Question

Ptyalin is
(a)Strongly acidic
(b)Slightly acidic
(c)Slightly neutral
(d)Strongly alkaline

Answer 1

Hint: Ptyalin is salivary amylase. It is an enzyme that acts on starch (carbohydrates) and breaks it into maltose. Of the three pairs of salivary glands, ptyalin is secreted only by the parotid gland and has a pH similar to milk.

Complete answer:
 All enzymes are the proteins that catalyse the biochemical reactions in the living cells, hence are called biocatalysts.
 Salivary amylase is also known as Ptyaline. It hydrolyses the starch into sugars and is present in the saliva. The process of digestion starts from the ptyalin acting upon the complex carbohydrates.
The pH of saliva ranges from 6.2 to 7.6 with the average being 6.7 which is slightly acidic.
-Saliva contains ptyalin, which starts digesting the starch. Thus, digestion of starch begins in the mouth.
-The stomach is highly acidic and those conditions are not favourable for ptyalin, which prefers a higher pH or low acidity to neutral for activity.
-Overall, the ptyalin only degrades a small portion of the total starch in the diet. The rest is digested by the pancreatic amylase in the intestine.
 Salivary amylase as the name suggests is secreted in the salvia by the salivary gland and also is secreted by the pancreas.

Additional Information
There are numerous minor salivary glands situated in the mucous membrane of the lips, cheeks, tongue, and palate. The secretion of these glands helps in keeping the mouth moist, and provides a protective and lubricant coat of mucus.
-Around 1-1.5 litres of saliva is secreted per day.
-Saliva is a mixture of water, electrolytes (Na+, K+, Cl-, ${HCO_3}^-$), mucous, ptyalin, and lysozymes.
-Ions of thiocyanate are also present in the saliva.
In humans, there are 3 pairs of major salivary glands-
They are the parotid glands which are the largest of the salivary glands, sublingual glands, and submandibular glands.
-Parotid salivary gland is the largest salivary gland which secretes purely serous saliva through the Stenson’s duct which opens near the second maxillary molar tooth.
-Submandibular glands also known as Submaxillary gland secretes both mucous and serous saliva through Wharton’s duct.
-Sublingual Gland secretes pure mucous saliva through numerous small ducts which open in the floor of the mouth and are collectively known as Duct of Rivinus. The largest, the major duct is known as the Duct of Bartholin.

So, the answer is, “Slightly Acidic”.

Note:
-Salivary amylase is absent in herbivores.
-Mumps is a viral infection of one or both parotid salivary glands.
-The gastrointestinal tract switches between alkaline and acidic pH according to the ideal pH for the chief enzymes acting there. For example, pH in the mouth is slightly acidic for salivary amylase, whereas it is strongly acidic in the stomach for the pepsin that acts there. Intestinal pH is slightly basic for the biliary enzymes to act on fat.