Macromolecules - Carbohydrates and Lipids

macromolecules

large molecules, necessary for life, built from smaller organic molecules

four major classes of macromolecules

carbohydrates, lipids, proteins, nucleic acids

dehydration synthesis

to put together while losing water

monomers

single subunits that serve as building blocks for macromolecules

polymers

many monomers connected together with covalent bonds

hydrolysis

process in which polymers break down into monomers

carbohydrates

group the includes sugars and polymers of sugars. contribute to cell structure, play important role in energy, involved in cell recognition and identity

three classes of carbs

monosaccharide, disaccharide, polysaccharide

monosaccharides

simple sugars. number of carbons ranges from 3-7 and the most common is glucose

monosaccharides vary in these four ways:

location of carbonyl group, number of carbon atoms present, spacial arrangement of their atoms, can exist in linear and alternative ring forms

aldose

if carbonyl group is at the end

ketose

if carbonyl group is in the middle

triose

3 carbons

pentose

5 carbons

hexose

6 carbons

disaccharides

composed of two monosaccharides and joined by dehydration synthesis

glycosidic bonds

covalent bond between a carbohydrates and another molecule

polysaccharides

many monosaccharides linked by glycosidic bonds

energy storage polysaccharides:

starch and glycogen

structural polysaccharides

cellulose and chitin

starch

storage form of glucose in plants

glycogen

storage form of glucose in humans

cellulose

plant cell walls

chitin

arthropod exoskeletons

lipids

groups that include fats, oils, waxes, phospholipids, and steroids

mainly hydrocarbons and are hydrophobic

2 main components of fats

glycerol and fatty acid

glycerol

organic compound with 3 carbons, 5 hydrogens, and 3 hydroxyl groups

fatty acids

long chain of hydrocarbons with a carboxyl group (COOH)

fatty acids can be:

saturated or unsaturated

saturated

if in a long chain, there are only single bonds between neighboring carbon in hydrocarbon chain

unsaturated

when the hydrocarbon chain contains at least one double bond

oil

an unsaturated fat at room temperature

polyunsaturated

more than 1 double bond in the hydrocarbon chain

monounsaturated

one 1 double bond in hydrocarbon chain

phospholipids

comprised of 2 fatty acid chains, glycerol and phosphate group

amphipathic

molecule with hydrophobic and hyphilic part

steroids

fused ring structure of 4 interconnected rings of carbon atoms

why are steroids grouped with lipids?

they are hydrophobic and insoluble in water