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Flashcards for key vocabulary terms related to protein from Nutrition Basics: An Active Approach v3.0.

Proteins

Macromolecules composed of monomeric subunits called amino acids.

Amino Acids

Simple monomers composed of carbon, oxygen, hydrogen, and nitrogen.

Nonpolar Amino Acids

Hydrophobic amino acids with side groups that are long or bulky.

Polar Amino Acids

Hydrophilic amino acids that are not charged.

Acidic Amino Acids

Hydrophilic amino acids that are negatively charged.

Basic Amino Acids

Hydrophilic amino acids that are positively charged.

Nonessential Amino Acids

Amino acids made in the human body in sufficient amounts.

Essential Amino Acids

Amino acids not made by the human body and must be obtained from diet.

Conditionally Essential Amino Acids

Amino acids that become essential during certain times in life, such as child growth.

Transcription

Process of copying DNA into messenger RNA.

Translation

Process of decoding messenger RNA and synthesizing a protein.

Protein Folding

A sequence of amino acids transforms into its dictated shape.

Primary Structure

The first level of protein organization.

Secondary Structure

The second level of protein organization.

Tertiary Structure

The third level of protein organization.

Quaternary Structure

The fourth level of protein organization.

Denaturation

Physical changes that take place in a protein’s structure when it is exposed to an external stress.

Gastric Juices

Secreted by the stomach, contains hydrochloric acid and pepsin.

Pepsin

Enzyme in the stomach that dismantles protein chains.

Chymotrypsin

A major pancreatic enzyme.

Trypsin

A major pancreatic enzyme.

Protein Turnover

The process of continually breaking down proteins and building new ones.

Collagen

Strong, fibrous protein made up mostly of glycine and proline amino acids.

Enzymes

Proteins that catalyze specific chemical reactions.

Hormones

Chemical messengers produced by the endocrine glands.

Albumin

A protein that plays a role in fluid balance and the transport of biological molecules.

Lysozyme

An enzyme that destroys bacteria.

Antibodies

A protein that protects against unwanted intruders.

Kwashiorkor

Syndrome of severe protein and micronutrient deficiency.

Marasmus

A syndrome of severe protein and energy deficiency.

Nitrogen Balance

When the amount of protein input into the body equals the amount used up and excreted.

Incomplete Protein Sources

Foods that contain some, but not all, of the essential amino acids.

Complete Protein Sources

Foods that contain all nine of the essential amino acids in the proportions needed by the human body.

Complementary Foods

A combination of foods that when consumed together contain all nine essential amino acids at adequate levels.

PDCAAS

Protein Digestibility Corrected Amino Acid Score.

Sarcopenia

The age-related decline in muscle mass and strength.

Hydrochloric Acid

An acid secreted by the stomach to break down proteins.

RDA

Recommended Dietary Allowance.

AMDR

Acceptable Macronutrient Distribution Range.

Protein Food Group

Foods made from meat, seafood, poultry, eggs, soy, beans, peas, and seeds.

Vegan

A person who does not eat any animal products.

Vegetarian

A person who does not eat meat.

Lacto-ovo Vegetarian

A vegetarian who eats dairy products and eggs.

Protein deficiency

Can cause swelling, fatigue, skin problems, irritability, muscle wasting.

High-protein diets

May increase the risk of cardiovascular disease and diabetes.

Protein digestion

Requires the chemical actions of gastric juice and the mechanical actions of the stomach.

Protein quality

Determined by a food's amino acid content.

Transamination

The process of transferring an amino group from one molecule to another.

Deamination

The removal of an amino group from a molecule.

High-quality protein

Contains all the essential amino acids in the proportions needed by the human body.

Limiting amino acid

The essential amino acid found in the shortest supply in a particular protein source.

Muscle protein synthesis

The process of building new muscle tissue.

Branched-chain amino acids

Essential amino acids that are metabolized in the muscle rather than the liver.

Peptide Bond

A chemical bond that links two amino acids together.

Oligopeptide

A chain of between 2 and 12 amino acids linked together by peptide bonds.

Polypeptide

A chain of between 12 and 100 amino acids linked together by peptide bonds.

Globular Protein

A protein with a spherical shape.

Fibrous Protein

A protein with a long, rod-like shape.

Simple Protein

A protein that contains only amino acids.

Conjugated Protein

A protein that contains amino acids and a non-protein component.

Glycoprotein

A protein that contains a carbohydrate component.

Lipoprotein

A protein that contains a lipid component.

Nucleoprotein

A protein that contains a nucleic acid component.

Metalloprotein

A protein that contains a metal ion.

Phosphoprotein

A protein that contains a phosphate group.

Hemoprotein

A protein that contains a heme group.

Amphoteric

A molecule that can act as both an acid and a base.

Isoelectric Point

The pH at which a protein has no net electrical charge.

Hydrolysis

The breaking of a chemical bond by the addition of water.

Zwitterion

A molecule that has both a positive and a negative electrical charge, but no net charge.

Renaturation

The process of a protein returning to its native conformation after denaturation.

Prion

An infectious protein.

Proteome

The entire set of proteins expressed by a cell or organism.

Actin

A protein that forms the contractile filaments of muscle cells.

Myosin

A protein that interacts with actin to cause muscle contraction.

Keratin

A protein that is the main component of skin, hair, and nails.

Elastin

A protein that provides elasticity to tissues such as skin and blood vessels.

Antibody

A protein produced by the immune system to neutralize foreign invaders.

Enzyme Inhibitor

A molecule that binds to an enzyme and decreases its activity.

Cofactor

A non-protein molecule that is required for the activity of an enzyme.

Coenzyme

An organic cofactor.

Apoenzyme

An enzyme that requires a cofactor but does not have one bound.

Holoenzyme

An enzyme that has its cofactor bound and is catalytically active.

Proenzyme

An inactive precursor of an enzyme.

Allosteric Enzyme

An enzyme whose activity is regulated by the binding of a molecule to a site distinct from the active site.