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 statement(s) is/are true? P. Rings with five and six atoms monosaccharides are called pyranose and furanose forms, respectively. Q. In polysaccharides, monosaccharide units are joined by peptide bond. R. Trehalose consists of two glucose units.

  1. P only

  2. Q only

  3. R only

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The aldehyde or ketone group of a straight-chain monosaccharide will react reversibly with a hydroxyl group on a different carbon atom to form a hemiacetal or hemiketal, forming a heterocyclic ring with an oxygen bridge between two carbon atoms. Rings with five and six atoms are called furanose and pyranose forms, respectively, and exist in equilibrium with the straight-chain form. In polysaccharides, monosaccharide units are joined by glycosidic bond. Trehalose is a disaccharide and consists of two glucose monomeric units. Hence, only statement R is true.

Multiple choice

Which of the following carbohydrates is/are disaccharide(s)? P. Nigerose
Q. Lyxose
R. Laminaribiose
S. Sophorose

  1. P only

  2. Q only

  3. S only

  4. P, Q, R

  5. P, R, S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

P. Nigerose is a disaccharide and consists of two glucose monomer units.Q. Lyxose is a monosacharide.R. Laminaribiose two glucose monomer units.S. Sophorose is a disaccharide and consists of two glucose monomer units. Hence, P, R and S all are classified as disaccharides.

Multiple choice

Glucose is a/an:

  1. aldopentose

  2. ketopentose

  3. ketohexose

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

Glucose is an aldohexose. Fructose is a ketohexose.

Multiple choice

Which of the following is the correct statement about hyaluronic acid?

  1. Short polymer of D-glucoronic acid and N-acetylgalactosamine.

  2. A polymer of D-galactose and N-acetylglucosamine.

  3. A polymer of N-acetylglucosamine and D-glucoronic acid.

  4. A polymer of D-glucosamine-N-sulphate and D-glucoronic acid.

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

Hyaluronic acid is the straight chain polymer of N-acetylglucosamine and D-glucoronic acid,  which is linked together by (β-1 -> 3) linkages. Hyaluronic acid or hyaluronate is a glycosaminoglycan,  which is found in abundance in animal tissues and also in bacteria.

Multiple choice

Which of the following are contained in Gangliosides?

  1. Galactose, glucose and ceramide

  2. N-acetyl-D-galactosamine and ceramide

  3. Sialic acid

  4. Glucose and galactose

  5. Both 1 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Gangliosides are glycosphingolipids which are obtained from glucosylceramide. Gangliosides can contain more than one molecule of sialic acid along with galactose, glucose and ceramide. They are present in the nervous tissues in the form of membrane lipids.

Multiple choice

Which of the following disaccharides is formed by the hydrolysis of starch?

  1. Sucrose

  2. Maltose

  3. Trehalose

  4. Lactose

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Maltose (C12H22O11) is a reducing disaccharide which is obtained from the hydrolysis of starch with the help of amylases. Maltose in α and β forms are linked with α-1, 4-glycosidic linkage. Maltose is a crystalline solid, white in color and has melting point of about 160-165°C.

Multiple choice

Which glycoprotein has O-glycosidic linkage?

Glycoconjugate molecules are biologically active. They are formed as a result of the covalent bonding of oligosaccharides and polysaccharides with lipid or protein molecules.

  1. Plasma protein

  2. Mucin

  3. GPI-linked glycoprotein

  4. Uromodulin

  5. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mucin contains O-glycosidic bond between the hydroxyl side-chain of Thr or Ser and the anomeric carbon. Mucins are capable of forming gels and therefore is an important ingredient of gel-like secretions.

Multiple choice

Which glycoconjugate can have more than one oligosaccharide chain along with covalent linkage with the polypeptide backbone?

Glycoconjugate molecules are biologically active. They are formed as a result of the covalent bonding of oligosaccharides and polysaccharides with lipid or protein molecules.

  1. Proteoglycan

  2. Peptidoglycan

  3. Glycoprotein

  4. Ganglioside

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

The proteins having one or more oligosaccharide chains bound covalently to side-chains of polypeptides are called glycoproteins. Glycoproteins like TSH, HCG, FSH, etc., act as hormones. Other glycoproteins include transferrin, immunoglobin, lectin, calnexin, etc.

Multiple choice

Which of the following is the polysaccharide, which produces cellobiose and β-D-glucose on hydrolysis?

This fibrous structural polysaccharide is present in abundance in the plant cell walls but absent in animals.

  1. Peptidoglycan

  2. Hyaluronic acid

  3. Starch

  4. Inulin

  5. Cellulose
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Cellulose on hydrolysis produces cellobiose and β-D-glucose. The first step involves breaking of β-glycosidic bonds with the help of β-1, 4 glucanase to form cellobiose. Then, the β-1, 4 glycosidic bond is cleaved with the help of β-glucosidase to form glucose.