Plasmodesmata are found between A. Sieve-tube cells. B. Companion cells. C. Vess
ID: 82510 • Letter: P
Question
Plasmodesmata are found between A. Sieve-tube cells. B. Companion cells. C. Vessel elements. D. Tracheid. E. Meristematic cells. What keeps the ventricles from contracting at the same time as the atria? A. Nerves from the brain conduct separate signals to the atria and ventricles. B. The atria and ventricular pacemakers touch off contractions at different times. C. The sinoatrial node sends separate signals to the atria and ventricles. D. The atrioventricular node delays the signal from the sinoatrial node. E. A and B only.Explanation / Answer
The answer is 18 A and B between sieve-tube cells and companion cells. Plasmodesmata are the microsopical channels through which the plant cells transports molecules/proteins etc. In a symplastic pathway that is through cytoplasm of one cell to the cytoplasm of adjacent connecting cell. Plamodesmata plays a major role in phloem loading where the sieve tube element and companion cells forms a complex together known as sieve element-companion cell complex (se-cc ). As I have already mentioned that plasmodesmata works in a symplasm way so the sugars like sucrose moves from mesophyll cells to phloem parenchyma cells via diffusion through plasmodesmata directly into the se-cc complex. This route from sucrose to plasmodesmata to se-cc complex is the symplastic route/pathway.