monomers + polymers and carbohydrates

Define monomers

• smaller units which can create larger molecules

Define polymers

• made from lots of monomers joined together

Examples of monomers

• amino acids

• Nucleotides

• Monosaccharides

What forms a glycosidic bond

Condensation reaction between 2 monosaccharides

Hows a disaccharide formed

Condensation reaction between 2 monosaccharides

How is the disaccharide maltose, lactose and sucrose made

Glucose + glucose = maltose

Glucose + galactose = lactose

Glucose + fructose = sucrose

Hows a polysaccharide formed

Condensation of many glucose units

Function of starch and explain starch

• formed by 2 polymers of alpha glucose (amylose and amylopectin)

• Function - insoluble store of glucose in plant cells

• Amylose - unbranched chain of a-glucose, compact so good for storage

• Amylopectin - branched chain of a-glucose, side branches allow glucose to be released quickly

• Branched structure increases surface area for rapid hydrolysis back to glucose

• forms 1-4 glycosidic bonds, 1-6 glycosidic bonds forms a branch

Glycogen function and explain

• formed from a-glucose

• Function - insoluble store of glucose in animal cells

• Compacted so good for storage

• Highly branched, has even more 1-6 glycosidic bonds, has 1-4 bonds aswell

• More side branches so stored glucose can be released quickly

• branched structure increases surface area fro rapid hydrolysis back to glucose

Function of cellulose and explain

• formed from b-glucose

• Function - provides structural strength to cell wall in plants so they dont burst when turgid

• When beta molecules bond they form straight cellulose chains

• Cellulose chains are liked by hydrogen bonds to form strong fibres (micro fibrils)

• Strong vibes provide structural support for cells

• Only has 1-4 glycosidic bonds as its a straight chain

Whys it good that starch is insoluble

• starch is insoluble in water and doesnt affect water potential

• So it doesnt cause water to enter cells by osmosis which would make them swell

• So this makes them good fro storage

Test for sugars

• add Benedict’s reagent

• Changes from blue to brick red (green, yellow, orange)