carbohydrates

which elements make up carbohydrates

carbon, hydrogen, oxygen

metabolism

the sum of all chemical reactions in an organism/cell

catabolic reactions

break down larger molecules into smaller molecules

examples of catabolic reactions

digestion, maltose+water=glucose

anabolic reactions

build smaller molecules into larger moleculese

examples of anabolic reactions

photosynthesis, protein synthesis

monosaccharides

simples sugars that dissolve in water

what does the fact that monosaccharides dissolve in water affect

they can effect the water potential and osmotic balance of a cell

general formula of monosaccharides

CnH2nOn

structure of alpha glucose

hexagon ring, oxygen in top right corner, at carbon 1 hydrogen points up , hydroxyl points down- same at carbon 4- at carbon 5 carbon 6 sticks up from it

beta glucose

same strcture as alpha glucose except the hydroxyl and hydrogen are swapped on carbon 1

how can alpha and beta glucose be describes as

isomers of each other

isomers

have the same molecular formula but different structures

examples of monosaccharides

hexose and pentose sugars

hexose sugars

fructose, galactose

features of hexose sugars

6 carbons, formula- c6h12o6, all isomers of each other

pentose sugars

ribose, dioxyribose

features of pentose sugars

5 carbons, general formula- c5h10o5, all isomers of each other

disaccharides

2 monosaccharides joined with a glycosidic bond between the hydoxyl on carbon4 and carbon 1

what type of reaction forms disaccharides

condensation reaction- a water molecule is lost

types of disaccharides

maltose, lactose, sucrose

maltose

glucose+glucose= maltose

lactose

glucose + galactose= lactose

sucrose

glucose+ fructose = sucrose

formula for maltose

C12H22O10

reducing sugar

a sugar that can donate electrons or reduce another molecule or chemical

reducing sugars example with benedicts

Cu2+ (in benedicts solution) + e-(from reducing sugar) — Cu+ ions

qualitative tests

don’t give exact values give positive or negative results

semi quantitative tests

give a range of samples

examples of reducing sugars

galactose, glucose, fructose, maltose

examples of non reducing sugars

sucrose

what does the benedicts test test for

sugars

how does a benedicts test work with reducing sugars

they react with the copper (II) sulfate ions in the reagent which results in the addition electrons to the Cu2- ions reducing them to Cu2+ ions

positive results for beneditcs test

blue - red

what type of test is the bendeicts test

qualitative

steps of benedicts test

place sample in liquid form into boiling tube, add equal volume of reagent, heat gently in water abth for 5 mins

what does a greater amount of reducing sugar mean

more precipitate formed and less blue Cu2- ions so more red

what does a centrifuge do

spins test tube to speed up the seperation of the Cu+ ions that are red and the benedicts reagent

what does a large concentration of sugar mean for the colour

will be a paler blue

what does a large concentration of sugar mean in terms of absorption when using a colorimeter with a red filter

low absorption

what does a low absorption mean

high transmission

what does low absorption tell us about the colour and concentration of sugars

paler blue, high concentration of sugar

what is the relationship between colour, concentration and absorption

greater concentration= pale colour with little absorption

what is iodine used to test fpor

starch

positive results for starch

changes from a yellow/brown to a blue/black/purple colour

what does biuret test for

proteins

how does the biuret test work

biuret reacts with the peptide bonds present in proteins

steps for biuret test

add equal volume of sodium hydroxide to the solution, add copper sulfate solution in drops(biuret solution)

positive result for protein

blue- purple colour

why does a purple indicate a positive result

peptide bonds form violet coloured complexes with copper ions in alkaline solution

where are the copper ions found

the biuret solution

test for lipids

emulsion test

steps for emulstion test

mix sample with ethanol, mix with water ,shakep

positive result for lipids

white emulsion forms a layer on top of solution

why does the test for lipids work

lipids are soluble in ethanol so are dissolved, they are insoluble in water so they form an emulsion

what type of molecules are polysaccharides

macromolecules

are polysaccharides soluble or insoluble

insoluble

what bonds are in polysaccharides

glycosidic bonds

examples of polysaccharides

amylose, amylopectin, glycogen, cellulose

which polysaccharides are starches

amylose, amylopectin

what monomers is amylose made up of

alpha glucose

where is amylose found

plants

what is the shape of amylose

spiral shape due to bond angles between carbon 1 and 4

why is amylose important in plants

it stores the glucose made in photosynthesis

what is a benefit to the plant that amylose is a starch

starches are insoluble and metabolically inactive so don’t affect the chemical reaction within the cell or affect the osmotic balance or water potential

what is the benefit to the structure of amylose

the spiral is compact so a lot of starch can be stored in one small space so there are many glucose molecules in a small space that can be used

what bond holds the coil in place

hydrogen

how do enzymes enable glucose to be used from amylose

glucose molecules on the end of chains may be hydrolised by enzymes so it can be used

where does most enzyme action take place in amylose

at the end of chains

what monomers make up amylopectin

alpha glucose

what type of bond is between the carbon 1 and 4

glycosidic bond

what kind of molecule is amylopectin

branched

how does amylopectin achieve its branched structure

the hydroxyl on carbon 6 bonds to carbon1 on the next chain of alpha glucose with a glycosidic bond

how does the branched structure of amylopectin aid the plant

the branches means there are more end points so the are more glucose molecules available to be hydrolised and used

where is glycogen found

in animals as a storage for glucose

is glycogen a starch

no

is glycogen soluble or insoluble

insoluble

what kind of molecule is glycogen

branched

how is glycogen different to amylopectin

it has more 1,6 bonds

what does more 1,6 bonds mean glycogen is good for/ structurally

is more compact so more glucose can be stored- more branches exposed to hydrolytic enzymes so more glucose can be hydrolysed to use as energy

what is different about cellulose compared to other polysaccharides

it holds a storage not structural role

what monomer makes up cellulose

beta glucose

why is cellulose strong

it has to be able to withstand the tugor pressure from the permanent vacuole

what kind of molecule is cellulose

linear- it is made up of many long chains of beta glucose monomers and is unbranched

how do the beta glucose monomers bond together

the same way as alpha glucose- through a condensation reaction and glycosidic bonds

what is different about the way that beta glucose monomers bond

every other beta glucose monomer flips 180 degrees

why do alternate beta glucose monomers flip

the hydroxyl groups on carbon1 and 4 are too far apart from each other to react otherwise so they flip so they can form glycosidic bonds

how do cellulose molecules bond to form microfibrils

hydrogen bonds between each chain from the OH on carbon 2 to the H from the carbon 6 on the adjacent beat glucose

what do many chains of beta glucose make up

microfibrils

what do many microfibrils make up

macrofibrils

where are macrofibrils found

embedded in pectins to form the cell wall