Biology ยท 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

Which of the following is a three carbon sugar?

  1. Glucose

  2. Ribofuranose

  3. Arabinose

  4. Phosphor glyceraldehydes

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

Phosphoglyceraldehyde (PGAL) is a three-carbon sugar phosphate that is a key intermediate in glycolysis and the Calvin cycle.

Multiple choice

_________ is known as animal starch.

  1. Glucose

  2. Glyceraldehydes

  3. Ribose

  4. Glycogen

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

Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria, hence it is called animal starch.

Multiple choice

The simplest form of carbohydrates is:

  1. glycogen

  2. cane sugar

  3. starch

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

Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar molecule. Starch and glycogen are polysaccharides, and cane sugar is a disaccharide.

Multiple choice

Sucrose is made up of

  1. glucose and mannose

  2. glycogen and fructose

  3. glucose and galactose

  4. glucose and fructose
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sucrose is a disaccharide composed of one glucose molecule and one fructose molecule linked together.

Multiple choice

The examples of hexose sugars are:

  1. glyceraldehyde and dihydroxyacetone phosphate

  2. ribose and deoxyribose

  3. glucose, fructose, galactose

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hexose sugars are monosaccharides with six carbon atoms. Glucose, fructose, and galactose are all common examples of hexoses.

Multiple choice

The polysaccharide, known as animal starch, is

  1. amylase

  2. amyloprotein

  3. chitin

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

Glycogen is the primary storage polysaccharide in animals, often referred to as animal starch. Amylase is an enzyme, while chitin is a structural polysaccharide found in fungi and arthropods.

Multiple choice

Glucose, Galactose and fructose are

  1. trioses

  2. pentoses

  3. tetroses

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

Glucose, galactose, and fructose are all monosaccharides with the chemical formula C6H12O6, which classifies them as hexoses because they contain six carbon atoms.

Multiple choice

The chief constituent of cell wall of plants is

  1. cellulose

  2. chitin

  3. glycogen

  4. starch
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cellulose is a complex carbohydrate that provides structural support to plant cell walls. Starch and glycogen are storage polysaccharides, while chitin is found in fungal cell walls and insect exoskeletons.

Multiple choice

Glucose and galactose forms:

  1. maltose

  2. sucrose

  3. lactose

  4. all of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lactose is a disaccharide composed of one molecule of glucose and one molecule of galactose. Maltose consists of two glucose units, and sucrose consists of glucose and fructose.

Multiple choice

Which among the following is/are homopolysaccharide?

  1. Starch

  2. Glycogen

  3. Cellulose

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Starch, glycogen, and cellulose are all homopolysaccharides because they are composed entirely of glucose units. Since all listed options are homopolysaccharides, the correct answer is all of these.

Multiple choice

Which of the following is the correct order of absorption rate of the monosaccharides by the intestinal mucosa?

  1. Arabinose > Xylose > Mannose > Fructose > Glucose > Galactose

  2. Glucose > Fructose > Galactose > Mannose > Xylose > Arabinose

  3. Galactose > Fructose > Glucose > Mannose > Xylose > Arabinose

  4. Galactose > Glucose > Fructose > Xylose > Mannose > Arabinose

  5. Glucose > Fructose > Galactose > Xylose > Arabinose > Mannose
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Glucose and galactose are absorbed mainly by the jejuna enterocytes, against a concentration gradient, by a sodium-dependent active transport mechanism. Fructose crosses the apical membrane of enterocytes of the jejunum by facilitated (mediated) diffusion. Since this transfer is not energy dependent, fructose cannot be absorbed against a concentration gradient. Limited absorption of xylose, mannose, and arabinose seems to occur by a diffusion mechanism. This difference in mechanism of absorption of monosaccharides accounts for their absorption by the intestinal mucosa.