chap1chemicalcompositionofthecell-130207030039-phpapp02

The Chemical Composition of Organisms

What makes compounds inorganic or organic?

ELEMENTS IN THE CELL

There are about 92 element occurring naturally in nature.

From these 92 element, only about 25 element are needed to build living organisms.

Not all these element found in all living cell.Main elements (CHON) are the most

frequently found elements in cells, forming about 96% of the human body mass.

Trace-elements are the elements are found in small quantity in cells, but are important in biological processes.

CHEMICAL COMPOUNDS IN THE CELL

ORGANIC INORGANIC• Chemical compounds

contain carbon (exception are carbon monoxide, carbon dioxide, carbides and carbonates which are typically considered as inorganic)

• Are usually found in and originate from living organism.

• Usually consist of macromolecules (large molecules)

• Chemical compounds that do not contain carbon

• Usually a smaller and simpler than organic compounds

• Founds in cells water, acids, alkalis and mineral salts

There are 4 main group of organic compounds in cells

CarbohydratesLipids

ProteinsNucleic acids

CARBOHYDRATESThe carbohydrates are made up of carbon,

hydrogen and oxygen. The ratio of hydrogen to oxygen atoms in a molecule usually 2:1.

Many carbohydrates have the general formula CX(H2O)Y, where x is approximately equal to y.

Three basic types of carbohydrates are monosaccharide, disaccharides and polysaccharides

Monosaccharide'sMonosaccharide also called simple sugarThe common monosaccharide are six-carbon

sugar Examples of monosaccharide are glucose,

fructose (fruit sugar) and galactoseGlucose is the most common monosaccharideMonosaccharide are sweet-tasting crystalline

substances which are soluble in water

DisaccharidesDisaccharides are formed from two monosaccharide

molecules combining together with the elements of a molecule of water. The chemical reaction of the formation is known as condensation.

Disaccharides also called double sugar.Disaccharides can be broken down to their constituent

monosaccharide by a chemical reaction involving the addition of water. The reaction is know as hydrolysis.

Like monosaccharide, they are sweet-tasting crystalline substances that are soluble in water.

The most common disaccharides are maltose, lactose and sucrose.

PolysaccharidesMany monosaccharide molecules join together

in a condensation reaction (with the removal of water molecules) to form a large polysaccharides molecules.

Polymerisation is the process of condensing many individual monosaccharide molecules to form a large polysaccharides molecules.

In polymerisation, the individual monosaccharide molecule are called monomers.

Polymerisation of monosaccharide forms:Glycogen – in humans and animalsStarch and cellulose – in plants

Hydrolysis

Condensation

C12H22O11

sucrose

+ H2 O

water C6H12O6

fructose

C6H12O6

glucose

+

Starch structure

glucose

•Sub unit: Glucose

•Molecules with many side branches

•Major storage of carbohydrates in animals and fungi, for examples, in muscle cells and liver cells

glycogen

glucose

cellulose

Straight unbranched chain of glucose unitsPlant cell wall

ProteinsProteins are compounds of these element:

carbon, hydrogen, oxygen, nitrogen sulphur and phosphorus.

Amino acids are the subunits of all proteins.Each amino acids carries two functional

group:A carboxyl group (- COOH) which is acidic

andAn amino group (-NH2) which is basic.

Types of ProteinsTwo amino acids can combine together to form a

dipeptide by a condensation reaction between the carboxyl group of one and the amino group of the other. The resulting a bond linking the two amino acids that is called a peptide bond.

Long chains of amino acids are called polypeptides.A polypeptide is formed by the condensation

reaction of many amino acids, with the removal of water.

A polypeptide chain can also be hydrolysed, with the addition of water molecules to form individual amino acids.

cooh Hn c nC C c c NH2 hooc nh2 hooc

O h h

H2O

condensation

Peptide bond

LIPIDS

Lipids a diverse group of substance that contain carbon, hydrogen and oxygen, but in different proportions to carbohydrate's.

All lipids are insoluble in waterLipids dissolve readily in other lipids and in

organic solvent such as ether and ethanol.The main types of lipids are:

Fats, energy-storing moleculeOils, energy-storing moleculePhospholipids, an important component of the

cell membraneSteroids, act as hormones and vitamins

VitaminsOrganic molecules that are required for

normal functioning.Animals are able to synthesise some

vitamins but most are sourced from dietVitamins are either water or lipid solubleWater soluble vitamins are not stored in

the bodyLipid soluble vitamins can be stored Vitamins are essential for enzyme

development

Nucleic AcidsIs genetic material, it codes what makes up

an organismDeoxyribonucleic Acid, DNA, codes our

genesRibonucleic acid, RNA, is DNA that has

been transcribed.

Inorganic CompoundsWater, where life evolved and reactions

take placeOxygen (21%) and carbon dioxide (0.033%)Nitrogen (78%) a key component of proteinsMinerals such as calcium and potassium

The skeletal structure contains 99% of the bodies calcium, the phosphate salts in calcium provide the mechanical rigidity bones need to bear loads.