cytoskeleton

Question 1

protofilament

Answer 1

made of tubulin dimers, is the 13 structures that compose a microtubulin

Question 2

tubulin

Answer 2

protein that makes up protofilaments and thus microtubules

Question 3

positive versus negative end of microtubule

Answer 3

positive end; construction occurs more rapidly than destruction.

Question 4

9+0 arrangement

Answer 4

formation of a microtubule. 9 triplets + lumen in the middle

Question 5

function of intermediate filaments, and example

Answer 5

cell shape and strength . ex: keraton

Question 6

nuclear lamins

Answer 6

type of intermediate filament. support the nuclear envelope

Question 7

definition of interphase cell

Answer 7

cell that isn’t dividing. just sits in the cytoplasm.

Question 8

centrosome

Answer 8

a.k.a. Cell Center, or MTOC (microtubule organizing center) creates microtubules. Cytoplasmic microtubules emanate out from the centrosome

Question 9

location microtubules/centrosome during DNA replication

Answer 9

Replicated centrosome now the “poles” in the process of Mitosis

Question 10

microtubule role in cilia

Answer 10

Ciliated cells: have cilium- move around and beat back and forth- move things past cells. Actual motor inside cell.

Question 11

microtubule role in flagellum

Answer 11

Flagellated Cell- ex: sperm cells that swim- the long tail of sperm has microtubules, beat, lets it swim along.

Question 12

centrioles

Answer 12

always occur in a pair, 90 degree angles. Always found in centrosome. Made of microtubule triplets- 3 MT’s glued together. And then another set of 3, and another always 9 triplets in a row, in a circle . 9+0 arrangement

Question 13

Dynamic instability

Answer 13

microtubules are constantly growing and shrinking. When microtubules assemble tend to bind a GTP, turns into GDP + P, lets them pop off.

Question 14

how does dynamic instability work?

Answer 14

• tubulin dimers bind to GTP, another energy containing molecule. Tubulin dimers with a bound GTP are much more likely to assemble themselves. Grows until cell cell determines its enough- and then cell hydrolyzes GTP, just like ATP. GTP-> GDP + P(i). those dimers bound to GDP are much more likely to disassemble. Peel away. Whole microtubule begins to shrink, disassemble.

Question 15

tubulin

Answer 15

protein. dimer composed of alpha and beta protein

Question 16

how do chemo drugs take advantage of dynamic instability?

Answer 16

Taxol prevents the shrinking/rapid dividing- by stabilizing MT’s.

Question 17

GTP hydrolysis

Answer 17

cell eating the GTP. the microtubule will GROW when it adds stuff to the GTP cap faster than it hydrolyzes

Question 18

how do microtubules shrink?

Answer 18

when they are bound to GDP. in this form, protofilaments peel away from microtubule wall

Question 19

what is the role of centrosomes in cellular division?

Answer 19

• Division: centrosomes line up on POLES, pull chromosomes apart

Question 20

give an example of cilia in your body. and what type of filament is it?

Answer 20

lungs eliminate debris by using cilia . microtubule

Question 21

what kind of filament do paramecium use for locomotion?

Answer 21

cilia

Question 22

• difference between cilia and flagella?

Answer 22

• Cilia are short. Come in large numbers. Made of microtubules.

Flagella are long. Come in 1, or 2 on surface (ex: sperm

Question 23

internal arrangement structure of cilia/flagella?

Answer 23

9+2 arrangement

Question 24

axoneme

Answer 24

internal structural component of a cilia/flagella composed of DYNEIN PROTEIN- a molecular motor- that uses the energy of ATP to reach out and grab on to the side of the next doublet and try and push it down past them. Source of the waving, beating motion that u see

Question 25

dynein

Answer 25

protein that connects the internal microtubules and causes motion in cilia/flagellum

Question 26

9+2 arrangement

Answer 26

arrangement of microtubules in cilia/flagellum

Question 27

why do flagellum bend and not slide?

Answer 27

dynein- linking protein- causes the microtubule stalks to bend

Question 28

how do prokaryotic flagellum work?

Answer 28

• Prokaryotic flagellum: not made from microtubules. Not the same thing!!! Rotates differently- like my arm exercise- by using a rotary motor.

Question 29

kinesins

Answer 29

motor proteins that only move towards the plus end of microtubles. live in axons, and only walk on MT’s

Question 30

how does a dinein motor protein ‘walk’ ?

Answer 30

binding and hydrolysis of ATP each cause conformational changes in the motor protein, allowing it to “walk” along the MT track):

Question 31

microvilli are supported by ___ filaments

Answer 31

actin

Question 32

myesin

Answer 32

Motor protein- myesin- makes muscle proteins move

Question 33

give an example of an actin binding protein

Answer 33

myesin

Question 34

where would you find elastin and collagen? what kind of structures are these?

Answer 34

Cells also produce other fibrous structures in addition to cytoskeleton. The difference is these guys are secreted out. Common ones: elastin, collagen.

Elastin: gives elastic effect to tissues. Collagen: resists stretch.

Question 35

immunoflurescence: how does it work?

Answer 35

common laboratory technique, which is based on the use of specific antibodies which have been chemically conjugated to fluorescent dyes. These labeled antibodies bind directly or indirectly to cellular antigens

Question 36

antibody

Answer 36

• protein that has specific binding sites for particular targets “antigens”. Part of immune system.

Question 37

desmosome

Answer 37

connects 2 cells

Question 38

what does the cell like to have around it, like a blanket?

Answer 38

extracellular matrix is full of elastin, collagen and other Collective fibers that are held in place by integrin/fibronectin proteins and actin filaments.

Question 39

globular actin vs fibrous actin?

Answer 39

G actin is a little ball, F actin is a long fiber

Question 40

which way do kinesin vs dynein move?

Answer 40

• Dynein- works towards minus end
• Kinesin- works toward + end