1. Biology Chapter 12 DNA and RNA Unit 12.1 Unit 12.2 Unit 12.3 Unit 12.4

2. DNA In class assignment.
1. Draw four different symbols (i.e. Ω ∆ π ).
2. Write down any five letter word.
3. Develop a code for the five letters of that word using only your four symbols. How can you code for five different letters with only four different symbols?
4.How many different letters can you code for using only two of your symbols to stand for each letter.
5. How many different letters could you code for using a string of three symbols for each letter?

3. WHAT IS THE CHEMICAL NATURE OF THE GENE?
DNA
Essential Questions of mid 1900’s
How do genes work?
What are they made of?
Are genes single molecules or longer structures made up of many molecules?
WHAT IS THE CHEMICAL NATURE OF THE GENE?

4. DNA 1928 Frederick Griffith - How do pneumonia make people sick?
Two strains of bacteria
smooth strain - caused disease
rough edges - no disease

5. DNA Griffith’s Experiment Thought that poison killed mice
1928 Frederick Griffith - How do pneumonia make people sick?
Two strains of bacteria
smooth strain - caused disease
rough edges - no disease
Griffith’s Experiment
Thought that poison killed mice
But heat-killed smooth bacteria didn’t kill mice
Transformation
Griffith mixed dead smooth cell bacteria
with live rough bacteria
Mice died
Somehow the rough bacteria had been transformed

6. DNA Heat-killed, disease-causing bacteria (smooth colonies)
Harmless bacteria (rough colonies)
Harmless bacteria (rough colonies)
Heat-killed, disease-causing bacteria (smooth colonies)
Control (no growth)
Disease-causing bacteria (smooth colonies)

7. DNA Heat-killed, disease-causing bacteria (smooth colonies)
Harmless bacteria (rough colonies)
Control (no growth)
Harmless bacteria (rough colonies)
Heat-killed, disease-causing bacteria (smooth colonies)
Disease-causing bacteria (smooth colonies)
Dies of pneumonia
Dies of pneumonia
Lives
Lives
Live, disease-causing bacteria (smooth colonies)

8. DNA Avery and DNA Repeated Griffith’s experiment
Thought that poison killed mice But heat-killed smooth bacteria didn’t kill mice
Transformation
Griffith mixed dead smooth cell bacteria
with live rough bacteria; Mice died
Somehow the rough bacteria had been transformed
Avery and DNA
Repeated Griffith’s experiment
Treated extract with enzymes to destroy proteins, lipids, carbohydrates, RNA
Transformation still occurred
Finally broke down DNA
No transformation occurred

9. DNA HERSHEY-CHASE EXPERIMENT 1952 Alfred Hershey & Martha Chase
Avery and DNA
Repeated Griffith’s experiment
Treated extract with enzymes to destroy proteins, lipids, carbohydrates, RNA
Transformation still occurred
Finally broke down DNA; no transformation occurred
AVERY AND OTHERS DISCOVERED THAT DNA STORES AND TRANSMITS GENETIC INFORMATION
HERSHEY-CHASE EXPERIMENT
1952 Alfred Hershey & Martha Chase
Bacteriophages (bacteria eaters)
Used radioactive markers phosphorus-32 and sulfur-35
Phosphorus only in DNA, Sulfur only in protein
Showed DNA, not protein was genetic material

10. DNA

11. DNA
Structure of DNA
•Must carry genetic information to new generations
•Must be easily copied
Polymer DNA
Monomer - nucleotide
deoxyribose (sugar)
phosphate group
nitrogenous base
adenine & guanine are purines
cytosine & thymine are pyrimidines
By early 1950’s scientists wondered how DNA, just a string of nucleotides could be the genetic code

12. DNA Structure of nucleotides Purines Pyrimidines Adenine Guanine
Cytosine
Thymine
Deoxyribose
Phosphate group

13. DNA Chargaff’s Rule Erwin Chargaff discovered
Source of DNA A T G C
Streptococcus
Yeast
Herring
Human
Erwin Chargaff discovered
•percentages of G and C are almost equal
•percentages of A and T are almost equal

14. DNA X-Ray Evidence Early 1950’s Rosalind Franklin X-ray diffraction
Chargaff’s Rule
Erwin Chargaff discovered
•percentages of G and C are almost equal
•percentages of A and T are almost equal
X-Ray Evidence
Early 1950’s Rosalind Franklin
X-ray diffraction
X-shaped pattern showed twisted
or helix shape

15. DNA BASE PAIRING - explained Chargaff’s rule A bonds to T G bonds to C
The Double Helix
Francis Crick and James Watson
Made cardboard and wire models
When they say Franklin’s X-ray pattern the light came on:
Credited with the double-helix model
Two strands wound around each other
BASE PAIRING - explained Chargaff’s rule A bonds to T
G bonds to C

16. DNA Base Pairing Key Nucleotide Adenine (A) Thymine (T) Cytosine (C)
Guanine (G)
Sugar-phosphate backbone
Nucleotide

17. DNA Base Pairing Nucleotide Key Adenine (A) Thymine (T) Cytosine (C)
Page 294
Base Pairing
Nucleotide
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Sugar-phosphate backbone

18. DNA
The Double Helix
Francis Crick and James Watson, 1953

19. DNA The Double Helix Nucleotide Hydrogen bonds Page 294
Sugar-phosphate backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

20. 12.2Chromosomes and RNA Replication
Goals
Summarize the events of DNA replication
Relate the DNA molecule to chromosome structure

21. 12.2Chromosomes and RNA Replication
DNA and Chromosomes
Prokaryotes: One circular DNA molecule

22. 12.2Chromosomes and RNA Replication
DNA and Chromosomes
Prokaryotes: One circular DNA molecule
Eukaryotes: 1,000 times as much DNA
DNA found in nucleus
Organized into chromosomes
46 in human beings
8 in drosophila
22 in redwood trees

23. 12.2Chromosomes and RNA Replication
DNA length
E. Coli
4,639,221 base pairs
1.6 millimeters
inside a 1.6µm (1/1,000 of a mm)
imagine 1m yarn inside 1mm ball

24. 12.2Chromosomes and RNA Replication
Chromosome Structure
Eukaryote DNA packed more tightly
Human chromosome > 30 million base pairs
A human cell has more than 1METER of DNA!
How does it all fit?

25. 12.2Chromosomes and RNA Replication
Chromosome Structure
A human cell has more than 1METER of DNA!
How does it all fit?
DNA and protein(histones) pack together into bead-like nucleosomes which coil into tight loops and coils chromatin
Chromatin is dispersed until cell division when chromosomes form

26. 12.2Chromosomes and RNA Replication
Chromosome Structure
A human cell has more than 1METER of DNA! How does it all fit?
DNA and protein(histones) pack together into bead-like nucleosomes which coil into tight loops and coils chromatin
Chromatin is dispersed until cell division when chromosomes form

27. 12.2Chromosomes and RNA Replication
DNA Replication
Two strands are, “complimentary”
You could construct one strand from the other (remember base-pairing)
DNA separates into two strands
Each strand is a model for a duplicate complimentary strand

28. 12.2Chromosomes and RNA Replication
DNA Replication
DNA separates into two strands
Each strand is a model for a duplicate complimentary strand
Enzymes unzip the molecule
DNA polymerase
Nucleotides are arranged on the template strand.

29. 12.2Chromosomes and RNA Replication
DNA Replication
Page 298

30. Quiz 1
15 points
3 questions
5 points for each question
You will need a piece of paper and a pen or pencil. Get those out now.
You may use your notes; please put books neatly away
This paper must have a standard heading at the top of the page, full name, date, and period
Yes, neatness does count.
Drawings must be clearly labeled

31. 1. Make a drawing or several drawings of DNA that demonstrate your understanding of its basic structure. Be sure to include and label the sugar-phosphate backbone, base pairing and double helix. Correctly show the relationship between the Adenine, Thymine, Guanine, and Cytosine
2. Make a labeled drawing and explain how DNA is replicated
3. Describe one of the experiments that demonstrated that DNA is the substance that carries genetic information.

32. 12.RNA and Protein Synthesis
Essential Questions
•How does RNA differ from DNA?
•What are the different types of RNA?
•What is transcription of RNA?
•What is the genetic code?
•Explain translation
•What is the relationship between genes and protein?
Click for a great animation

33. 12.RNA and Protein Synthesis
A part of the genetic code is copied from DNA to mRNA
RNA carries out process of making proteins

34. 12.RNA and Protein Synthesis
“The Central Dogma”
The information encoded with the DNA nucleotide sequence of a double helix is transferred to a mRNA molecule.
The mRNA molecule travels out of the nucleus and attaches to a ribosome
Using the RNA nucleotide sequence and the genetic code, the ribosome assembles a protein

35. 12.RNA and Protein Synthesis
TRANSCRIPTION
DNA stays in the nucleus
mRNA is copied from DNA and sent out into the cytoplasm
Animations:
Transcription showing full complex
Transcription – cool sounds

36. 12.RNA and Protein Synthesis
The Central Dogma (brief)
DNA is copied to mRNA
mRNA is used as blueprint to make protein

37. 12.RNA and Protein Synthesis
Structure of RNA
RNA’s sugar backbone contains ribose instead of deoxyribose
RNA is like one strand of the DNA double-helix
RNA uses uracil instead of Thymine

38. 12.RNA and Protein Synthesis
RNA’s sugar backbone contains ribose instead of deoxyribose
RNA is like one strand of the DNA double-helix
RNA uses uracil instead of Thymine
Types of RNA
PROTEIN SYNTHESIS
•Messenger RNA brings a copy of gene code from nucleus to cytoplasm
Ribosomal RNA
Transfer RNA transfers code to protein

39. 12.RNA and Protein Synthesis
•Messenger RNA brings a copy of gene code from nucleus to cytoplasm
Ribosomal RNA
Transfer RNA transfers code to protein
Transcription
•RNA polymerase separates strands
makes a transcript of one strand on mRNA
Promoters tell RNA polymerase where to start transcribing

40. tRNA tRNA - transfer Specified amino acids are attached to tRNA
each anti-codon corresponds to the amino acid specified by the genetic code
Each tRNA has an anti-codon (3 nucleotides)
Anti-codon region base pairs with mRNA trascript

41. 12.RNA and Protein Synthesis
RNA polymerase separates strands
makes a transcript of one strand on mRNA
Promoters tell RNA plymerase where to start transcribing
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA polymerase
DNA
RNA

42. 12.RNA and Protein Synthesis
RNA polymerase separates strands
makes a transcript of one strand on mRNA
Promoters tell RNA plymerase where to start transcribing
RNA Editing
Some editing takes place once RNA is transcribed
•Introns - sections of mRNA to are cut out
•Exons - spliced back together to form final mRNA

43. 12.RNA and Protein Synthesis
•Introns - sections of mRNA to are cut out
•Exons - spliced back together to form final mRNA
Genetic Code
Polymer - protein
Monomer - amino acid (there are 20 possibilities)
codon - 3 nucleotides codes for each amino acid

44. 12.RNA and Protein Synthesis
Polymer - protein
Monomer - amino acid (there are 20 possibilities)
3 nucleotides = 1 codon - codes for each amino acid
Translation
Assembly happens in ribosome
Transfer RNA anticodon matches to mRNA codon and brings attached amino acid
Polypeptide chain grows until STOP codon is reached

45. 12.RNA and Protein Synthesis
Assembly happens in ribosome
Transfer RNA anticodon matches to mRNA codon and brings attached amino acid
Polypeptide chain grows until STOP codon is reached

46. 12.RNA and Protein Synthesis
Assembly happens in ribosome
Transfer RNA anticodon matches to mRNA codon and brings attached amino acid
Polypeptide chain grows until STOP codon is reached

47. 12.RNA and Protein Synthesis
Assembly happens in ribosome
Transfer RNA anticodon matches to mRNA codon and brings attached amino acid
Polypeptide chain grows until STOP codon is reached
Roles of DNA / RNA
DNA - master plan
kept safe in nucleus
RNA - working blueprints
brought out to cytoplasm

48. 12.RNA and Protein Synthesis
DNA - master plan
kept safe in nucleus
RNA - working blueprints
brought out to cytoplasm
Genes and Proteins
Genes code proteins
Proteins are enzymes
catalyze chemical reactions
Color, antigens, blood type
Proteins are the key

49. 12.RNA and Protein Synthesis

50. 12.RNA and Protein Synthesis animations
Translation
Translation – no sound, basic

51. Four Roles •DNA - Agent DiNA Provides code to be broken
CODE Breaker Activity
Four Roles
•DNA - Agent DiNA
Provides code to be broken
•mRNA - Agent miRNA
Translates code for Agent tuRNA
•tRNA - Agent tuRNA picks up code
delivers it to
•rRNA - Agent R.B.Some
compiles information

52. Step 1 DNA - Agent DiNA •counts 3 numbers starting from left
CODE Breaker Activity
Step 1
DNA - Agent DiNA
•counts 3 numbers starting from left
•cuts 1 group
•passes it off to Agent miRNA
•only 1 group of 3 may be cut at a time

53. CODE Breaker Activity
Step 2
mRNA - Agent miRNA
• Using secret table code, Agent miRNA decodes and translates to a letter
•Relays letter information to Agent tuRNA

54. Step 3 tRNA - Agent tuRNA • Gets letter information from Agent miRNA
CODE Breaker Activity
Step 3
tRNA - Agent tuRNA
• Gets letter information from Agent miRNA
•Turns letter over to R.B.Some

55. Step 3 R.B.Some • Assembles letters After step four is completed,
CODE Breaker Activity
Step 3
R.B.Some
• Assembles letters
After step four is completed,
REPEAT
Until code is broken

56. Cells make mistakes 12.4 Mutations
1. Copy the following information about Protein X: Methionine—Phenylalanine—Tryptophan—Asparagine—Isoleucine—STOP.
2. Use Figure 12–17 on page 303 in your textbook to determine one possible sequence of RNA to code for this information. Write this code below the description of Protein X. Below this, write the DNA code that would produce this RNA sequence.
3. Now, cause a mutation in the gene sequence that you just determined by deleting the fourth base in the DNA sequence. Write this new sequence.
4. Write the new RNA sequence that would be produced. Below that, write the amino acid sequence that would result from this mutation in your gene. Call this Protein Y.
5. Did this single deletion cause much change in your protein? Explain your answer.

57. Mutate - to change Cells make mistakes
12.4 Mutations
Cells make mistakes
Mutate - to change
•Gene mutations are changes in a single gene
•Chromosomal mutations involve changes in whole chromosomes

58. change in one nucleotide •Substitution changes 1 amino acid
12.4 Mutations
Gene Mutations
Point mutations
change in one nucleotide
•Substitution changes 1 amino acid
•Frameshift mutation
insertion or deletion of one nucleotide
throws off subsequent codons
can prevent functioning of gene

59. 12.4 Mutations
Gene Mutations

60. 12.4 Mutations
Gene Mutations

61. Change in number or structure of chromosomes •deletion •duplication
12.4 Mutations
Chromosomal Mutations
Change in number or structure of chromosomes
•deletion
•duplication
•inversion
•translocation

62. 12.5 Gene Regulation
Every cell in your body, with the exception of gametes, or sex cells, contains a complete copy of your DNA. Why, then, are some cells nerve cells with dendrites and axons, while others are red blood cells that have lost their nuclei and are packed with hemoglobin? Why are cells so different in structure and function? If the characteristics of a cell depend upon the proteins that are synthesized, what does this tell you about protein synthesis? Answer the questions that follow:
1. Do you think that cells produce all the proteins for which the DNA (genes) code? Why or why not? How do the proteins made affect the type and function of cells?
2. Consider what you now know about genes and protein synthesis. What might be some ways that a cell has control over the proteins it produces?
3. What type(s) of organic compounds are most likely the ones that help to regulate protein synthesis? Justify your answer.

63. 12.5 Gene Regulation
Every cell in your body, with the exception of gametes, or sex cells, contains a complete copy of your DNA. Why, then, are some cells nerve cells with dendrites and axons, while others are red blood cells that have lost their nuclei and are packed with hemoglobin? Why are cells so different in structure and function? If the characteristics of a cell depend upon the proteins that are synthesized, what does this tell you about protein synthesis? Answer the questions that follow:
1. Do you think that cells produce all the proteins for which the DNA (genes) code? Why or why not? How do the proteins made affect the type and function of cells?
2. Consider what you now know about genes and protein synthesis. What might be some ways that a cell has control over the proteins it produces?
3. What type(s) of organic compounds are most likely the ones that help to regulate protein synthesis? Justify your answer.

64. Describe a typical gene
12.5 Gene Regulation
Goals
Describe a typical gene
Describe how the lac genes are turned on and off
Explain how most eukaryotic genes are controlled
Relate gene regulation to development

65. Not every gene is expressed in every cell
12.5 Gene Regulation
Gene Expression
Not every gene is expressed in every cell
Cells in your finger don’t produce amylase
Promoters tell RNA to start transcription
What are the regulatory sites next to the promoter ?

66. Gene Regulation: An Example the lac operon
Gene Expression
Not every gene is expressed in every cell
Cells in your finger don’t produce amylase
Promoters tell RNA to start transcription
What are the regulatory sites next to the promoter ?
Gene Regulation: An Example the lac operon
In E. coli 3 genes are turned on and off together
Operon - genes that operate together
These 3 genes help E. coli use lactose -
lac operon

67. 12.5 Gene Regulation Gene Regulation: An Example the lac operon
In E. coli 3 genes are turned on and off together
Operon - genes that operate together
These 3 genes help E. coli use lactose - lac operon
Lac operon codes for proteins that
take lactose across the cell membrane
break lactose up into galactose and glucose
The lac operon genes are turned on by the presence of lactose
Beside the 3 lac operon genes are two other regions
Promoter Operator

68. 12.5 Gene Regulation
Lac operon codes for proteins that
take lactose across the cell membrane
break lactose up into galactose and glucose
The lac operon genes are turned on by the presence of lactose
Beside the 3 lac operon genes are two other regions
Promoter Operator
When RNA polymerase gets to the promoter, it transcriptions begins
The operator blocks it by binding to a protein called the lac repressor
BUT if lactose binds to the repressor, it falls off
allowing RNA polymerase to begin transcription

69. 12.5 Gene Regulation Eukaryotic Gene Regulation Operons are not used
When RNA polymerase gets to the promoter, it transcriptions begins
The operator blocks it by binding to a protein called the lac repressor
BUT if lactose binds to the repressor, it falls off
allowing RNA polymerase to begin transcription
Eukaryotic Gene Regulation
Operons are not used
Genes are controlled individually
Regulatory sequences more complex than lac
TATATA or TATAAA region
“TATA Box” helps position RNA polymerase
Found just before eukaryotic promoters

70. 12.5 Gene Regulation Many, “enhancer,” sequences found in eukaryotes
Eukaryotic Gene Regulation
Operons are not used
Genes are controlled individually
Regulatory sequences more complex than lac
TATATA or TATAAA region
“TATA Box” helps position RNA polymerase
Found just before eukaryotic promoters
Many, “enhancer,” sequences found in eukaryotes
•unwind tightly twisted chromatin
•attract RNA polymerase
•block access (like prokaryote repressor proteins)

71. 12.5 Gene Regulation Many, “enhancer,” sequences found in eukaryotes
•unwind tightly twisted chromatin
•attract RNA polymerase
•block access (like prokaryote repressor proteins)
Regulatory sites
Promoter (RNA polymerase binding site)
DNA strand
Start transcription
Stop transcription

72. 12.5 Gene Regulation WHY IS THE SYSTEM SO COMPLEX IN EUKARYOTES
Many, “enhancer,” sequences found in eukaryotes
•unwind tightly twisted chromatin
•attract RNA polymerase
•block access (like prokaryote repressor proteins)
WHY IS THE SYSTEM SO COMPLEX IN EUKARYOTES
•Complex multicellular organisms
•All cells carry the code
•Each cell uses only a tiny fraction of the code

73. 12.5 Gene Regulation Regulation and Development
WHY IS THE SYSTEM SO COMPLEX IN EUKARYOTES
•Complex multicellular organisms
•All cells carry the code
•Each cell uses only a tiny fraction of the code
Regulation and Development
“hox genes” control embryo development
Which cells develop into what
Master control genes
Fruit fly legs growing in the place of antennae
Copy of mouse eye growth gene inserted into drosophila leg caused fruit fly to grow an eye on its knee! Onward to Genetic Engineering next week