| what is transport of phleom | from source to sink |
| what is the xylem | Long column of dead cells with no contents |
| what does the lignin do in the xylem | waterproof, also strengthnes the wall, prevents collpase even when water is in short supply |
| whats special about the placement of lignin | pits in adjacent vessels line up, allows water to travel to other parts of the plant |
| how is lignin deposited? | in patterns , spiral, annular (rings) or reticulate (broken rings). prevents vessel from being too rigid |
| importance of xylem being narrow | The narrow structure of xylem vessels allows capillary action to occur more effectively, aiding the upward movement of water. It also ensures cohesion between water molecules, which helps maintain a continuous water column. |
| importance of xylem being dead and hollow | The absence of cell contents creates an uninterrupted lumen, allowing water and dissolved minerals to flow freely without obstruction. This maximizes the efficiency of water transport from the roots to the leaves. |
| what is transport of phleom | from source to sink |
| how is the phloem formed | from 2 types of "cell" connected by the plasmosdesmata, sieve tube elements and companion cells |
| sieve tube elements are lined up end to end | form sieve tubes, no nucleus and little cytoplasm |
| the ends are peirced cross walls called sieve plates, what does the perforations (peircings) help with | allow movement of sap between elements (sieve) |
| what does the sieve tube elements also have / help with | have thick and rigid cell walls to withstand the hydrostatic pressures which facilitate flow. |
| what do companion cells provide | metabolic support for sieve elements cells and facilitate the loading and unloading of materials at source and sink |
| what do companion cells contain which is very helpfull | contain lots of mitochondria to fuel the active transport or materials between the sieve tube and the source or sink |
| what does the companion cell also have. | appropriate transport proteins within the plasma membrane to move materials in or out of the sieve tube |
| where is cambium found? | between the xylem and the phloem tissues. |
| role of cambium part 1. | role of actively dividing the cells that are responsible for the secondary growth of stems and roots |
| role of cambium part 2. | cambial cells divide to produce secondary xylem cells toward the central axis of the stem and secondary phloem cells toward the outside |
