What is the composition of sucrose?

Appeared in: DSSSB 12 August 2024

Explanation

Sucrose is a disaccharide, a type of carbohydrate made of two monosaccharide units.
It is formed from the combination of one glucose molecule and one fructose molecule.
This combination occurs through a glycosidic bond, specifically an α-1,β-2 linkage.
Commonly known as table sugar, it is found naturally in sugarcane, sugar beets, and many fruits.

Option B: This combination forms lactose, not sucrose.
Option C: This combination forms maltose, not sucrose.
Option D: This option is fundamentally incorrect. Isomaltose is itself a disaccharide composed of two glucose units (with a different linkage than maltose). Combining it with galactose does not form a standard dietary disaccharide.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Composition of Disaccharides as background academic context rather than a clinical decision trigger.
Understanding the composition of sugars is vital for patient education, especially for those with diabetes mellitus, hereditary fructose intolerance, or sucrase-isomaltase deficiency.
Nurses use this knowledge to help patients interpret food labels, as 'sugars' can include sucrose, high-fructose corn syrup, and others, each with different metabolic effects.
What if? A patient with hereditary fructose intolerance must strictly avoid sucrose. If they consume it, the breakdown releases fructose, which they cannot metabolize, leading to severe hypoglycemia and potential liver damage.

How to Approach the Question

This is a factual recall question based on fundamental biochemistry.
Identify the core term in the question: 'sucrose'.
Recall that sucrose is a disaccharide, meaning it is composed of two monosaccharide units.
Mentally review the composition of the three major dietary disaccharides: Sucrose (Glucose + Fructose), Lactose (Glucose + Galactose), and Maltose (Glucose + Glucose).
Compare this recalled information with the provided options.
Select the option that correctly matches the composition of sucrose.

Concept Tested & Keywords

QF6xth9JVNvWUPRN0SHNJ7

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 1 (pp 26-370 of 370) p. 75-77

E6 Biochemistry U Satyanarayana— Part 1 (pp 26-420 of 840) p. 6-8

E6 textbook of Applied Biochemistry and Nutrition & DieteticsHarbans Lal (pp 26-464 of 479) p. 53-55

Practise the full DSSSB 12 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.