Tag: bio-chemistry

Questions Related to bio-chemistry

Which one of these is not correct regarding peroxisomes?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Single membrane bound organelles

  2. Perform photorespiration in ${C} _{3}$ plants

  3. Take part in synthesis and storage of lipids

  4. Protect a cell from the toxic effects of ${H} _{2}{O} _{2}$

Show answer
Correct Option: C
Explanation:
SER takes part in the synthesis and storage of lipids. Peroxisomes are the single membrane bound cell organelles, which perform photorespiration in association with chloroplasts and mitochondria. They protect the cell from the toxic effects of $H2 _O$. 
So, the correct answer is 'Take part in the synthesis and storage of lipids'.

_______ are the microbodies, which take part in glyoxylate pathway, bounded by a single membrane and are usually present in germinating fatty seeds.

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Glyoxysomes

  2. Peroxisomes

  3. Sphaerosomes

  4. Lysosomes

Show answer
Correct Option: A
Explanation:

Glyoxysomes are microbodies which contain enzymes for $\beta$-oxidation of fatty acids and glyoxylate pathway. They are considered to be special peroxisomes. They occur abundantly in gerrminating endosperm cells of oil seeds.

Food  is largely absorbed in 

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Stomach

  2. Oesophagus

  3. Small intestine

  4. Colon

Show answer
Correct Option: A
Explanation:
Stomach - It is a hotbed of digestive activity, but virtually nothing (except alcohol) is absorbed there. 
Oesophagus - Nothing is absorbed in the oesophagus.  The esophagus is a tube that connects the throat and the stomach. If the mouth is the gateway to the body, then the esophagus is a highway for food and drink to travel along to make it to the stomach. 

Small Intestine - It is the site of virtually all nutrient absorption, including proteins, carbohydrates, fats and water, as well as vitamins and minerals.

Colon - It extracts water and salt from solid wastes before they are eliminated from the body and is the site in which flora-aided (largely bacterial) fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a major role in absorption of foods and nutrients.
So. the correct option is 'Stomach'.

Which of the following is the most rapidly transported monosaccharide into the bloodstream from the intestine?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Mannose

  2. Glucose

  3. Galactose

  4. Fructose

Show answer
Correct Option: C
Explanation:

Transportation of galactose is most rapid as it attaches with sodium ion and easily dragged by the protein carries so it is very easy to transport it while glucose and fructose require energy to transport as they are transported by active transport.

So the correct option is 'Galactose'.

Which of the following electrolyte pumps helps in active absorption of glucose in the intestinal walls?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Sodium

  2. Potassium

  3. Chloride

  4. Bicarbonate

Show answer
Correct Option: A
Explanation:

Active absorption occurs against the concentration gradient which requires energy. $Na^+$ which transports by facilitated transport that means it is taken by a protein carrier which has a peculiarity. It drags glucose with sodium ion from the lumen of the intestine to blood and helps in its absorption.

So the correct option is 'Sodium'.

In which of the following parts of the alimentary canal does absorption of nutrients and drugs takes place?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Mouth

  2. Stomach

  3. Small intestine

  4. All of the above

Show answer
Correct Option: D
Explanation:

Absorption of nutrients and drugs is mainly carried out by the small intestine but the stomach also absorbs certain drugs, water, and alcohol while mouth absorbs a very little amount of water and drugs and breaks down starch.

So the correct option is 'All of the above'.

State which of the following statement is true OR false.
(A) No absorption of food takes place in mouth and oesophagus.
(B) Absorption of glucose depends on sodium ion.
(C) Whole protein particles can be engulfed by pinocytosis.

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. B and C are true, A false

  2. All are true

  3. A and C are true, B is false

  4. A and B true, C false

Show answer
Correct Option: D
Explanation:

  • After food is being swallowed, from the mouth it is transported to the stomach. No absorption of nutrients takes place in the mouth and oesophagus. Hence, No absorption of food takes place in the mouth and oesophagus.
  • Active glucose absorption is thought to depend on a gradient of sodium ion concentration across the brush border membrane of intestinal epithelial cells. Specifically, glucose absorption was minimally reduced when intraluminal sodium concentration was reduced. Hence, Absorption of glucose depends on sodium ion.
  • Pinocytosis is the absorption of liquids, whereas phagocytosis is the absorption of solid objects which are essentially food for the cell. Phagocytosis engulfs whole particles, which are later broken down by enzymes, such as cathepsins, and absorbed into the cells. Hence, Whole protein particles cannot be engulfed by pinocytosis.
So, the correct answer is 'A and B true, C false'.

What is correct about microvilli?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Also known as brush bordered epithelia

  2. Found in small intestine and PCT both

  3. Increase absorption of food

  4. These are infoldings of cell membrane

Show answer
Correct Option: C
Explanation:
  1. Brush bordered epithelium is microvilli covered Epithelial surface found in the body.
    2. The columnar and cuboidal epithelium of small intestine and PCT have the surface covered with microvilli for increasing absorption.
    3. Cilia are meant for the movement of fluid while microvilli function to increase the absorption and secretion.
    4. Microvilli are microscopic cellular membrane protrusions that increase the surface area for diffusion and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.
    So, the correct option is 'Increase absorption of food.

In which part of gastro-intestinal tract does maximum absorption of water occur?

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. Colon

  2. Duodenum

  3. Jujenum

  4. Ileum

Show answer
Correct Option: A
Explanation:

Maximum absorption of water occurs in the large intestine, that is, in the colon. Certain drugs and metals are also absorbed here. 

So, the correct answer is 'Colon'. 

Choose the correct answers from the alternatives given.
The villi present on the wall of the small intestine

bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

  1. secrete digestive enzymes

  2. increase the surface area for absorption

  3. hold mucus, so ulcers do not form

  4. hold products of digestion, so they do not enter the large intestine

Show answer
Correct Option: B
Explanation:

 The absorption of digested carbohydrates, proteins and fats  is done in the small intestine with the help of villi which helps increase the surface area of the intestine. Villi are finger like projections on the intestinal wall that absorbs digested food material. Carbohydrates and proteins are absorbed into blood, while fats are absorbed into the lymph

So, the correct answer is 'increase the surface area for absorption'