Biology Quiz Phospholipids and Steroids

Phospholipids

A lipid consisting of a glycerol bound to two fatty acids and a phosphate group., giving the molecule a two non-polar hydrophobic tails and a polar hydrophilic head.

Steriods

A lipid in which the carbon skeleton contains four fused rings with various chemicals attached. Examples are cholesterol, and sex hormones such as testosterone, and estrogen.

Polymer

A long molecule consisting of many similar or identical monomers linked together. This is a covalent compound.

Monomer

A molecule that can be bonded to other identical molecules to form a polymer.

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

Anaboilic steriod

A synthetic variant of the male hormone testosterone that mimics some of its effects.

Protein

A three dimensional polymer made of monomers of amino acids.

Tertiary structure

The third level of a protein structure; the overall three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up a chain.

Amino acids

Building blocks (monomers) of protein. An organic group containing a carboxyl group and and amino group.

Cholesterol

Steroid common in the cell membranes of animals, and is a precursor molecule for making many hormones including sex hormones.

Peptide bond

The covalent bond between two amino acid units in a polypeptide, formed by a dehydration reaction.

Primary structure

The first level of a protein structure; the specific sequence of amino acids making up a polypeptide chain.

Quaternary structure

The fourth level of a protein structure; and the shape resulting from the association of two or more polypeptide subunits.

Secondary structure

The second level of a protein structure; the regular local patterns of coils or folds of a polypeptide chain.

Denaturation

When the three dimensional structure of a protein is changed or unraveled and can no longer function.