N C H N C H C H C C N N N C H N C CH H Nitrogenous Base 4´4´ 5´5´ 1´1´ 3´3´2´2´ O P O–O– –O–O Phosphate group Sugar Nitrogenous base O CH 2 N N O N NH 2 OH in RNA Cytosine (both DNA and RNA) Thymine (DNA only) Uracil (RNA only) OH H in DNA

Phosphodiester bond –Bond between adjacent nucleotides –Formed between the phosphate group of one nucleotide and the 3′ —OH of the next nucleotide The chain of nucleotides has a 5′-to-3′ orientation 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Base CH 2 O 5´5´ 3´3´ O P O OH CH 2 –O–OO C Base O PO 4 Phosphodiester bond

Chargaff’s Rules Erwin Chargaff determined that –Amount of adenine = amount of thymine –Amount of cytosine = amount of guanine –Always an equal proportion of purines (A and G) and pyrimidines (C and T) 12

13 Rosalind Franklin Performed X-ray diffraction studies to identify the 3-D structure –Discovered that DNA is helical –Using Maurice Wilkins’ DNA fibers, discovered that the molecule has a diameter of 2 nm and makes a complete turn of the helix every 3.4 nm

14 James Watson and Francis Crick – 1953 Deduced the structure of DNA using evidence from Chargaff, Franklin, and others Did not perform a single experiment themselves related to DNA Proposed a double helix structure

Double helix 2 strands are polymers of nucleotides Phosphodiester backbone – repeating sugar and phosphate units joined by phosphodiester bonds Wrap around 1 axis Antiparallel 15 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5´5´ 3´3´ P P P P OH 5-carbon sugar Nitrogenous base Phosphate group Phosphodiester bond O O O O 4´4´ 5´5´ 1´1´ 3´3´ 2´2´ 4´4´ 5´5´ 1´1´ 3´3´ 2´2´ 4´4´ 5´5´ 1´1´ 3´3´ 2´2´ 4´4´ 5´5´ 1´1´ 3´3´ 2´2´

16

Complementarity of bases A forms 2 hydrogen bonds with T G forms 3 hydrogen bonds with C Gives consistent diameter 17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. A H Sugar T G C N H N O H CH 3 H H N N N H N N N H H H N O H H H N NH N N H N N Hydrogen bond Hydrogen bond

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

Fig Parent cell First replication Second replication (a) Conservative model (b) Semiconserva- tive model (c) Dispersive model DNA Replication Meselson and Stahl – 1958

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

21

22 DNA Replication Requires 3 things –to copy Parental DNA molecule –to do the copying Enzymes –Building blocks to make copy Nucleotide triphosphates DNA replication includes –Initiation – replication begins –Elongation – new strands of DNA are synthesized by DNA polymerase –Termination – replication is terminated

23

DNA polymerase –All have several common features Add new bases to 3’ end of existing strands(3’- free) Synthesize in (5’  3’) direction Require a primer of RNA 24 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5´5´ 3´3´ 5´5´ 5´5´ 5´5´ 3´3´ 3´3´ RNA polymerase makes primerDNA polymerase extends primer

Prokaryotic Replication E. coli model Single circular molecule of DNA Replication begins at one origin of replication Proceeds in both directions around the chromosome Replicon – DNA controlled by an origin 25

26

27 E. coli has 3 DNA polymerases -- Polymerase activity (5’  3’ polermerization and need primer ) DNA polymerase I (pol I) –Acts on lagging strand to remove primers and replace them with DNA DNA polymerase II (pol II) –Involved in DNA repair processes DNA polymerase III (pol III) –Main replication enzyme –Nuclease activity (exo-, endo-) All 3 have (3’  5’) exonuclease activity – proofreading DNA pol I has (5’  3’) exonuclase activity

Unwinding DNA causes torsional strain –Helicases – use energy from ATP to unwind DNA –Single-strand-binding proteins (SSBs) coat strands to keep them apart –Topoisomerase prevent supercoiling DNA gyrase is used in replication 28 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supercoiling Replisomes No Supercoiling Replisomes DNA gyrase DNA gyrase can relieve supercoiling)

29 Semidiscontinous Okazaki fragments

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

31 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 5´ 3´ Primase RNA primer Okazaki fragment made by DNA polymerase III Leading strand (continuous) DNA polymerase I Lagging strand (discontinuous) DNA ligase Discontinuous synthesis DNA pol III All RNA primers removed and replaced by DNA Backbone sealed –DNA gyrase unlinks 2 copies

Fig

Replisome Enzymes involved in DNA replication form a macromolecular assembly 2 main components –Primosome Primase, helicase, accessory proteins –Complex of 2 DNA pol III One for each strand 33

34

35 Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

36 Eukaryotic Replication Complicated by –Larger amount of DNA in multiple chromosomes – Linear structure Basic enzymology is similar –Requires new enzymatic activity for dealing with ends only

Fig Origin of replication Parental (template) strand Daughter (new) strand Replication fork Replication bubble Two daughter DNA molecules (a) Origins of replication in E. coli Origin of replicationDouble-stranded DNA molecule Parental (template) strand Daughter (new) strand Bubble Replication fork Two daughter DNA molecules (b) Origins of replication in eukaryotes 0.5 µm 0.25 µm Double- stranded DNA molecule Multiple replicons Initiation phase of replication requires more factors

Telomeres Specialized structures found on the ends of eukaryotic chromosomes Protect ends of chromosomes from nucleases and maintain the integrity of linear chromosomes Gradual shortening of chromosomes with each round of cell division –Unable to replicate last section of lagging strand 39

40

41 Telomerase enzyme makes telomere of lagging strand using and internal RNA template (not the DNA itself) –Leading strand can be replicated to the end Telomerase developmentally regulated –Relationship between senescence and telomere length Cancer cells generally show activation of telomerase

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at

43 DNA Repair Errors due to replication –DNA polymerases have proofreading ability Mutagens – any agent that increases the number of mutations above background level –Radiation and chemicals Importance of DNA repair is indicated by the multiplicity of repair systems that have been discovered

44 DNA Repair Falls into 2 general categories 1.Specific repair –Targets a single kind of lesion in DNA and repairs only that damage 2.Nonspecific –Use a single mechanism to repair multiple kinds of lesions in DNA

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at