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CHAPTER 11.1 GENES ARE MADE OF DNA. What is in your GENES? No not that kind! No not that kind! These kind of genes! These kind of genes!

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Presentation on theme: "CHAPTER 11.1 GENES ARE MADE OF DNA. What is in your GENES? No not that kind! No not that kind! These kind of genes! These kind of genes!"— Presentation transcript:

1 CHAPTER 11.1 GENES ARE MADE OF DNA

2 What is in your GENES? No not that kind! No not that kind! These kind of genes! These kind of genes!

3 GRIFFITH’S “TRANSFORMING FACTOR” IS THE GENETIC MATERIAL Frederick Griffith proved that a substance in one strain of bacteria causes a change in another strain Frederick Griffith proved that a substance in one strain of bacteria causes a change in another strain

4 FIGURE 11.1

5 AVERY SHOWS DNA IS THE TRANSFORMING FACTOR Oswald Avery, Alfred Hershey, and Martha Chase took Griffith’s experiment one step further Oswald Avery, Alfred Hershey, and Martha Chase took Griffith’s experiment one step further Did experiments with viruses Did experiments with viruses Concluded that DNA is the genetic material of the cell Concluded that DNA is the genetic material of the cell

6 VIRUS EXPERIMENTS PROVIDE MORE EVIDENCE A virus consists of a package of nucleic acid in a protein coat A virus consists of a package of nucleic acid in a protein coat Bacteriophage- a virus that infect bacteria Bacteriophage- a virus that infect bacteria

7 VIRUS

8 Figure 11-4

9 DNA’S STRUCTURE 1950 Rosalind Franklin and Maurice Wilkins produced photographs of DNA using x-ray crystallography 1950 Rosalind Franklin and Maurice Wilkins produced photographs of DNA using x-ray crystallography

10 Erwin Chargaff Observed that the number of adenine equals the number of thymine. Observed that the number of adenine equals the number of thymine. Observed that the number of guanine equals the number of cytosine. Observed that the number of guanine equals the number of cytosine.

11 DOUBLE HELIX In 1953 James Watson and Francis Crick looked at the photographs and with Chargaff’s discovery gave DNA a shape of a double helix In 1953 James Watson and Francis Crick looked at the photographs and with Chargaff’s discovery gave DNA a shape of a double helix

12 DOUBLE HELIX Double Helix- twisting shape Double Helix- twisting shape Hypothesized that the strands were connected by hydrogen bonds Hypothesized that the strands were connected by hydrogen bonds Double Helix- twisting shape Double Helix- twisting shape Hypothesized that the strands were connected by hydrogen bonds Hypothesized that the strands were connected by hydrogen bonds

13 CLASS WORK Make a list of at least four of the scientists we discussed today and discuss their contribution to the discovery of DNA. Make a list of at least four of the scientists we discussed today and discuss their contribution to the discovery of DNA.

14 CHAPTER 11.2 NUCLEIC ACIDS STORE INFORMATION IN THEIR SEQUENCE OF CHEMICAL UNITS

15 THE BUILDING BLOCKS OF DNA  DNA- deoxyribonucleic acid, heritable genetic information of an organism  Polymer built from monomers  Nucleotides- monomers of DNA, building blocks, contain three parts

16 NUCLEOTIDES  1) A ring shaped sugar called deoxyribose  2) A phosphate group  3) A nitrogenous base

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18 NITROGENOUS BASE  Divided into two groups  Pyrimidines- single ring structures  Purines- double ring structures

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20 DNA STRANDS  Nucleotides are joined together by covalent bonds between the sugar and phosphate

21 COMPLEMENTARY BASE PAIRS  Adenine (A) bonds to Thymine (T)  Guanine (G) bonds to Cytosine (C)  EXAMPLE:  AAT GCT ATG  TTA CGA TAC

22 PRACTICE  1) AAT GGC TAT  2) CAT GAT TAC  3) CCG TTA CCA  4) GCG ATA GAC  5) CAG TCA GCA

23 THE TEMPLATE MECHANISM  When a cell divides a complete new set of genetic instructions is made

24 THE TEMPLATE MECHANISM  DNA Replication- the process of copying the DNA molecule

25 Enzymes Involved in Replication  DNA Helicase- unzips DNA, breaks the Hydrogen bonds between the base pairs in order to create origin of replication

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27 REPLICATION OF THE DOUBLE HELIX  DNA Polymerase- makes the covalent bonds between the nucleotides

28 Class Work  1. Describe how DNA replicates by using a template. 2. List the steps involved in DNA replication. 3. Under what circumstances is DNA replicated?

29 Class Work  1. What are the three parts of a nucleotide? Which parts make up the backbone of a DNA strand? 2. List the two base pairs found in DNA. 3. If six bases on one strand of a DNA double helix are AGTCGG, what are the six bases on the complementary section of the other strand of DNA?

30 THE TEMPLATE MECHANISM  When a cell divides a complete new set of genetic instructions is made

31 THE TEMPLATE MECHANISM  DNA Replication- the process of copying the DNA molecule

32 REPLICATION OF THE DOUBLE HELIX  DNA Polymerase- makes the covalent bonds between the nucleotides

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34 Class Work  1. Describe how DNA replicates by using a template. 2. List the steps involved in DNA replication. 3. Under what circumstances is DNA replicated?

35 CHAPTER 11.4 and 11.5 A GENE PROVIDES THE INFORMATION FOR MAKING A SPECIFIC PROTEIN

36 ONE GENE, ONE POLYPEPTIDE- Don’t need to write  George Beadle and Edward Tatum worked with the bread mold neurospora crassa

37 ONE GENE, ONE POLYPEPTIDE- Don’t need to write One Gene-One Enzyme Hypothesis- the function of an individual gene is to dictate the production of a specific enzyme One Gene-One Enzyme Hypothesis- the function of an individual gene is to dictate the production of a specific enzyme Now…ONE GENE-ONE POLYPEPTIDE HYPOTHESIS Now…ONE GENE-ONE POLYPEPTIDE HYPOTHESIS

38 INFORMATION FLOW: DNA TO RNA TO PROTEIN  RNA- ribonucleic acid, has a sugar or ribose, base uracil, single stranded

39 INFORMATION FLOW: DNA TO RNA TO PROTEIN  DNA  Deoxyribose  Thymine  Double-Stranded  RNA  Ribose  Uracil  Single Stranded

40 INFORMATION FLOW: DNA TO RNA TO PROTEIN

41  Transcription- when DNA is converted into single stranded mRNA, in nucleus  mRNA moves to cytoplasm while DNA stays in the nucleus

42 INFORMATION FLOW: DNA TO RNA TO PROTEIN Translation- the nucleic acid information (RNA) is converted into amino acids, in cytoplasm Translation- the nucleic acid information (RNA) is converted into amino acids, in cytoplasm Codon- a three-base “word” that codes for one amino acid Codon- a three-base “word” that codes for one amino acid Several codons form a polypeptide Several codons form a polypeptide

43 TRANSLATION: RNA TO PROTEIN  Transfer RNA- translates the 3 letter codon of mRNA into an amino acid

44 TRANSLATION: RNA TO PROTEIN  Anticodon- a triplet of bases that is complementary to a specific mRNA sequence

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47 THE TRIPLET CODE  Marshall Nirenberg figured out that the codon UUU makes the amino acid phenylalanine

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49 CHANGE THE DNA to mRNA  1. TAT CAT GAT  2. CCA GGG CTA  3. TAC TAG TTC  4. GCA ATA TTC  5. GCA ATG CCT  PAGE 12 CLASSWORK/HW

50 CLASS WORK 1. How did Beadle and Tatum's research result in the "one gene–one polypeptide" hypothesis? 2. Which molecule completes the flow of information from DNA to protein? 3. Which amino acid is coded for by the RNA sequence CUA? 4. List two ways RNA is different from DNA. 1. How did Beadle and Tatum's research result in the "one gene–one polypeptide" hypothesis? 2. Which molecule completes the flow of information from DNA to protein? 3. Which amino acid is coded for by the RNA sequence CUA? 4. List two ways RNA is different from DNA.

51 CHAPTER 11.5 THERE ARE TWO MAIN STEPS FROM GENE TO PROTEIN

52 TRANSCRIPTION: DNA TO RNA 3 types of RNA 3 types of RNA –Messenger RNA (mRNA) –Transfer RNA (tRNA) –Ribosomal RNA (rRNA) Messenger RNA- an RNA molecule which is transcribed (COPIED) from a DNA template Messenger RNA- an RNA molecule which is transcribed (COPIED) from a DNA template RNA Polymerase- links the RNA nucleotides together RNA Polymerase- links the RNA nucleotides together

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54 EDITING THE RNA MESSAGE Intron- non-coding regions of DNA Intron- non-coding regions of DNA Exon- parts of a gene that will be translated or expressed Exon- parts of a gene that will be translated or expressed RNA Splicing- when the introns are removed from the RNA before it moves to the cytoplasm RNA Splicing- when the introns are removed from the RNA before it moves to the cytoplasm

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56 TRANSLATION: RNA TO PROTEIN Transfer RNA- translates the 3 letter codon of mRNA into an amino acid Transfer RNA- translates the 3 letter codon of mRNA into an amino acid

57 TRANSLATION: RNA TO PROTEIN Anticodon- a triplet of bases that is complementary to a specific RNA sequence Anticodon- a triplet of bases that is complementary to a specific RNA sequence Ribosomal RNA- located in the ribosome Ribosomal RNA- located in the ribosome

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60 CLASS WORK 1. What kind of nucleic acid is made during transcription? 2. How do introns and exons relate to RNA splicing? 3. List the three RNA types involved in transcription and translation, and describe the role of each. 4. Briefly describe the steps of protein synthesis. 1. What kind of nucleic acid is made during transcription? 2. How do introns and exons relate to RNA splicing? 3. List the three RNA types involved in transcription and translation, and describe the role of each. 4. Briefly describe the steps of protein synthesis.

61 CHAPTER 11.6 MUTATIONS CAN CHANGE THE MEANING OF GENES

62 HOW MUTATIONS AFFECT GENES Mutation- any change in the nucleotide sequence of DNA Mutation- any change in the nucleotide sequence of DNA Two types Two types –Base Substitution –Base Insertion/Deletion

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64 WHAT CAUSES MUTATIONS? Errors in DNA replication Errors in DNA replication Mutagens- physical or chemical agents that cause mutations Mutagens- physical or chemical agents that cause mutations –X-rays –UV Light –Smoking Mutations can be harmful or beneficial Mutations can be harmful or beneficial

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74 CLASS WORK 1. Explain why a base substitution is often less harmful than a base deletion or insertion. 1. Explain why a base substitution is often less harmful than a base deletion or insertion. 2. Describe how a mutation could be helpful rather than harmful. 2. Describe how a mutation could be helpful rather than harmful. 3. Give an example of a mutagen. 3. Give an example of a mutagen. PAGE 13 in Packet PAGE 13 in Packet


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