How Does the Cell Wall Support Plant Growth and Form?

1) chloroplasts2) central vacuole3) cell wall

Central Vacuole: watery sac containing a high conc. of solutes (enzy., ammino ac., sugars)
tonoplasts: pump solutes to vacuole
-accumulation of solutes provides osmotic pressure for H2O uptake in2 vac.
-->expanding vacuole leads to turgor pressure on cell wall
-T. pressure keeps plant upright, and essential for plant growth

-volume, shape, protect cell contents
-middle lamella: thin layer between the wall of two daughter cells-cellulose, hemicellulose, pectin

Cellulose: linear polymers (k's glucose molecules), orgnz'd into bundles microfibrils, which form lattice within the cell wall (thick hashtag rods)
Hemicelluloses: highly branched polysaccharide chains that cross-link with cellulose microfibrils
Pectin: heterogeneous polysaccharide, more soluble than cellulo., and hemicellu.

Osmotic pressure-->expansion of c. vacuole-->turgor pressure on cell wall-- inc. volume of protoplasts (everything inside) causes loosening of linkages between cellulose microfibrils
to prevent cell wall thinning new cell wall components are synthesized

Secondary cell wall: additional cellulosic layers, internal to primary cell wall