Chapter 3.1: Lipids Are Characterized by Their Insolubility in Water

Flashcards from Chapter 3.1 of Principles of Life, 3rd Edition.

Polymers

Molecules made of smaller molecules called monomers; in macromolecules, these contain carbohydrates, nucleic acids, and proteins as they form long chains

Residues

The name for monomers when inside a polymer

Lipids

Non-monomers characterized by insolubility and aggregation in water, formed out of C—C and C—H bonds

• Have variable melting points due to size and packing

Fatty acid

A non-polar hydrocarbon chain with a polar terminal carboxyl functional group, thus giving it amphipathic traits

Phospholipid

Fatty acids bound to glycerol that also contain an amphipathic phosphate; these help form water-excluding bilayers as a result of aggregation and can transport materials with proteins

Lipoproteins

Structures with hydrophobic interiors and hydrophilic exteriors to transport lipids like triglycerides and cholesterol in water

Glycerol

A three-carbon molecule with three hydroxyl groups

Saturation

• Possessing this gives a lipid a straight, long chain with only single bonds for hydrogen and carbon, allowing for higher melting points

• Without this, lipids can have double bonds with carbons and be more loosely packed, giving it lower melting points

Triglycerides

Lipids with 3 fatty acids linked to glycerol via condensation; these are the most common and are best for energy storage

Wax

A lipid with a long-chain alcohol bound to a fatty acid; these are very hydrophobic

• This coats the leaves of plants to reduce water loss and protect against pathogens

Carotenoid

Lipids with a repeating, branched five-carbon unit; these enable light absorption

Steroid

Lipids with a 17-carbon atom core in four fused rings

• Some hormones are a type of these, functioning as signals

White fat

This type of fat stores energy and provides insulation in mammals

Brown fat

This type of fat gets its color from iron-rich mitochondria and regulates temperature in infants