cytoskeleton and cell motility

define the cytoskeleton

network of fibers extending throughout the cytoplasm

the cytoskeleton is composed of 3 types of molecular structures, what are they?

1. microtubules

2. microfilaments

3. intermediate filaments

what are the three main roles of the cytoskeleton

1. support cell and maintain shape

2. interact with motor proteins, producing cell motility

3. vesicle travel along tracks provided by the cytoskeleton

describe the structure of microtubules

hollow rods about 25nm in diameter and about 200nm to 25 microns long

microtubule are constructed of dimers of …

tubular

give three functions of microtubules

1. shaping cell

2. guiding movement of organelles

3. separating chromosomes during cell division

microtubules grow out from a … near the nucleus

centrosome

centrosomes have a pair of …

centrioles

… control the beating of flagella/ cilia

microtubules

unicellular eukaryotes propel through water by …

cilia/ flagella

cilia and flagella have … (same/ different) beating patterns

different

what anchors the cilia/ flagella

basal body

what drives the bending movements of cilia/ flagellum

motor protein called dynein

microfilaments are made up of…

actin

describe the structure of microfilaments

solid rods about 7nm in diameter, built as twisted double chain of actin subunits

microfilaments form a … inside the plasma membrane to support ….

cortex, cell’s shape

another bundle of microfilaments are found …

core of microvilli of intentional cells

when cells require cellular motility the microfilament will contain the protein … as well as actin

myosin

define cytoplasmic streaming

circular flow of cytoplasm within cells, driven by actin-myosin interactions

how do cells crawl along surfaces…

extending pseudopodia (cellular extensions) and moving toward them

describe the structure of intermediate filaments

range in diameter from 8-12 nanometers (larger than microfilaments, but smaller than microtubules)

intermediate filaments are more…

permanent

give 2 roles of intermediate filaments

support cell shape and fix organelles in place