NEET BIOLOGY

Detailed explanation-1: -The glucose prepared in the leaves is converted into sugar. The sugar in the form of sucrose is moved into the companion cells and then into the living phloem sieve tube cells by active transport. This creates a hypertonic condition in the phloem. Water in xylem vessels adjacent to phloem moves through endosmosis.

Detailed explanation-2: -Sucrose, RFOs and polyols are transported in the sieve tubes to the sink organs in the transport phloem. All along the path, they can be leaked from and reloaded into the phloem via the same mechanism (not shown). Sucrose is unloaded into the release phloem where the hydrostatic pressure is supposed to be lower.

Detailed explanation-3: -Sucrose transport is favorable for the following reasons: (i) 1 mol sucrose contains more energy than 1 mol of a monosaccharide such as glucose or fructose, thus using the disaccharide is more energy efficient for transport and storage.

Detailed explanation-4: -Sucrose is the transport sugar in the phloem. Transport of substances in the phloem is called translocation . Translocation requires energy as it is an active process.

Detailed explanation-5: -The one word to denote transportation of food via Phloem is “Translocation”. Sucrose and amino acids are transported by Phloem up and down through the plant. The process of translocation involves transportation of food into sieve tubes from where food can travel upward or downward to all the parts of the plant.