1. Nucleic acids Nucleic acids: Maintain genetic information
Determine Protein Synthesis
DNA = deoxyribonucleic acid
“Master Copy” for most cell information.
Template for RNA
RNA = ribonucleic acid
Transfers information from DNA
Template for Proteins

2. external & internal characteristics
Nucleic Acids
Chromosomes
(in nucleus)
Have genes
1 gene
1 enzyme or protein
Enzymes determine
external & internal characteristics

3. NUCLEIC ACIDS Long chains (polymers) of repeating nucleotides.
Each nucleotide has 3 parts:
A heterocyclic
Amine Base
A sugar
A phosphate unit

4. Nucleotide = phosphate + sugar + base
-N-glycosidic
linkage
Nucleoside = sugar + base

5. Nucleic Acids Nucleic Acids = polymers of Nucleotides. B B B B B B P S
base B B B B B B P S P S P S P S P S P S
phosphate
sugar

6. THE SUGAR PART
The major difference between RNA and DNA is the different form of sugar used.
Ribose C5H10O5
in RNA
DeoxyRibose C5H10O4
in DNA O
HOCH2 H OH O
HOCH2 H OH
The difference is at carbon #2.

7. 5 bases used fall in two classes
The Nitrogenous Bases
5 bases used fall in two classes
Purines & Pyrimidines
A double ring
(6 & 5 members)
A single ring
(6 membered)

8. The Nitrogenous Bases Purines: Pyrimidines: Adenine (A) Guanine (G)
Thiamine (T)
In DNA only
Uracil (U)
In RNA only
Cytosine (C)

9. Nucleotides Di- & Tri- Phosphates
Adenine
ribose
Adenosine 5’-monophosphate
(AMP)

10. Nucleotides Di- & Tri- Phosphates
Adenine
ribose
Adenosine 5’-monophosphate
(AMP)
Adenosine 5’-diphosphate (ADP)

11. Nucleotides Di- & Tri- Phosphates
Adenine
Adenosine 5’-triphosphate (ATP)
ribose
Adenosine 5’-monophosphate
(AMP)
Adenosine 5’-diphosphate (ADP)

12. Primary structure

13. Primary structure 5’ Phosphate bonds link DNA or RNA
Adenine (A)
Similar to proteins
with their peptide
bonds and side
groups. 5’
Guanine (G)
Thymine (T)
Phosphate bonds
link DNA or RNA
nucleotides together
in a linear sequence. 3’

14. Structure of DNA

15. In 1938 William Thomas Astbury took the first fiber diffraction pictures of DNA, correctly predicting, in an article in the journal Nature, the overall dimensions of the molecule and that the nucleotide bases were stacked at intervals of 3.3Å perpendicular to its long axis. It was left, however, to Watson and Crick after the Second World War to elucidate the detailed double helical structure of DNA.

16. Maurice Wilkins with one of the cameras he developed specially for X-ray diffraction studies

17. Work on x-ray diffraction patterns by Maurice Wilkins and Rosalind Franklin in 1953, revealed that the molecule had a "helical shape“.

18. Rosalind Franklin is most associated with the discovery of the structure of DNA. At 26, after she had her PhD, Franklin began working in x-ray diffraction - using x-rays to create images of crystallized solids. She pioneered the use of this method in analyzing complex, unorganized matter such as large biological molecules, and not just single crystals. Franklin made marked advances in x-ray diffraction techniques with DNA. She adjusted her equipment to produce an extremely fine beam of x-rays. She extracted finer DNA fibers than ever before and arranged them in parallel bundles. And she studied the fibers' reactions to humid conditions. All of these allowed her to discover crucial keys to DNA's structure. Maurice Wilkins, her laboratory's second-in-command, shared her data, without her knowledge, with James Watson and Francis Crick, at Cambridge University, and they pulled ahead in the race, ultimately publishing the proposed structure of DNA in March, It is clear that without an unauthorized peek at Franklin's unpublished data, Watson and Crick probably would neither have published their famous paper on the structure of DNA in 1953, nor won their Nobel Prizes in Franklin did not share the Nobel Prize; she died in 1958 at the age of 37.

19. 1953, James Watson & Francis Crick and their scale model for DNA

20. DNA secondary and tertiary structure
Sugar-phosphate backbone
Causes each DNA chain to coil around the outside of the attached bases like a spiral stair case.
Base Pairing
Hydrogen bonding occurs between purines and pyrimidines. This causes two DNA strands to bond together.
adenine - thymine guanine - cytosine
Always pair together!
Results in a double helix structure.

21. Base pairing and hydrogen bonding
| | O
H - N N O
| |
- H
N - H
guanine
cytosine N
| | O
H3C
- H N | H
thymine
adenine

22. DNA - Secondary Structure
Complementary Base Pairing
Position of H bonds and distance match with:

23. Hydrogen bonding G T C A Each base wants to form either two or three
hydrogen bonds.
That’s why only certain
bases will form pairs.

24. Sugar-phosphate backbone
DNA coils around outside of attached bases like a spiral stair case.
Results in a double helix structure.

25. The double helix One complete
twist
is 3.4 nm
The combination of the stairstep sugar-phosphate backbone and the bonding
between pairs results
in a double helix.
2 nm
between
strands
Distance between
bases = 0.34 nm

26. DNA - Secondary Structure
Complementary Base Pairing 29 29

27. The actual chain is like a coiled spring.
It is something similar to what happens when protein chains form an alpha helix.
It is the sequence (order) of the amines coming off of the backbone that give us all our genetic information
Just like the sequence of words in a sentence give it meaning.
Of the like in words meaning just sentence a give sequence it. (Get my meaning ? )

28. Crick and Watson
(1962 Nobel Prize)
Proposed the basic structure of DNA
2 strands wrap around each other
Strands are connected by H-bonds between the amines.
Like steps of a spiral staircase

29. Chromosomes Chromosomes consists of DNA strands coiled
around protein - histomes. The acidic DNA’s are
attracted to the basic histones.

30. It also was clear in the 1960s that the chromosomes of cells

31. Chromosomes
The normal number of chromosome pairs varies among the species.
Animal Pairs Plant Pairs
Man Onion
Cat Rice
Mouse Rye
Rabbit Tomato
Honeybee, White pine
male Adder’s
female 16 tongue fern

32. Role of RNA and DNA in Heredity
RNA and DNA are involved in three major processes in a cell related to heredity as shown below:
Replication is an important process during mitosis
Replication (DNA copies itself)
Transcription (The genetic code in DNA is rewritten into RNA and carried to the ribosomes by mRNA
Translation (tRNA carries amino acids to the ribosomes as part of protein synthesis
Transcription and translation are two steps in the biosynthesis of a protein

33. DNA: Self - Replication
When a cell nucleus divides, the bridging hydrogen bonds break (with the aid of enzymes) and the intertwined strands unwind from each other.
The amines left sticking out from each strand are now free to pick up new partners from the plentiful supply present in the cell.

34. P S A T G C E a c h p i k s u , e t . v n l y r m g o d w f D b x

35. DNA: Self - ReplicationG T C A P C A G T

36. DNA: Self - ReplicationG T C A P A G G T C C

37. Replication of DNA Replication occurs on both halves
in opposite directions.

38. DNA Replication 37 37

39. RNA synthesis In the first step, RNA polymerase binds
to a promotor sequence
on the DNA chain.
This insures that transcription occurs in the correct direction.
The initial
reaction is to
separate the two
DNA strands.

40. RNA synthesis ‘Special’ base sequences in the DNA indicate where RNA
initiation
sequence
termination
sequence
‘Special’ base
sequences in the
DNA indicate
where RNA
synthesis starts
and stops.

41. RNA synthesis Once the termination sequence is reached, the
new RNA molecule
and the
RNA synthase
are released.
The DNA recoils.

42. The messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival.
rRNA
rRNA
Nucleus

43. The messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival.
rRNA
rRNA
Nucleus

44. The messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival.
rRNA
rRNA
Nucleus

45. The messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival.
rRNA
rRNA
Nucleus

46. Ribosomal RNA – rRNA: Platform for protein synthesis
Ribosomal RNA – rRNA: Platform for protein synthesis. Holds mRNA in place and helps assemble proteins.
rRNA
rRNA 52 52

47. The Ribosomes are like train stations
The mRNA is the train slowly moving through the station.
rRNA
Codons
AUG
GCU
UUG 5’ 3’
mRNA
rRNA 54 54

48. Transfer RNA - tRNA =
relatively small compared to other RNA’s (70-90 bases.)
transports amino acids to site of protein synthesis.

49. Anticodons on t-RNA Site of amino acid attachment Point of attachment
to mRNA
Three base
anticodon site

50. UUU or UUC is the codon for Phe. UUG is the codon for Leu
UUU or UUC is the codon for Phe. UUG is the codon for Leu. AUG is the codon for Met.

51. Codons There are two additional types of codons: Initiation AUG
(same as methionine)
Termination UAG, UAA, UGA
A total of 64 condons are used for all amino
acids and for starting and stopping. All protein
synthesis starts with methionine. After the poly-
peptide has been made, an enzyme removes this
amino acid.

52. Protein Synthesis 1: Activation
Each AA is activated by reacting with an ATP
The activated AA is then attached to particular tRNA... (with the correct anticodon)
activated AA C G A
MET
anticodon 58 58

53. Translation Psite A site 3’ 5’ Initiation factors ribosome unit mRNA
MET
AUG
GCU
UUG
mRNA 5’ 3’
Psite
A site
Initiation
factors
ribosome unit 61 61

54. Translation Psite A site 3’ 5’ ribosome unit mRNA UUG AUG GCU Ala MET63 63

55. Translation peptide bond forms 3’ 5’ ribosome unit mRNA UUG AUG GCU
MET C G A
Ala
AUG
GCU
UUG
mRNA 5’ 3’
ribosome unit 65 65

56. Translation peptide bond 3’ 5’ ribosome unit G U A mRNA Phe Met AlaC A G
Phe
peptide bond
Met C G A
Ala U A C
GCU
UUC
UUG
mRNA 5’ 3’ A U G
ribosome unit 68 68

57. Translation peptide bond forms 3’ 5’ ribosome unit G U A mRNA Met AlaC
peptide bond
forms
Met C G A
Ala A G
Phe
GCU
UUC
UUG
mRNA 5’ 3’ A U G
ribosome unit 69 69

58. Termination
After the last translocation (the last codon is a STOP), no more AA are added.
“Releasing factors” cleave the last AA from the tRNA
The polypeptide is complete 70 70

59. Recombinant DNA Circular DNA found in bacteria E.Coli plasmid bodies
Restriction endonucleases cleave DNA at specific genes
Result is a “sticky end”
Addition of a gene from a second organism
Spliced DNA is replaced and organism synthesizes the new protein 83 83

60. Recombinant DNA Remove gene segment DNA sticky ends Plasmid Cut gene
Bacterium
Remove
gene segment
DNA
Plasmid
sticky ends
Cut gene
for insulin
Replace in
bacterium 84 84