Why do we Study DNA?

1. Why do we Study DNA? Disease Better vegetable, fruit, and animals. Crime History of life

2. DO YOU UNDERSTAND THE RELATIONSHIP BETWEEN A GENE, DNA, AND CHROMOSOMES????????

5. DNA: nucleic acid that builds chromosomes. • Gene: segment of DNA on your chromosomes that determines your traits. • Trait: characteristics about you. It can be a part or a behavior. You inherited your traits from your parents. Remember BB, Bb,or bb!! • Chromosomes: 23 pairs made up of DNA wind around histones (proteins). • What is the human genome?

8. DNA Karotype – Appearance of the chromosome of a somatic cells. Paired in descending size.

9. Karotype • A display of metaphase chromosomes of a cell arranged by size and centromere positions. • From these pictures, doctors can study to chromosomes to look for disorders.

10. DNA Facts • One chromosome has 50 – 250 million base pairs(A,T,C,AND G). This is why we are all different!!! • DNA is found in the mitochondria. • One sequence of DNA is a genome or gene. • *DNA molecules are incredibly long. • If all of the DNA from all of your cells was stretched out into a single thread, it would extend to the moon and back about one million times!

11. The human genome is contained in 23 pairs of chromosomes. • The DNA within the human genome makes up 60,000 to 100,000 genes. The nucleus, or control centre, of a cell, is where DNA is located.

13. http://genomics.energy.gov/gallery/chromosomes/gallery-01.htmlhttp://genomics.energy.gov/gallery/chromosomes/gallery-01.html

14. Discovery of DNA Invented X-ray diffraction photography. Photo used to determine the shape of DNA is spiral. Rosalind Franklin -

15. DISCOVERY OF DNA James Watson and Francis Crick used the information from Franklin and other scientists to build a 3-D model of DNA. Won the Nobel Piece Prize in Chemistry in 1961.

16. Watson & Crick proposed… • DNA had specific pairing between the nitrogen bases: • ADENINE – THYMINE • CYTOSINE – GUANINE • DNA was made of 2 long stands of nucleotides arranged in a specific way called the “Complementary Rule”

17. A HISTORY OF THE STRUCTURE OF DNA • Discovery of the DNA double helix A. Rosalind Franklin- Used X-ray photo of DNA to discover the shape was a double helix. (1952) B. Watson and Crick- Used Franklin’s work to build the first model of DNA. They figured out the exact structure. (1953)

18. Why Do You Think We All Are Different????

19. DNA – stands for!!!(Deoxyribonucleic Acid)

20. DNA DNA stands for – Deoxyribonucleic acid Functions of DNA: 1. Carries the codes to make proteins. • Carries the genetic material that is passed on from the parents to the offspring.

21. “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone DNA Double Helix – SHAPE!!!

22. STRUCTURE OF DNA These three parts the basic unit of DNA NUCLEOTIDE(monomer). phosphate Nitrogen base Can be A, T, C or G Sugar (deoxyribose)

23. Phosphate Group O O=P-O O 5 CH2 O N Nitrogenous base (A, G, C, or T) C1 C4 Sugar (deoxyribose) C3 C2 DNA Nucleotide

24. STRUCTURE OF DNA Side Pieces(The Rope Part) Are alternating units of a 5 carbon sugar and a phosphate group. These go down both sides of the molecule phosphate Sugar (called deoxyribose)

25. STRUCTURE OF DNA Nitrogen Bases (Steps of the ladder) - • Adenine - A • Thymine – T • Cytocine – C • Guanine - G 2. The bases are connected to the sugar only !!!!!

26. A or G T or C Nitrogenous Bases • PURINES – double ring 1. Adenine (A) 2. Guanine (G) • PYRIMIDINES – single ring 3. Thymine (T) 4. Cytosine (C)

27. H-bonds G C A T BASE-PAIRINGS 2 Bonds 3 bonds

28. phophate adenine sugar thymine cytocine guanine

29. How are the nucleotides held together? • Nucleotides are held together by covalent bonds between the sugar of one nucleotide and the phosphate of the next.

30. DNA

31. Amount of DNA • Amount of DNA in a sample can be determined by how much UV light is absorbs. DNA absorbs UV light!!!

32. STRUCTURE OF DNA One complete turn of the double helix is 10 base pairs or 10 steps on the ladder

33. DNA is antiparallel The two strand of DNA run opposite of each other. The happens because of the structure of the nitrogen bases. To fit together,they must be upside down.

34. 5 O 3 3 O P P 5 5 C O G 1 3 2 4 4 2 1 3 5 O P P T A 3 5 O O 5 P P 3 DNA Double Helix

35. C T A G Chargaff’s Rule • Adeninemust pair with Thymine • Guanine must pair with Cytosine • Their amounts in a given DNA molecule will be about the same.

36. Chargaff’s Rule • In his experments on several different organisms, Chargaff discovered that the percentage of A and T were equal. The same for C and G. This observation became Chargaff’s rule. This is always the same no matter what organisms.

37. Genetic Diversity… • Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.

38. What makes us all different? Our alphabet!!!! • The “code” of the chromosome is the SPECIFIC ORDER that bases occur. A T C G T A T G C G G…

39. How does our DNA fit into the nucleus? DNA is wrapped tightly around histones and coiled tightly to form chromosomes

40. Why extract DNA? • To show there is DNA in the food we eat. • TO show how much DNA there is in a small piece of banana • To show where DNA is located in organisms. • To discuss the function of DNA. • To demonstrate how to remove DNA from organism

41. What Happens to the DNA in the foods we eat? • Our digestive system will break it down into nucleotides we can use. • It can be broken down into even smaller parts of phoshate, sugars, and nitrogen.

42. Video of girl burned!! • United streaming

43. Watson and Crick • The model that Watson and Crick where the nitrogen bases pair suggested a mechanism for DNA to replicate.

44. Messelson and Stahl • They proved that DNA is semiconservative by attaching radioactive material to DNA. As the cell divided, they observed the new DNA in each cell and saw that it contain half of the old.

46. How does DNA copy itself? Purpose:DNA copies itself to ensure that each new cell that is produced in gets the correct number of chromosomes and receives an EXACT copy of the DNA molecule. This is called DNA REPLICATION. The DNA molecule serves as its own pattern or templateso as an exact copy can be made.

47. DNDA Replication • DNA must copy itself so each new cell has a copy so you can – • GROW • REPAIR

48. STEPS OF DNA REPLICATION • Helicase begin to unzip the double helix at many different places breaking the hydrogen bonds between the bases creates a replication fork. Occurs in two different directions. • Leading strand – read normal • Lagging strand – upside down – reads in fragments • Okazaki Fragments • This occurs in many places along the DNA!! • Sites of replication – places where replication is occurring

49. Okazaki Fragments Small segments of DNA that are used on the 3’ DNA. DNA ligase puts them together.

50. 2. Free floating in the cytoplasm nucleotides pair with the bases on the template. DNA polyermase bonds together the nucleotides. Small segments are bonded together.