UHS Punjab MDCAT Biology: Digestion MCQs

Practice Digestion MCQs for UHS Punjab MDCAT Biology — topic-wise sets with solved answers.

UHS Punjab MDCAT Biology: Digestion MCQs — sample questions

  1. Question 1

    Q1. In the mouth, salivary amylase breaks down starch into

    • A) Maltose
    • B) Glucose
    • C) Dextrins
    • D) Fructose

    Answer: Dextrins

    Explanation: Salivary amylase breaks down starch into dextrins and maltose, but primarily dextrins initially. Fructose is not a product.

  2. Question 2

    Q2. Gastric juice contains an enzyme that works best at a very low pH. This enzyme is

    • A) Pepsin
    • B) Gastric amylase
    • C) Trypsin
    • D) Chymotrypsin

    Answer: Pepsin

    Explanation: Pepsin is the gastric enzyme that works best at low pH. Trypsin and chymotrypsin work in the small intestine.

  3. Question 3

    Q3. The pancreas secretes bicarbonate ions to

    • A) Activate digestive enzymes
    • B) Neutralize acidic chyme
    • C) Emulsify fats
    • D) Absorb nutrients

    Answer: Neutralize acidic chyme

    Explanation: Bicarbonate ions neutralize acidic chyme from the stomach, creating an optimal pH for pancreatic enzymes.

  4. Question 4

    Q4. The brush border enzyme that splits maltose into two glucose molecules is

    • A) Maltase
    • B) Lactase
    • C) Sucrase
    • D) Amylase

    Answer: Maltase

    Explanation: Maltase is the enzyme that hydrolyzes maltose into glucose. Lactase and sucrase act on different disaccharides.

  5. Question 5

    Q5. The presence of fatty acids in the duodenum stimulates the release of

    • A) Secretin
    • B) Gastrin
    • C) CCK
    • D) Insulin

    Answer: CCK

    Explanation: CCK is released in response to fatty acids and peptides in the duodenum. Secretin is released due to acidic chyme.

  6. Question 6

    Q6. The enzyme enterokinase is involved in activating

    • A) Pepsinogen
    • B) Trypsinogen
    • C) Chymotrypsinogen
    • D) Procarboxypeptidase

    Answer: Trypsinogen

    Explanation: Enterokinase activates trypsinogen to trypsin, which then activates other pancreatic zymogens.

  7. Question 7

    Q7. The major site for the absorption of nutrients is the

    • A) Stomach
    • B) Duodenum
    • C) Jejunum
    • D) Ileum

    Answer: Jejunum

    Explanation: The jejunum is the primary site for nutrient absorption due to its large surface area and specialized transport mechanisms.

  8. Question 8

    Q8. Bile salts are important for the digestion of

    • A) Carbohydrates
    • B) Proteins
    • C) Fats
    • D) Nucleic acids

    Answer: Fats

    Explanation: Bile salts emulsify fats, increasing their surface area for lipase action. They are not directly involved in carbohydrate, protein, or nucleic acid digestion.

  9. Question 9

    Q9. The hormone gastrin primarily stimulates the secretion of

    • A) Gastric juice
    • B) Pancreatic juice
    • C) Bile
    • D) Intestinal juice

    Answer: Gastric juice

    Explanation: Gastrin stimulates the secretion of gastric juice, which contains pepsinogen and HCl.

  10. Question 10

    Q10. The pH of the stomach is lowered by the secretion of

    • A) Pepsinogen
    • B) Gastrin
    • C) Hydrochloric acid
    • D) Mucus

    Answer: Hydrochloric acid

    Explanation: Hydrochloric acid (HCl) secretion lowers the stomach pH, activating pepsinogen to pepsin.

  11. Question 11

    Q11. The digestion of proteins begins in the

    • A) Mouth
    • B) Stomach
    • C) Small intestine
    • D) Large intestine

    Answer: Stomach

    Explanation: Protein digestion starts in the stomach with pepsin. The small intestine continues this process with pancreatic enzymes.

  12. Question 12

    Q12. The enzyme lactase is involved in the digestion of

    • A) Maltose
    • B) Sucrose
    • C) Lactose
    • D) Starch

    Answer: Lactose

    Explanation: Lactase breaks down lactose into glucose and galactose. Maltase acts on maltose, and sucrase on sucrose.

  13. Question 13

    Q13. The absorption of vitamin B12 requires

    • A) Intrinsic factor
    • B) Gastrin
    • C) Secretin
    • D) CCK

    Answer: Intrinsic factor

    Explanation: Intrinsic factor, produced by the stomach, is necessary for vitamin B12 absorption in the ileum.

  14. Question 14

    Q14. Chyme is a mixture of

    • A) Food and saliva
    • B) Food and gastric juice
    • C) Pancreatic juice and bile
    • D) Intestinal juice and nutrients

    Answer: Food and gastric juice

    Explanation: Chyme is the semi-fluid mixture of food and gastric juice that leaves the stomach.

  15. Question 15

    Q15. The release of bile into the duodenum is facilitated by

    • A) Secretin
    • B) CCK
    • C) Gastrin
    • D) The presence of fatty acids

    Answer: CCK

    Explanation: CCK stimulates the gallbladder to contract, releasing bile into the duodenum. Secretin also plays a role but is not the primary stimulus.

  16. Question 16

    Q16. The primary function of the gallbladder is to

    • A) Produce bile
    • B) Store bile
    • C) Release digestive enzymes
    • D) Absorb water

    Answer: Store bile

    Explanation: The gallbladder stores and concentrates bile produced by the liver, releasing it when needed.

  17. Question 17

    Q17. The enzyme carboxypeptidase is a pancreatic enzyme that

    • A) Activates trypsinogen
    • B) Hydrolyzes peptides at the carboxyl end
    • C) Emulsifies fats
    • D) Digests nucleic acids

    Answer: Hydrolyzes peptides at the carboxyl end

    Explanation: Carboxypeptidase removes amino acids one by one from the carboxyl end of a peptide chain.

  18. Question 18

    Q18. The main function of the small intestine's villi is to

    • A) Secrete digestive enzymes
    • B) Absorb nutrients
    • C) Store bile
    • D) Produce hormones

    Answer: Absorb nutrients

    Explanation: Villi increase the surface area of the small intestine, enhancing the absorption of nutrients.

  19. Question 19

    Q19. A deficiency in pancreatic amylase would primarily affect the digestion of

    • A) Proteins
    • B) Fats
    • C) Carbohydrates
    • D) Nucleic acids

    Answer: Carbohydrates

    Explanation: Pancreatic amylase breaks down starch into simpler sugars. Its deficiency affects carbohydrate digestion.

  20. Question 20

    Q20. The hormone secretin is released in response to

    • A) The presence of proteins in the stomach
    • B) Acidic chyme entering the duodenum
    • C) Fatty acids in the duodenum
    • D) Glucose in the blood

    Answer: Acidic chyme entering the duodenum

    Explanation: Secretin is released when acidic chyme enters the duodenum, stimulating the pancreas to secrete bicarbonate-rich fluid.

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