Macromolecules: Carbohydrates & Lipids

Flashcards for reviewing lecture notes on Macromolecules, Carbohydrates, and Lipids.

Macromolecule

Polymers built from monomers, synthesized via dehydration reactions sped up by enzymes. They are huge molecules with a relatively high concentration in our bodies.

Polymer

A macromolecule constructed by covalent bonding of smaller molecules called monomers.

Monomer

The building block of a polymer.

Carbohydrate

Macromolecule whose monomer is a monosaccharide.

Lipid

Macromolecule whose monomer is a fatty acid.

Starch

A polymer of glucose used by plants as a source of stored energy, with two forms: amylose (simple chain) and amylopectin (loosely branching).

Glycogen

A polymer of glucose used by animals, fungi, and bacteria as a source of stored energy. It is similar in shape to amylopectin but much more densely branching.

Cellulose

A structural molecule that gives organisms shape. It's the most abundant organic compound on Earth, found in plant cell walls. Plants produce ~100 billion tons of cellulose/year.

Chitin

A structural molecule found in fungal cell walls as well as insect and crustacean exoskeletons.

Monosaccharide

Simple sugars with 2-7 carbons, such as glucose, fructose, etc. (CₓH₂ₓOₓ)

Disaccharide

Two sugars bonded together.

Oligosaccharide

Few sugars (3-10) bonded together.

Polysaccharide

Many sugars (10+) bonded together.

Glycosidic Link

A covalent bond formed between two monosaccharides by a dehydration reaction.

Lipids

Nonpolar, hydrophobic compounds composed of carbon-carbon and carbon-hydrogen bonds.

Fatty Acid

A monomer of lipids that can be saturated (single C-C bonds) or unsaturated (one or more C=C double bonds), attached to a glycerol head by a dehydration reaction.

Saturated Fatty Acid

Fatty acids with only single C-C bonds; linear and pack tightly together, solid at room temperature, high melting point.

Unsaturated Fatty Acid

Fatty acids with one (mono-) or more (poly-) C=C bonds; kinked, pack loosely together, fluid at room temperature, low melting point.

Glycerol

An alcohol composed of three carbons; the 'head' to which fatty acids attach to form triglycerides.

Triglyceride

Three fatty acids + 1 glycerol; fats and oils that are entirely hydrophobic and used for energy storage, thermal insulation, and organ cushioning.

Phospholipid

Two fatty acids + 1 glycerol + 1 phosphate group; amphipathic and form lipid bilayers in plasma membranes.

Steroid

Four fused hydrocarbon rings; hydrophobic molecules involved in membrane fluidity, lipid-soluble vitamins, and sex hormones.

Amphipathic

Having both hydrophilic and hydrophobic regions.

Trans fat

An unsaturated fat containing one or more trans double bonds.