Nutrition Chapter 6 - Amino Acids

Peptide Bond

A bond that connects the acid end of one amino acid with the amino end of another, forming a link in a protein chain.

Ammonia

A compound with the chemical formula NH3; produced during the domination of amino acids

Peptidase

A digestive enzyme that hydrolyzes peptide bonds.

Pepsin

A gastric enzyme that hydrolyzes protein. Pepsin is secreted in an inactive form, pepsinogen* which is activated by hydrochloric acid in the stomach

Essential Amino Acids

Amino Acids that the body cannot synthesize amounts sufficient to meet physiological needs

Nonessential amino acids

Amino acids that the body can synthesize

Conditionally Essential Amino Acid

An amino acid that is normally nonessential, but must be supplied by the diet in special circumstances when the need for it exceeds the body's ability to produce it.

Keto Acid

An organic acid that contains a carbonyl group

Amino Acids

Building blocks of proteins. Each contains an amino group, an acid group, a hydrogen atom, and a distinctive side group, all attached to a central carbon atom.

Neurotransmitters

Chemicals that are released at the end of a nerve cell when a nerve impulse arrives there. They diffuse across the gap to the next cell and alter the membrane of that second cell to either inhibit or excite it.

Proteins

Compounds composed of carbon, hydrogen, oxygen, and nitrogen atoms, arranged into amino acids linked in a chain. Some amino acids also contain sulfur atoms.

Bases

Compounds that accept hydrogen ions in a solution.

Buffers

Compounds that keep a solutions pH constant when acids or bases are added.

Proteases

Enzymes that hydrolyze protein.

Sickle-Cell Anemia

Hereditary form of anemia characterized by abnormal sickle- or creasent-shaped red blood cells.

Acidosis

Higher-than-normal acidity in the blood and body fluids

Alkalosis

Higher-than-normal alkalinity (base) in the blood and fluids

Antibodies

Large proteins of the blood and body fluids, produced by the immune system in response to the invasion of the body by foreign molecules (usually proteins called antigens). Antibodies combine with and inactive the foreign invaders, and thus protecting the body.

Polypeptide

Many amino acids bonded together

Enzymes

Proteins that facilitate chemical reactions without being changed in the process; protein catalysts

Deamination (dee-AM-in-ation)

Removal of the amino group from a compound such as an amino acid

Antigens

Substances that elicit the formation of antibodies or an inflammation reaction from the immune system. A bacterium, a virus, a toxin, and a protein in food that causes allergy are all examples of antigens

Nitrogen Balance

The amount of nitrogen consumed (N in) as compared with the amount of nitrogen excreted (N out) in a given period of time.

Matrix

The basic substance that gives form to a developing structure; in the body, the formative cells from which teeth and bones grow.

Immunity

The body's ability to defend itself against diseases

Denaturation (dee-NAY-chur-AY-shun)

The change in a protein's shape and consequent loss of its function brought about by hear, agitation, acid, base, alcohol, and heavy medals

Limiting Amino Acid

The essential amino acid found in the shortest supply relative to the amounts needed for protein synthesis in the body. Four Amino acids are most likely to be limitingL Lysine, methionine, threonine, tryptophan.

Branched-Chain Amino Acids

The essential amino acids leucine, isoleucine, and valine, which are are present in large amounts in skeletal muscle tissue ; falsely promoted as fuel for exercising muscles

Gene Expression

The process by which a cell convert the genetic code into RNA and protein

Collagen (KOL-ah-gen)

The structural protein from which connective tissues such as scars, tendons, ligaments, and the foundations of bones and teeth are made

Amino Acid Pool

The supply of amino acids derived from either food proteins or body proteins that collect in the cells and circulation blood and stand ready to be incorporated in proteins and other compounds or used for energy.

Edema

The swelling of the body tissue caused by excessive amounts of fluid in the interstitial spaces; seen in protein deficiency

Transamination

The transfer of an amino group from one amino acid to a keto acid, producing a new nonessential amino acid and a new keto acid.

Dipeptide

Two amino acids bonded together

Complementary Proteins

Two or more dietary proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other.

Protein digestibility

as measure of the amount of amino acids absorbed from a given protein intake.

Acids

compounds that release hydrogen ions in a solution.

High-Quality Proteins

dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require. They may also contain nonessential amino acids

Fluid balance

maintenance of the proper types and amounts of fluid in each compartment of the body fluids

Protein turnover

the degradation and synthesis of a protein

Hemoglobin

the globular protein of the red blood cells that transports oxygen from the lungs to tissues throughout the body; Hemoglobin accounts for 80% of the body's iron.