1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein...

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

Page 1: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Nucleic acidsNucleic acids

Nucleic acidsNucleic acids: – Maintain genetic informationMaintain genetic information– Determine Protein SynthesisDetermine Protein Synthesis

DNADNA = deoxydeoxyribonucleic acid– “Master Copy” for most cell information.– Template for RNA

RNA =RNA = ribonucleic acid– Transfers information from DNA– Template for Proteins

Page 2: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Nucleic AcidsNucleic AcidsChromosomes

(in nucleus)

Have genesgenes

1 gene

1 enzyme or protein

EnzymesEnzymes determine determine

external & internal characteristicsexternal & internal characteristics

Page 3: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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NUCLEIC ACIDSNUCLEIC ACIDS

Long chains (polymers) of repeating nucleotides.nucleotides.– Each nucleotide has 3 parts:3 parts:

A A phosphate unitphosphate unit H H

OO

H

H

OH

H

H

HO

A sugarsugar

A heterocyclic heterocyclic Amine BaseAmine BaseN

H

P OH

O

OH

HO

Page 4: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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NucleoNucleottide ide = phosphate + sugar + base= phosphate + sugar + baseNucleoNucleottide ide = phosphate + sugar + base= phosphate + sugar + base

P

O

O

ON

H H

OH

OH

H

H

O

-N-glycosidiclinkage

-N-glycosidiclinkage

BaseBase

SugarSugar

PhosphatePhosphate

Nucleoside = Nucleoside = sugar + basesugar + baseNucleoside = Nucleoside = sugar + basesugar + base

Page 5: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Nucleic AcidsNucleic Acids

Nucleic AcidsNucleic Acids = polymerspolymers of Nucleotides.Nucleotides.

phosphate sugar

base

SS SS SSSSSSSS

BB BB BBBBBBBB

PPPP PP PPPPPP

Page 6: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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THE SUGAR PARTTHE SUGAR PART• The major difference between RNA and DNA is

the different form of sugar used.

OHOCH2

H HHH

OH OHOH

OHOHOCH2

H HHH

OH HH

OH

Ribose C5H10O5

in RNADeoxyDeoxyRibose C5H10O4

in DNA

The difference is at carbon #2carbon #2.

Page 7: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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The Nitrogenous BasesThe Nitrogenous Bases

5 bases5 bases used fall in two classestwo classes

Purines Purines & & PyrimidinesPyrimidines

N

N

N

NH

A double ringdouble ring (6 & 5 members)

A single ringsingle ring(6 membered)

N

N

Page 8: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Pyrimidines:Pyrimidines:

The Nitrogenous BasesThe Nitrogenous Bases

Purines:Purines:N

N

N

N

NH2

H

N

N

N

NH

H2N

O

H

N

N

O

O

CH3

H

HN

N

O

O

H

H N

NO

H

H

NH2

Adenine (A)Adenine (A)Adenine (A)Adenine (A) Guanine (G)Guanine (G)Guanine (G)Guanine (G)

Thiamine (T)Thiamine (T)In In DNADNA only onlyThiamine (T)Thiamine (T)In In DNADNA only only

Uracil (U)Uracil (U)In In RNARNA only only

Uracil (U)Uracil (U)In In RNARNA only only

Cytosine (C)Cytosine (C)Cytosine (C)Cytosine (C)

Page 9: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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H

N

N

N

N

NH2

P

O

O

H H

OH

OH

H

O

OH

1'

2'3'

4'

5'

H

HN

N

N

NP

O

O

H H

OH

OH

H

O

OH

O

H2N

1'

2'3'

4'

5'

1'

2'3'

4'

5'

H

N

P

O

O

H H

OH

OH

H

O

OH

N

O

O

CH3

Primary structurePrimary structure

Page 10: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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H

N

N

N

N

NH2

P

O

O

H H

OH H

O

OH

H

HN

N

N

NP

O

O

H H

OH H

O

O

O

H2N

H

N

P

O

O

H H

OH

OH

H

O

N

O

O

CH3

O

1'

2'3'

4'

5'

1'

2'3'

4'

5'

1'

2'3'

4'

5'

Primary structurePrimary structure

Phosphate bondsPhosphate bondslink DNA or RNAlink DNA or RNAnucleotides togethernucleotides togetherin a linear sequence.

Similar to proteinswith their peptide

bonds and sidegroups.

5’

3’

Adenine (A)

Guanine (G)

Thymine (T)

Page 11: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Structure of DNAStructure of DNA

Page 12: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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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.

Page 13: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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

Page 14: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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

Page 15: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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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, 1953.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 1962. Franklin did not share the Nobel Prize; she died in 1958 at the age of 37.

Page 16: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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

Page 17: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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DNA secondary and tertiary structureDNA secondary and tertiary structure

Sugar-phosphate backboneSugar-phosphate backboneCauses each DNA chain to coilcoil around the outsideoutside of the attached basesof the attached bases like a spiral stair case.

Base PairingBase PairingHydrogen bonding occurs between purines and purines and pyrimidinespyrimidines. This causes two DNA strands to bond together.

adenine - thymineadenine - thymine guanine - cytosineguanine - cytosineAlways pair together!Always pair together!

Results in a double helix structure.

Page 18: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Base pairing and hydrogen bondingBase pairing and hydrogen bonding

N

N

O| |

- H

N - H

N

NN

N

O| |

H - N

N

N O| |

O| |

H3C

- H

guanine cytosine

thymine adenineN

N N

N|

HH

N

Page 19: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Hydrogen bondingHydrogen bonding

Each base wants toform either two or three hydrogen bonds.

That’s why only certain bases will form pairs.

G

T

C

A

C G

A

C

T

G

Page 20: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Sugar-Sugar-phosphate phosphate backbonebackboneDNA coilscoils around outsideoutside of of attached attached basesbases like a spiral stair case.

Results in a double helix structure.

Page 21: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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• 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

Page 22: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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ChromosomesChromosomes

The normal number of chromosome pairs varies among the species.

AnimalAnimal Pairs Pairs PlantPlant PairsPairsMan 23 Onion 8Cat 30 Rice 14Mouse 20 Rye 7Rabbit 22 Tomato 12Honeybee, White pine 12

male 8 Adder’s 1262female 16 tongue fern

Page 23: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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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:

1. Replication (DNA copies itself)

2. Transcription (The genetic code in DNA is rewritten into RNA and carried to the ribosomes by mRNA

3. Translation (tRNA carries amino acids to the ribosomes as part of protein synthesis

Replication is an important process during mitosis

Transcription and translation are two steps in the biosynthesis of a protein

Page 24: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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TTCC

AA

SS SSSS SSSSSS

GG TT CCAA

PPPP PP PPPPPP

CC GG

GG

DNA: Self - ReplicationDNA: Self - Replication

Page 25: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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GGGGAA

SS SSSS SSSSSS

GG TT CCAA

PPPP PP PPPPPP

CC GG

DNA: Self - ReplicationDNA: Self - Replication

TT CCCC

Page 26: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Replication of DNAReplication of DNA

ReplicationReplication occurs on both halvesboth halvesin opposite directions.opposite directions.

Page 27: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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DNA DNA ReplicationReplication

Page 28: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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RNA synthesisRNA synthesis

In the first step, RNA polymeraseRNA polymerase bindsto a promotorpromotor sequenceon the DNA chain.

This insuresinsures that transcription occurs in the correct directioncorrect direction.

The initial reaction is toseparate the twoseparate the twoDNA strandsDNA strands.

Page 29: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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RNA synthesisRNA synthesis

initiationsequence

terminationsequence

‘Special’ baseSpecial’ basesequencessequences in theDNA indicatewhere RNARNAsynthesis startssynthesis startsand stops.and stops.

Page 30: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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RNA synthesisRNA synthesis

Once the terminationsequence isreached, thenew RNA moleculenew RNA moleculeand the RNA synthaseare released.released.

The DNA recoils.The DNA recoils.

Page 31: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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• The messenger RNAmessenger RNA (mRNA) move outside the nucleus to the cytoplasmto the cytoplasm where RibosomesRibosomes are anxiously awaiting their arrival.

rRNA

rRNA

Page 32: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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• The messenger RNAmessenger RNA (mRNA) move outside the nucleus to the cytoplasmto the cytoplasm where RibosomesRibosomes are anxiously awaiting their arrival.

rRNA

rRNA

Page 33: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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• The messenger RNAmessenger RNA (mRNA) move outside the nucleus to the cytoplasmto the cytoplasm where RibosomesRibosomes are anxiously awaiting their arrival.

rRNA

rRNA

Page 34: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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• The messenger RNAmessenger RNA (mRNA) move outside the nucleus to the cytoplasmto the cytoplasm where RibosomesRibosomes are anxiously awaiting their arrival.

rRNA

rRNA

Page 35: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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rRNA

rRNA

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

Page 36: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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AUG GCU AUG UUG

5’

3’

rRNArRNA

•The RibosomesRibosomes are like train stationslike train stations

–The mRNA is the trainmRNA is the train slowly moving through the station.

rRNArRNA

Codons

mRNAmRNA

Page 37: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Transfer RNA Transfer RNA - tRNA- tRNA =• relatively small small compared to other RNA’s

(70-90 bases.)70-90 bases.)• transports amino acidstransports amino acids to site of protein synthesis.

A

C

C

A

C

C

U

C

G

U

CU

U

C

G

G

G

G

G

CC GGG

CC GG

A CGG

CC GGU

C

C

C

C

U

C

A

U

G

G

A

G

G

G

G

GU

U

CC G

U

C GC

AU

G

G

C

U

AG U

A GU

G

GC

HO-A

C

C

A

C

C

U

C

G

U

CU

U

C

G

G

G

G

G

CC GGG

CC GG

A CGG

CC GGU

C

C

C

C

U

C

A

U

G

G

A

G

G

G

G

GU

U

CC G

U

C GC

AU

G

G

C

U

AG U

A GU

G

GC

HO-

Page 38: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Anticodons on t-RNAAnticodons on t-RNA

A

C

C

A

C

C

U

C

G

U

CU

U

C

G

G

G

G

G

CC GGG

CC GG

A CGG

CC GGU

C

C

C

C

U

C

A

U

G

G

A

G

G

G

G

GU

U

CC G

U

C GC

AU

G

G

C

U

AG U

A GU

G

GC

HO-

Site of aminoacid attachment

Site of aminoacid attachment

Three base anticodon site

Three base anticodon site

Point ofattachmentto mRNA

Point ofattachmentto mRNA

Page 39: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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

Page 40: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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CodonsCodons

There are two additional types of codons:

Initiation Initiation AUGAUG(same as methionine)

TerminationTermination UAG, UAA, UGAUAG, UAA, UGA

A total of 64 condons are used for all aminoacids and for starting and stopping. All proteinsynthesis starts with methionine. After the poly-peptide has been made, an enzyme removes thisamino acid.

Page 41: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Protein SynthesisProtein Synthesis1: Activation1: Activation

Each AA is activated by reacting with an ATP

The activated AA is then attached to particular tRNAtRNA... (with the correct anticodon)

C G A

MET

anticodon

activated AA

Page 42: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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TranslationTranslation

AUG GCU AUG UUG mRNA

5’

3’

Initiationfactors

ribosome unit

U A C

MET

PPsitesite AA site site

Page 43: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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U A C

MET

TranslationTranslation

ribosome unit

AUG GCU AUG UUG mRNA

5’

3’

PPsitesite AA site site

C G A

Ala

Page 44: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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ribosome unit

AUG GCU AUG UUG mRNA

5’

3’

TranslationTranslation

U A C

MET

C G A

Ala

peptide bondforms

Page 45: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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ribosome unit

GCU UUC UUGmRNA

5’

3’

TranslationTranslation

C G A

Ala

peptide bond

Met

A A G

Phe

AU G

U A C

U A C

Page 46: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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ribosome unit

GCU UUC UUGmRNA

5’

3’

TranslationTranslation

C G A

Ala

peptide bondforms

Met

A A G

Phe

AU G

U A C

Page 47: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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TerminationTermination

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

Page 48: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Recombinant DNARecombinant DNA

Circular DNA found in bacteriaE.Coli plasmid bodiesRestriction endonucleases cleave DNA at

specific genesResult is a “sticky end”Addition of a gene from a second

organismSpliced DNA is replaced and organism

synthesizes the new protein

Page 49: 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid –“Master Copy”

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Recombinant DNARecombinant DNA

Bacterium

Remove gene segment

DNAPlasmid sticky ends

Cut genefor insulin

Replace inbacterium