NS lec 12

These flashcards cover the key vocabulary and concepts related to proteins, their structure, functions, digestion, and dietary requirements.

Proteins

Complex molecules made of amino acids joined together by peptide bonds.

Essential Amino Acids

Amino acids that cannot be synthesized by the body and must be obtained through diet.

Nonessential Amino Acids

Amino acids that can be synthesized by the body.

Conditionally Essential Amino Acids

Amino acids that are usually nonessential but can become essential under certain conditions.

Complete Proteins

Foods that contain adequate amounts of all nine essential amino acids.

Incomplete Proteins

Foods that lack one or more essential amino acids.

Protein Complementation

Combining incomplete protein sources to provide all essential amino acids.

Proteolysis

The breakdown of proteins into smaller polypeptides and amino acids.

R-group

The variable group attached to the central carbon in an amino acid that determines its properties.

Digestion of Proteins

Occurs in the stomach and small intestine, involving the breakdown of proteins by various enzymes.

Amino Acid Absorption

Most amino acids are absorbed in the duodenum and transported into circulation via capillaries.

Hydrochloric Acid (HCl)

Substance in gastric juice that denatures proteins and activates pepsinogen to pepsin.

Pepsin

An enzyme that begins protein digestion in the stomach by hydrolyzing peptide bonds.

Trypsin

An enzyme produced in the pancreas that continues protein digestion in the small intestine.

Gastrin

Hormone that stimulates gastric juice secretion and promotes digestion in the stomach.

Cholecystokinin (CCK)

Hormone that stimulates the release of pancreatic enzymes in the small intestine.

Amino Acid Transport

Amino acids are transported into enterocytes and then into the bloodstream.