MCB 502A-2014. Lecture #1— Introduction to Molecular Biology. Course introduction — the questions — the nature of the “scientific fact”Introduction into Molecular BiologyMolecular Biology and Physiology vs Genetics and BiochemistryBiopolymers (BPs)Ways to transfer information in and between biopolymersThe Cellular Organization of Life The structure and dimensions of eukaryotic and prokaryotic cells— DNA as the main information carrier of life.The biochemistry of chromosomes. The tetranucleotide structure of DNA. Gene as a unit of information multiplication and transfer Experiments of Griffith: the “transforming principle”Experiments of Avery, MacLeod and MacCarty on pneumococcal transformationExperiment of Hershey and Chase Observations of ChargaffThis is the second transition year— chalk-talk— regular homework assignments are back — the purpose of the homeworkI need you here, all 90 minutesCourse introduction-1— The objective of this course — useless information. — the logic of select experiments, …the original observations and questions, the approaches, the ideas, the major contradictionsCourse introduction-2—keep alive the original questions— thinking experimentalists — without thinking, even having all the "right" answers…Questions are seeds of knowledge, but the tree of knowledge grows under the light of active understanding.The nature of the “scientific fact”-1— experimental science does not produce “facts”— understanding is a process, rather than a product. —light bulb goes dark when we shut down electricityThe nature of the “scientific fact”-2ideahypothesisconcepttheoryInstruments of understandingThe nature of the “scientific fact”-3— paradoxical for non-scientists: a theory does not need to be correct to be “right” — the right theory for the moment— “scientific fact” as a red flagUseful today versus correct tomorrowIntroduction into Molecular Biology—Molecular Biology is “experimental study of the molecular basis of Life”. — “Molecular” refers to the “chemical” level of organization of the matter— what is “experimental” …— and what is “Life”? —several characteristics that distinguish a live matter from the dead one…… but most of them will be shared only by a subset of life forms.Self-replication of metabolismThe two functional principles defining life that all life forms must perform: 1) the ability to extract from the environment and process energy (e) and matter (m), —“metabolism”.2) the ability to produce independently-functioning and almost exact copies of itself, —self-replication. Functionally, Life can be described as self-replication of metabolism. — or metabolism-driven self-replication… growthreproductionWhat about Evolution?— Parenthetically, not only all forms of Life possess metabolism and self-replication, but they also constantly strive to excel in both through the process of Evolution (propagation of the fittest). — Both metabolism and reproduction would be impossible if the organism cannot secure resources to maintain and perform the two functions. — The ability to secure the needed resources for metabolism in a particular environment is called “survival in this environment”. Survival: the ability to secure resources for growth.Evolution-2— Although the measure of survival at the level of organism is individual growth, the integral measure of adaptation in this specific environment is the number of successful progeny the organism produces compared to other similar organisms. — Indeed, the only point of securing resources for robust metabolism is to make efficient use of this metabolism for self-reproduction. — Thus, “survival” and “productivity” measure organism’s evolutionary success (adaptation), based on how well the metabolism is supported and how efficiently it is translated into self-replication.— Reproduction: the ability to leave progeny.Experimental science starts with good description of the phenomenon— Molecular Biology is an experimental science— Experimentation starts with … … but then <…> repeats the magic stepsThe cycle of experimental science— conceive ideas; — derive predictions; — test the predictions; — modify ideas, generate new predictions. The power of experimental science to produce useful knowledge.A side-step to straighten out important termsModel vs Mechanism-1— Confusing usage in the scientific literature—models explain phenomena—mechanisms are reconstructions of phenomena.NTSB investigationTWA Flight 800 1996-07-17Model vs Mechanism-2— Model specifies relationships and follows logic. — The emphasis. — "competing" models— Mechanism is a collection of observations. — The emphasis. — Always incompleteModel vs Mechanism-3— The process of understanding operates at two levels. — Ideally, they meet one day. — When this happens, the "magic words" to utter: "our mechanism of such and such phenomenon is consistent with such and such model of it".model mechanismThe differences between an idea, a hypothesis, a concept and a theory-1— Idea is an explanation via relationship.—simplicity and scope. —elegant idea.The differences between an idea, a hypothesis, a concept and a theory-2— A hypothesis has testable predictions. —a falsifiable idea. — Very few hypotheses survive. — Once survived tests, a hypothesis becomes a concept.The differences between an idea, a hypothesis, a concept and a theory-3— A concept is an affirmation that the relationship between elements, theoretically conceived in the original idea, does indeed exist in nature. — A concept is immediately useful. — An intellectual tool facilitating human activities.The differences between an idea, a hypothesis, a concept and a theory-4— A theory is a group of concepts explaining various aspects of the same complex phenomenon. — Is based on many observations, always produced by diverse methods. — A solid experimental base.The end of the side-step and return to the lecture — We defined Molecular Biology as "experimental study of the molecular basis of Life." — Now that we know what “life” is and what “experimental study” means, let us explore the place of Molecular Biology among the related and neighboring scientific disciplines.Molecular Biology and Physiology vs Genetics and BiochemistryAnalytical HolisticGenetics offers a holistic approach—
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