Biology · Chemistry

Carbohydrates and Biomolecules

1,073 Questions

Carbohydrates and biomolecules questions test your understanding of sugars, monosaccharides, and metabolic substrates. The topic covers food transportation in plants and the biochemical properties of sweeteners. Practicing these questions builds a strong foundation for exam preparation.

Disaccharides and monosaccharidesArtificial sweetenersGlycogen storagePlant food transportGlycoprotein hormones

Carbohydrates and Biomolecules Questions

Multiple choice

Assertion: Treatment of D-glucose with dilute alkali affords an equilibrium mixture consisting of D-mannose, D-fructose and starting substance D-glucose. Reason: The reaction involves an intermediate in which hybridization of C2 changes from sp3 to sp2.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because this reaction involves an intermediate in which hybridization of C2 changes from sp3 to sp2.

Multiple choice

Assertion: Glucose and fructose give the same osazone. Reason: During osazone formation, stereochemistry at C1 and C2 is destroyed.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is correct because osazone formation involves the reaction with C1 and C2 and the asymmetry in both carbon atoms is destroyed.

Multiple choice

Which of the the following statements about sucrose is/are correct?

  1. It is an α-D-glycoside.
  2. It undergoes mutarotation.
  3. It does not have a free aldehydic or ketonic group.
  4. Invert sugar, obtained by the hydrolysis of sucrose by enzyme, has negative rotation.

  1. 1, 2, and 3

  2. 1, 3, and 4

  3. 2, 3, and 4

  4. 1, 2, and 4

  5. All are correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct,  because sucrose being a non-reducing sugar, does not undergoes mutarotation. Therefore, statements 1, 3 and 4 are correct.

Multiple choice

Carrageenan is a general name for polysaccharides extracted from certain kinds of algae. Which among the following algae is used for extracting carrageenan?

  1. Porphyra

  2. Gracilaria

  3. Pelvetia canaliculata

  4. Eucheuma

  5. Chlorella
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Eucheuma is a group of red seaweeds representing the Tribe Eucheumatoideae used in the production of carrageenan, an important product used in cosmetics, food processing, and industrial uses, as well as a food source for those living in Indonesia and the Philippines.

Multiple choice

Which of the following is a set of heteropolysaccharides?

  1. Cellulose, Chitin, Dextran

  2. Cellulose, Dextran, Agarose

  3. Peptidoglycan, Agarose, Chitin

  4. Peptidoglycan, Agarose, Hyaluronate

  5. Peptidoglycan, Hyaluronate, Dextran
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Peptidoglycan, Agarose, Hyaluronate: All are heteropolysaccharides

Multiple choice

__________ is used to decolourise raw sugar.

  1. Animal charcoal

  2. Sugar charcoal

  3. Coconut charcoal

  4. Wood charcoal
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Wood charcoal is used to decolorize raw sugar through the process of adsorption where impurities stick to the porous charcoal surface. The activated carbon in wood charcoal has a massive surface area that traps colored compounds. This process filters out the brown color from raw sugar juice, producing the white refined sugar we commonly use.

Multiple choice

The charcoal used to decolourise raw sugar is

  1. animal charcoal

  2. sugar charcoal

  3. coconut charcoal

  4. wood charcoal

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Wood charcoal (also called activated carbon) is used in sugar refineries to decolorize raw sugar through adsorption. Its porous structure efficiently removes colored impurities. Animal charcoal (bone char) can also be used, but wood charcoal is the standard. Sugar and coconut charcoals have specialized uses.

Multiple choice

Insulin and glucagon are ______.

  1. polypeptides

  2. polysaccharides

  3. polynucleotides

  4. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Insulin and glucagon are protein hormones composed of amino acid chains, making them polypeptides. Insulin has two polypeptide chains; glucagon is a single chain. They are not carbohydrates (polysaccharides) or nucleic acids (polynucleotides). Option A correctly classifies them.

Multiple choice

Rayon is chemically _________.

  1. Glucose

  2. Amylase

  3. Cellulose

  4. Peptin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rayon is chemically composed of regenerated cellulose. It's produced from cellulose (usually from wood pulp) through a chemical process that creates a semisynthetic fiber. Glucose is a simple sugar, amylase is an enzyme, and peptin is also related to carbohydrates - none describe rayon's chemical nature.

Multiple choice

Which of the following is used in making artificial sweetener saccharine?

  1. Benzene

  2. Toluene

  3. Phenol

  4. Aniline
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Saccharine is synthesized from toluene (C7H8) through a series of chemical reactions including the oxidation of toluene derivatives. The sweetener was accidentally discovered in 1879. Benzene, phenol, and aniline are aromatic compounds but toluene is the specific starting material for commercial saccharine production.