Proteins and Nucleic Acidspp

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Proteins and nucleicProteins and nucleicacidsacids


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MoreMore MacrmoleculesMacrmolecules

Proteins:Proteins:

Amino acid chainAmino acid chain polypeptidepolypeptide proteinprotein

Nucleic Acids:Nucleic Acids:

DNA, RNADNA, RNA


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What do proteins do?What do proteins do?

EnzymesEnzymes

Structural supportStructural support

StorageStorage

TransportTransportHormonesHormones

ReceptorsReceptorsMotor/contractileMotor/contractile


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What is a Protein?What is a Protein?Proteins are made up ofProteins are made up ofaminoaminoacidsacids (monomers for protein)(monomers for protein)

There are 20 total differentThere are 20 total differentamino acids.amino acids.

Amino acids have carboxylAmino acids have carboxyland amino groupsand amino groupsthe Rthe Rgroup/side chain differs andgroup/side chain differs anddetermines the amino acidsdetermines the amino acidsproperties.properties.

Amino Acids can beAmino Acids can be nonpolarnonpolar,,polar, or charged based onpolar, or charged based ontheir side chains.their side chains.


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ProteinsProteinsPolypeptidePolypeptide: polymer: polymer

of amino acidsof amino acids

One or moreOne or more

polypeptidespolypeptides

folded/coiled make afolded/coiled make a

wholewhole proteinprotein..

Amino acids are joinedAmino acids are joined

by dehydration:by dehydration:

forming aforming a

peptidepeptide

bondbond..


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Protein StructureProtein StructureWhat a protein can do is determined by itsWhat a protein can do is determined by its

shape!shape!

Protein structure or shape is determinedProtein structure or shape is determined

by the amino acids in the chain.by the amino acids in the chain.

Interactions between R groups causeInteractions between R groups causeattractions/bonds/overall shape or folding!attractions/bonds/overall shape or folding!


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Four Levels of Protein StructureFour Levels of Protein Structure

1.1. Primary Structure:Primary Structure:

The unique sequence ofThe unique sequence of

amino acids.amino acids.

The sequence of aminoThe sequence of amino

acids are determined byacids are determined by

DNA.DNA.


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2.2. Secondary StructureSecondary Structure: Common repeated: Common repeated

coils and folds in the polypeptide chains.coils and folds in the polypeptide chains. Result fromResult from hydrogen bondshydrogen bonds between thebetween the

amino and carboxyl groups of theamino and carboxyl groups of the a.aa.a..

Two types:Two types:

helix (alpha):helix (alpha): coilingcoiling

pleated sheet (beta):pleated sheet (beta): two or more regionstwo or more regionslying side by sidelying side by side


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3.3. Tertiary Structure:Tertiary Structure: the overall shapethe overall shape

resulting from interactions between the sideresulting from interactions between the sidechains (R groups)chains (R groups)

Types of interactions:Types of interactions:

Hydrophobic (with surroundings)Hydrophobic (with surroundings)

Hydrophilic (with surroundings)Hydrophilic (with surroundings)

vanvan derderWaalsWaals --Disulfide bridgesDisulfide bridges

Hydrogen BondsHydrogen Bonds --Ionic bondsIonic bonds


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4.4. QuaternaryQuaternary

Structure:Structure:resulting fromresulting from

more than onemore than one

polypeptidepolypeptide

interacting withinteracting with

each other.each other.


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QuizQuiz

Build the modelBuild the model

On a separate sheet of paperdescribeOn a separate sheet of paperdescribe

how your model illustrates proteinhow your model illustrates protein1. Primary structure1. Primary structure

2. Secondary structure2. Secondary structure

3. Tertiary structure3. Tertiary structure

4.4. QuartenaryQuartenary structurestructure


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DenaturationDenaturation

Changing the confirmation of a protein/orChanging the confirmation of a protein/or

the ability for these interactions to occurthe ability for these interactions to occurcan make it noncan make it non--functional.functional.

Changes in pH, salt concentration,Changes in pH, salt concentration,

temperature etc. can cause a protein totemperature etc. can cause a protein to

denature.denature.


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DenaturationDenaturation

http://www.sumanasinc.com/webcontent/ahttp://www.sumanasinc.com/webcontent/a

nisamples/nonmajorsbiology/proteinstructunisamples/nonmajorsbiology/proteinstructure.htmlre.html


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Nucleic AcidsNucleic Acids

Nucleic acids code for protein. (OneNucleic acids code for protein. (One genegene

codes for a protein.)codes for a protein.)

Two types of nucleic acids:Two types of nucleic acids: Deoxyribonucleic Acid (DNA)Deoxyribonucleic Acid (DNA)

Ribonucleic Acid (RNA)Ribonucleic Acid (RNA)


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DNADNA RNARNA ProteinProtein

DNA codes for theDNA codes for the

synthesis of RNAsynthesis of RNA(also called(also called

messenger RNA ormessenger RNA or

mRNA)mRNA)

mRNA codes for themRNA codes for thesynthesis of proteinsynthesis of protein


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Nucleic Acids:Nucleic Acids: PolynucleotidesPolynucleotidesNucleic acids areNucleic acids are

polymers of nucleotidespolymers of nucleotides

Nucleotide:Nucleotide:

Nitrogenous baseNitrogenous base

A pentose (5 carbonA pentose (5 carbon

sugar)sugar)

And a phosphate groupAnd a phosphate group


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BasesBasesPyrimidinesPyrimidines::

One ring of six carbonsOne ring of six carbons

Cytosine (C), Thymine (T)Cytosine (C), Thymine (T)andand UracilUracil (U)(U)

PurinesPurines:: Two rings: six carbons andTwo rings: six carbons and

fivefive

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

A always pairs with T or UA always pairs with T or U

G always pairs with CG always pairs with C


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SugarsSugars

Ribose (RNA)Ribose (RNA)

DeoxyriboseDeoxyribose

(DNA): lacks an(DNA): lacks anoxygen atom onoxygen atom on

the secondthe second

carbon.carbon.

Last part of a nucleotide: phosphate group


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Double helixAntiparallel

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Proteins and Nucleic Acidspp