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THE STRUCTURE AND FUNCTION THE STRUCTURE AND FUNCTION OF MACROMOLECULESOF MACROMOLECULES

Polymer principles

And

Macromolecules

Polymer principles

And

Macromolecules

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• Cells join تربط smaller organic molecules (MonomersMonomers) together to form larger molecules (macromolecules) macromolecules) ((PolymersPolymers)), which may be composed of thousands of atoms.

• Macromolecules are organic molecules that weigh more than 100,000 daltons (ATOMIC MASS UNIT).

• The four major classes of macromolecules are:

1)1)-Carbohydrates, -Carbohydrates, 2)2)-Lipids, -Lipids, 3)3)-Proteins, -Proteins, 4)4)-Nucleic acids (-Nucleic acids (will be studied laterwill be studied later))

Polymers principlesPolymers principles

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• Monomers are connected by Monomers are connected by covalent covalent bondsbonds by by a a dehydration reaction dehydration reaction

الماء نزع الماء تفاعل نزع ..تفاعل– One monomer provides a One monomer provides a hydroxyl hydroxyl

groupgroup and and the other provides a the other provides a hydrogenhydrogen to form water.to form water.

– This process requires energy and is This process requires energy and is aided by aided by enzymes. enzymes.

• The covalent bonds connecting monomers in a polymer are disassembledThe covalent bonds connecting monomers in a polymer are disassembled

ــر ــرتُـكَس� الماء تفاعلتفاعل by by hydrolysis hydrolysis (hydration) reaction (hydration) reaction تُـكَس� الماء إضافة إضافة ..– In hydrolysis as the covalent bond is broken a In hydrolysis as the covalent bond is broken a

hydrogen atom and hydroxyl group from a split hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent water molecule attaches where the covalent bond used to be.bond used to be.

– Hydrolysis reactions dominate the digestive Hydrolysis reactions dominate the digestive process, guided by specific enzymes. process, guided by specific enzymes.

(Carbohydrates, Lipids, Proteins and nucleic (Carbohydrates, Lipids, Proteins and nucleic acids)acids)

Mono-mer Di-mer Poly-mer

PolymerPolymer is a long molecule consists of a chain of is a long molecule consists of a chain of similar building molecules (similar building molecules (monomersmonomers) covalently ) covalently bonded together.bonded together.

أحادأحاديي

ثنائثنائيي

عديدعديد

A. CarbohydratesA. Carbohydrates

1. Monosaccharides: are the simplest carbohydrates (simple sugars).are the simplest carbohydrates (simple sugars).

contain a single sugar moleculecontain a single sugar molecule

2. Disaccharides: contain two monosaccharides joined via dehydration contain two monosaccharides joined via dehydration

synthesissynthesis

3. Polysaccharides: are polymers of many monosaccharides.are polymers of many monosaccharides.

Sugars, Carbo = carbon, hydrate = water; Used as an immediate energy sourceCarbon to hydrogen to oxygen ratio = 1:2:1

AldosAldosee

AldosAldosee

Asymmetric Asymmetric CC

Asymmetric Asymmetric CC

1- Monosaccharides 1- Monosaccharides الَسكرالَسكر األحادياألحادي

C

C

C

C

C

C

OOHH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

OOHH

HH

HH

CC

C

C

C

C

C

OOHH

OOHH

OOHH

OOHH

OOHH

HH

HH

HH

HH

OOHH

HH

HH

GlucosGlucoseeCC66HH1212OO66

GalactoseGalactoseCC66HH1212OO66

Aldehyde sugars

• An OH group is attached to each carbon except one, which is double bonded to an oxygen (carbonyl).

KetosKetosee

C

C

C

C

C

C

OOHH

HH

OOHH

OOHH

OOHH

OOHH

HH

HH

HH

HH

OO

HH

HH

FructosFructoseeCC66HH1212OO66

C

C

C

OOHH

OOHH

HH

OOHH

HH

HH

Glyceraldehyde

C

C

C

C

C

OOHH

OOHH

OOHH

OOHH

HH

HH

HH

OOHH

HH

HH Ribose

Ketone sugar

Triose Triose SugarSugar

Pentose SugarPentose Sugar Hexose Hexose SugarSugar

Monosaccharides are classified as followingMonosaccharides are classified as following

Aldoses: are the monosaccharides with the carbonyl group

(C=O) at the end of CC chain (e.g. Glucose).

Ketoses: are the monosaccharides with the C=O carbonyl group within داخل the CC chain (e.g. Fructose).

Triose (3C3C): e.g. Glyceraldehyde.

A- Based on the location of the A- Based on the location of the

carbonyl groupcarbonyl groupC=OC=O

B- Based on the number of B- Based on the number of CC in the skeleton in the skeleton

Pentose (5C5C): e.g. Ribose.

HexoseHexose (6C6C): e.g. Glucose, Fructose and Galactose.

2- Disaccharides 2- Disaccharides السكر السكرييالثنائالثنائ

Consist of 2 monosaccharide molecules joined during Consist of 2 monosaccharide molecules joined during a a dehydrationdehydration reaction reaction الماء نزع الماء تفاعل نزع ..تفاعل

SucroseSucrose ( (table sugartable sugar): consists of ): consists of Glucose + Glucose + FructoseFructose..

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3- Polysaccharides 3- Polysaccharides السكر السكرالعديدالعديد

Consists of few Consists of few hundredshundreds to few to few thousandsthousands of monosaccharides. of monosaccharides.

They are two types:They are two types:

1- Storage1- Storage تخزينيةتخزينية. . Provide sugarProvide sugar for cell by hydrolysis for cell by hydrolysis إضافة إضافة . .ماءماء

2- Structural 2- Structural تركيبية. . Serve as Serve as building materialsbuilding materials for the for the organism. organism.

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I- Starch (in plants) النشا

A storage polysaccharide of plants (A storage polysaccharide of plants (within plastids).).

It consists of thousands of It consists of thousands of glucose glucose molecules. molecules.

Thus, it gives glucose when Thus, it gives glucose when hydrolysed hydrolysed الماء by special enzymes in by special enzymes in بإضافةhumanshumans . . PotatoesPotatoes and and grainsgrains are the major source of starch. are the major source of starch.

A)- Storage A)- Storage تخزينيةتخزينية PolysaccharidesPolysaccharides

II- Glycogen II- Glycogen (in animals)

الجليكوچـينالجليكوچـينStored in animal cells (Stored in animal cells (e.g. liver and muscle cells in Human).).

It is consists of thousands of It is consists of thousands of glucose moleculesglucose molecules..

Thus, it gives glucose when hydrolysed. Thus, it gives glucose when hydrolysed.

B)- Structural B)- Structural تركيبيةتركيبية PolysaccharidesPolysaccharides

I- CelluloseI- Cellulose

Forms the micro-fibrils and cell wall in plants.Forms the micro-fibrils and cell wall in plants.

It is consists of thousands of It is consists of thousands of ββ glucoseglucose molecules. molecules.

Humans cannot digest it, but some bacteria and protozoa can (Humans cannot digest it, but some bacteria and protozoa can (e.g. in Termites and Cows stomach). ).

It is the building material of plants (cell wall).It is the building material of plants (cell wall).

II- Chitin II- Chitin الكيتينالكيتين

It is consists of thousands of glucose molecules with a NN atom in one end.

It is used to manufacture the surgical threads.

It is the building material of the cuticle يد� ـَل Kالُج in insects.

CarbohydratesCarbohydrates

AldoseAldoseC=O on top

KetoseKetoseC=O in chain

(Glucose)(Glucose)

MonosaccharidMonosaccharideses

DisaccharideDisaccharidess

PolysaccharidePolysaccharidess(Sucrose)(Sucrose)

StorageStorage StructuraStructurallStarch (Starch (inin plantsplants) )

& &

Glycogen (Glycogen (inin animalsanimals))

Cellulose (Cellulose (inin plantsplants))

& & Chitin ( Chitin (inin insectsinsects))

No. of sugar moleculesNo. of sugar molecules

Location of Location of Carbonyl Carbonyl

GroupGroup

No. of No. of CC atoms atoms

TrioseTriose ( (3C3C) ) GlyceraldehydeGlyceraldehyde

Pentose (Pentose (5C5C) ) RiboseRibose

Hexose (Hexose (6C6C))GlucoseGlucose