Introduction -1 1 Lecture no.1 BCH 361/ Section: xxxxx Recommended Text books 5th edition. 2- Molecular Biology: Principles and Practice - 5th edition. By Michael M. Cox., Jennifer Doudna & Michael O'Donnell. 2 7th Edition. 1- Biochemistry - 7th Edition. By Jeremy M. Berg, John L. Tymoczko, & Lubert Stryer Lecture Outline 3 Lecture no.1 What is Molecular Biology? The RNA World hypothesis. Biochemical Unity Underlies Biological Diversity A timeline of discoveries. Definition Molecular Biology is the study of biology at a molecular level. Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis. 4 Lecture no.1 Continue This field overlaps with other areas of genetics and biochemistry. There is not a defined line between these disciplines. 5 Lecture no.1 This figure represent one possible view of the relationship between the fields: ''Biochemistry'' is the study of the chemical substances and vital processes occurring in living organisms. ''Genetics'' is the study of the effect of genetic differences on organisms. ''Molecular biology'' is the study of molecular underpinnings of the process of replication, transcription and translation of the genetic material. The central dogma of molecular biology where genetic material is transcribed into RNA and then translated into protein. 6 Continue Lecture no.1 Classical genetics showed that genes control the transmission of phenotype from one generation to the next. Biochemistry showed that within one generation, proteins had a determining effect on phenotype. Molecular biology is the hereditary information passed between generations in a form that is truly, digital. Understanding how that digital code directs the creation of life is the goal of molecular biology. 7 Continue Lecture no.1 8 9 All Life depends on 3 critical molecules DNAs Contains the genetic instructions used in the development and functioning of living organisms RNAs Provide templates to synthesize into protein Proteins The workhorses within cells, participating in all processes Lecture no.1 10 These 3 molecules can link together By Central Dogma Don t panic you will take it in detail later Lecture no.1 The RNA World The RNA world hypothesis posits that RNA based life predates DNA based life. RNA function in modern cells (enzyme, information molecule) are onlyremnants of its previous roles. 11 RNA is the only currently used macromolecule that is both a carrier of genetic information and an enzyme. Lecture no.1 12 Possible remnants of the RNA World Self-splicing introns Rnase P- ribozyme that cleaves tRNA precursors Self-cleaving viral RNAs Peptidyl transferase in the ribosome Nucleotides (ribo) involved in metabolism, Signalling..etc Lecture no.1 Biochemical Unity Underlies Biological Diversity All organisms are built from similar molecular components distinguishable by relatively minor variations. On the basis of their biochemical characteristics, the diverse organisms of the modern world can be divided into three fundamental groups called domains: Eukarya (eukaryotes), Bacteria, and Archaea. 13 The Tree of Life : A possible evolutionary path from a common ancestral cell to the diverse species present in the modern world can be deduced from DNA sequence analysis. Lecture no.1 The Modern Era: The Impact of Molecular Biology The molecular biology revolution in the middle of the Twentieth Century provided the means to study the role of genes in development. The key technological advance for the study of gene control of development was the ability to isolate and clone genes. The patterns of expression of individual genes could be followed by tracing the products of their expression. Molecular biology obtained a very powerful tool to facilitate the study of nucleic acids when the polymerase chain reaction (PCR) was developed, which amplify specific sequences of DNA many-fold from a minute amount of starting material. 14 Lecture no.1 Molecular Biology Timeline The term molecular biology first appeared in mid 1800s in a report prepared for the Rockefeller Foundation by Warren Weaver. Two studies performed in the 1860s provided the foundation for molecular biology. 15 Gregor Mendel s (1865) Three Laws of Inheritance Friedrich Miescher (1869) identified DNA & called it nuclein Lecture no.1 16 Thomas H. Morgan (1910) discovers genes on chromosomes Beadle & Tatum (1941) One gene - one enzyme Lecture no.1 17 Lecture no.1 (1944) Avery, Mcleod & McCarty (1944) DNA is genetic material 18 Lecture no.1 (1953) Watson, Crick, Franklin, Wilkins (1953) Structure of DNA (1950) Edwin Chargaff (1950) find C complements G and A complements T 19 Lecture no.1 (1961) Brenner, Jacob & Meseleson (1961) Discovery of mRNA 20 Central Dogma ; Crick & Gamov 1956 Recombinant DNA made in vitro ; P. Berg 1972 DNA cloned on a plasmid ; H. Boyer & S. Cohen 1973 Discovery of reverse transcriptase ; H. Temin 1973 Finished unraveling the code ; Nirenberg & Khorana 1966 Lecture no.1 21 Rapid DNA sequencing ; F. Sanger & W. Gilbert 1977 Discovery of split genes ; Sharp, Roberts et al Discovery of ribozymes ; T. Cech & S. Altman 1982 Creation of PCR ; K. Mullis et al Lecture no.1 Molecular Biology Present The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. Scientists have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy. 22 The genome sequence of Drosophila melanogaster. Science. 287: Lecture no.1 Continue The Human Genome Project (HGP) began in October 1990 with a primary goal of determining the sequence of chemical base pairs which make up DNA, and of identifying and mapping the approximately 20,00025,000 genes of the human genome from both a physical and functional standpoint. Due to widespread international cooperation and advances in the field of genomics (especially in sequence analysis), as well as major advances in computing technology, a 'rough draft' of the genome was finished in 2000 (announced jointly by U.S. President Bill Clinton and the British Prime Minister Tony Blair on June 26, 2000). 23Lecture no.1 24 Continue The Human Genome Project (HGP). Mouse genome is sequenced Rat genome sequenced Understanding the function of all genes within their cellular, organismal and evolutionary context of Arabidopsis thaliana 24 Lecture no.1 Nobel Prize Laureates in Physiology or Medicine from 2006 to present ANDREW Z. FIRE, and CRAIG C. MELLO for their discovery of RNA interference - gene silencing by double- stranded RNA MARIO R. CAPECCHI, SIR MARTIN J. EVANS, and OLIVER SMITHIES for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells ELIZABETH H. BLACKBURN, CAROL W. GREIDER, and JACK W. SZOSTAK for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase 25 Lecture no.1 Golden Era We are in the midst of a "Golden Era" of biology, and the revolution is mostly about treating biology as an information science, and not only as specific biochemical technologies 26 Lecture no.1 27Lecture no.1 28 Homework : Can you identify the most important terms that you have gone through a lecture today and find a scientific definition for it. Remember this will be your next lecture, so be prepared. Lecture no.1