Biological molecules: Carbohydrates

What elements are carbohydrates made of

What elements are carbohydrates made of

Carbon, hydrogen, oxygen

3 types of carbohydrates

Monosaccharides, disaccharides, polysaccharides

Name 3 monosaccharides

glucose, fructose, galactose

Name 3 disaccharides

sucrose, maltose, lactose

Name 3 polysaccharides

Starch, cellulose, glycogen

What is the classification of monosaccharides based on

Number of carbon atoms

Chemical formula for glucose, fructose, galactose

C₆H₁₂O₆

Chemical formula for sucrose, maltose, lactose

C₁₂H₂₂O₁₁

General formula for monosaccharides

C_nH_2nO_n

Single sugar is a

Monosaccharide

How many orientations can glucose be in

Any

How many structural isomers does glucose have

2

Structural isomer meaning

Same molecular formula, different structure

Draw alpha glucose

Draw beta glucose

a glucose + a glucose?

starch (storage molecule)

b glucose + b glucose?

cellulose (structure)

Describe a condensation reaction

Smaller monomer joins to another, water molecule is removed. Remainder = residue. Produces polymer (larger molecule)

What kind of bond does a condensation reaction create?

Covalent / glycosidic bond

Glycosidic bond

Chemical formed as a result of condensation between to monosaccharides

2 alpha glucoses create

maltose + water

beta fructose + alpha glucose

Sucrose + water

galactose + alpha glucose

lactose

molecular formula for lactose, maltose, sucrose

C₁₂H₂₂O₁₁

What are carbohydrates used for

By body for fuels (respiration) and to build cells

Monomers join together to form

Polymers

Hydrolisis

opposite of condensation. Polymer broken down into molecules. Water is added

Starch’s monomer

monomer = alpha glucose, mixture of 2 polymers

starch digested by

amylase

2 polymers that make up starch

amylose, amylopectin

Amylose structure

curly (forms helix) to be compact. only a 1-4 glycosidic bonds

Amylopectin structure

Highly branched. a 1-6 + 1-4 glycosidic bonds. Lots of terminal starch molecules to allow many glucose units to be synthesised and stored effectively

Glycogens monomer

alpha glucose

Function of glycogen

storage of glucose which allows for fast energy release when needed and is present in muscle tissue

Function of starch

Store glucose for later energy use

Glycogen structure

1-4, 1-6 alpha glycosidic bonds. highly branched. compact to store more (coiled),

polymer = large molecule, insoluble, osmotically inert.

Branched molecule = many terminal glucose molecules = easily hydrolysed for energy released in respiration

Cellulose monomer

beta glucose

Chemical equation for respiration

6H12O6 + 6O2 → 6CO2 + 6H2O

glucose + oxygen -> carbon dioxide + water

Cellulose structure

beta glucose bonds 1-4, 1-6

alternate molecuules rotate 180 degrees

parallel chains cross linked to form microfibrils for strength. prevents osmotic lysis in hypotonic solutions

long straight chains

Similarities between starch and cellulose

C,H,O

carbohydrate

monomer: glucose

polysaccharide

alpha 1 -4 glycosidic bond

Other “polysaccharides”

Contain nitrogen

Chitin: fungal cell wall

Peptidoglycon (meurin): component of prokaryotic (bacteria) cell wall