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Lesson Flashcards: Structure of Proteins Biology


An amino acid that has a sulfhydryl group (–SH), which is a special functional group that can join together with another amino acid with a sulfhydryl group to form a disulfide group (–S–S–)


A biological catalyst that speeds up the rate of reactions without being used up

Alpha helix

A common structure in proteins in which a hydrogen bond is formed every fourth amino acid along a polypeptide chain, causing it to take a helical shape

Peptide bond

The chemical bond that forms between the amino and carboxyl groups of two amino acids


The most abundant protein in mammals, which provides structure for connective tissues like ligaments and cartilage and for the skin

R group (side chain)

One of twenty different side chains of an amino acid that gives the amino acid its chemical properties

Actin and myosin

Two structural proteins that are important components of muscle cells

Condensation reaction (dehydration synthesis)

A chemical reaction in which a chemical bond is formed, causing a molecule of water to be released

Regulatory proteins

Proteins that regulate different processes and activities within an organism


The complex formed by the association of two proteins


A single linear chain of amino acids that are held together by peptide bonds, which can fold into a protein with a specific function

Amino acid

The monomers making up proteins, each of which containing a central carbon linked to an amino group, a carboxyl group, a hydrogen atom, and a side chain that varies between the 20 standard amino acids

Structural protein

The building materials of the body that provide structure to cells


A complex network of interlinking protein filaments that gives the cell its shape and structure


A type of structural protein that is found predominantly in hair, skin, and nails

Polar molecule

A molecule that has experienced a separation of electric charge, where one side has a slightly negative charge and the other side has a slightly positive charge

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