Human Anatomy and Physiology : II. Digestive System

Total Questions: 42

1. In human body most of the digestive process, takes place in - [U.P.P.C.S. (Pre) 1991]

(a) Pancreas
(b) Large intestine
(c) Small intestine
(d) Stomach

Correct Answer: (c) Small intestine

Solution:Digestion begins in the mouth when we chew and swallow and is completed in the small intestine. The small intestine is a long tube loosely coiled in the abdomen (spread out, it would be more than 20 feet long). The small intestine continues the process of breaking down food by using enzymes released by the pancreas and bile from the liver.

2. Which of the following are not the tastes of the tongue? [69th B.P.S.C. (Pre) 2023]

Sweet
Bitter
Salty
Spicy
Umami
Sour
Pungent

Select the correct answer using the codes given below.

(a) 2, 5 and 7
(b) 1, 3 and 4
(c) 4 and 7
(d) 3 and 6

Correct Answer: (c) 4 and 7

Solution:The tongue of human beings has different types of papillae associated with taste buds and are responsible for detecting the tastes like – Sweet, Bitter, Salty, Umami, and Sour. They do not detect the 'Spicy' taste and the 'Pungent,' which is associated with smell. The sensation of something as 'hot' or 'spicy' is quite often described as a taste. Technically, this is just a pain signal sent by the nerves that transmit touch and temperature sensations. The substance 'capsaicin' in foods seasoned with chilli causes a sensation of pain and heat. Hence, option (c) is the correct answer.

3. The sensitive area of the human tongue to bitterness is: [66th B.P.S.C. (Pre) 2020]

(a) Tip
(b) Middle part
(c) Posterior part
(d) Edge
(e) None of the above / More than one of the above

Correct Answer: (c) Posterior part

Solution:Sweet, sour, salty, bitter and savory (umami) tastes can actually be sensed by all parts of the human tongue. Only the sides of the tongue are more sensitive than the middle overall. This is true for all tastes with one exception; the back of our tongue (i.e., posterior part) is very sensitive to bitter tastes. This is apparently to protect us so that we can spit out spoiled or poisonous foods or substances before they enter the throat and are swallowed.

4. In the buccal cavity of human being digestion of which one of the following gets started? [M.P.P.C.S. (Pre) 2019]

(a) Protein
(b) Fat
(c) Carbohydrate
(d) None of the above

Correct Answer: (c) Carbohydrate

Solution:In the buccal cavity of human beings, amylase enzyme in saliva breaks down starch (a form of carbohydrate) into maltose and dextrin. Thus, in the buccal cavity, digestion of carbohydrate gets started.

5. The saliva helps in the digestion of – [R.A.S./R.T.S. (Pre) 2012]

(a) Starch
(b) Proteins
(c) Fibres
(d) Fat

Correct Answer: (a) Starch

Solution:Saliva is a watery substance located in the mouths of man and animals, secreted by the salivary glands. Human saliva is about 99.5% water, while the other 0.5% consists of electrolytes, mucus, glycoproteins, enzymes (e.g., amylase) and antibacterial compounds such as secretory IgA and lysozyme. The enzymes found in saliva are essential to begin the process of digestion of dietary starches.

6. Which of the following is digested with the help of saliva? [Jharkhand P.C.S. (Pre) 2013]

(a) Protein
(b) Starch
(c) Fibre
(d) None of the above

Correct Answer: (b) Starch

7. Enzyme involved in the hydrolysis of starch to glucose is– [R.A.S./R.T.S. (Pre) 1999]

(a) Invertase
(b) Amylase
(c) Dehydrogenase
(d) Anhydrase

Correct Answer: (b) Amylase

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

Invertase: Specifically, it hydrolyzes the glycosidic bond in sucrose, resulting in the separation of glucose and fructose.

Dehydrogenase: This is a broader class of enzymes that catalyze oxidation-reduction reactions, often involving the transfer of hydrogen atoms.

Anhydrase: This group of enzymes catalyzes reactions involving the addition or removal of water molecules, such as in the interconversion of carbon dioxide and bicarbonate.

8. Assertion (A) : In human body, the liver has an important role in fat digestion. [I.A.S. (Pre) 2008]

Reason (R) : Liver produces two important fat-digesting enzymes.

Code :

(a) Both (A) and (R) are individually true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are individually true, but (R) is not a correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (c) (A) is true, but (R) is false.

Solution:The liver does not produce fat-digesting enzymes. It detoxifies chemicals and metabolizes drugs. The liver has multiple functions such as secretion of bile, storage of fat, synthesis of urea, glycogenesis, gluconeogenesis, and glycogenolysis, etc. Although the bile lacks digestive enzymes, yet it plays an important part in the digestion, especially in the digestion of fats by bringing about their emulsification.

9. In which organ hydrochloric acid is secreted? [M.P. P.C.S. (Pre) 2021]

(a) Intestine
(b) Liver
(c) Stomach
(d) Pancreas

Correct Answer: (c) Stomach

Solution:Hydrochloric acid is secreted by the parietal cells (also known as oxyntic cells) of the gastric glands in the stomach. Gastric juice contains mucus, hydrochloric acid and certain enzymes such as pepsin. Hydrochloric acid kills the harmful bacteria present in the food. Hydrochloric acid secretion by the gastric parietal cells is necessary for pepsinogen activation and the reduction of bacterial colonization.

10. Enzyme is a – [Uttarakhand P.C.S. (Pre) 2010]

(a) Vitamin
(b) Bacterium
(c) Bio-catalyst
(d) Virus

Correct Answer: (c) Bio-catalyst

Solution:Enzymes are biological molecules (proteins) that act as bio-catalysts and help complex reactions occur in the body. These are basically proteins which accelerate chemical reactions in living systems. Almost all metabolic processes in the cell need enzymes catalysis in order to occur at rates fast enough to sustain life.

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