Dictionary of Biological Psychology
Digestion is one of the four stages through which food is processed: these are ingestion digestion, absorption and elimination. Ingestion is the act of FEEDING; digestion is the process of degrading food components into their MOLECULE constituents for use—molecules small enough to be transported across a cell MEMBRANE have to be generated.
CARBOHYDRATES are broken down to simple SUGARS (principally GLUCOSE), FATS to GLYCEROL and FATTY ACIDS, PROTEINS to AMINO ACIDS) and NUCLEIC ACIDS to NUCLEOTIDES. The essential process in this is known as enzymatic hydrolysis—the addition of water to molecules by ENZYME activity, causing them to break down. The third stage, absorption (the absorptive phase) involves cells taking up the molecules presented by digestion; the final stage is elimination, the voiding of waste material.
See also: digestive system; fasting phase; osmoregulation
This is the complete article, containing 132 words
(approx. 1 page at 300 words per page).
View More Summaries on Digestion
