Saccharides Packet #9 Chapter - PowerPoint Presentation

Slide1

Saccharides

Packet #9Chapter #5

9/16/2009 9:24:06 PM

1Slide2

General CharacteristicsSlide3

Introduction

Saccharides are mainly used for energy and are also known as starches or sugars.Empirical FormulaCn

H2nOnWhen n = 3Called a

triose

sugar

When n = 5

Called a pentose sugar

When n = 6Called a hexose sugar

9/16/2009 9:24:13 PM

3Slide4

Isomers of SaccharidesSlide5

Isomers

There are two forms in which a triose, pentose and hexose can exist.Aldose

KetoseAldoseAn aldose sugar is identified by the presence of the functional group called the

aldehyde

.

Ketose

A

ketose sugar is identified by the presence of the functional group called the ketone.

9/16/2009 9:24:13 PM

5Slide6

MonosaccharidesSlide7

Monosaccharides

IntroductionSlide8

Monosaccharide

The “single” form of a sugarHas basic formula C6H12O6

All reduce Benedict’s reagentA solution of sodium citrate, sodium carbonate, and copper sulfate that changes from blue to yellow or red in the presence of reducing sugars, such as glucose.SweetSoluble

Easily transported

Main respiratory substrates.

9/16/2009 9:24:13 PM

8Slide9

Monosaccharides

Triose SugarsSlide10

Trioses

GlyceraldehydeAldose sugarThe

phosphorylated form is the first formed sugar in photosynthesisMay be used as a respiratory substrate or converted to starch for storageIntermediate in the Kreb’s

Cycle (Cell Respiration)

Dihydroxacetone

Ketose

sugar

Respiratory substrateIntermediate in the Kreb’s Cycle

9/16/2009 9:24:17 PM

10Slide11

Monosaccharides

Pentose SugarsSlide12

Pentose Sugars

Ribose/DeoxyriboseAldose sugarsMake up part of nucleotides

Gives structural support to the nucleic acids RNA & DNAComponent of hydrogen carrierNAD

NADP

FAD

Component of ATP

9/16/2009 9:24:18 PM

12Slide13

Pentose Sugars

RibuloseKetose sugarCarbon dioxide acceptor in photosynthesis

9/16/2009 9:24:21 PM

13Slide14

Monosaccharides

Hexose SugarsSlide15

Hexose Sugars

GlucoseAldose sugarThe presence of all the oxygen molecules ensure that glucose is strongly hydrophilicRemember, that oxygen is very electronegative and helps increase the polarity of an atom

Contains a lot of energy within it’s chemical bondsSlide16

Linear & Ring Structures of GlucoseSlide17

Ring Structures of Glucose

Glucose, when in a ring form, can exist in two different forms (isomers)α glucoseβ glucoseSlide18

Hexose

SugarsGalactoseAldose sugarRespiratory substrate

Used in the synthesis of lactoseFructoseKetose sugar

Respiratory substrate

Used in the synthesis of insulin

Component of nectar

Sweetens fruits to attract animals to aid in seed dispersal

9/16/2009 9:24:22 PM

18Slide19

MonosaccharidesSlide20

Polymerization

The process of joining monomers to form polymers.Slide21

Polymerization

Monosaccharides, a monomer, and other organic compounds, can be combined/linked together by a chemical process known as polymerization to form polymers.Di-saccharides

Occurs when two monosaccharides are joined together.PolysaccharideOccurs when many monosaccharides

are joined together.

9/16/2009 9:24:23 PM

21Slide22

Polymerization

Polymerization can occur via a dehydration synthesis/condensation chemical reaction.Water is a by-product of the chemical reaction.Slide23

PolymerizationSlide24

Disaccharides

CharacteristicsSlide25

Disaccharides

Formed by the condensation of any two monosaccharideBasic chemical formulaC12H

24O12Some reduce in Benedict’s solutionMaltoseOthers are non-reducing sugars

Sucrose

All are sweet, soluble in water and are readily converted into

monosaccharides

by the addition of a water molecule

Hydrolysis

9/16/2009 9:24:24 PM

25Slide26

Disaccharides

ExamplesSlide27

Disaccharides

Sucrose (Cane sugar)Glucose+ FructoseRespiratory substrate

The form in which most carbohydrates are transported in plantsStorage material in some plantsAllium – onionsNon-reducing sugar

Lactose (Milk Sugar)

Glucose +

Galactose

Respiratory substrate

Mammalian milk contains 5% lactoseMajor carbohydrate source for sucklings

Maltose (Malt sugar)Glucose + GlucoseRespiratory substrate

Reduce in

Benedit’s

solution

9/16/2009 9:24:25 PM

27Slide28

PolysaccharidesSlide29

Introduction

Vast majority of carbohydrates in nature are found in the form of very large polymers made up by the joining of various monosaccharides.Glucose is the most abundant sugar used in making these large polymersMost polysaccharides are

polydisperseEven when in a pure form, any given sample of the substance will vary in its size and the number of monomer units in its structureFor example, starch may have any where between 100 and 10,000 glucose monomers in a chainSlide30

Starch

StarchMade by plants as a way of storing chemical energyMajor storage carbohydrate in plants

Comes in two formsAmyloseAmylopectin

9/16/2009 9:24:26 PM

30Slide31

Amylose

AmyloseLong unbranched chain of

-glucose molecules9/16/2009 9:24:26 PM

31Slide32

Amylopectin

Contains unbranched chain of -glucose with 1,4 glycosidic

linksPlus branched chain of -glucose units with 1,4 and 1,6 glucosidic links

Branches occur every20-24 units

9/16/2009 9:24:26 PM

32Slide33

Cellulose I

Probably* the most prevalent and abundant source in naturePossible that 50% of all of the organic carbon, on the planet, is in the form of glucoseMost commonly found in plantsGives structural support to cell walls

Is in its purest form in cottonHomeworkWhat are the advantages of cotton containing 90% cellulose?Slide34

Cellulose II

Formed when -glucose molecules are joined together using their 1st and 4

thcarbonsUnbranched chain of -glucose units with 1,4

glycosidic

links + cross bridges

Reaches lengths of between 300 and over 2000 unitsSlide35

Glycogen

Animal equivalent of starchMajor storage carbohydrate in animals and fungiFound in the liver and muscles

Branched moleculeHighly branched chains of -glucose units with 1,4 glycosidic links

New branch occurring every 10 or so units along the chain

9/16/2009 9:24:27 PM

35Slide36

Chitin

A tough, protective, semitransparent substance, primarily a nitrogen-containing polysaccharide, forming the principal component of arthropod exoskeletons and the cell walls of certain fungi.Forms the basis of the hard shells of crustaceansCrab; lobster; shrimpSlide37

Chitin II

Long unbranched molecule consisting of -glucose molecules are joined together using their 1st

and 4thcarbonsMay be thought of as cellulose in which the hydroxyl groups on the second carbon are replaced with NHCOCH3 groups