1. Biology: Life on Earth Chapter 9 DNA: The Molecule of Heredity and holds the Genetic Code
2. Watson & Crick Wilkins Franklin Scientists who discovered structure of DNA 1953 X-ray diffraction
3. The 4 Nucleotides of DNA Nitrogen base order is the code for genes Purines Pyrimidines
4. Watson-Crick model of DNA Double Helix Hydrogen bonds between complementary nitrogen base pairs Covalent bonds between phosphates & deoxyribose sugars
5. DNA Replication in Nucleus Both strands of helix used as template http:// www.youtube.com/watch?v =AGUuX4PGlCc is Semiconservative
6. DNA Helicase: unwinds DNA by breaking H bonds between bases DNA polymerase: adds loose complementary nucleotides to growing strands DNA ligase: connects short strands together Proofreading/Repair enzymes: from 1/10,000 to 1/billion mistakes
7. Mutation: permanent change in DNA base sequence Mutation in gamete is inherited
9. Ancient DNA – 100 million year old Biting Midge preserved in amber
Editor's Notes
Biology: Life on Earth (Audesirk) DNA: Molecule of Heredity
Figure :10-9 Title: Barr bodies Caption: The black spot on the upper right side of the nucleus is an inactivated X chromosome called a Barr body, usually found only in the cells of female mammals.
Insects (such as this biting midge) some 100 million years old have been found almost perfectly preserved in amber, which dehydrates them. Recent research has dashed hopes of finding intact DNA from these insects, from their stomach contents, or from the bones of fossilized dinosaurs.
