1. BTY100-Lec#4.1
Genetic Basis of Life
Genetic Makeup
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2. Outline
Genetic Material DNA RNA Structure DNA and RNA comparison Central Dogma
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3. These specifications are basically information
Every human creation comes with some specifications which are found on a particular location.
These specifications are basically information
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4. Information in ATGC…..really
Just like a computer stores all its information in 0 and 1 (Binary Language) all human information is stored in Genetic Language which is having only 4 alphabets (ATGC).
These alphabets are stored in our Genetic Material
DNA and RNA
How???
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5. The Genetic Material DNA and RNA
Genetic material refers to the material that determines the inherited characteristics of a functional organism.
It plays a fundamental role in determining the nature and structure of a cell.
It can either be DNA or RNA.
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6. Information Storage Unit of Life
DNA
Blue Print of life
Most stable structure
Information Storage Unit of Life
The illustration is a ‘model’ of the double helix forming part of a DNA molecule
(Slide 14)
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7. Different features
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8. All these difference are because of different information stored in your DNA.
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9. This 0.1 % different makes us so different from other.
99.9% of all human DNA is the same; only 0.1% is different in each person.
This 0.1 % different makes us so different from other.
Observe your friends around you……..
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10. Where is DNA located?
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11. DNA molecule
DNA is a very large molecule made up of a long chain of sub-units
The sub-units are called nucleotides
Each nucleotide is made up of
A sugar- Deoxyribose
An nitrogenous base (A T G C )
A phosphate group -PO4 and
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12. THE SUGARS:RIBOSE & DEOXYRIBOSE4
THE SUGARS:RIBOSE & DEOXYRIBOSE
Ribose is a sugar, with only five carbon atoms in its molecule
Deoxyribose is almost the same but lacks one oxygen atom at C2
Both molecules may be represented by the symbol
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13. Organic Bases
The nucleotide bases found in nucleic acids are related either to the purine or pyrimidine ring system.
Both DNA and RNA contain two major purine bases, adenine (A) and guanine (G), and two major pyrimidines.
In both DNA and RNA one of the pyrimidines is cytosine (C), but the second major pyrimidine is not the same in both: it is thymine (T) in DNA and uracil (U) in RNA.

14. Nitrogenous Bases of DNA
Pyrimidines
Single Ringed
Purines
Double Ringed
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15. Purines V/S Pyrimidines
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16. Nucleoside and Nucleotide
Nucleotides Are the Monomeric Units of Nucleic Acids
A unit consisting of a base bonded to a sugar is referred to as a nucleoside.
A nucleotide is a nucleoside joined to one or more phosphate groups by an ester linkage

17. Nucleoside and Nucleotide
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18. PHOSPHODIESTER LINKAGE
These nucleotides are joined together to form Chains of Nucleic acids.
This linkage between the nucleotides is known as Phosphodiester Linkage.
The successive nucleotides of both DNA and RNA are covalently linked through phosphate-group “bridges,” in which the 5’-phosphate group of one nucleotide unit is joined to the 3-hydroxyl group of the next nucleotide, creating a Phosphodiester linkage
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19. Phosphodiester Linkage
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20. The chain has a 5 end, which is usually attached to a phosphate, and a 3 end, which is usually a free hydroxyl group.
This forms the sugar-phosphate backbone of one DNA strand.

21. From Single Strand to Double Strand
DNA molecules are double stranded.
The sugar-phosphate chains are on the outside and the strands are held together by chemical bonds between the bases.
The formation of hydrogen bonds between the bases takes place according to Chargaff’s Rule.
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22. CHARGAFFS RULE:
“It states that DNA from any cell of all organisms should have a 1:1 ratio of pyrimidine and purine bases and more specifically that the amount of guanine is equal to amount of cytosine and amount of adenine is equal to amount of thymine”
%A=%T
%G=%C
%(A+G)= %(T+C)

23. Rule of Complementary Base pairing:
Adenine and Thymine always join together
A T
Cytosine and Guanine always join together
C G
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24. COMPLEMENTARY NATURE OF DNA
The two strands of DNA are complementary to one another because of the properties of base pairing:
A will only pair with T by two hydrogen bonds
G will only pair with C by three hydrogen bonds
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25. Base pairing rules A T C G
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26. ANTIPARALLEL NATURE
The two strands of DNA are also antiparallel(run in opposite directions) to one another.
A strand of DNA can have the direction 5'-3' or 3'- 5'.
One strand in the DNA molecule is 5'-3' and the other strand is 3'-5'.

27. DNA Structure
James Watson and Francis Crick worked out the 3D structure of DNA, based on work by Rosalind Franklin.
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28. DNA is Double Helical Structure
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29. Watson and Crick Model of DNA Double Helix
Draw the diagram
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30. The two strands run antiparallely and are complimentary to each other.
The coiling is right handed.
The major groove occurs where the backbones are far apart, the minor groove occurs where they are close together.
The sugar-phosphate backbones are on the outside and, therefore, the purine and pyrimidine bases lie on the inside of the helix. Adenine always pairs with Thymine, Guanine binds with Cytosine
The bases are nearly perpendicular to the helix axis, and adjacent bases are separated by 3.4 Å.
The helical structure repeats every 34 Å, so there are 10 bases (= 34 Å per repeat/3.4 Å per base) per turn of helix.
There is a rotation of 36 degrees per base (360 degrees per full turn/10 bases per turn).
The diameter of the helix is 20 Å.

31. RNA: Ribonucleic Acid
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32. Nitrogenous base (A, G, C, or U)
RNA is also a nucleic acid
The bridge between DNA and protein synthesis is the nucleic acid RNA.
Different sugar, U instead of T, Single strand, usually
RNA is made of ribonucleic acids instead of deoxyribonucleic acids
RNA is single-stranded
In RNA sequences, Thymine (T) is replaced by Uracil (U) 
mRNA carries the message from genome to proteins
Nitrogenous base (A, G, C, or U)
Phosphate group
Uracil (U)
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Sugar (ribose)

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34. Character
RNA
DNA
Nitrogenous bases
RNA contains adenine, uracil, cytosine, and guanine.
DNA contain adenine, thymine, cytosine, guanine;
Strandedness
RNA is single-stranded.
DNA is double-stranded
Location
RNA can be found in both the nucleus and cytoplasm.
DNA is only found in the nucleus
Functions
RNA carries out protein synthesis.
RNA transfers the information to other places in the cell
DNA contains the information for protein synthesis.
DNA stores genetic information
Pentose sugar
Hydroxyl group present at 2 carbon of the pentose sugar
Absence of hydroxyl group at 2 C of the pentose sugar

35. What DNA and RNA do in a cell?
Central Dogma
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36. Next Class: DNA to Protein
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