Tag: digestive system of human

Questions Related to digestive system of human

The absorption of glycerol, fatty acids and monoglycerides takes place by the

  1. Wall of the stomach

  2. Lymph vessels within the villi

  3. Capillaries within the villi

  4. Colon


Correct Option: B
Explanation:

Each villus has a network of capillaries and fine lymphatic vessels called lacteals close to its surface. The epithelial cells of the villi transport nutrients from the lumen of the intestine into these capillaries (amino acids and carbohydrates) and lacteals (lipids). The absorbed substances are transported via the blood vessels to different organs of the body, where they are used to build complex substances such as the proteins required by our body. The food that remains undigested and unabsorbed passes into the large intestine.

Which of the following nutrient is absorbed by the active absorption?

  1. Amino acids

  2. Glucose

  3. Fatty acids

  4. Both A and B


Correct Option: D
Explanation:
Absorption is a process by which the end products of digestion pass from the alimentary canal into the blood and lymph through intestinal mucosa. It is carried out by the passive, active and facilitated type of transport mechanism.
Active transport mechanism occurs against the concentration gradient and is involved in the absorption of amino acids, monosaccharides like glucose, and electrolytes like Na+.
So the correct answer is 'Both A and B'.

Fats are mostly absorbed in

  1. Duodenum

  2. Jejunum

  3. Ileum

  4. Both A and B


Correct Option: D
Explanation:
The small intestine is the main site for absorption of nutrients and digestion of fat. Fats are consist of glycerol and fatty acids. They are mostly absorbed in duodenum and jejunum part of the small intestine. Duodenum is the upper portion of the intestine that gives hormonal signal whereas jejunum has microvilli that help in increasing the surface area for the absorption of fats.
So the correct answer is 'Both A and B'.

Protein digesting enzyme is

  1. Pepsin

  2. Ptyalin

  3. Amylase

  4. Maltase

  5. Sucrase


Correct Option: A
Explanation:
  1. Pepsin is produced in the stomach and is one of the main digestive enzymes, which helps in digestion of the proteins in food. Zymogenic cell or peptic cell is a cell in the stomach that releases pepsinogen and chymosin.
  2.  The inactive pepsinogen, on exposure to hydrochloric acid, gets converted to the active enzyme pepsin, the proteolytic enzyme of the stomach. Pepsin converts proteins into proteoses and peptones (peptides). 
  3. Pepsin hydrolyses proteins to polypeptide chains and initiates protein digestion  Hence, the protein-digesting enzyme is pepsin.
So, the correct answer is 'pepsin'.

I. Amylase
II. Lipase
III. Pepsin
IV. Trypsin

Out of the aforementioned enzymes, the protein-digesting enzymes are

  1. I and II.

  2. I and III.

  3. II and III.

  4. II and IV.

  5. III and IV.


Correct Option: E
Explanation:

Protein digestive enzymes are pepsin and trypsin. They break down proteins into smaller peptides and amino acids. Pepsin is secreted by the gastric gland in the stomach where as trypsin is secreted by Pancreas.

Amylase and Lipase are other important digestive enzymes as well and they help in digestion of starch and fats respectively. Hence option E is correct.

Emulsification of fats is done by .... 

  1. saliva

  2. gastric juice

  3. bile

  4. intestinal juice


Correct Option: A

With reference to a normal human being, which one of the following statements is not correct?

  1. Human saliva is slightly acidic

  2. An adult human may secrete $1$ to $1.5$ litres of saliva per day

  3. Saliva is secreted by six pairs of salivary glands in human beings

  4. The salivary enzymes(ptyalin) breaks down cooked starch into maltose


Correct Option: A

What is optimum pH for the action of salivary anylase?

  1. $1.8$

  2. $6.8$

  3. $7.4$

  4. $8$


Correct Option: B
Explanation:

The optimum pH for the enzymatic activity of salivary amylase ranges from 6 to 7. Above and below this range, the reaction rate reduces as enzymes get denaturated. The enzyme salivary amylase is most active at pH 6.8. 

So, the correct option is '6.8'.

Salivary glands secrete

  1. Amylase

  2. Pepsin

  3. Trypsin

  4. Bile juice


Correct Option: A
Explanation:

An amylase is an enzyme that catalyses 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. Bile juice is secreted by liver. Pepsin and trypsin are produced in small intestine. 

Therefore, the correct answer is option A.

A digestive enzyme, salivary amylase, in the saliva being digestion of 

  1. Protein

  2. Nucleic acids

  3. Fats

  4. Carbohydrates


Correct Option: D
Explanation:
  • First, salivary glands in your mouth make salivary amylase, which begins the digestive process by breaking down starch when you chew your food, converting it into maltose, a smaller carbohydrate. 
  • The breakdown of starch is just one of the many steps in the process of digestion. Although digestion begins in the mouth, it continues in the stomach and intestines.
  • Amylase is an enzyme that breaks down starch to sugar. The amylase in the mouth, salivary amylase, is called ptyalin. 
  • Ptyalin can do digestive can work in the stomach for several hours. Iodine and Benedict's solution is used to recognize starch and sugar (maltose) in our saliva.
Therefore, the correct answer is option D.