xylem and phloem

what cells are found in the xylem and what are their functions?

• xylem vessels - transport water and minerals from roots to other parts of plants - end walls of xylem vessels break down to form long tubes that extends from roots to stem and leaves

• tracheids - strength to tissue

• xylem parenchyma - thin wall - living in cells that act as packing tissues between xylem vessels

what do the walls of the xylem have?

• lignin - impermeable to water

how does water leave or enter the xylem vessels?

• holes in wall called pits

draw the transverse section and longitude section of a xylem.

in a xylem are the cells dead or alive?

• tracheids and xylem vessels dead - no cell contents

are cells in phloem dead or alive?

• all alive

explain the phloems components and what their functions are.

• phloem sieve tubes - contains dense cytoplasm + few/no organelles - to keep elements in ST alive

• cell wall - cellulose

• companion cells - accompany sieve tubes - provide support needed to keep alive

• companion cells - transport substances in and out of sieve tubes

• mitochondria - required for active transport

how are companion cells and sieve tubes connected, and why?

plasmodesmata - easy and efficient transport and communication between cells.

what are the ends of a phloem sieve tube cells called?

• sieve plates - have small pores - strands of cytoplasm pass through these pores from one phloem sieve tube to the next.

draw and label the transverse section and the longitude section of a phloem.

what are the differences in xylem vs phloem?