Sample Questions on Monosaccharides

Question 1: Why are carbohydrates usually optically active?

Answer:

Carbohydrates are usually optically active because they contain one or more chiral carbon atoms.

Due to the presence of one or more chiral or asymmetric carbon atoms and the absence of a plane of symmetry, carbohydrates are usually optically active.

Question 2: What are monosaccharides?

Answer:

Monosaccharides are polyhydric aldehydes and ketones that cannot be hydrolyzed into simple carbohydrates. Monosaccharides with aldehyde group (-CHO) are called aldoses while monosaccharides with ketonic group (C=0) are called ketoses. For example, glucose, fructose, ribose, etc.

Question 3: Explain what is meant by the pyranose structure of glucose?

Answer:

The six-membered cyclic structure of glucose is called the pyranose structure (α or β) in analogy to pyran. Pyran is a cyclic compound consisting of one oxygen atom and five carbon atoms in the ring.

Question 4: What are the structural features of reducing sugars?

Answer:

Reducing sugars contain free aldehyde or ketonic groups.

Question 5: What are the two functions of carbohydrates in plants?

Answer:

The two functions of carbohydrates in plants are:

• Carbohydrates are used as storage molecules in plants in the form of starch.
• The cell wall of bacteria and plants is made up of cellulose.

The branch of chemistry that deals with the molecules involved in living things is called biochemistry. Carbohydrates, proteins, vitamins, and nucleic acids are some of the major components of our body. These are collectively called biomolecules.

A biomolecule is sometimes associated as a biological molecule, a term that refers to molecules found in living objects that are important for one or additional biological processes, analogous to cell division, morphogenesis, or development. Large macromolecules (or polyanions) similar to proteins, carbohydrates, lipids, and nucleic acids, as well as primary metabolites, secondary metabolites, and smaller moieties, similar to natural products, are all examples of biomolecules. Natural material is the more broad term for this type of material. Biomolecules are essential factors of living organisms. While endogenous biomolecules are made within the organism, organisms usually require external biomolecules, such as specific nutrients, to be present.

Carbohydrates are optically active polyhydroxy aldehydes or polyhydroxy ketones or substances that upon hydrolyzed would produce these types of compounds.