Tag: chemistry

Questions Related to chemistry

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

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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

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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.

Which sugar does not increases the calorific value?

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Sucrose

  2. Glucose

  3. Aspartame

  4. Fructose

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Correct Option: C
Explanation:

Aspartame is artificial sugar so it does not increases the calorie intake it only induces the sweetness.


Option C is correct.

State whether the following statements are True or False:
Aldohexoses exist in $2^6$ optical forms.

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. True

  2. False

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Correct Option: B
Explanation:

False-Aidohexoses exist in $2^4(= 16)$ optical forms.


Aldohexoses, with four chiral centers, have $2^4$ = 16 stereoisomers.

State whether the following statements are True or False:
Raffinose is a trisaccharide. On hydrolysis, it gives three molecules of glucose.

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. True

  2. False

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Correct Option: B
Explanation:

False-On hydrolysis, it gives three molecules of monosaccharide units one each of glucose, fructose and galactose

State whether the following statements are True or False:
Glucose is more sweeter than fructose

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. True

  2. False

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Correct Option: B
Explanation:

False-Fructose is more sweeter than glucose

To separate a mixture of monosaccharides, you would use :

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. Centrifuge

  2. Chromatograph

  3. Mass spectrometer

  4. Electrolytic cell

  5. Dialysis

Show answer
Correct Option: B
Explanation:

Two-dimensional ascending chromatography has been employed to separate a mixture of monosaccharides.

The minimum number of carbon atoms that should be present in a monosaccharide is :

carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

  1. 2

  2. 3

  3. 4

  4. 6

Show answer
Correct Option: B
Explanation:

Monosaccharide is single polyhydroxy aldehyde (aldose) or ketone (ketose) units. Glucose is a single polyhydroxy aldehyde, while fructose is a single polyhydroxy ketone. A monosaccharide contains a skeleton, of carbon atoms. The minimum number of carbon atoms is three and it can go up to seven.