Digestion( NCERT Books) |Biology

Important MCQ Questions On Digestion Part Number — 1

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1. Which component of food is digested by the pancreatic secretions?

A – Carbohydrates
B – Fats
C – Proteins
D – All of the above

Answer: All of the above.

Explanation: Pancreas produce: Amylase that digests starch to maltose. Lipase that digests fats to fatty acids and glycerol. Trypsin digests proteins to peptones and polypeptides.

2. Which structure is responsible for ingestion of food in the case of ameoba?

A – Cilia
B – Pseudopodia
C – Lysosomes
D – Mouth

Answer: Pseudopodia

Explanation: Amoeba sends its pseudopods around the food particle and forms food vacuole.

3.  Villi are found on the inner surface of?

A – Pharynx
B – Stomach
C – Esophagus
D – Small Intestine

Answer: Small Intestine

4. Which structure is responsible for the velvety appearance of ileum?

A – Villi
B – Lacteals
C – Epithilial folds
D – Muscle layers

Answer: Villi

Explanation: Villi are finger like outgrowths present on ileum surface.

5.  Pepsin, protein digesting enzyme sets best pH:

A – 3
B – 4.5
C – 2
D – 6

Answer: 2

Explanation: Pepsin is most active in acidic environments between 37 °C and 42 °C. Accordingly, its primary site of synthesis and activity is in the stomach (pH 1.5 to 2).

6.  Which group of animals have teeth structurally and functionally intermediate between the extremes of specialization?

A – Omnivores
B – Herbivores
C – Carnivores
D – Macrophagous feeders

Answer: Omnivores

Explanation: These feed on both plant and animal food, so teeth are not on extreme specializations.

7. What happens in the 1st phase of digestion in amoeba?

A – Absorbtion
B – Softening and killing
C – Breakdown into smaller components
D – Assimilation

Answer: Softening and killing

Explanation: This happens in acidic medium with pH of 5.6

7.  What is the benefit of capturing prey in insectivorous plants?

A – Autotrophism
B – Rapid growth.
C – Food variety.
D – Fast metabolism.

Answer: Rapid growth.

Explanation: These plants are true autotophs but when they capture prey, their growth becomes rapid.

8.  How many principle layers are present in human stomach wall?

A – 1
B – 2
C – 3
D – 4

Answer: 3

Explanation: There are three layers, Outer layer of connective tissue. Middle layer of smooth muscles. Inner layer of connective tissue and many glands.

9. In large intestine vitamin K is formed by the activity of :

A – Obligate bacteria
B – Parasitic bacteria
C – Symbiotic bacteria
D – Facultative bacteria

Answer: Symbiotic bacteria

Explanation: The bacterias that form vitamin K in the large intestine and in return absorb some substances from large intestine for its use are called symbiotic bacterias.

10.  What kind of nutrition is seen in Puccinia?

A – Autotrophic
B – Saprophytic
C – Parasitic
D – Symbiotic

Answer: Parasitic

Explanation: Puccinia is a parasitic fungus that destroys the wheat plant.

11.  The following reaction occurs in the human alimentary canal. starch -> enzyme -> products What is the enzyme and the product?

A – Alkali, Energy
B – Acid, Glucose
C – Amylase, Maltose
D – Bile, Amino acid

Answer: Amylase, Maltose

Explanation: • Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine • Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine • Amylase catalyses the breakdown of starch into maltose in the mouth and small intestine • Maltase catalyses the breakdown of maltose into glucose in the small intestine.

12.  Which of the following is the last part of the small intestine?

A – Duodenum
B – Ileum
C – Jejunum
D – Colon

Answer: Ileum

Explanation: Sequence is duodenum, jejunum and ileum while colon is the part of large intestine.

13.  Which is the most common example of filter feeders?

A – Mosquito
B – Mussels
C – Whales
D – Hydra

Answer: Mussels

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Digestion – Biology

Explanation: Mussel has 2 large gills covered with cilia and is the most common example.

14.  Which part of digestive system grounds the food in cockroach?

A – Crop
B – Malpighian tubule
C – Gizzard
D – Mesenteron

Answer: Gizzard

Explanation: Food moves to mid gut after being grounded in gizzard.

15.  Histamine is produced by which cells?

A – Basophils
B – Platelets
C – Monocytes
D – Eosinophils

Answer: Basophils

Explanation: Basophils are the histamine producing cells.

16.  What component of a prey is beneficial in insectivorous plants?

A – Nitrogenous compounds.
B – Fatty acids.
C – Minerals.
D – Enzymes.

Answer: Nitrogenous compounds.

Explanation: The prey is decomposed by bacteria or digested by enzymes secreted by leaves and nitrogenous compounds are absorbed by the plants.

17.  Which cells in hydra are responsible for mixing of food with enzymes and breaking it up into fine particles?

A – Glandular cells.
B – Flagellate cells.
C – Cnidocil.
D – Nematocyst.

Answer: Flagellate cells.

Explanation: Gastrodermal flagellate cells and contractions of body cavity helps in mixing of food with enzymes and breaking up into fine particles.

18.  In planaria, how many branches do the intestine initially divides into?

A – 2
B – 3
C – 4
D – 5

Answer: 3

Explanation: Intestine immediately divides into 3 branches, an anterior one extending forward and 2 lateral branches.

19.  Which of the following correctly matches the cells in the human digestive system with their secretions?

A – Goblet cells –> Amylase.
B – Endocrine cells –> Gastrin.
C – Parietal cells –> Pepsinogen.
D – Zymogen cells –> HCl.

Answer: Endocrine cells –> Gastrin.

Explanation: Correct matching of the cells in the human digestive system with their secretions is shown below: Zymogen cells –> Pepsinogen. Parietal cells –>HCl. Endocrine cells –> Gastrin. Goblet cells –> Mucus.                               

20.  What are the 3 kinds of cells present in the human gastric glands?

A – Mucous, parietal and oxyntic.
B – Zymogen, parietal, oxyntic.
C – Mucous, oxyntic, zymogen.
D – Parietal, oxyntic, chief cells.

Answer: Mucous, oxyntic, zymogen.

21.  Which of the following gland in the human digestive system secretes saliva with amylase?

A – Duodenal gland.
B – Sublingual gland.
C – Parotid gland.
D – Both B and C.

Answer: Parotid gland.

Explanation: Parotid gland produces saliva with amylase while Sublingual gland produces saliva with mucus only. Duodenal gland is in small intestine.

22.  Which type of large animals has filter feeding?

A – Lion.
B – Whales.
C – Sea horse.
D – Hydra.

Answer: Whales.

Explanation: Not all. but certain types of whales have filter feeding.

23.  What is the main function of gall stones?

A – Digest proteins.
B – Generate bile pigments.
C – Activate trypsinogen.
D – Block the release of bile.

Answer: Block the release of bile.

Explanation: Cholesterol precipitation cause formation of gall stones which then may block the release of bile.

24.  How does the planaria engulfs the prey?

A – Prey is paralyzed by ejecting poison and grasped and pushed into mouth.
B – By protruding eversible pharynx through mouth and pushes it into gastrovascular cavity.
C – By forming a food vacuole.
D – By simple mouth feeding.

Answer: By protruding eversible pharynx through mouth and pushes it into gastrovascular cavity.

25.  Which of these lives as a twining parasite?

A – Dodder
B – Puccinia
C – Lichen
D – Mycorrhiza

Answer: Dodder

Explanation: Dodder (cuscata) is a leafless plant that lives as a twining parasite.

26.  What of the following causes hunger pangs in humans?

A – Hypoglycemia
B – Hypotension
C – Hyperglycemia
D – Hypocalcemia

Answer: Hypoglycemia

Explanation: Low blood glucose levels causes sufficiently strong peristaltic movements called hunger pangs.

27.  Which plant has a characteristic bilobed leaves with midrib between them and a row of long stiff bristles along margin of each lobe?

A – Brassica campestris.
B – Sarracenia pupurea.
C – Drosera intermedia.
D – Dionaea muscipula.

Answer: Dionaea muscipula.

Explanation: This plant is also called venus fly trap. It is an insectivorous plant.

28.  What is the pH required for the 2nd phase of digestion in amoeba during which it is completed?

A – 5.6
B – 7
C – 7.3
D – 4.7

Answer: 7.3

Explanation: 2nd phase requires alkaline medium pH 7.3. First phase of digestion takes place in acidic medium pH 5.6.

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