*Poly = many; -mer = part. A polymer is a large molecule consisting of many smaller sub-units bonded together called monomers

*Monomers are covalently linked to one another through the removal of water (dehydration reaction) to form polymers.

What is a polymer?Polymer is a long molecule consists of a chain of similar building molecules (monomers) covalently bounded together.

Polymers principles:Polymers principles:

•Carbohydrates Carbohydrates •Lipids Lipids •ProteinsProteins•Nucleic acidsNucleic acids

Q: How do monomers connect?A: By dehydration reaction

One monomer One monomer provides a provides a hydroxyl hydroxyl groupgroup

One monomer One monomer provides a provides a hydrogyn hydrogyn groupgroup

Covalent Bond

Monomers Polymer

Polymer Monomers

By DehydrationForms Covalent

bonds

By Hydrationbreaks Covalent

bonds

1. Carbohydrates:

• The hydration reaction disassembles the covalent bonds in the polymer and convert it to small monomers. This reaction dominate the

digestive process with the help of specific enzymes.

• THIS REACTION NEEDS WATER.

• It happens when H and OH (from the water) attaches where the bond used to be.

Add water

Add water

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• The dehydration reaction convert the small monomers into one large polymer.

• THIS REACTION PROVIDES WATER.• It happens when H atom

from one monomers attaches with OH from another one to create water and new polymer.

DisaccharidesDisaccharides

Consisted of 2 monosaccharide molecules during Consisted of 2 monosaccharide molecules during

a a dehydrationdehydration reaction. reaction.

e.g. Sucrosee.g. Sucrose ( (table sugartable sugar): consists of ): consists of Glucose + Glucose + FructoseFructose..

It is consisted of ββ glucose molecules.glucose molecules.

““Human cannot digest itHuman cannot digest it, but some bacteria and , but some bacteria and protozoa can”protozoa can”

It is the building material in insects.It is consisted of thousands of glucose molecules and an N atom at the end.

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Consisted of few hundreds to few thousands of monosaccharaides

Cellulose (in Plants):It forms the micro-fibrils and

cell wall in plants & it consisted of beta glucose molecules.

Cellulose (in Plants):It forms the micro-fibrils and

cell wall in plants & it consisted of beta glucose molecules.

ChitinIt is the building material of the cuticle in insects. It consists of 1000s of glucose with N atom

at the end.

ChitinIt is the building material of the cuticle in insects. It consists of 1000s of glucose with N atom

at the end.

Surgical threadSurgical thread

insectsinsects

* Starch is a plant storage from of energy, easily hydrolyzed to glucose units

* Cellulose is a fiber-like structural material - tough and insoluble - used in plant cell walls

* Glycogen is a highly branched chain used by animals to store energy in muscles and the liver.

* Chitin is a polysaccharide used as a structural material in arthropod exoskeleton and fungal cell walls.

Proteins is a polymer of amino acids “ there are 2o different amino acids” .

The proteins are consisted of Hydrogen atom, carboxyl group, Amino acid and R group ( variable )

Amino acids are joined together with peptide bond by dehydration reaction.

Side chain

Amino group

Carboxyl group

CCHH

RRNN

HH

HHCC

OOHH

OO

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The repeated sequence (N-C-C) is the polypeptide backbone.

the amino acids that have hydrophobic R groups (non-

polar).

the amino acids that have hydrophobic R groups (non-

polar).

the amino acids that have polar R groups, making them hydrophilic.

the amino acids that have polar R groups, making them hydrophilic.

the amino acids with functional

groups that are charged

(ionized) at cellular pH (7).

So, some R groups are

bases, others are acids.

the amino acids with functional

groups that are charged

(ionized) at cellular pH (7).

So, some R groups are

bases, others are acids.

None Polar R Group

Polar R Group

Functional R Group

Lipids do not form polymer

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store large amounts of

energy

major components of cell membranes

include cholesterol and

certain hormones

In a fat, three fatty acids are joined to glycerol by

an ester linkage, creating a triacylglycerol.

In a fat, three fatty acids are joined to glycerol by an ester In a fat, three fatty acids are joined to glycerol by an ester linkage creating a triacylglycerol. linkage creating a triacylglycerol.

Phospholipids have two fatty acids attached Phospholipids have two fatty acids attached to glycerol and a phosphate group( Two tails to glycerol and a phosphate group( Two tails and a head ) the tails are hydrophobic and and a head ) the tails are hydrophobic and the head is hydrophilic . the head is hydrophilic .

form sex hormones and CholesterolCholesterol

The Fatty acid components are saturated (there is no double bonds between the carbons. All C are linked with H. Thus, it

is saturated with H

The Fatty acid components are saturated (there is no double bonds between the carbons. All C are linked with H. Thus, it

is saturated with H

Most animal fats are saturated. They are solid at room temperature. Saturated fats-rich diet results in

Atherosclerosis.

Most animal fats are saturated. They are solid at room temperature. Saturated fats-rich diet results in

Atherosclerosis.

These double bonds are formed by the removal of H atoms. They can be synthetically converted to saturated (solid) by adding H (Hydrogenation).

These double bonds are formed by the removal of H atoms. They can be synthetically converted to saturated (solid) by adding H (Hydrogenation).

Most vegetable fats (oils) and fish fats are unsaturated.

They are liquid at room temperature.

Most vegetable fats (oils) and fish fats are unsaturated.

They are liquid at room temperature.

there is there is no double bonds no double bonds between the between the carbonscarbons“ “ Most animals Fats are saturated” And they Most animals Fats are saturated” And they are solid at the room temperature. are solid at the room temperature.

The double bonds are formed by removing the H atoms. “ Most vegetables oils and fish oils are Un-saturated “ And they are liquid at room temperature.

Hydro

genat

ion

l-fah

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They are arranged as a bilayer and it forms a barrier between the cell and the outside

since they are a part of the cell membranes.

They have two fatty acids

Attached to glycerol

And a phosphate group

The

phos

phol

ipid

s

are

amph

ipat

hic

amph

ipat

hic

* Q1: Write whether each of the following statements is True (T) or False (F):

* 1-The four classes of organic compounds- carbohydrates, proteins, lipids and nucleic acids are called polymers.

* 2-Polysaccharides are polymers with few hundred to few thousand monosaccharides joined by peptide bond.

* 3- The glucose monomers of cellulose are in the a configuration.

* 4- Chitin is a structural polysaccharide.

* 5-Starch can be digested by humans.

* 6-Saturated fatty acids contain double bonds between carbon atoms.

* 7-Stored polysaccharides in animals are known as starch.

* 8-In cellulose, all glucose monomers are in Ɣconfiguration.

* 9-Lipids are not polymers.

* 10- Glycogen is built up of several units of glucose monomers.

*  11- DNA and RNA molecules contain a hexose sugar called fructose.

*  

* 6-Based on the number of C, sugars are classified into:

* a)- trioses b)- pentoses

* c)- hexoses d)- all a, b and c

* 7-Which of the following polysaccharide is stored in plant cells:

*a)- starch b)- cellulose

* c)- glycogen d)- chitin

* 

* 8-Polypeptides are formed when amino acids link together by:

*a)- ionic bonds b)- hydrogen bonds

* c)- ester bonds d)- peptide bonds

* 9-Sex hormones are:

* a-steroids b-fats c-phospholipids

* 10-Saturated fats are:

*a)- found in oils, and liquid at room temperature

*b)- contain double bonds

*c)- found in animal fats and solid at room temperature

*d)- can be transformed into unsaturated fats by hydrogenation

*  

*  

*