Biology · Chemistry

Carbohydrates and Biomolecules

986 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

Which of the following is/are example(s) of pentoses?

  1. Arabinose

  2. Galactose

  3. Glucose

  4. Fructose

  5. Both (1) and (2)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because arabinose is an aldopentose, a monosaccharide containing five-carbon atom and including an aldehyde functional group.

Multiple choice

Sucrose on acidic hydrolysis gives

  1. two glucose units

  2. glucose and galactose

  3. glucose and fructose

  4. glucose and mannose

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because sucrose is known as cane sugar. When sucrose is hydrolysed with an acid or an enzyme, it gives an equimolar mixture of D-glucose and D-fructose.

Multiple choice

The process of dehydration is associated with ---------------------- formation.

  1. glycosidic bond

  2. peptide bond

  3. agostic bond

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

A peptide bond (amide bond) is a covalent chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, causing the release of a molecule of water. Hence the process is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids.

Multiple choice

The cyclic structure of monosaccharides is represented by

  1. Newman projection

  2. Fischer projection

  3. Haworth projection

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

A Haworth projection is a common way of representing the cyclic structure of monosaccharides with a simple three-dimensional perspective.

Multiple choice

The core of pyranose sugars consists of

  1. pivaloyloxymethyl

  2. silyl ethers

  3. tetrahydropyran

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

Tetrahydropyran is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. The tetrahydropyran ring system is the core of pyranose sugars.

Multiple choice

Which of the following is commonly called table sugar?

  1. Glucose

  2. Fructose

  3. Sucrose

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sucrose is a disaccharide that contains glucose and fructose. Sugar is transported within the plant's body in the form of sucrose, and this the sugar we use at the table to sweeten our food.

Multiple choice

Which of the following is a non reducing sugar?

  1. Sucrose

  2. Maltose

  3. Lactose

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

Sucrose is a non-reducing sugar because its glycosidic bond links the anomeric carbons of both glucose and fructose (C1 of glucose to C2 of fructose). This leaves no free anomeric carbon available to reduce other compounds. In contrast, maltose and lactose both have free anomeric carbons and act as reducing sugars.

Multiple choice

Assertion: Cellulose is not digested by humans. Reason: Cellulose is a branched polymer of high molecular weight.

  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
C Correct answer
Explanation

This option is correct,  because human digestive system does not contain enzymes,  which can hydrolyse cellulose into glucose.

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.