Explain how and why different parts of a plant are sinks for the translocation of sucrose at different times of the year in a country where there are season, such as Russia ​

The sucrose is transported around the plant in phloem vessels. It needs to be able to reach all cells in the plant so that the sucrose can be converted back into glucose for respiration. The movement of sucrose and other substances like amino acids around a plant is called translocation .

Belowground organs of plants (e.g. roots and rhizomes) are sinks during plant growth since they cannot perform photosynthesis. Some organs are both a source and sink. Leaves are sinks when growing and sources when photosynthesizing

ability to bond woth oxygen

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.