Genetic MaterialGenetic Material

TaryonoTaryonoFaculty of AgricultureFaculty of Agriculture

Gadjah Mada UniversityGadjah Mada University

DefinitionDefinitionAll biological substances which control the All biological substances which control the

process in organism and able to be transmitted process in organism and able to be transmitted to the progenyto the progeny

1. Carbohydrate

2. Fat

3. Protein

4. DNA - RNA

Biological Substances

Gregor Johan Mendel (1865)Gregor Johan Mendel (1865) Discovered genetics (Modes Discovered genetics (Modes

of Heredity)of Heredity)

Which substance is the genetic material?

Which substance is the genetic material?

Walter Sutton (1902)Walter Sutton (1902) Discovered Discovered

ChromosomesChromosomes

Which substance is the genetic material?

Which substance is the genetic material?

Thomas Hunt Morgan (1910)Thomas Hunt Morgan (1910) Discovered how genes are Discovered how genes are

transmitted through transmitted through chromosomeschromosomes

Which substance is the genetic material?

Which substance is the genetic material?

Fred Griffith (1928), MicrobiologistFred Griffith (1928), Microbiologist Diplococcus pneumonieae (ball shaped bacterium)Diplococcus pneumonieae (ball shaped bacterium) Two naturally occurring strains have markedly different Two naturally occurring strains have markedly different

propertiesproperties1.1. The virulent smooth (s) strain → a smooth The virulent smooth (s) strain → a smooth

polysaccharide capsule that is essential for infectionpolysaccharide capsule that is essential for infection2.2. The non virulent rough (r ) strain → lacks of outer The non virulent rough (r ) strain → lacks of outer

capsule, giving its surface a rough appearancecapsule, giving its surface a rough appearance

Which substance is the genetic material?

Which substance is the genetic material?

Griffith’s experiment (1928) The discovery of transformation

Oswald T. Avery, Colin Mcleod, Maclyn McCarty (1944) Expand Griffith experiment Mixed R strain with DNA from S strain and isolated S

bacteria Added DNase which broke down DNA and prevented R

bacteria from transforming to S bacteria Proteases (broke down proteins) did not inhibit

transformation DNA was determined to be the “transforming principle”

Which substance is the genetic material?

Which substance is the genetic material?

• ””

Avery, MacLeod, and McCarty (1944)Avery, MacLeod, and McCarty (1944)

“Transforming substance is DNA”

Erwin Chargaff (1947)Erwin Chargaff (1947) He found the complementary relationship between the He found the complementary relationship between the

nucleotide in each pairnucleotide in each pair Adenine always pairs with thymine and cytosine always Adenine always pairs with thymine and cytosine always

pairs with guaninepairs with guanine

Which substance is the genetic material?

Which substance is the genetic material?

Rosalind Elsie Franklin Rosalind Elsie Franklin (1948)(1948)

Research led to the Research led to the discovery of the double helix discovery of the double helix structure of DNAstructure of DNA

She took the clearest X-ray She took the clearest X-ray diffraction photo of DNAdiffraction photo of DNA

Which substance is the genetic material?

Which substance is the genetic material?

Which substance is the genetic material?

Which substance is the genetic material?

Alfred Hershey, Martha Chase (1952) → Blender Experiment Used T2 bacteriophages (phages), a virus that infects

bacteria Radiolabeled the bacteriophage with S35 (Protein) and P32

(DNA) Bacterial cells were infected and put in a blender to remove

phage particles√ DNA, not protein, is the hereditary material√ Expt: sulfur(S) is in protein, phosphorus (P) is in DNA;

only P was found in host cell

Hershey and Chase (1952)Hershey and Chase (1952)

James Watson and Francis Crick James Watson and Francis Crick (1953)(1953)

They described the DNA molecule They described the DNA molecule from Franklin’s X-ray and discovered from Franklin’s X-ray and discovered DNADNA

Which substance is the genetic material?

Which substance is the genetic material?

DNA is Genetic MaterialDNA is Genetic Material

DNA encodes all the information in the cell The composition of the DNA is the same in all cells within an

organism Variation among different cells is achieved by reading the

DNA differently DNA contains four bases that encode all the information to make

a bacteria or a human In some viruses the genetic material is RNA

How is Information Encoded in DNA?

How is Information Encoded in DNA?

DNA Consists of four kinds of bases (A,C,G,T) joined to a sugar phosphate backbone

Bases carry the genetic information while the phosphate backbone is structural

Two complementary strands of bases (C-G) and (A-T)

DNA is a Polymer of Deoxyribonucleotide Units

DNA is a Polymer of Deoxyribonucleotide Units

DEOXYRIBONUCLEOTIDE

DEOXY RIBO NUCLEOTIDE

Deoxyribonucleic Acid Deoxyribonucleic Acid (DNA)(DNA)

NucleotideNucleotide:: Phosphate groupPhosphate group 5-carbon sugar5-carbon sugar

Nitrogenous baseNitrogenous base

DNA NucleotideDNA Nucleotide

OO=P-O O

PhosphatePhosphate GroupGroup

NNitrogenous baseNitrogenous base (A, G, C, or T)(A, G, C, or T)

CH2

O

C1C4

C3 C2

5

SugarSugar(deoxyribose)(deoxyribose)

DNA Double HelixDNA Double Helix

NitrogenousNitrogenousBase (A,T,G or C)Base (A,T,G or C)

““Rungs of ladder”Rungs of ladder”

““Legs of ladder”Legs of ladder”

Phosphate &Phosphate &Sugar BackboneSugar Backbone

DNA Double HelixDNA Double Helix

P

P

P

O

O

O

1

23

4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A

DNA is Composed of Four Different RibonucleotidesDNA is Composed of Four Different Ribonucleotides

HN

CHN

C

CN

CN

C

NH2

HHN

CHN

C

CN

CN

C

O

H2N

H

NC

CC

HN

C

O

CH3

HO

H

NC

CC

N

CH

O

H

H

NH2

Adenine Guanine

Thymine Cytosine

TwoPurines

TwoPyrimidines

9 9

1 1

Nitrogenous BasesNitrogenous Bases

PURINESPURINES

1.1. Adenine (A)Adenine (A)

2.2. Guanine (G)Guanine (G)

PYRIMIDINESPYRIMIDINES

3.3. Thymine (T)Thymine (T)

4.4. Cytosine (C)Cytosine (C)T or C

A or G

BASE-PAIRINGSBASE-PAIRINGS

BaseBase # of # of

PurinesPurines PyrimidinesPyrimidines PairsPairs H-BondsH-Bonds

Adenine (A)Adenine (A) Thymine (T)Thymine (T) A = TA = T 2 2

Guanine (G)Guanine (G) Cytosine (C)Cytosine (C) C GC G 3 3

CG

3 H-bonds

BASE-PAIRINGSBASE-PAIRINGS

CG

H-bonds

T A

Base Pairing Occurs Through Hydrogen Bonds

Base Pairing Occurs Through Hydrogen Bonds

A-TG-C

Chargaff’s RuleChargaff’s Rule

AdenineAdenine must pair with must pair with ThymineThymine

GuanineGuanine must pair with must pair with CytosineCytosine

Their amounts in a given DNA molecule will be Their amounts in a given DNA molecule will be about about the samethe same..

G CT A

Backbone Sugar Molecules

Deoxyribose (DNA) Ribose (RNA)

O

OH

H

OH

H

H

H

HOCH2

HO

OH

OH

H

H

H

HOCH2

HO H

1´

2´3´

4´

5´

1´

2´3´

4´

5´

Ribose= Five Carbon Sugar Molecule

Deoxy ribo nucleotide

The DNA Backbone is a Deoxyribose Polymer

The DNA Backbone is a Deoxyribose Polymer

Deoxyribose sugars are linked by Phosphodiester Bonds

O

P O

O

O-

H2C

O-

O-

OH

OH

H

H

HH

H2C

H2C

HH

H

H

OHH

O

O

P O

O

O

OP

O HH

H

H

OHH

O

HO

5´

3´

5´

5´

3´

3´

2´

2´

2´

1´

1´

1´

5´-p 3´-OH

5´ 3´

5´

3´

5´

3´ 5´

3´O

P O

O

O-

H2C

O-

O-

OH

OH

H

H

HH

H2C

H2C

HH

H

H

OHH

O

O

P O

O

O

OP

O HH

H

H

OHH

O

HO

5´

3´

5´

5´

3´

3´

2´

2´

2´

1´

1´

1´

O

P O

O

O-

H2C

O-

O-

OH

OH

H

H

HH

H2C

H2C

HH

H

H

OHH

O

O

P O

O

O

OP

O HH

H

H

OHH

O

HO

5´

3´

5´

5´

3´

3´

2´

2´

2´

1´

1´

1´

Base

Base

Base

O

P O

O

O-

H2C

O-

O-

OH

OH

H

H

HH

H2C

H2C

HH

H

H

OHH

O

O

P O

O

O

OP

O HH

H

H

OHH

O

HO

5´

3´

5´

5´

3´

3´

2´

2´

2´

1´

1´

1´

NCH

N

NHCN

NH2

O

H

H

HHO

H

H

OCH2PO

O

PO

O

P

O- O-O-

O-

O

(dATP)

Deoxyadenosine 5´-triphosphateO

H

H

HHO

H

H

NCH

N

NHCN

NH2

HOCH2

DeoxyRibonucleotide

DeoxyRibonucleoside Deoxyadenosine

5´

3´ 5´

3´

NC

CC

N

CH

O

H

NH2

NC

CC

HN

C

O

CH3

HO

NC

CC

HN

C

O

CH3

HO

HO

OH

H

H

HHO

P O

O

O

OP

O

OH

H

H

HH

H2C

H2C

HH

H

H

HO

O-

O-

H2C

O-

O

OP

O

T

C

T

A

G

A

=

G C

A T

Double-stranded DNA Forms a Double Helix

Double-stranded DNA Forms a Double Helix

Central Dogma of BiologyCentral Dogma of Biology

DNA, RNA, and the Flow of Information

DNA, RNA, and the Flow of Information

TranslationTranscription

Replication

Central Dogma (Modifications)Central Dogma (Modifications)

Transcription TranslationDNA

(1) Reverse transcription

Replication

RNA

(2)Self Replication

Protein

(3)Self Replication

(2)Ribozymes