PBIO EXAM 2 Terms Flashcards
Plasma Membrane
a microscopic membrane of lipids and proteins which forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and regulates the passage of molecules in and out of the cytoplasm.
Phosphorlipid bilayer
two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward. Also called: lipid bilayer
Hydrophobic
Water fearing
Hydrophilic
Water loving
Glycoprotein
any of a class of proteins that have carbohydrate groups attached to the polypeptide chain. Also called glycopeptide
primary cell wall
cellulose-containing layer laid down by cells that are dividing and growing. To allow for cell wall expansion during growth, primary walls are thinner and less rigid than those of cells that have stopped growing.
Pectin
is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides
Hemicellulose
is a heterogeneous polymer composed of many sugars, such as xylose, arabinose, mannose, and galactose, that are C5 and C6 sugars. BLANK is known as the second most abundant carbohydrate material and consists of 25%–35% dry weight wood material
Cellulose
an insoluble substance which is the main constituent of plant cell walls and of vegetable fibers such as cotton. It is a polysaccharide consisting of chains of glucose monomers.
middle lamella
is a layer that cements together the primary cell walls of two adjoining plant cells. It is the first formed layer to be deposited at the time of cytokinesis. The cell plate that is formed during cell division itself develops into middle lamella or lamellum.
Microfibril
a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose.
cellulose synthase
the enzyme that catalyzes the covalent attachment of these glucose subunits into a linear chain
