Question

The carbohydrate synthesized in the leaves is transported through sieve tubes in the form of
A. Glucose
B. Triose sugar
C. Sucrose
D. Soluble starch

Answer 1

Hint: Food in the leaves of the green plants is prepared by the process of photosynthesis in the form of glucose. Sieve tube elements of the phloem tissue help in the translocation of sugars. Sucrose contains more energy than monosaccharide.

Complete answer:
The process of converting raw material into food by green plants is called photosynthesis. It is also known as the process of conversion of solar energy into chemical energy. Sugars are synthesized during this process.
Glucose is the most commonly synthesized sugars. It is converted to sucrose for transportation through sieve elements. Sucrose is then converted into starch for its long term storage.
Starch is stored in the fruits, seeds and other vegetative parts. Transportation of sucrose from leaves to the other part of the plant is known as translocation. Phloem tissues help in this transportation. For the active transportation of sucrose into vascular pathways, pump proteins are present in the cell membrane of the sieve cells of the phloem.
Fructose or glucose is converted into sucrose because sucrose contains more energy than a monosaccharide. It is more entry efficient both in transport and storage.
From the above information we have found that the carbohydrate synthesized in the leaves is transported through sieve tubes in the form of sucrose.

Hence, the correct answer is option (C).

Note: Water transportation occurs with the help of xylem tissues. Xylem cells draw water from the roots of the plant in order to replace the water which has been lost from the leaves by the process of transpiration. Transpiration is an unavoidable consequence of photosynthesis. Very less amount of water is used by leaves in the process of photosynthesis. Other substances such as amino acids can also be transported by the process of translocation.