unit 1

Flashcards covering key vocabulary terms from the Chemistry of Life lecture notes.

Proteins

Polymers made up of amino acid monomers.

Amino acids

A central carbon bonded to a carboxyl group (COOH) at one end, an amino group (NH2) at the other end, a hydrogen atom, and an R group (variable group or side chain).

Peptide bonds

Link amino acids through dehydration synthesis between the amino and carboxyl groups of adjacent monomers.

Primary structure

The unique sequence in which amino acids are joined.

Secondary structure

One of two three-dimensional shapes that are the result of hydrogen bonding between members of the polypeptide backbone

Alpha (a) helix

A coiled shape, much like a slinky.

Beta (B) pleated sheet

An accordion shape.

Tertiary structure

A complex globular shape resulting from interactions between the side chains (R groups), such as hydrophobic interactions, van der Waals interactions, hydrogen bonds, and disulfide bridges.

Quaternary structure

The association of two or more polypeptide chains into one large protein.

Denatured (protein)

When a protein loses its shape and ability to function because of heat, a change in pH, or some other disturbance.

Fatty acids

Hydrocarbon chains of variable lengths that are nonpolar and therefore hydrophobic.

Saturated fatty acids

Have no double bonds between carbons and tend to pack solidly at room temperature; commonly produced by animals.

Unsaturated fatty acids

Have some C=C (carbon double bonds); these result in kinks and tend to be liquid at room temperature; commonly produced by plants.

Energy storage (fats)

Store more than twice as many calories per gram as carbohydrates.

Phospholipids

A major component of cell membranes with a hydrophilic (polar) head that includes a phosphate group and two fatty acid tails, which are hydrophobic.

Steroids

Has a carbon skeleton of four rings that are fused together.

Polysaccharides

Polymers of monosaccharides.

Starch

A storage polysaccharide found in plants.

Glycogen

A storage polysaccharide found in animals.

Cellulose

A major component of plant cell walls.

Chitin

Found in the exoskeleton of arthropods and the cell walls of fungi.

Polymers

Long chain molecules made of repeating subunits called monomers.

Dehydration reactions

Create polymers from monomers by joining two monomers by removing one molecule of water.

Hydrolysis

Occurs when water is added to split large molecules; the reverse of dehydration.

Atomic number

The number of protons in an element.

Mass number

The sum of its protons and neutrons.

Chemical bonds

Interactions between the valence electrons of atoms; hold atoms together to form molecules.

Covalent bonds

Occur when valence electrons are shared by two atoms.

Nonpolar covalent bonds

Occur when the electrons being shared are shared equally between the two atoms.

Electronegativity

A tendency to attract the electrons of a covalent bond.

Ionic bonds

Chemical bonds resulting from the attraction between oppositely charged ions.

Hydrogen bonds

Weak chemical interactions that form between the positively charged hydrogen atom of one molecule and the strongly negative oxygen or nitrogen of another molecule.

Van der Waals interactions

Very weak, transient connections that are the result of asymmetrical distribution of electrons within a molecule.