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Biotechnology Bell Ringers September 27 th , 2010

Biotechnology Bell Ringers September 27 th , 2010. What are some differences between plant cells and animal cells? What two resources were used to examine different examples of cells? Bacteria are prokaryotes. What is a prokaryote?.

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Biotechnology Bell Ringers September 27 th , 2010

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  1. Biotechnology Bell RingersSeptember 27th, 2010 • What are some differences between plant cells and animal cells? • What two resources were used to examine different examples of cells? • Bacteria are prokaryotes. What is a prokaryote?

  2. Biotechnology Objectives September 27th, 2010 (EB04.03) • We will explore the structure of DNA • We will explore DNA’s relationship to the cell • We will Extract DNA from a Strawberry • Time permitting, we will go over some Biotechnology current events

  3. Genetics and DNA • 1860s, Gregor Mendel discovered that “factors” determine inheritance in pea plants • He observed that many traits control these factors

  4. Genetics and DNA • 1903, researcher William Sutton made connection between Mendel’s “factors” and chromosomes-microscopic structures in the cell nucleus that carry genetic material

  5. Genetics and DNA • The genetic material itself, known as DNA, was discovered by Johann Miescher in Switzerland in 1869

  6. Genetics and DNA • Yet, it wasn’t until two researchers, Francis Crick and James Watson, proposed a double-helix structure for the molecule that we began to understand how this material carries the genetic code of life

  7. Early drawing by Watson and Crick of the DNA Double-helix

  8. Genetics and DNA • A gene is a unit of information that can be passed on to offspring • They are a power influence on physical and mental characteristics • They aren’t just found in people, they are found in all living things

  9. Genetics and DNA • As powerful as genes are, however, it’s important to remember that environment also helps shape organisms • The interactions between a living thing and its environment affect how it will turn out

  10. Domineering Genes • With few exceptions, every organism has two of each kind of gene • Genes are usually either dominant or recessive

  11. Domineering Genes • A dominant gene is expressed in the offspring no matter what gene the other parent contributes • A recessive gene is expressed in the offspring only if both parents contribute recessive genes

  12. Domineering Genes

  13. Mutations Rule • Over billions of years the earth has been around, plants, animals, and other living things have evolved through the changing of genes • Genes have been transferred, deleted, and mutated between generations

  14. Mutations Rule • Mutation has produced the countless variations of living things we see around us • Many mutations are neutral and have no effect at all • Some mutations place a living thing at a disadvantage • Some mutations, however, give an individual a better chance of survival • This makes them more likely to survive to have offspring • Over time, this mutant gene will likely become established in the gene pool (the genes of a breeding population

  15. Mutations Rule

  16. Secret Codes • DNA holds the secret code to make and maintain proteins (long chains of molecules that help living things grow and function • But how does this secret code move from the nucleus to the protein-making factories in the cells?

  17. Secret Codes • Rather than move the DNA out of the nucleus, the cell makes a copy of the gene(s) and sends it to the protein assembly site outside the cell nucleus • The copy is messenger RNA (ribonucleic Acid)

  18. Secret Codes • RNA is a single-stranded copy of a single cell of a single gene • It carries codes from the DNA to the protein assembly sites outside the nucleus

  19. Genes Across the Ages • In nature, genes generally are transferred between members of the same species • Some new studies, however, suggest that genes also move between unrelated organisms • For the most part, such “horizontal” gene transfer takes place among bacteria and viruses

  20. Genes Across Ages • Today, horizontal gene transfer also can occur through genetic engineering • DNA can be transferred via direct injection or by inserting the DNA into bacteria or viruses that carry it into the cells they infect • This means that traits determined by single genes can be transferred from one kind of organism to another

  21. Genes Across Ages • Characteristics coded for by more than one gene are much harder to transfer, since the contributing genes must all first be identified, found, and isolated • Many human diseases are thought to result from interactions of multiple genes

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