BIOL110s05-27 - BIOL 110: Principles of Biology Spring 2005...

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Unformatted text preview: BIOL 110: Principles of Biology Spring 2005 • ONLINE Quizzes link: – (Cañada College I.D. [G#] for login and password) (Cañ Lecture 27, W 4/6/05 – Time-limited (so study well first!); ~ 30 minutes to complete Time- – Can view twice, submit once only. • Midterm 2 was Returned Friday. – Extra credit if scored <70%: Thoroughly rewrite answers to all missed questions; “Why the correct answer is right, why your answer was incorrect.” Due Mon. 4/11!! incorrect.” • Journal Reports #1 Were due Friday!! (-5% each day late!) • Next: Ch. 12, bits of 13, 14….. REVIEW: • Ch. 11: Studying and Manipulating Genomes – Recombinant DNA technology • Cutting and Splicing; DNA carriers (“VECTORS”) (“ VECTORS” • Amplifying DNA – bacteria as host; or in test tube (PCR) TODAY: • Ch. 11: Studying and Manipulating Genomes – Recombinant DNA technology • Cloning & Gene Libraries – Genetic engineering: bacteria, Plants, Animals • Ch. 12: Processes of Evolution – Artificial selection; evidence for evolution – old & new theories; Darwin’s voyage Darwin’ 1 DNA Fingerprints • Unique array of DNA fragments – Eg: Alu fragments Eg: Alu • Inherited from parents in Mendelian fashion • Even full siblings can be distinguished from one another by this technique D. Gel Electrophoresis D. • DNA is placed at one end of a gel (negative electrode) • A current is applied to the gel • DNA molecules are negatively charged, move with current toward positive end of gel • Smaller molecules move faster than larger ones 2 Analyzing DNA Fingerprints • DNA is stained or made visible by use of a radioactive or fluorescent PROBE radioactive – Finds and binds to complementary sequences in the sample DNA by normal A-T/G-C base-pairing rules A- T/G- base- • Pattern of bands is used to – Identify or rule out criminal suspects – Identify bodies – Determine paternity F. Gene Libraries • Bacteria that contain different cloned DNA fragments – Genomic library – cDNA library (from messenger RNA) • Can use a probe to find a particular gene in a library probe 3 Use of a Probe colonies on plate 1. Your short “tagged” DNA sequence short tagged” will “find” it’s complementary find” it’ cells adhere sequence among all the sequence to filter clones/colonies. 2. Isolate the detected colony, and you have a “clone” that carries your clone” DNA/gene sequence for further DNA/gene studies. • With the DNA sequence of a gene, you can: 1. Predict the protein sequence 2. Produce the protein for further study 3. Produce the protein for pharmaceutical use 4. Transfer the gene into diseased or vulnerable organisms to improve survival. cells are lysed; DNA sticks to filter probe is added the location where probe binds produces a dark spot on film indicates colony with your gene G. Genetically Engineering: 1. Bacteria • Produce medically valuable proteins – Insulin – Growth hormones – Immune proteins • Breakdown environmental contaminants (petroleum…) • Designed to survive only under narrow conditions (nutritional mutants) 4 2. “Frankenfood” Genetically Engineered Plants • Food products containing materials from genetically engineered plants are already widespread in the U.S. • Proponents: say these plants cut costs, reduce herbicide use, enhance yields • Opponents: worry about the effects of these plants on humans and ecosystems 3. Transgenic Animals • Early experiments in mice – Injection of rat gene corrected a growth-hormone deficiency – Injection of human growthhormone gene produced giant mice • Human genes are now routinely transferred into animals to produce human proteins for use as drugs – Hormones, insulin, antibodies, blood clotting factors, blood/immune cell growth factors….. 5 Processes of Evolution Chapter 12 Rise of the Super Rats • Warfarin is a chemical pesticide used against rodents • When introduced the the 1950s it was extremely effective • Over time, the proportion of warfarin-resistant rats has risen in warfarinplaces where the chemical is used – “Microevolution” Microevolution” – Small but persistent changes in a species population over time. 6 I. Selective Breeding & Evolution • Evolution is genetic change in a line of descent through successive generations • Selective breeding practices yield evidence that heritable changes do occur Domestication of Dogs • Began about 50,000 years ago • 14,000 years ago - artificial selection – Dogs with desired forms of traits were bred • Modern breeds are the result 7 Results of Artificial Selection • Extremes in size – Great Dane and Chihuahua • Extremes in form – Short-legged dachshunds – English bulldog • Short snout and compressed face • Extreme traits lead to health problems II. Evolutionary Theories • Widely used to interpret the past and present, and even to predict the future • Reveal connections between the geological record, fossil record, and organismal diversity 8 Early Scientific Theories: Observations by great thinkers! • Hippocrates - All aspects of nature can be traced to their underlying causes • Aristotle - Each organism is distinct from all the rest and nature is a continuum or organization Confounding Evidence 1. Biogeography 2. Comparative anatomy 3. Geologic discoveries 9 A. Biogeography • Size of the known world expanded enormously in the 15th century – exploration! • Discovery of new organisms in previously unknown places could not be explained by accepted beliefs – How did species get from center of creation to all these places? B. Comparative Morphology • Study of similarities and differences in body plans of major groups • Puzzling patterns: – Animals as different as whales and bats have similar bones in forelimbs – Some parts seem to have no function 10 ...
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