MCQ Detailed View

Monosaccharides are the simplest form of carbohydrates and are often referred to as simple sugars. They are the basic building blocks of more complex carbohydrates such as disaccharides (e.g., sucrose, lactose) and polysaccharides (e.g., starch, glycogen). Monosaccharides consist of a single sugar unit with the general formula CₙH₂ₙOₙ, typically containing 3 to 7 carbon atoms.The main examples of monosaccharides are:

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   Glucose:

   
   
   
   
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     Known as blood sugar, it is the primary source of energy for cells.

     
     
   
   
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     Produced during photosynthesis in plants and released during the digestion of carbohydrates in animals.

     
     
   
   
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     Essential for cellular respiration, providing ATP (energy currency of the cell).

     
     
   
   
   
   


2. 
   

   Galactose:

   
   
   
   
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     Commonly found as a component of lactose, the sugar present in milk and dairy products.

     
     
   
   
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     While not as sweet as glucose, it plays an important role in energy metabolism and is used to form glycolipids and glycoproteins in cell membranes.

     
     
   
   
   
   


3. 
   

   Fructose:

   
   
   
   
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     Known as fruit sugar, naturally present in fruits, honey, and some vegetables.

     
     
   
   
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     It is the sweetest natural sugar and a key source of energy, often metabolized in the liver.

     
     
   
   
   
   

All three are simple, water-soluble sugars that can be absorbed directly into the bloodstream without needing further digestion. They are monomers that combine to form larger carbohydrates via glycosidic bonds.

Other options in the question are not incorrect individually, but since all three (glucose, galactose, fructose) are monosaccharides, the correct answer is D. All of these.

Monosaccharides are vital for energy production, biosynthesis of nucleic acids, and structural components in living organisms, making them fundamental biomolecules in biology.