Proteins Flashcards
What is wasting?
The breakdown of body tissue such as muscle and organs for use as a protein source when the diet lacks protein.
Define essential (indispensable) amino acids.
Amino acids that the body cannot make at all or cannot make enough of to meet physiological needs.
What are nonessential (dispensable) amino acids?
Amino acids that the body can make if supplied with adequate nitrogen.
What are conditionally essential amino acids?
Amino acids that are normally made in the body but become essential under certain circumstances, such as during critical illness.
What are the building blocks of proteins?
Amino acids.
What is a peptide bond?
The bond between two amino acids formed when a carboxyl group of one amino acid joins an amino group of another, releasing water.
What is a dipeptide?
Two amino acids joined by a peptide bond.
What is a tripeptide?
Three amino acids joined by peptide bonds.
What defines an oligopeptide?
Four to 10 amino acids joined by peptide bonds.
What is a polypeptide?
More than 10 amino acids joined by peptide bonds.
What is hemoglobin?
The oxygen carrying protein in red blood cells that consists of four heme groups and four globin polypeptide chains.
Define hydrophilic amino acids.
Amino acids that are attracted to water.
Define hydrophobic amino acids.
Amino acids that are repelled by water.
What is a disulfide bridge?
A bond between the sulphur components of two sulphur-containing amino acids that helps stabilize the structure of protein.
What is denaturation?
An alteration in the three-dimensional structure of a protein resulting in an unfolded polypeptide chain.
What is the most abundant fibrous protein in the body?
Collagen.
What is keratin?
A water-insoluble fibrous protein that is the primary constituent of hair, nails, and the outer layer of the skin.
What are motor proteins?
Proteins that use energy and convert it into some form of mechanical work.
What are antibodies?
Large blood proteins produced by B lymphocytes in response to exposure to particular antigens.
What is the immune response?
A coordinated set of steps taken by the immune system in response to an antigen.
What is intracellular fluid?
The fluid in the body’s cells, high in potassium and phosphate and low in sodium and chloride.
What is extracellular fluid?
The fluid located outside of cells, composed largely of plasma and interstitial fluid.
What is interstitial fluid?
The fluid between cells in tissues, also called intercellular fluid.
What is intravascular fluid?
The fluid portion of the blood (plasma) contained in arteries, veins, and capillaries.
What is oedema?
Swelling caused by the buildup of fluid between cells.
What are buffers?
Compounds that can take up and release hydrogen ions to keep the pH of a solution constant.
What is acidosis?
An abnormally low blood pH resulting from increased acidity.
What is alkalosis?
An abnormally high blood pH resulting from increased alkalinity.
What is deamination?
The removal of the amino group from an amino acid.
What are the vital functions of proteins?
Enzymes, hormones, immune protection, fluid and acid-base balance, and transport substances.
What is a precursor?
A substance that is converted into another active substance.
What are proteases?
Enzymes that break down protein into peptides and amino acids.
What is trypsinogen?
A protease produced by the pancreas converted to the active form trypsin in the small intestine.
What is chymotrypsinogen?
A protease produced by the pancreas converted to the active form chymotrypsin in the small intestine.
What are peptidases?
Enzymes that act on small peptide units by breaking peptide bonds.
What is celiac disease?
A chronic autoimmune disorder that involves an inability to tolerate gluten.
What is cystic fibrosis?
An inherited disorder causing dysfunction of the exocrine glands.
Where does protein digestion begin?
In the stomach with the enzyme pepsin.
What is DNA?
The carrier of genetic information.
What is messenger RNA (mRNA)?
Molecules that carry the amino acid sequence of proteins from the cell nucleus to the cytoplasm.
What is transfer RNA (tRNA)?
A type of RNA that inserts the appropriate amino acid during protein synthesis.
What is ribosomal RNA (rRNA)?
A major component of ribosomes providing a structural framework for protein synthesis.
What is the amino acid pool?
The amino acids in body tissues and fluids available for new protein synthesis.
What is protein turnover?
The constant synthesis and breakdown of proteins in the body.
What are neurotransmitters?
Substances released at the end of a stimulated nerve cell that bind to another nerve or muscle cell.
What is urea?
The main nitrogen-containing waste product in mammals.
What is positive nitrogen balance?
Nitrogen intake exceeds the sum of all sources of nitrogen excretion.
What is negative nitrogen balance?
Nitrogen intake is less than the sum of all sources of nitrogen excretion.
What is nitrogen equilibrium?
Nitrogen intake equals the sum of all sources of nitrogen excretion.
What are complete (high-quality) proteins?
Proteins that supply all the essential amino acids in the proportions the body needs.
What are incomplete (low-quality) proteins?
Proteins that lack one or more essential amino acids.
What are complementary proteins?
An incomplete food protein that, when combined with another, provides sufficient essential amino acids.
What is protein-energy malnutrition (PEM)?
A condition resulting from long-term inadequate intakes of energy and protein.
What is kwashiorkor?
A type of malnutrition occurring primarily in young children with marginal energy and protein intake.
What is marasmus?
A type of malnutrition characterized by severe wasting of muscle, fat, and other body tissue.
What is gout?
An intensely painful form of inflammatory arthritis resulting from deposits of uric acid crystals.
True or False: Protein-energy malnutrition (PEM) can manifest in two forms: kwashiorkor and marasmus.
True.
