KD 6.6-6.7
Terms
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- _______bring about the bending of cilia and flagella by gripping microtubules within those organelles and sliding them against each other
- motor proteins
-
put these in order of thickest to thinnest:
intermediate filaments
microtubules
microfilaments -
microtubules
intermediate filaments
microfilaments -
a molecule made up of two subunits
also a ______ protein -
dimer
tubulin - polypeptides of tubulin dimers
-
a-tubulin
b-tubulin - how do microtubules grow in length?
- adding tubulin dimers-one end accumulates and releases tubulin dimers at a higher rate than the other (called plus end)
- microtubules grow out of _______
- centrosomes
- this has an undulating moton that generates force in the same direction as the axis
- flagellum
- these work like oars, alternating power and recovery strokes generating force in a direction perpendicular to the axis
- cilia
- what is the structural arrangement of eukaryotic flagella and motile cilia?
-
nine doublets of microtubules are arranged in a ring
in the center of the ring are two microtubules
"9+2 pattern" - acts as a microfilament based motor protein-contractions of muscle cells result from actin and these filaments sliding past each other
- myosin
-
brought about by actin-myosin interactions; a circular flow of cytoplasm within cells
speeds up distribution of materials within cell - cytoplasmic streaming
- ______ made out of the polysaccharide _______ are synthesized by enzyme (cellulose synthase) and secreted to extracellular space where they become embedded
-
microfibrils
cellulose -
between the layers of the cell walls
thin layer rich in sticky pectins
glues adjacent cells together - middle lamella
-
accounts for 40 percent of the total protein in the human body
embedded in a web of proteoglycan complexes - collagen
-
consists of a small core protein with carb chains covalently attached
could be up to 95 percent carbohydrates - proteoglycans
- attaches the ECM to integrins in the plasma membrane
- fibronectin
- plant cell channels that cytosol passes through to connect the chemical environments of adjacent cells
- plasmodesmata
-
plasma membranes of neighboring cells are very tightly pressed against each other
prevents leakage of extracellular fluid
ex. skin cells - tight junctions
- fasten cells together into sheets. anchored by keratin-intermediate filaments. Attach muscle cells to each other
- desmosomes
-
provide cytoplasmic channels from one cell to an adjacent cell to an adjacent cell
consist of membrane proteins that surround a pore through which ions, sugars, amino acids, and other small molecules may pass - gap junctions