Unraveling the DNA Mysteries: Structure, Function, and Replication Explained

1. 1 DNA The Twisting Tale of DNA: Ted ED

2. Quiz #1 Nucleotide Base Pairing Transformation Deoxyribose Double Helix Chromatin Replication DNA Polymerase Helicase Chromosome Complementary DNA 2 DNA Vocabulary quizzes

3. 3 UNIT GOALS • Distinguishbetween DNA andRNA. • Explainthe role of DNAin storing and transmitting cellular information. • Describethe relationshipsbetween changesin DNA and potential appearance of new traits including– alterations during replication, insertions, deletions, substitutions, mutagenic factors, radiation, chemicals. • Examinethe use ofDNA technologyin forensics, medicine and agriculture.

4. DNA • Function: Store & Transmit genetic information • Acts as a library or storehouse of informtion. • DNA is located in the nucleus. CLIP 4

5. Discovery of DNA Many People contributed to the discovery of DNA. 5

6. 6 1928 Frederick Griffith (Transformation) Experiments with Diplococcus pneumonia (bacterium responsible for pneumonia), witnessed a transformation. • These experiments are recognized as the first in a series that lead to theconclusion that DNA is the carrier of genetic information, the genetic material. DNA is the molecule of inheritance

7. 7 1944 Oswald Avery • Repeated Griffith’s experiment • Looking for“what” is being transferred. • Used enzymes to break up carbohydrates, lipids and proteins-transformation still took place. • Used enzymes to break up DNA-transformation did not happen. • Conclusion:DNA is a Nucleic Acid

8. 1952 Rosalind Franklin & Maurice Wilkins • Used x-ray diffraction to see DNA. • Conclusions:DNA is twisted like a spiral staircase Double helix 8

9. 1952 Erwin Chargaff • Discovered that the • amount of Adenine = amountThymine • amount of cytosine = amount of guanine. • True in all organisms tested. • Called Chargaff’s Rule. • Conclusions: 1. amt A is = to amt of T 2. amt C is = to amt of G 9

10. 1953 Watson and Crick “Put it all together” Developed the structure of DNA that we know today. Conclusions: Described the complete structure of DNA. 10 CLIP

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12. What we Know Now........ 12

13. Structure of DNA • Double Helix. -Twisted ladder or spiral staircase • Two stranded • Held together by hydrogen bonds • Made of four Nucleotides • Phosphate • Base ( Nitrogen) • Sugar 13

14. Structure of DNA Remember: • DNA is a nucleic acid. • Nucleic acids are made of nucleotides 14

15. Long chain of Nucleotides There are four nucleotide that make up DNA Each nucleotide has three parts: 1-Sugar, 2-Phosphate, 3-Base) The sugar is Deoxyribose There are four bases Structure of DNA Nucleotides 15

16. Adenine Guanine Cytosine Thymine 14 4 Bases Sides of the “Ladder” are made up of sugar and phosphate. 16

17. Adenine always pairs with ThymineCytosine always pairs with Guanine 17

18. Would Thymine be able to pair up with Guanine? NO!! 18

19. 19 CLIP

20. 20 The sequence of nucleotides forms the unique genetic information of an organism.

21. 21 Flashback Before a cell divides it needs to make a copy of its DNA. (Remember S-phase?) How does it do that?

22. DNA REPLICATION DNA has the unique ability to make an exact copy of itself in a process called Replication. 20 22

23. Chromosome Structure • DNA is packed very tightly in the nucleus. • Human nucleus has ~1 meter of DNA! • Smallest human chromosome has 30 million base pairs. 23

24. A chromosome has DNA and protein-chromatin. • Tiny sections of DNA are called genes 24

25. 25.1 DNA Replication • Before Cell Division, the DNA must be replicated exactly.

26. DNA Replication 25.2 Each strand is used to make a new strand.

27. 26 • Many enzymes are involved. Complementary Strands

28. Steps: • The two parent strands are unwound and unzipped with the help of DNA helicases. Replication Bubble 27

29. Replpication Bubbles 28

30. 29 Steps: 2. DNA polymerase attaches new nucleotides (base paring) to the parent strands **Each new strand formed is a complement of one of the original, or parent, strands.

31. This process will continue until the entire molecule has been unzipped and replicated. 30

32. Each new strand formed is a complement of one of the original, or parent strands. The replication of DNA is calledSemi-conservative replication 31 DNA replication website

34. When all of the DNA in the chromosomes of the cell have been copied by replication, there are now two copies of the genetic information that will be passed on to new cells during mitosis or to new generations through the process of meiosis. 32 Review Clip

35. Quiz#2 Messenger RNA Transfer RNA Transcription Translation Codon Anti-Codon Promoter Intron Exon Genetic Code Amino Acid Protein Polypeptide Mutation DNA RNA 2 DNA Vocabulary quiz

36. DNA stores the information needed by a ribosome to make a protein. • How does the ribosome get the information? • How does the ribosome read the information? • How does it make the protein? 33

37. 3 UNIT GOALS • Distinguishbetween DNA andRNA. • Explainthe role of DNAin storing and transmitting cellular information. • Describethe relationshipsbetween changesin DNA and potential appearance of new traits including– alterations during replication, insertions, deletions, substitutions, mutagenic factors, radiation, chemicals. • Examinethe use ofDNA technologyin forensics, medicine and agriculture.

38. EQ: How does a protein get made? “PROTEIN SYNTHESIS” 34

39. DNA contains the code for all of the cell proteins. 35

40. Flashback: DNA is located in the Nucleus Proteins are made on the ribosomes. DNA makes a copy (send a message) called “mRNA” 36

41. 1. Transcription 2. Translation Two Steps of Protein Synthesis LOCATIONS 37 Where do the steps take place?

42. Animation 1. Transcription: Nucleus • During transcription a “backwards copy” of the DNA is made…the copy is called messenger RNA or mRNA. • The mRNA takes the code to the ribosome. • During transcription the DNA unwinds and RNA nucleotides are paired up with DNA bases. 38

43. DNA vs. RNA • Single Stranded • AGUC • Ribose • YES! • Double Stranded • AGTC • Deoxyribose • NEVER! 40

44. 1. Transcription: Nucleus • The section that is copied is called a gene. • The gene contains the code for a protein. “backwards copy” During transcription the DNA opens up and RNA nucleotides are paired up with the DNA bases. 39

46. 2. Translation: Cytoplasm 41 • Once the mRNA copy is made, it can go to the ribosome and be used to make a protein (translated)

47. Clip

48. To have the correct translation of the code, mRNA codons must join with the correct anticodon of the tRNA. 2. Translation: Cytoplasm Ribosome tRNA anticodon mRNA codons The ribosome reads every 3 letters 42

49. 2. Translation: Cytoplasm • To have the correct translation of the code, mRNA codons must join with the correct anticodon of the tRNA. tRNA brings the amino acids to the ribosomes tRNA anticodon mRNA codons A codon is a group of 3 nitrogenous bases on an mRNA molecule that carries the code for a specific amino acid. An anticodon is a set of 3 nitrogenous bases on a tRNA molecule that matches a codon on an mRNA molecule. 43 animation

50. Remember….Proteins are made out of amino acids. There are 20 different amino acids. 3 bases code for each amino acid. 44