Digestive System (Part-I)

Total Questions: 29

11. Which of the following enzymes is found in saliva? [S.S.C. Online Stenographer 13.09.2017 (Shift-I)]

(a) Lactose
(b) Diastase
(c) Sucrose
(d) Ptyalin

Correct Answer: (d) Ptyalin

Solution:Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking down starch into simpler sugars such as maltose and dextrin that can be further broken down in the small intestine.

12. The enzyme present in saliva is: [S.S.C. Online MTS (T-II) 11.01.2017 (Shift-I)]

(a) Pepsin
(b) Ptyalin
(c) Lipase
(d) Gastrin

Correct Answer: (b) Ptyalin

13. Which enzyme is present in saliva? [S.S.C. Online CHSL (T-1) 06.06.2022 (Shift-I)]

(a) Amylase
(b) Rennin
(c) Trypsin
(d) Pepsin

Correct Answer: (a) Amylase

Solution:Amylase is an enzyme that catalyzes the hydrolysis of starch into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion.

Rennin, also called chymosin, is a protein-digesting enzyme that curdles milk by transforming caseinogen into insoluble casein; it is found only in the fourth stomach of cud-chewing animals, such as cows.
Trypsin is produced in the pancreas as the inactive proenzyme trypsinogen. In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides.
Pepsin is a stomach enzyme that digests proteins found in ingested food.

14. The fat-digesting enzyme Lipase is secreted by which of the following: [S.S.C. Online CHSL (T-1) 24.01.2017 (Shift-I)]

(a) Kidneys
(b) Pancreas
(c) Large Intestine
(d) Liver

Correct Answer: (b) Pancreas

Solution:While some minor lipase activity occurs in the stomach (gastric lipase) and mouth (lingual lipase), the vast majority of fat digestion in the small intestine is carried out by pancreatic lipase. The pancreas is the primary organ responsible for secreting significant amounts of lipase into the duodenum.

15. The main protein found in milk is: [S.S.C. Online Graduate Level (T-1) 4.09.2016 (Shift-III)]

(a) Albumin
(b) Globulin
(c) Globin
(d) Casein

Correct Answer: (d) Casein

Solution:Casein is the predominant protein in milk, accounting for about 80% of total milk protein. It's a phosphoprotein that forms micelles and is responsible for the white, opaque appearance of milk. It also plays a crucial role in the nutritional value of milk, providing amino acids and calcium.

16. Curdling of milk in the stomach is due to the action of: [S.S.C. Online MTS (T-1) 13.01.2017 (Shift-II)]

(a) Myosin
(b) Rennin
(c) HCL
(d) Pepsin

Correct Answer: (b) Rennin

Solution:Rennin (also known as chymosin) is an enzyme primarily found in the stomachs of young mammals (including human infants). Its main function is to coagulate milk proteins (casein), forming a curd. This process slows down the passage of milk through the digestive system, allowing more time for other enzymes to act on it. While HCl helps in the overall acidic environment and protein denaturation, rennin is specifically responsible for the curdling action.

17. ______ is generally called as milk sugar as it is found in milk. [S.S.C. Online C.H.S.L. (T-1) 12.04.2021 (Shift-I)]

(a) Lactose
(b) Fructose
(c) Glucose
(d) Maltose

Correct Answer: (a) Lactose

Solution:Lactose is a disaccharide (a sugar made of two simple sugars, glucose and galactose) that is naturally present in milk. It is commonly referred to as "milk sugar."

18. To which group of organic molecules do "Monosaccharides" belong? [S.S.C. Online C.H.S.L. (T-1) 12.08.2021 (Shift-II)]

(a) Nucleic acids
(b) Proteins
(c) Carbohydrates
(d) Lipids

Correct Answer: (c) Carbohydrates

Solution:Carbohydrates are a broad class of organic molecules that include sugars, starches, and fibers. Monosaccharides are the simplest form of carbohydrates, meaning they cannot be hydrolyzed into smaller sugar units. Examples include glucose, fructose, and galactose.

19. The original function of the vertebrate stomach was: [S.S.C. Online MTS (T-1) 10.01.2017 (Shift-II)]

(a) Storage
(b) Digestion
(c) Bile juice secretion
(d) Mixing of food

Correct Answer: (a) Storage

Solution:While digestion is a critical function of the stomach in many vertebrates today, its evolutionary origin is believed to have been primarily for food storage. This allowed early vertebrates to consume larger meals when available and then digest them over a longer period. The acidic environment and digestive enzymes evolved later to enhance the efficiency of digestion.

20. Which enzyme digests proteins in the stomach? [S.S.C. Online Graduate Level (T-1) 11.09.2016 (Shift-III)]

(a) Trypsin
(b) Pepsin
(c) Salivary amylase
(d) Pancreatic canal

Correct Answer: (b) Pepsin

Solution:Pepsin is the principal enzyme responsible for protein digestion in the stomach. It is secreted in an inactive form called pepsinogen, which is then activated by hydrochloric acid (HCl) in the stomach to become active pepsin. Pepsin breaks down large protein molecules into smaller polypeptides.

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