1. DNA & RNA
THE GENETIC MATERIAL

3. Vocabulary you should know…
DNA: (deoxyribonucleic acid) the material that contains the information that determines inherited characteristics
Nucleotide: in a nucleic-acid chain, a sub-unit that consists of a sugar, a phosphate, & a nitrogenous base

4. More Vocab…
Nitrogenous base: an organic base that contains nitrogen, such as a purine or pyrimidine; a sub-unit of a nucleotide in DNA or RNA
Purine: a nitrogenous base that has a double- ring structure; one of two general categories of nitrogenous bases found in DNA & RNA; either adenine or guanine

5. More Vocab…
Pyrimidine:a nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA& RNA; thymine, cytosine or uracil
Base-Pairing Rules: the rules stating that cytosine pairs w/ guanine & adenine pairs w/ thymine in DNA & adenine pairs w/ uracil in RNA

6. More Vocab…
Complementary Base Pair: the nucleotide bases in one strand of DNA or RNA that are paired w/ those of another strand; adenine pairs w/ thymine or uracil, and guanine pairs with cytosine
Base Sequence: the order of nitrogenous bases on a chain of DNA
Double Helix: shape of a DNA molecule formed when two twisted DNA strands are coiled into a springlike structure & held together by hydrogen bonds b/t the bases

7. DNA – deoxyribonucleic acid
The genetic information for an organism
DNA contains the instructions that cells need to make every protein required for essential life functions
Found mostly in the nucleus of cells
Composed of 100’s of 1000’s of repeating units of nucleotides

8. DNA
Photographed through x-ray crystallography by Rosalind Franklin in the 1950s (w/ help from Maurice Wilkins)
1st model was created by James Watson & Francis Crick in the ‘50s, with the use of Franklins x-ray crystallography picture

9. Rosalind Franklin

10. Maurice Wilkins

11. James Watson & Francis Crick

12. DNA Made of subunits called nucleotides: 1 phosphate group
1 deoxyribose – simple sugar **this is what DNA is named for
1 of 4 nitrogen bases
Either purines or pyrimidines

13. NITROGEN BASES Purines: double ringed structure Adenine (A)
Guanine (G)

14. Nitrogenous Bases Pyrimidines: single ringed structure Thymine (T)
Cytosine (C)

15. STRUCTURE OF DNA Shape: double helix – repeating units of nucleotides
**the sequence of nucleotides determines gene function

16. DOUBLE HELIX 2 chains of nucleotide monomers running anti - parallel
Phosphate groups make up the backbone of the double helix
Covalent bonds hold the nucleotides together by connecting the deoxyribose of one nucleotide to the phosphate group of the adjacent nucleotide

17. Double Helix Cont’d
The nitrogen bases of the nucleotides pair up to link the 2 helixes
hydrogen bonds b/t the nitrogen bases hold the strands of the double helix together

18. Double Helix Structure

19. Base-Pairing Rules Adenine (A) & Thymine (T) are always together
Cytosine (C)
& Guanine (G)
must then pair together

20. DNA Basics Quiz What is DNA?
The first person to photograph DNA was ____________.
The first people to make a model of DNA were ________ & ______.
A strand of DNA is made up of repeating units of __________.

21. DNA Basics Quiz Cont’d
A nucleotide is composed of 3 parts, name all three.
List the 4 different nitrogenous bases.
Which part of the nucleotide makes up the backbone of the strand of DNA?

22. DNA Basics Quiz Cont’d
What type of bonds hold the deoxyribose of one nucleotide to the phospate of the adjacent one?
What type of bonds hold the complementary nitrogenous bases together?
Out of Adenine, Guanine, Cytosine & Thymine, tell me the two complementary pairs.

23. DNA Technology DNA is manipulated for many different reasons:
Crime scene analysis
Genetic counseling
Research
Treatment of disease

24. DNA Technology DNA ID Only identical twins have identical DNA
Only 10% of the human genome varies between all humans
The 10% that differs falls on the same chromosome region so we can isolate this DNA and use it to make important discoveries

25. Identifying DNA Step 1: Copying DNA: Polymerase Chain Reaction
Method of quickly copying DNA from small samples
Step 2: Cutting DNA: Restriction Enzymes
Restriction enzymes recognize specific short DNA sequences & cut in or near them
This isolates the DNA needed for ID

26. Identifying DNA cont’d
Step 3: Sorting DNA by Size: Gel Electrophoresis
Gel electrophoresis separates DNA according to size and charge
Does this by running an electrical current through gel that the DNA cut by the restriction enzymes has been placed in, + & - charged pieces move to opposite ends
The resulting pattern is called the DNA fingerprint

27. Identifying DNA Step 4: Comparing DNA: DNA Fingerprints Accuracy??
Compare the DNA sample to other DNA fingerprints until you find a match, or pattern that you are looking for
Accuracy??
The odds that 2 people will share the same DNA fingerprint: 1: 100 billion
# of people on Earth: approx 7 billion

28. Gel Electrophoresis

29. Recombinant DNA
Genetic engineering: the process of altering the genetic material of cells or organisms to allow them to make new substances
DNA recombination/Recombinant DNA:
Joining together DNA from two different organisms

30. DNA Recombination Step 1: isolate the DNA and the plasmid of interest
Plasmids: small rings of DNA found naturally in some bacterial cells in addition to the main bacterial chromosome
Step 2: restriction enzymes cut the DNA into fragments
Step 3: fragments and plasmid DNA are joined together permanently by DNA ligase

31. DNA Recombination Cont’d
Step 4: recombinant DNA plasmids, each with different fragments of DNA, are inserted into bacterial cells
These recombinant DNA plasmids are then copied each time the bacterial cell copies its own DNA
Step 5: once a colony of bacterial cells containing the recombinant DNA plasmids is created, the recombinant DNA is removed to be used

32. Recombinant DNA

33. Central Dogma of Molecular Genetics
How we go from DNA to RNA
1. replication (DNA copies itself)
2. transcription (DNA acts as a template for the production of messenger RNA (mRNA))
3. translation (mRNA carries coded information to ribosomes; ribosomes "read" this information and use it to make proteins)

34. The Central Dogma Cont’d

35. Dogma Cont’d

36. Replication: Vocab you should know…
DNA replication: process by which DNA is copied in a cell before a cell divides by mitosis, meiosis or binary fission
Helicase: enzymes that separate DNA strands by breaking the hydrogen bonds that hold the nitrogenous bases together

37. Replication: More vocab…
Replication Fork: a Y shaped point that results when the two strands of DNA double helix separate so that the DNA molecule can be replicated
DNA Polymerase: an enzyme that catalyzes the formation of the DNA molecule

38. Replication: More Vocab…
Semi-conservative Replicaiton: in each new DNA double helix, one strand is from the original molecule & one strand is new
Mutation: a change in the nucleotide-base sequence of a gene or DNA molecule

39. Facts about Replication
Occurs during interphase of both the cell cycle for mitosis and for meiosis
Happens to all of the DNA in the cell, not just selected parts (every chromosome)

40. Replication (of DNA) Strands of DNA separate
Helicase enzymes move along the strand of DNA
They break the hydrogen bonds between the nitrogen bases
The two strands separate, exposing a a Y-shaped region called the replication fork

41. Replication: Helicase & the Replication Fork

42. Replication Cont’d
DNA polymerase enzymes add complementary nucleotides to the two separated strands
The nucleotides are found free-floating around inside the nucleus
As the nucleotides are added, covalent bonds form b/t the deoxyribose of one and the phosphate of the next

43. Replication: Adding Nucleotides Cont’d
Hydrogen bonds are formed b/t the nitrogenous bases from the original strand and the nitrogenous bases on the newly added nucleotides

44. Replication: Adding Nucleotides Cont’d
DNA synthesis (creation) occurs in different directions on each strand
As the replication fork moves along the original DNA, synthesis of one strand, the leading strand, follows the movement of the replication fork
Synthesis of the other strand, the lagging strand, moves in the opposite direction, away from the replication fork

45. Replication: Adding Nucleotide Cont’d
Adding Nucleotides Cont’d
Because the nucleotides are added to the leading and lagging strands in opposite directions, it leaves gaps in the newly synthesized DNA, called Okazaki Gaps
These gaps are later joined together by the enzyme DNA ligase

46. Replication: Leading & Lagging Strands

47. Replication Okazaki Fragments

48. Replication Cont’d
DNA polymerase enzymes finish replicating the DNA & fall off
The result of replication of a strand of DNA is two completely identical strands of DNA, each containing one old strand & one new stand = semiconservative replication

49. Semi-Conservative Replication

50. Replication cont’d
DNA replication flash interactive

51. DNA Replication Quiz
What are the three parts of the Central Dogma of molecular genetics?
What is the first thing that must happen in order for DNA to replicate itself?
What is the name of the enzyme that separates the two strands of DNA?

52. Replication Quiz Cont’d
Helicase breaks the ________ bonds that hold the nitrogenous bases together.
The Y-shaped region that appears as the two strands separate is called the ________ _______.
After the strands separate, what is the second thing that happens as DNA replicates itself?

53. Replication Quiz Cont’d
What is the name of the enzyme that adds the free-floating nucleotides to the two exposed strands of DNA?
The gaps created as the new DNA strands are being synthesized are called _________ __________.

54. Replication Quiz Cont’d
What happens to the DNA polymerase after is finished being replicated?
Replication results in _____ (#) strands of DNA, each having one ____ strand and one _______ strand.

55. RNA: Vocabulary You Should Know
Ribonucleic Acid (RNA): a natural polymer that is present in all living cells & that plays a role in protein synthesis
Transcription: the process of forming a nucleic acid by using another molecule as a template; particularly the process of synthesizing RNA by using one strand of a DNA molecule as a template
Translation: the portion of protein synthesis that takes place at ribosomes & that uses the codons in mRNA molecules to specify the sequence of amino acids in ploypeptide chains

56. RNA: move vocab…
Protein Synthesis: the formation of proteins by using infomration contained in DNA & carried by mRNA
Ribose: a five-carbon sugar present in RNA
Messenger RNA (mRNA): a single-stranded RNA molecule that encodes the information to make a protein

57. RNA: more vocab…
Ribosomal RNA (rRNA): an organelle that contains most of the RNA in the cell & that is responsible for ribosome function
Transfer RNA (tRNA): an RNA molecule that transfers amino acids to the growing end of a polypeptide chain during translation
RNA Polymerase: an enzyme that starts (catalyzes) the formation of RNA by using a strand of DNA molecule as a template

58. RNA: More vocab…
Promoter: a nucleotide sequence on a DNA molecule to which an RNA polymerase molecule binds, which initiates the transcription of a specific gene
Termination Signal: a specific sequence of nucleotides that marks the end of a gene
Genetic Code: the rule that describes how a sequence of nucleotides, read in groups of three consecutive nucleotides (triplets) that correspond to specific amino acids, specifies the amino acid sequence of a protein

59. RNA: More Vocab…
Codon: in DNA, a three-nucleotide sequence that encodes an amino acid or signifies a start signal or a stop signal
Anticodon: a region of tRNA that consists of three bases complementary to the codon of mRNA
Genome: the complete genetic material contained in an individual

60. RNA – Ribonucleic Acid

61. RNA: Structure & Comparison to DNA
Double stranded
Sugar = deoxyribose
Bases:
Adenine
Cytosine
Guanine
Thymine
Usually much longer: 100s or 1000s of genes
RNA
Single stranded
Sugar = ribose
Nitrogenous bases:
Adenine
Cytosine
Guanine
Uracil
Usually much shorter

62. RNA v. DNA

63. RNA: Types of mRNA: messenger RNA Single stranded
carries instruction from a gene to make a protein
Eukaryotic cells: carries messages from DNA in the nucleus to a ribosome in the cell’s cytoplasm

64. mRNA

65. RNA: Types of …
tRNA: transfer RNA
transports amino acids to the ribosomes (rRNA) to be assembled into proteins
Made of many nucleotides linked together

66. tRNA

67. RNA: Types of … rRNA: ribosomal RNA
This type of RNA makes up a part of ribosomes
Ribosomes are organelles in each cell where protein synthesis occures
clamp onto the mRNA & use its info to assemble amino acids in the correct order to make proteins

68. rRNA

69. COMPOSITION OF RNA
Made of nucleotides:
1 phosphate group
1 ribose – type of sugar
1 of 4 nitrogen bases

70. RNA’s NITROGEN BASES
Purines:
Adenine (A)
Guanine (G)
Pyrimidines:
Cytosine (C)
Uracil (U) ***instead of Thymine

71. RNA Base-Pairing Rules
Adenine pairs w/ Uracil (because there is no thymine)
Cytosine pairs w/ Guanine

72. RNA Base- Pairing

73. RNA Quiz Protein synthesis results in the creation of ________.
RNA has _______ strands.
RNA has the sugar _________.
Name the 4 bases for RNA.
RNA is usually ______ than DNA.
Name the 3 types of RNA.
What does mRNA do?

74. RNA Quiz Cont’d What does tRNA do? rRNA is found on what cell part?
What are the base-pairing rules for RNA?

75. Transcription The rewriting of genetic instructions from DNA into RNA
“transcribes” DNA into genes
Takes place in the nucleus of eukaryotic cells
Takes place in the cytoplasm of prokaryotic cells

76. Transcription Steps Unwinding & separating the DNA strands
The enzyme RNA polymerase binds to a promoter (a specific codon that starts transcription) on the DNA molecule
DNA unwinds & separates

77. Transcription Steps: Unwinding & Separating DNA

78. Transcription Steps Adding RNA nucleotides to create a strand of RNA
RNA polymerase adds free-floating RNA nucleotides to one of the exposed DNA strands
The nucleotides that are added are complementary to one of the DNA strands
Only a specific section of the DNA strand is used to create the strand of RNA

79. Adding RNA Nucleotides

80. Transcription Steps Release of the RNA molecule
RNA polymerase reaches a termination signal that tells it to stop
RNA polymerase releases both the DNA & the newly formed RNA molecule
RNA created is mRNA
The RNA molecule is free to perform its “job”
RNA polymerase is available to transcribe more genes

81. Releasing both DNA & RNA

82. Transcription Quiz Transcription rewrites what?
Where does transcription take place in eukaryotic cells?
What is the 1st step in transcription?
What is the enzyme that unwinds & separates DNA?

83. Transcription Quiz Cont’d
What is the second step of transcription?
What are added to the exposed strand of DNA?
What tells RNA polymerase when to stop adding nucleotides?
The newly formed RNA is __RNA.

84. Transcription Quiz Cont’d
When RNA polymerase reaches the terminal signal it releases both _______ & _______.
What does RNA polymerase do after it releases the DNA & newly formed RNA molecule?

85. Protein Synthesis
Gene: segment of DNA , located on a chromosome that codes for a hereditary characteristic (like hair color)
Genes direct the synthesis or making of proteins for that particular trait
Genes use RNA to help make the appropriate proteins

86. Protein Synthesis Genetic information flows in the following order:
Transcription
Translation / Protein synthesis
DNA → RNA → protein
Proteins are important b/c they create & do everything that our body is & does

87. The Genetic Code
The code needed to convert the language of mRNA into proteins
Proteins are made of amino acids
Amino acids are made based on the nucleotide sequence in mRNA
3 adjacent nucleotides in mRNA specify a particular amino acid
The 3 nucleotide sequence that encodes an amino acid, a start signal or a stop signal = a codon

88. Codons Codons can only code for one amino acid
i.e.: UUA = Leucine and only leucine
Each amino acid can be coded for by more than one codon
the amino acid leucine can be coded for by all of the following codons
i.e.: UUA = Leucine, UUG = Leucine
CUU = Leucine, CUC = Leucine
CUA = Leucine, CUG = Leucine

89. Codons Cont’d
Start codons: sequence of nucleotides in mRNA that signals where translation should begin
Codes for the amino acid methionine
Stop codons: sequence of nucleotides in mRNA that signals where translation should stop
Does not code for any amino acid

90. Codons in mRNA

91. Proteins Made of polypeptides
Polypeptides are chains of amino acids linked by peptide bonds
20 different amino acids
Polypeptide chains are 100s of 1000s of amino acids long
The sequence of amino acids determine how the protein will fold & twist into a 3d shape, the shape gives the protein its function

92. Proteins

93. Translation Is the synthesis or making of a protein
The instructions for making a protein are transcripted from DNA into mRNA
All three types of RNA are involved in translation

94. Translation Steps Joining RNAs rRNAs & tRNAs attach to a mRNA
Enzymes attach an amino acid to one end of each tRNA
The other end of the tRNA contains the anticodon for mRNA
A tRNA carrying the amino acid methionine must be present to start the reading of mRNA & attaches to a start codon on mRNA

95. T-RNA

96. Translation

97. Translation Steps Cont’d
Creation of a polypeptide chain
tRNAs carrying correct amino acids, pair their anticodons w/ the codons on the mRNA strand
Methionine detaches from the 1st tRNA after the 2nd anticodon is added
A peptide bond forms b/t methionine & the 2nd amino acid to start a polypeptide chain
The 1st tRNA exits the ribosome
Ribosome moves one codon down on the mRNA strand

98. Translation

99. Translation Step Cont’d
Polypeptide Chains Grow
mRNA continues to move through the ribosome
New tRNAs w/ correct anticodons move in & peptide bonds are created b/t the amino acids of each tRNA
The polypeptide chain moves from one tRNA to the next tRNA & attaches to its amino acid

100. Translation

101. Translation Steps Stop Codon
Polypeptide grows one amino acid at a time until it reaches a stop codon
Polypeptide falls off

102. Translation

103. Translation Steps Cont’d
End of Translation
All the parts that are needed for translation come apart
The last tRNA exits the ribosome
The ribosome moves away from the mRNA
All the parts are free to be used over & over again

104. Translation

105. Translation Quiz
Proteins are made of ____ ____, which are made of 3 RNA ______.
Polypeptides are chains of amino acids linked by _____ ____.
Translation is the synthesis of ________.
List the types of RNA involved in protein synthesis.

106. Translation Quiz Cont’d
The first tRNA to be used during translation must carry the amino acid ________.
A polypeptide chain is started when methionine is bonded to the __________.
For the polypeptide chain to grow the mRNA must ____________.

107. Translation Quiz Cont’d
The polypeptide chain stops growing when it reaches the ______ ________.
When the polypeptide chain reaches the stop codon what happens to the chain?
Once the polypeptide chain falls off, what happens to all the parts that assembled to translate RNA?