BIO 127 Chapter IIC: Cell Shape and Movement in Animal Cells

what is the most common mode of locomotion in many cells

amoeboid movement (crawling)

in the developing embryo, these two movements can be observed

long distance migrations of individual cells to specific target locations and coordinated movements of whole epithelial sheets

in the adult animal, these two cells crawl to the sites of infection

macrophages and neutrophils

_____ tunnel into bones and ______ follow them in a continuous bone remodeling and renewal

osteoclasts; osteoblasts

_______ migrate through connective tissues for repair of injured sites

fibroblasts

____________ travel up the intestinal villi to replace absorptive cells lost at the tip of the villus

epithelial cells

an example of cells that migrate and spread to form tumors

metastatic cancer cells

cell crawling is dependent on the ________ beneath the plasma membrane

actin-rich cortex

[3 distinct activities of cell crawling] actin-rich structures are pushed out at leading edge of polarized cells

protrusion/extension

[3 distinct activities of cell crawling] actin cytoskeleton connects across the plasma membrane to the substratum

attachment/adhesion

[3 distinct activities of cell crawling] the bulk of the trailing protoplasm is drawn formward

traction/translocation and de-adhesion

three types of protrusive structures during protrusion

filopodia/microspikes

lamellipodia

pseudopodia

filopodia/microspikes are formed by migrating ______ and some types of ______

growth cones, fibroblast

[protrusive structures] slender, fingerlike extension

filopodia/microspikes

[protrusive structures] contain a core of long, bundled actin filaments

filopodia

lamellipodia are formed by _______, _______, and _______.

epithelial cells, fibroblasts, and some neurons

[protrusive structures] 2d sheet-like structure

lamellipodia

[protrusive structures] contain an orthogonally cross linked mesh of actin filaments in a plane parallel to the solid substratum

lamellipodia

pseudopodia are formed by _____ and ______

amoebae and neutrophils

[protrusive structures] stubby 3d projections

pseudopodia

pseudopodia are filled with an _______

actin filament gel

[3 distinct activities] a form of membrane extension whose mechanism is actin polymerization-based

protrusion

[assembly of actin network] _____ adds to the filament end and pushes the membrane forward

ATP-G-actin

[assembly of actin network] with time, filament ends are capped by ________

capping protein

[assembly of actin network] _______ binds to sides of filaments and forms a branch at a 70 degree angle from the filament

Arp 2/3 complex

[assembly of actin network] the ATP-G-actin converts into ADP-G-acton and dissociates from the filament through the action of severing proteins _____ and ______

cofilin and gelsolin

[assembly of actin network] the released ADP-G-actin subunits form complexes with _______ to regernerate ATP-G-actin subunits

profilin

supports the elongation of filaments and the generation of pushing forces

network of actin filaments

actin bundles in the leading edge become anchored to the extracellular matrix, resulting to

focal adhesion

two purposes of attachment/adhesion

1. prevents the leading edge from retracting

2. attaches the cell to the substratum, allowing it to push forward

the extracellular domain binds to proteins in the _________

extracellular matrix

the intracellular domain binds to ________

intacellular adapter proteins

4 examples of intracellular adapter proteins

talin, filamin, a-actinin, vinculin

[translocation] cortical contraction moves the cytoskeleton forward, which is a process dependent on

myosin

[de-adhesion] the ______ at the rear of the cell are broken and the ______ is brought forward

focal adhesions, freed tail

when treated with colchicine, fibroblasts exhibit _______ of the microtubules

depolymerization

what happens to the movement of the fibroblast when exposed to colchicine

the cell ceases to move directionally and the lamellipodia instead extends in random directions

neurites (axon and dendrites) can form outgrowths called _______

growth cones

when neurites are treated with colchicine, what happens?

no formation of growth cone

the neurite , when treated with this drug, results to no formation of lamellipodia and microspikes

cytochalasin

in nerve cells, migration is dependent on _______

both microtubules and AFs

in signal transduction pathways, external signals activate ______ and control the _______ and therefore the ________ of movement of a cell

cell migration, polarity, direction

external factors that trigger cell migration and formation of protrusive structures

growth factors

response exhbited when two migrating cells come into contact

contact inhibition of movement

CIM involves rapid changes in the ________ at the region of contact

actin-based cortical skeleton

process wherein cells stop immediately as soon as the different margins of the cells make contact

wound healing in animals

junctions that form between newly adjacent cells as a result of migration

continuous cell sheet

flagella and cilia are absent in

higher plants

[cilia or flagella] thread-like

flagella

[cilia or flagella] hair-like

cilia

[cilia or flagella] numerous

cilia

[cilia or flagella] short and hairlike at 5-10um long

cilia

[cilia or flagella] present on only one end, two ends, or all over the surface

flagella

[cilia or flagella] there are less than 10 per cell

flagella

[cilia or flagella] beat ndependently of each other

flagella

[cilia or flagella] motor, fast-moving

cilia

[cilia or flagella] functions for locomotion, circulation, absorption, sensory, etc

cilia

medium through which flagella propels cells through

liquids

a type of cilia that transports fluids and helps particles move past cells

motile cilia

example of motile cilia in animals

epithelial cells of internal organs

a type of cilia that anchors membrane receptors and processes incoming isgnals from morphogens

non-motile cilia

structure in cilia that regulates pathways

cellular antennae

[signal transduction pathways] critical in the development of CNS

Shh Signaling

[signal transduction pathways] critical in the development of the forebrain

Wnt signaling

[signal transduction pathways] essential for protein translation, lipid synthesis, autophagy, as well as nervous ones neural differentiation

MTOR signaling

[signal transduction pathways] cellular degradative process by which cells gain nutrients to maintain homeostasis

autophagy

disease caused by defects in ciliary structure and function such as reporatory infections, loss of smell, male infertility

primary cilia dyskinesia

distinguishing symptom of primary cilia dyskinesia

situs inversitus