biological molecules

monomers

small single units that create bigger molecules

polymers

made up of many monomers bonded together

condensation reaction

removal of a water molecule from monomers enables a chemical bond to form (between 2 monomers)

hydrolysis reaction

water molecule added between 2 monomers to break the chemical bond

name the 3 monomers and their polymers

nucleotides → polynucleotide

monosaccharides (glucose) → polysaccharides (starch)

amino acids → polypeptides (proteins)

function of carbohydrates

provide energy and structural support to plant cells

name the 3 monosaccharides and their disaccharides they make

glucose + glucose → maltose

glucose + fructose → sucrose

glucose + galactose → lactose

property & function of monosaccharides

sugars and soluble in water

provide energy or act as building blocks for large molecules

what do all carbohydrates contain

carbon, hydrogen and oxygen

2 isomers of glucose

alpha glucose & beta glucose

alpha glucose

OH group on bottom

beta glucose

OH group on top

what are disaccharides

2 monosaccharides bonded together by glycosidic bond (condensation reaction)

what are polysaccharides

polymers made up of many monosaccharides

made by condensation reactions

3 main polysaccharides

starch, glycogen, cellulose

starch

found in plants, NOT animal cells & is energy store

made from excess glucose from photosynthesis & converted into starch for storage

structure of starch

alpha glucose

joined via condensation reactions

held by 1,4 and 1,6 glycosidic bonds

2 polymers that make up starch

amylose and amylopectin

amylose structure

coiled shape, joined by 1,4 glycosidic bonds

amylopectin structure

1,4 and 1,6 glycosidic bonds, branched structure (due to 1,6)

properties of starch (inc. amylose & amylopectin)

insoluble, can be stored within cell and not dissolve & won’t change water potential of cell and osmosis won’t occur

amylose; spiral shaped so compacted

amylopectin; branched so large surface area for enzymes to attach to

starch is readily hydrolysed back into glucose when plant cells running low on glucose for respiration