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281 lec2 model_organisms
- 1. Lecture 2: Model Organisms Readings(chapter 1) Course 281 Introduction to Molecular Biology
- 2.
- 3. AIMS • Understand theimportance of models in science. • Introduce models organisms. • Present the most important model organisms. • Present the general characteristics of the model organisms.
- 4. The molecules This classis about the molecules of life ! DNA RNA ProteinTranscription Translation structure structure structure Chemical composition Genomics Transcriptomics Proteomics Chemical composition Genetic material Chemical composition Genetic material DNA replication Mutation DNA repair DNA damage Types regulation Types regulation
- 5. The molecules How canwe study these molecules? How can we learn about their biology? We need models! All branches of science need model systems
- 6. Science and models •To study physical sciences, we need a model of weights, volumes etc. • We need a simple system that can be easily studied to gain the knowledge to understand more complicated systems.
- 7. Science and models •The hydrogen atom is a model to study physics and chemistry. • The hydrogen atom is simple (one proton and one electron).
- 8. Model organisms How dowe learn about all these molecules and mechanisms involved? Saccharomyces cerevisiae (budding yeast) Escherichia coli (intestines’ bacterium) Mus musculus (mouse) Homo sapiens (Human)? Arabidopsis thaliana (plant) Zea mays (corn) Neurospora crassa (bread mold) Drosophila melanogaster (fruit fly) Pisum sativum (garden pea) Danio rerio (zebrafish) Bacteriophage (virus) Caenorhabditis elegans (worm)
- 9. Bacteriophage (virus) • Virus(living?) • 24-200 nm in length • single entities. • Simple structure • Haploid
- 10. Bacteriophage (virus) • Growson/in bacteria • Can be grown into millions of copies • Fast growth • Easy to culture, store, and manipulate genetically
- 11. Bacteriophage (virus) The hydrogenatom for biologists
- 12. Escherichia coli (intestines’bacterium) • Prokaryote. • Single celled organism. • haploid • Small in size • ~ 2um in length • ~ 0.5 um in width
- 13. Escherichia coli (intestines’bacterium) • Easy to grow in lab • Can be grown into millions of copies • Fast growth • Easy to culture, store, and manipulate genetically
- 14. Saccharomyces cerevisiae (buddingyeast) • Eukaryote. • Fungi. • Single celled organism. • Grows haploid or diploid. • Sexual and asexual life cycles. • Small in size (~ 5-10 um in diameter).
- 15. Saccharomyces cerevisiae (buddingyeast) • Easy to grow in lab • Fast growth • Easy to culture, store, and manipulate genetically
- 16. Caenorhabditis elegans (worm) •Eukaryote. • Animal - Nematode. • Multicellular. • Hermaphrodite. • Sexual and asexual life cycles. • Small in size (~ 1 mm in length). • Diploid.
- 17. Caenorhabditis elegans (worm) •Easy to grow in lab • Fast growth • Short life cycle • Known number of cells • Easy to culture, store, and manipulate genetically. • Eggs can be stored.
- 18. Drosophila melanogaster (fruitfly) • Eukaryote. • Animal - Insect. • Multicellular. • Diploid • Sexual life cycle. • Sexual dimorphism • ~ 2.5 mm in length
- 19. Drosophila melanogaster (fruitfly) • Easy to grow in lab • Occupies relatively a small space • Short life cycle • Easy and manipulate genetically. • A living stock has to be maintained.
- 20. Danio rerio (zebrafish) •Eukaryote. • Animal - Vertebrate. • Diploid. • 4-6 cm in length.
- 21. Danio rerio (zebrafish) •Easy to grow in lab • Occupies relatively a small space • Short life cycle • Good development model.
- 22. Danio rerio (zebrafish) •First cloned vertebrate! • Fun scientific community.
- 23. Mus musculus (mouse) •Eukaryote. • Animal - mammal. • Diploid • Model for human. • Small mammal. • 7.5 - 10 cm in length. • Long history as a model in biology and medicine.
- 24. Mus musculus (mouse) •Small mammal. • Can be grown in lab. • Genome can be manipulated. • Knockout mice. • A variety of phenotypes can be studied.
- 25. Arabidopsis thaliana (plant) •Eukaryote. • Plant - Dicot. • Diploid. • 20-25 cm in height
- 26. Arabidopsis thaliana (plant) •Easy to grow in lab • Occupies a small space • Short life cycle • Easy to cross • Seeds can be stored.
- 27. Zea mays (corn) •Eukaryote. • Plant - monocot. • Diploid. • Agricultural importance. • ~ 2.5 m in height.
- 28. Zea mays (corn) •Large plant. • Can’t be held in lab. • Crosses must be conducted in the field. • Long breeding history • Model for cytogenetics.
- 29. Zea mays (corn) BarbaraMcClintock and jumping genes
- 30. Homo sapiens Humans: Amodel organism?
- 31. Model organisms. Why? •Genome can be manipulated experimentally. • Short life-cycle. • Minimal living requirements. • Small genome (some of them)! • Easy to grow in lab. • Small in size. • Accumulated knowledge about the organism. • Organism does NOT need to be BEAUTIFUL!!
- 32. Molecular Biology The biologyof molecules Sub-cellular biology Molecular Biology
- 33. Why molecular biologyis fun? • Physical characters start with a molecule. • Cognitive and emotional characters also start with a molecule (I think ☺).
- 34. To study Saccharomyces cerevisiae (buddingyeast) Escherichia coli (intestines’ bacterium) Mus musculus (mouse) Homo sapiens (Human)? Arabidopsis thaliana (plant) Zea mays (corn) Drosophila melanogaster (fruit fly) Danio rerio (zebrafish) Bacteriophage (virus) Caenorhabditis elegans (worm) prokaryotes Eukaryotes Hermaphrodite Asexual life cycle sexual life cycle short life cycle haploid diploid
- 35. Expectations • You knowthe importance of models in science. • You know the most important model organisms. • You know general characteristics of the model organisms. • You know the taxonomic representation of each model organism.
- 36.