Proteins
A polypeptide is
a chain of amino acids.
The building blocks of proteins are
amino acids.
Amino acids have an ______ at one end and a _____ at the other end.
amino group carboxyl group
In secondary structure, a polypeptide chain forms
an alpha helix or a beta-pleated sheet.
Four elements always found in proteins are
carbon, hydrogen, oxygen, and nitrogen.
Enzymes are
catalysts in living systems.
Peptide bonds are
covalent bonds between amino acids.
Four things that cause a protein to denature are
heat, radiation, pH changes, and certain chemicals.
Protein function is determined by
its distinct conformation created by its primary, secondary, and tertiary structures.
When a protein denatures, it
loses its tertiary or secondary structure.
The four levels of protein structure are
primary, secondary, tertiary, and quaternary.
Hydrogen bonding determines
secondary structure.
The quaternary structure of a protein forms when
several polypeptide chains connect to form a very large protein.
One element sometimes found in proteins is
sulfur.
The folding of secondary structure is called
tertiary structure.
The primary structure of a protein is
the amino acid sequence of the polypeptide chain.
The twenty amino acids differ in
their side chains or R groups.
Three important functions of proteins are
to serve as structurel materials, energy sources, and chemical messengers. Proteins also function as receptors, antibodies, and enzymes.