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Absorption mechanism - class-XI

Description: absorption mechanism
Number of Questions: 20
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Tags: digestive system of human digestion and absorption digestion bio-chemistry biology
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What is the basic difference between fertilizers and manures?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Fertilizers are natural and manures are artificial

  2. Fertilizers are artificil and manures are natural

  3. Fertilizers increase the fertility of the soil and manures reduce the fertility of the soil

  4. Fertilizers prevents the growth of crop and manures increase the fertility of the soil

  5. None of these

Show answer
Correct Option: B
Explanation:

  • Fertilizers are  chemicals manufactured industrially, added to soil or land to increase its fertility.
  • Manure is organic matter, mostly derived from animal feces except which can be used as organic fertilizer in agriculture.

So, the correct option is 'Fertilizers are artificial and manures are natural'.

.......... is the form in which digested fats are absorbed into the intestinal walls.

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Chylomicrons

  2. Micelles

  3. Bile salts

  4. Both A and B

Show answer
Correct Option: B
Explanation:

Micelles are formed when bile emulsifies the fat which makes it water soluble and can be absorbed by the intestinal wall. Later on, they convert into chylomicrons by coating them with proteins are absorbed by the lymph vessels which transport it into a blood and then it reaches the cell.

So the correct option is 'Micelles'.

Which of the following is TRUE regarding micelles in the intestine?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Micelles are very small fat molecules

  2. Micelles are small spherical water soluble droplets

  3. Micelles help fatty acids and glycerol to be absorbed in to the lymph vessels

  4. Micelles are also called chylomicrons

Show answer
Correct Option: B,C
Explanation:

Micelles are formed when bile emulsifies the fat which makes it water soluble and can be absorbed by the intestinal wall, later on, they convert into chylomicrons by coating them with proteins are absorbed by the lymph vessels which transport it into a blood and then it reaches the cell.

So the correct option is 'Micelles are small spherical water-soluble droplets and Micelles help fatty acids and glycerol to be absorbed into the lymph vessels'.

Chylomicrons are protein coated small fat globules formed in

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Lumen of intestine

  2. Lacteals of villi

  3. Cells of mucosa

  4. Blood vessels of villi

Show answer
Correct Option: A
Explanation:
Chylomicrons are protein coated small fat globules formed in lumen of the small intestine, it is in this form that the fats are absorbed across the intestinal lumen into the circulatory system
So, the correct answer is 'Lumen of intestine'

Which of the following chemical substance is absorbed by passive transport from the intestine?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Glucose

  2. Galactose

  3. Amino acid

  4. Fructose

Show answer
Correct Option: A
Explanation:
The chemical substance which is absorbed by the passive transport from the intestine is glucose, transported by SGLUT 1 and SGLUT 2
So, the correct answer is 'Glucose'

The absorption of nutrients, like amino acids, occurs via co-transport channels, which couple with the movement of $Na+$. Which of the following statement is true for this type of co-transport?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. In this both amino acids and $Na+$ move down a electrochemical gradient.

  2. Both amino acids and $Na+$ are absorbed agfainst the electrochemical gradient

  3. Amino acids are absorbed against the electrochemical gradient and $Na+$ moves towards the electromagnetic gradient.

  4. Amino acids move towards the electrochemical gradient and $Na+$ against the electrochemical gradient.

Show answer
Correct Option: D
Explanation:
The transport of amino acids takes place with the help of co-transporters where amino acids move along the concentration gradient while Na^+ moves against the concentration gradient. 
So, the correct answer is 'Amino acids move towards the electrochemical gradient and Na+Na+ against the electrochemical gradient'

Fatty acids and glycerol are first absorbed by

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Lymph vessels

  2. Blood

  3. Blood capillaries

  4. Hepatic portal vein

Show answer
Correct Option: A
Explanation:

Triglycerides are emulsified by bile and hydrolyzed by the enzyme lipase, resulting in a mixture of fatty acids and monoglycerides. These then pass from the intestinal lumen into the enterocyte, where they are re-esterified to form triacylglycerol. The triacylglycerol is then combined with phospholipids, cholesterol ester, and apolipoprotein to form chylomicrons. These chylomicrons then pass into the lacteals, forming a milky substance known as chyle. The lacteals merge to form larger lymphatic vessels that transport the chyle to the thoracic duct where it is emptied into the bloodstream at the subclavian vein.

Fatty acids are primarily absorbed through blood capillaries, has which of the following number of carbon molecules?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Up to 10 carbons

  2. More than 10 carbons

  3. Up to 20 carbons

  4. More than 20 carbons

Show answer
Correct Option: A
Explanation:
Fatty acids with two to six carbon atoms are called short-chain fatty acids or volatile fatty acids. They are primarily absorbed through blood capillaries. 
So the correct answer is 'Up to 10 carbons'.

Absorption of amino acid is dependent upon

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Sodium gradient

  2. ATP

  3. Protein gradient

  4. All of the above

Show answer
Correct Option: D
Explanation:
Amino acids together constitute the proteins. They are absorbed in the blood by active transportation mechanism. They are transported from the lumen into the cells by Na+ amino acid co-transporter using ATP in apical membrane energy by sodium gradient. 
So the correct answer is 'All of the above'.

Which of the following mineral is needed for amino acid to pass into the bloodstream?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Potasium

  2. Sodium

  3. Iron

  4. Both A and B

Show answer
Correct Option: D
Explanation:
Amino acids constitute the proteins. They are absorbed in the blood by active transportation using sodium-potassium amino acid transporter. They use ATP in the process and transported from the lumen to the cells against the gradient.
So the correct answer is 'Both A and B'.

The villi present on the wall of the small intestine

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Secretes digestive enzyme

  2. Increase surface area for absorption

  3. Hold mucus to protect wall

  4. None of the above

Show answer
Correct Option: B
Explanation:


  • Villi present in small intestine increase intestinal absorptive surface area providing efficient absorption of nutrients in lumen.
  • Mucosa is an innermost layer of tissues seen in the small intestine and is a mucous membrane that secretes digestive enzymes and hormones.
  • A submucosa layer provides blood vessels, nerves and lymphatic vessels to support mucosa on the surface to protect the wall.
So the correct answer is 'Increase surface area for absorption'.

The absorbed fatty acids are used in synthesizing fat in which of the following cells?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Liver cells

  2. Intestinal cells

  3. Cardiac cells

  4. All of the above

Show answer
Correct Option: B
Explanation:
The absorbed fatty acids are used in synthesizing fat in the intestinal cells. They are primarily stored as fat in the adipose cells. They have an important role in providing energy to the body in fasting.
So the correct answer 'Intestinal cells'.


Which of the following pathways would increase its activity level during starvation?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Fatty acid degradation

  2. Amino acid synthesis

  3. Fatty acid synthesis

  4. None of these

Show answer
Correct Option: A
Explanation:
  • During starvation the priority of the metabolism in body is to provide sufficeint glucose to the brain and other tissues that are absolutely dependent on this fuel,. 
  • However precursors of the glucose are not abundant at the time of starvation and most of the stored fatty acid is utilised at times like this.
  • These fatty acid cannot be converted to glucose because acetyl CoA cannot be transformed to pyruvate.
  • Therefore the fatty acid that are stored in the body are converted to acetyl CoA and are used in the metabolism to provide energy to the body in the state of starvation.
  • Therefore the answer option 'Fatty acid degradation' is correct.

Absorption of nutrients
Read the following four statements (i) - (iv) with certain mistakes in two of them.
(i) Fructose is generally absorbed by simple diffusion.
(ii) The digestive wastes, solidified into coherent faeces in the rectum initiate an endocrinal action causing an urge or desire for its removal.
(iii) The food mixes thoroughly with the acidic gastric juke of the stomach by the churning movements of its muscular wall and is called the chyme.
(iv) The secretions of the brush border cells of the mucosa alongwith the secretions of the goblet cells constitute the succus entericus.
Which of the above two statements have mistakes?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (iii) and (iv)

  4. (i) and (iii)

Show answer
Correct Option: A

Which of the following statements are incorrect about chylomicrons?


(i) Chylomicrons are produced in the epithelial cells of the small intestine.
(ii) It contains triglycerides, cholesterol, and phospholipids.
(iii) They are protein-coated small vesicles.
(iv) Chylomicrons are released from the epithelial cell into lacteals.

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. (i) and (iv)

  2. (ii) and (iii)

  3. (i), (ii), (iii) and (iv)

  4. None of these

Show answer
Correct Option: D

Gaucher's disease is concerned with which of the following?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Abnormal fat metabolism

  2. Abnormal protein metabolism

  3. Abnormal carbohydrate metabolism

  4. Abnormal vitamin metabolism

Show answer
Correct Option: A
Explanation:
Gaucher's disease is an autosomal recessive inherited disorder in which glucocerebroside is not degraded and get a deposit in organs like spleen and bone marrow because the enzyme glucocerebrosidase is not able to break the lipid does not form this enzyme.
  • Liver and spleen enlargement (hepatosplenomegaly).
  • Reduction in RBCs number(anaemia).
  • Easy bruising caused, in part, by a low level of platelets (thrombocytopenia).
  • Bone disease (bone pain and fractures).
  • So the correct option is 'Abnormal fat metabolism'.

Small amounts of monosaccharides like glucose, amino acids and some of electrolytes like chloride ions are absorbed by    (i)   . However, some of the substances like fructose and some amino acids are absorbed by the mechanism called the      (ii)    . Various nutrients like amino adds and electrolytes like $Na^{+}$ are absorbed Into the blood by _(iii)   
(i)    (ii)    (iii)

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. facilitated transport active transport simple diffusion

  2. simple diffusion facilitated transport active transport

  3. active transport facilitated transport simple diffusion

  4. simple diffusion active transport facilitated transport

Show answer
Correct Option: B
Explanation:

(i) simple diffusion

(ii) facilitated transport
(iii) active transport
So, the correct answer is (b).

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

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Wall of the stomach

  2. Lymph vessels within the villi

  3. Capillaries within the villi

  4. Colon

Show answer
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?

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Amino acids

  2. Glucose

  3. Fatty acids

  4. Both A and B

Show answer
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

bio-chemistry digestive system of human absorption mechanism absorption digestion

  1. Duodenum

  2. Jejunum

  3. Ileum

  4. Both A and B

Show answer
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'.
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