（单词翻译:单击）
pH - a measure of how acid or alkali a solution is. As the pH gets lower, the solution is more acid. At a pH of 7 the solution is neither acid nor alkali. pH is the inverse1 of the logarithm of the concentration of hydrogen ions.
Phagocytosis - the ingestion of small particles, bacteria or viruses into the cell, by engulfing2 it in a vacuole.
Phosphate - a salt in which the negatively charged part is a phosphorus molecule3 joined to four oxygen molecules4 as PO4.
Phospho-proteins - proteins which contain available phosphate groups.
Phospholipids - are the most common lipids in our cell membranes5. The head group contains a phosphate and is readily soluble6 in water. Phospholipids are also found inmatrix vesicles, and they provide the first step in the synthesis of prostaglandins
Planktonic7 - a form of life style in which an organisms floats freely in a fluid without significant attachment8 or association with other living forms.
Plaque9 is a film of bacteria in a matrix of salivary10 and bacterial11 polymers. It can be called a biofilm as it has a complex population of organisms which when mature, reach an ecological12 balance with one another.
