1. Chapter 10: Nucleic Acids And Protein Synthesis Essential Question: What roles do DNA and RNA play in storing genetic information?

2. I. DNA: Deoxyribonucleic acid A.Function 1. DNA stores and transmits the genetic information that tells cells which proteins to make 2. Proteins form the structural units of cells and control chemical processes in cells

3. B. Structure of DNA 1. Made of repeating units called nucleotides a) Sugar: deoxyribose b) Phosphate group c) Nitrogen-containing bases DNADNA 2. Four types of nitrogen bases a) Adenine: Ac) Cytosine: C b) Guanine: Gd) Thymine: T

4. 3. Nitrogen bases can be put into two groups a) Purines: double ring of carbon and nitrogen atoms (adenine and guanine) b) Pyrimidines: single ring of carbon and nitrogen atoms (cytosine and thymine)

5. PurinesPyrimidines AdenineGuanine CytosineThymine Phosphate group Deoxyribose DNA Nucleotides Section 12-1 Go to Section:

6. C. Double helix: two nucleotide chains that wrap around each other to form a double spiral 1. Model of DNA by Watson and Crick in 1953 2. Watson and Crick used X-ray pictures from Rosalind Franklin to help create their model

7. D. Complementary Base Pairing: uses a hydrogen bond to connect bases 1. Adenine pairs with thymine 2. Guanine pairs with cytosine

8. 3. Base sequence: order of nitrogenous bases on a chain of DNA 4. A C C T G T G A G A C T G G A C A C T C T G Base Pairing

10. Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Structure of DNA Section 12-1 Go to Section:

11. DNA review Build a DNA model

12. E. Replication of DNA: process of copying DNA in a cell 1. DNA unwinds a) replication fork: point at which the two chains separate b) helicases: enzyme that separates the strands and breaks the hydrogen bonds 2. Each chain serves as a template for a new nucleotide

13. 3. DNA polymerase: enzyme used to add new chains of DNA using nucleotides that are complementary to the existing DNA chains a) Nucleotides are joined between the sugars and phosphate groups b) The bases bond to bases on the original strand c) If original strand bases are A T T C C then the new strand are T A A G G

14. 4. Replication can begin at many points along the DNA strand 5. High degree of accuracy: 1 error every 10,000 paired nucleotides

15. 6. Mutation: change in the nucleotide sequence and can cause serious effects in cells a) Proofreading enzymes can detect errors in the base pairing and repair enzymes can fix the error b) 1 error per 1 billion nucleotides

16. c) DNA can also be damaged by chemicals and ultraviolet radiation from the sun d) Mutations can cause cancer if the genes effected control how a cell divides 7. When replication is complete, two new exact copies of the original DNA molecule are produced Replication

17. Review DNA: double helix, made up of nucleotides (sugar, phosphate, and base) 4 Bases: A=T, C=G Replication: makes a copy of the DNA using helicase and DNA polymerase

18. DNA Replication Section 12-2 Go to Section: Growth Replication fork DNA polymerase New strand Original strand DNA polymerase Nitrogenous bases Replication fork Original strand New strand

19. II. Protein synthesis A. Flow of genetic information 1.Gene determines a person’s hair color 2. Gene directs the making of a protein (pigment in hair) 3. Protein is made by RNA 4. Steps involved a) transcription: DNA makes RNA b) translation: RNA makes the protein c) protein gives the characteristic Protein tour

20. B. RNA Function 1. RNA carries the genetic information from the nucleus to the cytoplasm 2. The proteins are then made in the cytoplasm

21. C. Structure of RNA 1. Made of repeating nucleotides 2. Sugar: ribose 3. Bases: Uracil replaces thymine so uracil will pair with adenine 4. Single strand Compare DNA to RNA

22. D. Types of RNA: each has a different function 1. Messenger RNA (mRNA): carries genetic information from the DNA in the nucleus to the cytoplasm 2. Transfer RNA (tRNA): strand folded into a hairpin shape that binds to specific amino acids 3. Ribosomal RNA (rRNA): globular form that combines with proteins to make the ribosomes where proteins will be made RNA types

24. E. Transcription: process by which genetic information is copied from DNA to RNA 1. RNA polymerase: enzyme that makes RNA copies of specific sequences of DNA 2. Promoters: region of DNA that marks the beginning of the DNA chain that will be transcribed 3. Steps a) RNA polymerase binds to promoters

25. b) DNA strands are separated c) RNA polymerase begins adding complementary RNA nucleotides using one DNA strand as a template d) Continues until the polymerase reaches a DNA region called the termination signal 4. Termination signal: specific sequence of nucleotides that marks the end

26. 5. RNA polymerase releases the DNA and newly formed RNA 6. All three forms of RNA are made by this process 7. mRNA will move through the pores of the nucleus into the cytoplasm and direct the making of the proteins

27. RNA DNA RNA polymerase Transcription Section 12-3 Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) Go to Section:

28. F. Genetic Code: nucleotides in mRNA that determine the sequence of amino acids in proteins 1. Codon: 3 mRNA nucleotides that are read together to determine a specific amino acid 2. Several codons code for each amino acid 3. Start codon: AUG : tells the ribosome to start translating 4. Stop codons: UAA, UAG, UGA: causes the ribosome to stop translating Codon

30. The Genetic Code Section 12-3 Go to Section:

31. G.Protein structure and composition 1. Proteins: made of one or more polypeptides which are sequences of amino acids held together by peptide bonds 2. 20 different amino acids arrange in a particular sequence make up the proteins

32. 3. Sequence of amino acids determines how the protein will twist and fold into its shape 4. Function depends on its ability to bind with other molecules 5. The function depends on its shape, the shape depends on the sequence of amino acids which is determined by the genetic information

33. H. Translation: process of assembling proteins from information encoded in mRNA 1. mRNA moves to ribosome where protein synthesis will take place 2. Amino acid are floating in the cytoplasm and tRNA picks them up and takes them to the ribosomes 3. tRNA: top section bonds to amino acid and the bottom section has three nucleotides called an anticodon

34. a) anticodon: complementary to the mRNA codon that it will pair up with b) pairing of the anticodon with the codon ensures that the amino acids are added to the growing protein in the correct order c) same base pairing rules: anticodon is AAA then codon is UUU

36. 4. Ribosomes: made of proteins and rRNA and have three binding sites for translation a) one site holds mRNA b) two other sites hold the tRNA whose anticodons will pair with the mRNA

37. 5. Ribosome attaches to the start codon (AUG) on the mRNA 6. tRNA with the anticodon UAC brings in the amino acid and links to the mRNA 7. Ribosome moves 3 nucleotides along the mRNA strand and next tRNA binds to the codon bringing the correct amino acid

38. 8. The two amino acids brought in and form a peptide bond 9. The process of moving the ribosome, binding the tRNA and forming a bond between the next amino acids continues until a stop codon is reached 10. mRNA is released from the ribosome and the protein is complete

40. Messenger RNA Messenger RNA is transcribed in the nucleus. Transfer RNA The mRNA then enters the cytoplasm and attaches to a ribosome. Translation begins at AUG, the start codon. Each transfer RNA has an anticodon whose bases are complementary to a codon on the mRNA strand. The ribosome positions the start codon to attract its anticodon, which is part of the tRNA that binds methionine. The ribosome also binds the next codon and its anticodon. mRNA Start codon Ribosome Methionine Phenylalanine tRNA Lysine Nucleus Translation Section 12-3 mRNA Go to Section:

41. The Polypeptide “Assembly Line” The ribosome joins the two amino acids— methionine and phenylalanine—and breaks the bond between methionine and its tRNA. The tRNA floats away, allowing the ribosome to bind to another tRNA. The ribosome moves along the mRNA, binding new tRNA molecules and amino acids. mRNA Ribosome Translation direction Lysine tRNA Ribosome Growing polypeptide chain mRNA Completing the Polypeptide The process continues until the ribosome reaches one of the three stop codons. The result is a growing polypeptide chain. Translation (continued) Section 12-3 Go to Section:

42. Translation Translate and Transcribe You Tube

43. I.Human Genome 1. Human genome: the complete gene sequence 2. 3.2 billion base pairs in the 23 human chromosomes 3. Now scientists need to understand what the DNA sequences encode 4. Bioinformatics: used computers to compare different DNA sequences 5. Will help to diagnose, treat, and prevent genetic disorders, cancer and infectious diseases in the future. Genome animationsGenome animations