plant cell wall Flashcards
(15 cards)
what is the plant cell wall
poly saccharide rich matrix that surrounds all plant cells
what is the cell wall composed of
- cellulose
- hemicellulose
- pectin
- glycoproteins
what is the function of cellulose
carbohydrate which is a polymer of glucose
what is hemicellulose
holds cellulose fibrils together
what is pectin
conveys stiffness
what is the linkage of glucose
b1-4 linked glucose
functions of the cellulose in the cell wall
tensile strength as its deposited in transverse to the direction of elongation
what are the structural layers of plant cell wall
middle lamella primary cell wall secondary 3 secondary 2 secondary 1 lumen
what is the ration of carbohydrates and proteins in the cell wall
90% carbohydrates 10% proteins
what cells lay down the primary cell wall
meristematic cells and the cells in succulent tissues
what are the 8 functions of the cell wall
- structural and mechanical support
- resist internal turgor pressure
- control rate and direction of growth
- regulates diffusion of material through the apoplast
- carbohydrate storage as walls of seeds may be metabolized
- protects against pathogens dehydrates and other environmental factors
- source of biologically active signalling molecules
- cell to cell interactions
what are the two types of primary cell walls
- all flowering plants 22-35% pectin
2. grasses 10% pectin
what is the secondary cell wall
surround cells that differentiate to form specialised functions
function of secondary cell wall
increase rigidity and structural support
often lignified help waterproof.
what is the secondary cell wall composed of
altered polysaccharide composition more cellulose and lignin
