B1.2 Proteins Flashcards

Vocabulary practice covering the structure, dietary requirements, levels of organization, and classification of proteins.

Amino acids

The monomeric building blocks from which proteins are constructed; there are 20 different ones universal to all living organisms.

Amine group

The functional group represented as $NH_2$ in the generalized structure of an amino acid.

Carboxyl group

The acidic functional group represented as $COOH$ in the generalized structure of an amino acid.

R-group

The variable side chain in an amino acid that determines the chemical characteristics of the polypeptide and its 3D form.

Essential amino acids

Amino acids that cannot be produced by the body and must be present in the diet.

Non-essential amino acids

Amino acids that can be produced by the body and are therefore not required as part of the diet.

Conditionally non-essential amino acids

Amino acids that can be produced by the body but at rates lower than requirements during specific periods like pregnancy or infancy.

Protein deficiency malnutrition

A condition caused by a shortage of one or more essential amino acids in the diet, preventing the production of specific proteins.

Titin

A polypeptide that can contain up to $30,000$ amino acids, illustrating the massive possible size of protein chains.

Denaturation

A change to the three-dimensional conformation of a protein, often permanent, caused by vibrations from heat or changes in charges from pH extremes.

Thermophiles

Organisms, often archaea or eubacteria, that live in hot conditions ($45$ to $122\text{ }^\text{o}C$) and possess proteins stable at high temperatures.

Primary structure

The unique amino acid sequence of a protein which is coded for by DNA and determines how the polypeptide will fold.

Secondary structure

The pleating and coiling of amino acid chains held together by hydrogen bonds between non-adjacent amine ($N-H$) and carboxylic ($C-O$) groups.

Tertiary structure

The complex 3D shape of a protein caused by R-group interactions such as hydrogen bonds, disulphide bridges, ionic bonds, and hydrophobic interactions.

Quaternary structure

The structure resulting from interactions among separate polypeptide chains.

Non-conjugated protein

A protein that is composed only of polypeptide subunits, such as insulin.

Conjugated protein

A protein that functions with other non-polypeptide chemical groups, such as hemoglobin which contains heme groups.

Prosthetic group

The non-amino acid portion of a conjugated protein, many of which are formed from vitamins.

Globular proteins

Spherically shaped proteins with irregular folds that are soluble in water and function as enzymes, transporters, or regulators.

Fibrous proteins

Proteins with a long, narrow shape and repeating structures that are insoluble in water and provide structural support and stability.

Collagen

A fibrous protein made of three polypeptide chains twisted in a triple helix, serving as the main component of connective tissue.

Cryogenic electron microscopy

A technology that allows the imaging of single-protein molecules and their interactions with other molecules.