Cytoskeleton

Question 1

Cytoskeleton

Answer 1

consists of a network of protein filaments extending throughout the cytoplasm of all eukaryotic cells

Question 2

The cytoskeleton is composed of what 3 types of protein filaments?

Answer 2

Actin filaments, intermediate filaments and microtubules

Question 3

Filamentous Actin

Answer 3

is a series of actin monomers that have been polymerized into filaments (helical structure).actin polymerization is reversible(non-covalent)

Question 4

Globular Actin

Answer 4

an actin monomer that has tight binding sites that mediate head-to-tail interactions with other actin monomers.

Question 5

actin filaments play and important role in what?

Answer 5

determination of cell shape, and providing structural support to cell

Question 6

Myosin

Answer 6

is a protein that interacts with actin, and acts as a molecular motor

Question 7

Intermediate filaments

Answer 7

largely play a structural role by providing mechanical strength to cells and tissues. Do not directly aid in movementl.

Question 8

What are examples of intermediate filaments?

Answer 8

keratins, vimentin,Desmin, Neurofilament proteins, nuclear lamins,

Question 9

Microtubules

Answer 9

rigid hollow rods that both determine cell shape and, more importantly, are involved in a variety of cell movements. Microtubules have polarity like actin does.

Question 10

Tubulin

Answer 10

protein that polymerase to form microtubules.

Question 11

Colchicine and colecmid

Answer 11

xperimental drugs that bind tubulin and inhibit microtubule polymerization, which in turn blocks mitosis.

Question 12

Vincristine and vinblastine

Answer 12

two drugs that are used in cancer chemotherapy, and inhibit microtubule polymerization and thereby cell division
! Another drug, taxol, stabilizes microtubules, rather than inhibiting their assembly (also blocks cell division)

Question 13

Kinesins

Answer 13

motor proteins that move along microtubules both toward the plus end and minus end, depending on the cell type and cargo, as well as the specific kinesin involved.

Question 14

Dyneins

Answer 14

motor proteins that move along microtubules only toward the minus end.

Question 15

Axoneme

Answer 15

the fundamental structural unit of organization of both cilia and flagella is known as an axoneme, and is composed of microtubules and their associated proteins.

Question 16

Basal Body

Answer 16

structure similar to a centriole that initiates the growth of axonemal microtubules and anchors cilia and flagella to the surface of the cell.

Question 17

How does the movement of cilia and flagella work ?

Answer 17

result from the sliding of outer microtubule doublets relative to one another, powered by the motor activity of the axonemal dyneins.

Question 18

Kinetichore microtubules

Answer 18

attach to the condensed chromosomes of mitotic cells at their centromeres.

Question 19

chromosomal microtubules

Answer 19

connect to the ends of the chromosomes via chromokinesin

Question 20

Astral microtubules

Answer 20

extend outward from the centrosomes to the cell periphery and contribute to chromosome movement by pushing the spindle poles apart.

Question 21

polar microtubules

Answer 21

are not attached to chromosomes but are stabilized by overlapping with each other in the center of the cell; they contribute to chromosome movement by pushing the spindle poles apart.

Question 22

Anaphase A of mitosis

Answer 22

movement of chromosomes toward the spindle poles along the kinetochore microtubules.

Question 23

Anaphase B of mitosis

Answer 23

separation of the spindle poles themselves