Tag: biomolecules

Questions Related to biomolecules

Which among the following is the main constituent of Biogas?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Methane

  2. Propane

  3. Butane

  4. Ethane

Show answer
Correct Option: A

For the reduction of glucose to n-hexane, the reagent used is:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. $HBr$

  2. $HCl$

  3. $HF$

  4. $HI$

Show answer
Correct Option: D
Explanation:

For the reduction of glucose to n-hexane, the reagent used is $HI$.
Glucose is heated with $HI$, n-hexane is obtained which suggests that all the six carbons are linked in a straight chain.

Which of the following is true regarding monosaccharides?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Always have six carbon atoms

  2. Always have five carbon atoms

  3. Always have four carbon atoms

  4. May contain 3 to 7 carbon atoms

Show answer
Correct Option: D
Explanation:

Monosaccharides may contain 3 to 7 carbon atoms. They have chemical formula $(CH _2O) _{n}$, where conventionally $n=3$. Monosaccharides can be classified by the number of carbon atoms they contain: diose(2), triose(3), tetrose(4), pentose(5), hexose(6), heptose(7) and so on.

Raffinose on hydrolysis forms_________

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Glucose

  2. Fructose

  3. Galactose

  4. All of these

Show answer
Correct Option: D
Explanation:

Raffinose is a trisaccharide and consists of 1 unit of glucose, fructose and galactose each. 


So on hydrolysis, it breaks into glucose, fructose and galactose. 

So, D is correct.

Which of the following is synthetic sweetener?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Saccharin

  2. Aspartame

  3. Dulcin

  4. All of  the above

Show answer
Correct Option: D
Explanation:

Saccharin, aspartame, dulcin all are synthetic sweetener. They have a sugar-like taste but with less food energy.

Artificial sweeteners are used in one of two ways. They may be used directly in commercially processed foods, or they are mixed with one or more starch-based sweeteners before sale to consumers.


$\therefore$ Option D is the correct answer.

Which of the following is incorrect?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Fructose is reducing sugar

  2. Cellulose has $\beta$-D Glucose units

  3. DNA has D-ribose

  4. Amylopectin is insoluble in water

Show answer
Correct Option: C
Explanation:

Fructose is reducing sugar.
 
Cellulose is a polysaccharide composed of a linear chain of  $\beta $ 1,4 linked d glucose unit.with a degree of polymerization ranged from several hundreds to over ten thousands.

Amylopectin is a highly branched polymer of glucose found in plants. It is one of the two components of starch, the other being amylose.

As the name suggest DNA is deoxyribonucleic acid hence it has deoxyribose sugar not ribose sugar.

Consider the given statements.
I. Dextrin and glycogen are polysaccharides
II. Lactose and glucose are disaccharides
III.Sucrose and maltose are disaccharides
IV. Raffinose is oligosaccharide
The incorrect statements is/are:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. only II

  2. I and II

  3. I, II and III

  4. IV only

Show answer
Correct Option: A
Explanation:

Option (A) is right. The incorrect statement is (II).
(II) Lactose is a disaccharide while glucose is an aldosic monosaccharide.

Consider the given statements:


I. Maltose is also known as malt sugar.
II. Sucrose is also known as cane sugar.
III. Lactose is also known as grape sugar.
IV. Starch is also known as amylum.

The correct statement(s) is/are:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. I, II and IV

  2. I, II and III

  3. II, III and IV

  4. All

Show answer
Correct Option: A
Explanation:

(I) Maltose is also known as malt sugar.


(II) Sucrose is also known as cane sugar.

(III) Lactose is also known as milk sugar.

(IV) Starch is also known as amylum.

Hence, option A is correct.

Consider the statements about mono, di and oligo saccharides:


I. These are crystalline solids.
II. These are soluble in cold water.
III. These are tasteless.

The incorrect statement(s) is/are:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. only III

  2. I, II and III

  3. I and II only

  4. I and III only

Show answer
Correct Option: A
Explanation:

Monosaccharides, disaccharides and oligo saccharides are crystalline solids, water soluble and sweet in taste. They are called sugar.
Thus only statement III is incorrect.

A carbohydrate which cannot be hydrolysed to simpler compounds is called:

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. monosaccharide

  2. disaccharide

  3. polysaccharide

  4. oligosaccharide

Show answer
Correct Option: A
Explanation:

Monosaccharide cannot be hydrolyzed to simpler compounds as it is itself the simplest unit.
Disaccharides, polysaccharides and oligosaccharides can be hydrolyzed to monosaccharides.