1. DNA Deoxyribonucleic Acid

2. DNA Structure

3. What is DNA? The information that determines an organisms traits. DNA produces proteins which gives it “The power” Many things contain and are made of proteins. Skin, hair, bones, etc are made of proteins.

4. What is DNA? Cont’d Enzymes are special proteins. Enzymes control chemical reactions needed for life. DNA contains all the information for making all and any proteins for human life.

5. DNA Structure: DNA is made of repeating subunits called nucleotides. Nucleotides have three parts: –Simple sugar –Phosphate group –Nitrogen base

6. 1 Nucleotide Phosphate Group Sugar (Deoxyribose) Nitrogen Base

7. DNA Structure The simple sugar is called deoxyribose. The phosphate group is made of phosphate and oxygen.

8. DNA Structure Four possible Nitrogen Bases: –Thymine (T) –Adenine (A) –Cytosine (C) –Guanine (G)

9. DNA Nucleotides join together to form long chains. The phosphate group of one nucleotide joins together with the deoxyribose sugar of an adjacent nucleotide. “Backbone” “Teeth”

10. DNA Nitrogen bases pair up –Adenine & Thymine (A-T) –Cytosine & Guanine (C-G) Complementary bases

11. Watson & Crick, 1953 Proposed DNA is put together like a “twisted zipper” DNA = 2 chains of nucleotides joined by nitrogen bases

12. Watson & Crick, 1953 Double Helix Double = DNA has two strands Helix = twisted like a spring, “spiral”

14. Importance of Sequencing The sequence of the four different nucleotides determines what organism is created. For instance: T-A-A-G-C-A is different than A-G-C-A-A-G Another example: E-A-R-T-H is different than H-E-A-R-T vs.

15. Importance of Sequencing The more similar the order of nucleotides are, the closer the relationship between 2 organisms

16. DNA Replication

17. Replication = to copy Process of copying DNA in the chromosomes Without DNA replication, a new cell would only have half of it’s information.

18. DNA Replication DNA Replication Video

19. DNA Replication 2 Replication VIDEO Replication VIDEO

20. DNA Replication Because of the pairing- if you have one strand, it is easy to predict the replicated strand.T-A-G-C-C-G-T Remember: A goes with T, C goes with GA-T-C-G-G-C-A

21. DNA Replication Remember: The nitrogen bases are held together by hydrogen bonds An enzyme goes to those hydrogen bonds and breaks them = Double Helix Unzips

22. DNA Replication Step 1: Separate the two DNA strands

23. DNA Replication Step 2: Original DNA strands act as templates & complementary nucleotides fill in.

24. DNA Replication Step 3: Nucleotides connected and a new sugar- phosphate “backbone” is formed.

25. DNA Replication Each new DNA molecule consists of one original strand and one new strand

26. So now what??

27. DNA to Protein DNA encodes the instructions for making proteins. Remember proteins make up your bones, skin, etc. Enzymes are special proteins Enzymes control all chemical reactions in an organism

28. DNA to Protein Proteins are made up of many amino acids The order of nucleotides in each gene has information on how to make the string of amino acids which is a protein. ESTIMATE: Each cell contains about 800,000 genes

29. We need to figure out how to get from DNA to Proteins!

30. RNA What is it? What does it do?

31. RNA vs. DNARNA Single Stranded- only half of a zipper Contains the sugar Ribose Contains the nitrogen bases: –Adenine –Uracil –Guanine –CytosineDNA Double Stranded- double helix Contains the sugar Deoxyribose Contains the nitrogen bases: –Adenine –Thymine –Guanine –Cytosine

32. RNA It’s job: Copying DNA It’s goal: To create proteins There are 3 types, each with a different job: –mRNA= Messenger RNA: copies DNA to take it out in the cytoplasm –rRNA= Ribosomal RNA: works on matching mRNA - to create the amino acids in the correct order –tRNA= Transfer RNA: gives amino acids to rRNA to produce the protein.

33. mRNA Brings information (in the form of an RNA strand) from the DNA in the nucleus to the cytoplasm

34. rRNA Ribosomes are made of rRNA Where are ribosomes found? Cytoplasm rRNA attaches to the mRNA and uses its information to set up the amino acids in the correct order Ribosome mRNA

35. tRNA The supplier Brings amino acids to the ribosome so that it can assemble the protein Amino Acid

36. Review Questions How does information from the DNA get to the cytoplasm? How does the zipper get unzipped in DNA replication? Who does the work in getting the amino acids to the worker? What is the formal name of the worker

37. Transcription

38. Transcription Transcription’s purpose is to create a single stranded RNA molecule rather than a double stranded DNA molecule. This is needed to allow the single stranded RNA to be taken out of the nucleus by the mRNA to the cytoplasm.

39. Transcription Transcription Tutorial / SHOW Transcription Tutorial / SHOW Transcription mRNA VIDEO Transcription mRNA VIDEO

40. Genetic Code with mRNA In order to take the DNA and create a mRNA, there are special codes used. In mRNA, three nitrogen bases together form a code – this is called a codon. Looking ahead: –this code is matched with an amino acid. –A string of amino acids form a protein.

41. Genetic Code with mRNA Some codons code for information other than amino acids UAG is an example of a stop codon. AUG is an example of a start codon. NOTE: For every one codon, there is only ONE amino acid that can join.

42. Transcription Pictures

43. Transcription Pic’s

44. How does this work in the cell? DNA AMINO ACIDS TRANSPORTED BY tRNA mRNA COPIES DNA INTO CYTOPLASM rRNA USES PLAN FROM mRNA TO PUT AMINO ACIDS IN ORDER TO MAKE PROTEINS RIBOSOME NUCLEUS

45. Translation

46. Translation: From mRNA to Protein The process of changing the information from an order of nitrogen bases in mRNA into the order of amino acids Occurs at the ribosomes in the cytoplasm

47. Translation When mRNA enters the cytoplasm, ribosomes attach 20 different amino acids must be brought to the ribosomes for proteins to be made tRNA brings the amino acids to the mRNA strand

48. Translation On the opposite side of the tRNA amino acid side is a set of three nucleotides that are the complement of the nucleotides codon This is called an Anticodon Amino Acid

49. Translation When a match is made between codons and anticodons- a temporary bond is formed. This places the amino acid in the correct position to enable it to bond with the next amino acid

50. Translation The next tRNA bonds to it’s codon and then the two amino acid’s bond together. The first amino acid then releases itself from the mRNA

51. Translation This continues until a stop codon is reached. Amino acid chains then become proteins when they are freed from the ribosome and twist and curl into complex three-dimensional shapes.

52. Translation

53. Translation Translation VIDEO