ch 5 cell surface (aprt VIII)

where is the cell wall present

Only in bacteria, fungi, some protists and plants

what are plant cell walls made of

polysccridies (cellulose), hemicullelouse, cutin, pectin, cell wall proetins)

funciton of plant cell walls

protection, physical support, and help with water conservation

primary cell walls

found in young and annual plants, are thin and flexible

secondary cell wall

found in older cells in herbaceous and woody plants, made of same thing as regular cell walls and Lignin, suberin to make it stronger (rigid)

how do secondary cell walls from

they form within the primary cell walls

middle lamella

layer between neigboring cells that contains stcky polysccride pectin

order of plant cell wall layers outside to inside

middle lamella, primary cell wall, secondary cell wall, plasma membrane

what degrades celluluse?

cellulase (mde by fungi and come bacteria)

plasmodesmata

microscopic channels that bridge adjacent plant cells, creating a shared cytoplasmic network for communication and transport

fungal cell walls are made of 

chintin (a beta 1-4 protein) and NAG

what degrades chitin>

enzyme called chiniase

where else is chiti foudn?

insects exoskleteons

what are bacteial walls made of

NAM and NAG

what degreades bacterial cell walls?

NAM-NAG linkage can be degraded by lysozyme present in our nasal secretions, tears and saliva

what is a gram positive cell wall

picks up gram stain

animal ell junctions what are they

instead of a cell wall animal cells have an extracelluar matrix made of glycoproteins and collagen fibers

tight junction

two cell membranes fused by integral membrane proteins that prevent ANY movement of solutes through the spaces inbetween

gap junctions

connections between 2 cells through connexons (channels). chemical signals or solultes can pass from one cell to another (cell-to-cell communicaitons

desomosomes

spots where two cells are connected together by keratin-like fibrous proteins. There are cytoplasmic protein plaques (raised areas) in desmosomes. not tightly sealed- things can pass through