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Biology 30 Nucleic Acids DNA RNA.

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1 Biology 30 Nucleic Acids DNA RNA

2 Students will explain classical genetics at the molecular level
Summarize the historical discovery of the DNA molecular structure by Franklin, Watson and Crick Describe how genetic information is contained in the sequence of bases in DNA Describe DNA replication

3 Some History 1928 Frederick Griffith (British)
Studied Streptococcus Pneumoniae pneumonia bacteria two genetic strains Colonies appeared smooth (S type) Surrounded by a mucous coat or capsule Colonies that appeared rough (R type)

4 R Bacteria

5 R Bacteria S Bacteria

6 R Bacteria S Bacteria Dead R Bacteria

7 R Bacteria S Bacteria Dead R Bacteria

8 R Bacteria S Bacteria Dead R Bacteria Dead S Bacteria

9 R Bacteria S Bacteria Dead R Bacteria Dead S Bacteria

10 R Bacteria S Bacteria Dead R Bacteria Dead S Bacteria Dead S & Live R

11 R Bacteria S Bacteria Dead R Bacteria Dead S Bacteria Dead S & Live R

12 Dead R Bacteria Dead S Bacteria Dead S & Live R
Capsule of S and live R

13 Dead R Bacteria Dead S Bacteria Dead S & Live R
Capsule of S and live R

14 Dead R Bacteria Dead S Bacteria Dead S & Live R
Capsule of S and live R DNA of S and live R

15 Dead R Bacteria Dead S Bacteria Dead S & Live R
Capsule of S and live R DNA of S and live R

16 He used two strains of Streptococcus pneumoniae:
In 1928, Frederick Griffith performed an experiment using pneumonia bacteria and mice. This was one of the first experiments that hinted that DNA was the genetic code material. He used two strains of Streptococcus pneumoniae: a “smooth” strain which has a polysaccharide coating around it that makes it look smooth when viewed with a microscope, a “rough” strain which doesn’t have the coating, thus looks rough under the microscope. When he injected live S strain into mice, the mice contracted pneumonia and died. When he injected live R strain, a strain which typically does not cause illness, into mice, as predicted they did not get sick, but lived.

17 Thinking that perhaps the polysaccharide coating on the bacteria somehow caused the illness and knowing that polysaccharides are not affected by heat, Griffith then used heat to kill some of the S strain bacteria and injected those dead bacteria into mice. This failed to infect/kill the mice, indicating that the polysaccharide coating was not what caused the disease, but rather, something within the living cell. Since Griffith had used heat to kill the bacteria and heat denatures protein, he next hypothesized that perhaps some protein within the living cells, that was denatured by the heat, caused the disease.

18 This evidence pointed to DNA as being the genetic material.
He then injected another group of mice with a mixture of heat-killed S and live R, and the mice died! When he did a necropsy on the dead mice, he isolated live S strain bacteria from the corpses. Griffith concluded that the live R strain bacteria must have absorbed genetic material from the dead S strain bacteria, and since heat denatures protein, the protein in the bacterial chromosomes was not the genetic material. This evidence pointed to DNA as being the genetic material.

19 Controls cellular activities of an organism by
Functions of DNA Controls cellular activities of an organism by Coding for structural proteins Coding for enzymes

20 Nucleic Acids DNA Deoxyribonucleic Acid Genetic material
Can self-replicate Made up of Nucleotides Shape = double helix A twisted rope ladder A full twist every 10 nucleotides

21 DNA Discovery Rosalind Franklin was using X-Ray Diffraction to study DNA Her work allowed Watson and Crick to come up with model of DNA Findings presented in 1953 Visually confirmed in 1969

22 Chromosome Section of Chromosome Section of DNA Double Helix

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24 Nucleotides Nucleotides are composed of A sugar A phosphate
five carbons Deoxyribose A phosphate PO4- One of 4 nitrogen bases Adenine [A] Thymine [T] Cytosine [C] Guanine [G] The sugar-phosphate groups are the side rails of ladder and the the nitrogen bases are the rungs

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26 Nucleotides The two strands of DNA are complimentary because the nitrogen bases bond with each other according to some rules. Adenine will only bond with Thymine Guanine will only bond with Cytosine Nitrogen bases bond via hydrogen bonds. These break over 70oC (denature)

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30 DNA REPLICATION DNA must have the ability to create an exact duplicate of itself The sequence in one strand determines precisely what the sequence of nucleotides in the other strand will be. (A-T, G-C)

31 DNA REPLICATION The hydrogen bonds holding the two complimentary strands together break DNA strands separate Free floating complimentary nucleotides match up with nucleotides on the parent DNA strand. Catalyzed by DNA polymerase New, semi-conservative strands are formed

32 DNA REPLICATION Semi-conservative
The daughter strands are made up of one half old strand on one half new strand The DNA unzips due to the hydrogen bonds between the bases being broken (DNA Helicase) These exposed bases attract free floating bases, which are attached to the chain by DNA polymerase.

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39 Students will explain classical genetics at the molecular level
Describe RNA transcription Describe how genetic information is translated into amino acid chains in proteins Explain how mutations result in abnormalities or create genetic variability Explain how base sequences in nucleic acids give evidence for evolution

40 DNA vs RNA DNA RNA

41 DNA vs RNA DNA Double stranded RNA

42 DNA vs RNA DNA Double stranded RNA Single stranded

43 DNA vs RNA DNA Double stranded Deoxyribose sugar RNA Single stranded

44 DNA vs RNA DNA Double stranded Deoxyribose sugar RNA Single stranded

45 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine RNA Single stranded Ribose sugar

46 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine RNA Single stranded Ribose sugar

47 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine RNA Single stranded Ribose sugar

48 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine Thymine RNA Single stranded Ribose sugar

49 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine Thymine RNA Single stranded Ribose sugar Nitrogen bases Cytosine

50 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine Thymine RNA Single stranded Ribose sugar Nitrogen bases Cytosine Guanine

51 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine Thymine RNA Single stranded Ribose sugar Nitrogen bases Cytosine Guanine Adenine

52 DNA vs RNA DNA Double stranded Deoxyribose sugar Nitrogen bases RNA
Cytosine Guanine Adenine Thymine RNA Single stranded Ribose sugar Nitrogen bases Cytosine Guanine Adenine Uracil [U]

53 DNA vs RNA DNA One type of DNA RNA

54 DNA vs RNA DNA One type of DNA RNA Many types of RNA

55 DNA vs RNA DNA One type of DNA RNA Many types of RNA
Messenger RNA (mRNA)

56 DNA vs RNA DNA One type of DNA RNA Many types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA)

57 DNA vs RNA DNA One type of DNA RNA Many types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)

58 DNA vs RNA DNA One type of DNA RNA Many types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Small nuclear RNA (smRNA)

59 DNA vs RNA DNA One type of DNA Mostly in nucleus RNA Many types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Small nuclear RNA (smRNA)

60 DNA vs RNA DNA One type of DNA Mostly in nucleus RNA Many types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Small nuclear RNA (smRNA) Mostly found in cytoplasm

61 DNA vs RNA DNA One type of DNA Mostly in nucleus
Can self-replicate under the right conditions RNA Many types of RNA Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Small nuclear RNA (smRNA) Mostly found in cytoplasm

62 DNA vs RNA DNA One type of DNA Mostly in nucleus
Can self-replicate under the right conditions RNA Many types of RNA Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA) Small nuclear RNA (smRNA) Mostly found in cytoplasm Cannot self-replicate

63 A gene is a segment of DNA
Genes and Proteins A gene is a segment of DNA Carries the information of the synthesis of a protein One gene codes for one protein

64 Proteins in the Body Enzymes Hormones Antibodies Hemoglobin
Cell membranes Receptor molecules Carrier molecules

65 Composition of Proteins
Made up of 20 different amino acids Sequence of a.a.’s identifies protein Sequence of bases in DNA determines Sequence of a.a.’s One gene = one protein Protein Synthesis relies on 3 types of RNA rRNA mRNA tRNA

66 Types of RNA Ribosomal RNA (rRNA) Messenger RNA (mRNA)
Makes up the ribosomes Messenger RNA (mRNA) Involved in transcription (first stage of protein synthesis) Carries message from DNA in nucleus to ribosome in cytoplasm Transfer RNA (tRNA) carries amino acids to mRNA tRNA & rRNA - In cytoplasm only mRNA in cytoplasm & nucleus All RNA produced in nucleolus.

67 1. Transcription 2. Translation
Protein Synthesis Occurs primarily in ribosomes Instructions for protein contained in DNA Message must get from nucleus to cytoplasm (DNA to ribosome) Process occurs in 2 steps watch animations – click on the words below 1. Transcription Translation

68 Protein Synthesis Summary
mRNA is made using DNA template mRNA exits nucleus tRNA picks up aa’s tRNA anticodon bonds to mRNA codon Peptide bond forms between aa’s Protein used by cell or packaged & exported mRNA breaks into free nucleotides tRNA’s free to pick up more aa’s Transcription Translation

69 Transcription mRNA made using DNA as a template
In nucleus mRNA made using DNA as a template If the DNA base sequence is A A T T C C G G A (3 triplets) The mRNA molecule manufactured would be U U A A G G C C U (3 triplets) Each triplet is a codon

70 Code must be transcribed then translated

71 Transcription DNA used as template to build mRNA

72 mRNA built using DNA as a template

73 Initiation Elongation Termination

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75 Codons Code for amino acids May code for start (initiator codon)
May code for stop (terminator codon) AUG is an initiator codon but also codes for the amino acid methioine If code AUG is in middle it must code for methionine

76 Data table of mRNA codons
supplied in diploma!! Can be used to work out DNA, tRNA or amino acid sequence

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78 Translation mRNA arrives at ribosome
tRNA molecules with a.a.’s are attracted to this mRNA complimentary rule (A attracts U etc….) 20 a.a.’s therefore 20 different tRNA’s

79 Translation mRNA U U A A G G C C U 3 codons

80 Translation mRNA U U A A G G C C U tRNA A A U U C C G G A 3 anticodons

81 Transfer RNA

82 Translation Initiation

83 Identify codons and anticodons

84 Identify peptide bonds, ribosome & protein

85 Translation 1

86 Translation 2

87 Translation 3

88 Translation 4

89 Translation 5 Name the products!

90 Requires many Ribosomes
Translation Requires many Ribosomes

91 The golgi apparatus will package the protein to be used for different functions throughout the body.

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93 Review Questions mRNA codon for AAT DNA triplet =
DNA triplet for CCG mRNA codon = tRNA anticodon for GCA DNA triplet = mRNA codon for GAU tRNA = tRNA anticodon for UUA mRNA codon = DNA triplet for CUA anticodon = codon for UAG anticodon = anticodon for CTA DNA triplet =

94 Answers to Review Questions
mRNA codon for AAT DNA triplet = UUA DNA triplet for CCG mRNA codon = GGC tRNA anticodon for GCA DNA triplet = GCA mRNA codon for GAU tRNA = CUA tRNA anticodon for UUA mRNA codon = AAU DNA triplet for CUA anticodon = CTA codon for UAG anticodon = AUC anticodon for CTA DNA triplet = CUA

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96 Mutations Changes in the sequence of bases in DNA
Caused by mutagenic substances like X-rays cosmic rays UV light Some chemicals Mutagens can affect a single point in the DNA or it can affect large sections. Result = the proteins that the DNA codes for will be altered.

97 Mutations 3 types of mutations. INSERTION DELETION SUBSTITUTION
An extra nucleotide is inserted into the DNA Causes a frame shift DELETION A nucleotide is deleted from the DNA SUBSTITUTION One nucleotide is substituted for another

98 Insertion

99 Deletion

100 Normal DNA Sequence Correct Amino Acid

101 SUBSTITUTION

102 Using DNA to explain Evolution
Species that are closely related will share very similar DNA sequences Scientists use mitochondrial DNA (mtDNA) to study the relationship between species Used to explain variety of ethnic groups found throughout the world (all from African descendents)

103 Using SINEs and LINEs SINEs and LINEs are repeated DNA sequences that don’t code for anything, but show an evolutionary relationship Finding a SINE or LINE in two species and not in other species, signifies that the first two species must be more closely related to each other than to the other species

104 Students will explain classical genetics at the molecular level
Explain DNA transformation (recombinant DNA) Describe the role of restriction enzymes and ligases in transformation

105 Genetic Engineering A desired gene can be isolated and millions of copies made These copies can then be analyzed to determine the gene’s nucleotide sequence This nucleotide sequence can be decoded to find the sequence of amino acids in the corresponding protein

106 Genetic Engineering Functioning genes can be transferred into cells or bacteria, yeasts, plants, animals i.e – Griffith DNA can be “made to order” using “gene machines” that can be programmed to produce short strands of DNA in any desired sequence Useful for studying DNA, protein synthesis experiments Change genetic code to eliminate particular amino acids from a protein Find how the amino acid affects the protein’s function

107 Transformation Transformation is the process whereby one strain of a bacterium absorbs genetic material from another strain of bacteria and “turns into” the type of bacterium whose genetic material it absorbed. Because DNA was so poorly understood, scientists remained skeptical up through the 1940s.

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110 Genetic Engineering Recombinant DNA
To recombine DNA A technique to determine gene expression Gene segments from different sources are recombined in vitro and transferred into cells (usually E. coli) to see what happens.

111 Genetic Engineering Recombinant DNA
First successful GE experiment with human DNA took place in 1980 Human gene which codes for the protein interferon was successfully introduced into a bacteria cell… The bacteria produced human protein. Interferon combats viral infections and may help in fighting cancer

112 Genetic Engineering Recombinant DNA
Genetic Engineering Recombinant DNA – How It Works Genetic Engineering Recombinant DNA The desired gene is isolated and cut out of the DNA A “restriction enzyme” (restriction endonuclease) does this Isolated gene is inserted into a bacterial plasmid using a ligase Ligase is an enzyme which normally repairs breaks in the DNA backbone New DNA now called recombinant DNA

113 Genetic Engineering Recombinant DNA
The plasmid is absorbed by a bacterium Reproduces asexually to produce many clones containing the recombinant DNA Bacterial cells produce the protein coded by the foreign gene Desired protein can be isolated and purified from the culture.

114 Genetic Engineering Recombinant DNA
Examples of recombinant DNA technology… Interferon Human growth hormone Human insulin Gene Therapy Agriculture…

115 Restriction Enzymes cut Ligase acts as glue rDNA

116 Recombinant DNA Technology
Restriction Enzyme Sticky end

117 Gene insertion

118 Genetic Engineering Recombinant DNA
Gene Therapy Replacement of defective genes with normal healthy genes e.g. Cystic fibrosis, hemophilia, sickle-cell anemia, immune-deficiencies OBSTACLES today include … How to fit genes into the body cells How to control the introduced genes

119 Genetic Engineering Recombinant DNA
Agriculture Introduction of genes for resistance to disease, drought, frost, increased protein production, larger fruit…

120 Genetic Engineering DNA Fingerprinting
Used in forensic studies… Small quantities of blood, semen, or other tissue can be tested for the DNA base sequence The DNA nucleotide sequence is unique for every individual (except identical twins) A technology called RFLP auto-radiography is used to display selected DNA fragments as bands

121 Genetic Engineering DNA Fingerprinting
Radioactive probes mark the bands that contain certain markers… Only 5 or 10 regions of the entire genetic content of the cell are tested This was a defense argument used by the O.J. Simpson lawyers The probability of having matching DNA fingerprints is about 1 in a million.


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