FREE NEET Biology Practice MCQ Test: Digestion And Absorption Exercise 1 Questions Answers With Detailed Explanations [PDF]

Answer: (d)

Answer: (b)

Kwashiorkar is caused due to the deficiency of protein and meat, lentils, milk and eggs are rich sources of protein. Scurvy is caused due to deficiency of vitamin C whose sources are citrus fruit, tomatoes, peppers, leafy green vegetables. Deficiency of vitamin D (sources - milk, egg yolk and liver) leads to rickets. Anaemia is caused due to deficiency of folic acid (sources - yeast, liver, fish, green vegetables) or vitamin $B_12$ (sources - liver, eggs, meat, fish) or iron (egg yolk, spinach).

Answer: (d)

Answer: (d)

Enterokinase is present in the intestinal juice.

Answer: (a)

Answer: (c)

Answer: (d)

Chemical process of digestion started in the oral cavity by the hydrolytic action of the carbohydrate (potato contains starch) splitting enzyme, the salivary amylase. Carbohydrates in the chyme are hydrolysed by pancreatic amylase into disaccharides.

Answer: (a)

Answer: (c)

The absorption of glucose and amino acids is mediated by carrier ions like $Na^{+}$. The concentration of $Na^{+}$ is higher in the intestinal lumen compared to mucosal cells. $Na^{+}$, therefore moves into the cells along its concentration gradient and simultaneously glucose is transported into the intestinal cells. Thus $Na^{+}$ diffuses into the cell and it drags glucose along with it. The intestinal $Na^{+}$ gradient is the immediate energy source. The mechanism for transport of amino acids is same as glucose.

Fructose absorption does not require energy and is independent of $Na^{+}$ transport.

Answer: (c)

Answer: (d)

Answer: (a)

Answer: (d)

Answer: (c)

Answer: (d)

Answer: (c)

Retinol (vitamin A) and calciferol are fat soluble vitamins but the pellagra is not the deficient disease of calciferol. Vitamin A cannot be synthesized by mammals and other vertebrates and must be provided in the diet. Green plants contain precursors of the vitamin, notably carotenes, that are converted to vitamin A in the intestinal wall and liver. The aldehyde derivative of vitamin A, retinal, is a constituent of the visual pigment rhodopsin. Deficiency affects the eyes, causing night blindness, xerophthalmia (dryness and thickening of the cornea), and eventually total blindness.

Pellagra is caused by the deficiency of vitamin $B_3$ or nicotinic acid or niacin.

Cobalamine and ascorbic acid (vitamin C) are water soluble vitamins. They are generally found together in the same foods with the exception of $B_12$ (cobalamine). The deficient disorders related to cobalamine, vitamin C and calciferol are –

Cobalamine – Pernicious anaemia

Ascorbic acid (vitamin C) – Scurvy

Calciferol (vitamin D) – Rickets (in children) and osteomalacia in adults.

Beri-beri is caused by the deficiency of vitamin $B_1$ (Thiamine).

Answer: (c)

Answer: (d)

Answer: (c)

Answer: (c)

The disaccharidases are secreted with intestinal juice. These disaccharidases help in the digestion of disaccharides.