Final Topic 22 - Eukaryotes Cytoskeleton

Question 1

Large tensile strength, main function is to help the cells withstand mechanical stress

Answer 1

Intermediate filaments

Question 2

Called intermediate because of

Answer 2

their diameter

Question 3

Intermediate filaments are found

Answer 3

throughout the cytoplasm and nucleus

Question 4

Intermediate filaments form

Answer 4

a large network of interconnected filaments

Question 5

Intermediate filaments are anchored to the plasma membrane at

Answer 5

cell-cell junctions called desmosomes

Question 6

Intermediate filaments are also found inside the nucleus and they make up the

Answer 6

nuclear lamina

Question 7

Intermediate filaments form strong rope-like

Answer 7

multi-protein assemblies

Question 8

An alpha-helical monomer with a globular N-terminus and a globular C-terminus

Answer 8

The subunit of intermediate filaments

Question 9

The intermediate filament subunit forms a

Answer 9

coiled-coil dimer

Question 10

The dimer forms a staggered

Answer 10

anti-parallel tetramer

Question 11

The tetramers bind together end-to-end and side-by-side to form a

Answer 11

twisted filament

Question 12

The twisted filaments are

Answer 12

non-covalent interactions

Question 13

Because of the anti-parallel way that the intermediate filament tetramers form, intermediate filaments lack

Answer 13

polarity

Question 14

Four classes of intermediate filaments

Answer 14

1. Keratins
2. Vimentin and vimentin-related
3. Neurofilaments
4. Nuclear Lamina

Question 15

In Epithelia

Answer 15

Keratins

Question 16

In connective tissue, muscle cells, and glial cells

Answer 16

Vimentin

Question 17

In nerve cells

Answer 17

Neurofilaments

Question 18

In all animal cells

Answer 18

Nuclear Lamina

Question 19

Long still hollow tubes of proteins that can rapidly assemble or disassemble

Answer 19

Microtubules

Question 20

Microtubules extend toward the cell periphery and provide tracks for organelle and vesicle movement

Answer 20

Interphase cell

Question 21

Microtubules make up the mitotic spindle

Answer 21

Dividing cell

Question 22

Provides the force and movement for chromosome separation

Answer 22

Mitotic spindle

Question 23

Microtubules are an important component of cilia and flagella, necessary for movement

Answer 23

Cilia and Flagella

Question 24

Microtubules subunit

Answer 24

Tubulin Heterodimer

Question 25

Alpha-tubuilin and Beta-tubulin

Answer 25

Tubulin Heterodimer

Question 26

The tubulin heterodimer

Answer 26

Binds and hydrolyzes GTP

Question 27

The tubulin heterodimer stacks end-to-end in a chain to make a

Answer 27

protofilament

Question 28

13 protofilaments align next to each other and fold over to form a hollow tube

Answer 28

Microtubule

Question 29

Microtubules have

Answer 29

polarity

Question 30

The end with alpha-tubulin exposed

Answer 30

Microtubule (-) end

Question 31

The end with the Beta-tubulin exposed

Answer 31

Microtubule (+) end

Question 32

Tubulin dimers add (polymerize) to the ______ end to grow the filament

Answer 32

(+)

Question 33

Microtubules in cells are formed by

Answer 33

Polymerizing from specialized organizing centers called centrosomes

Question 34

Complex of proteins and y-tubulin ring complexes

Answer 34

Centrosomes

Question 35

A special form of tubulin that acts as nucleation site for microtubule polymerization

Answer 35

y-tubulin ring complexes

Question 36

Centrosome also contain a pair of

Answer 36

Centrioles

Question 37

Small cylindrical array of microtubules

Answer 37

Centrioles

Question 38

Important for stabilizing the centrosome organization

Answer 38

Centrioles

Question 39

What structurally mimics the (+) end of a microtubule and acts as a nucleation site for polymerization from the centrosome?

Answer 39

y-tubulin ring complex

Question 40

Microtubules grow by

Answer 40

Addition of the (+) end from the centrosome

Question 41

Undergo dynamic instability

Answer 41

Microtubules

Question 42

Growing and shrinking cycle

Answer 42

Dynamic instability

Question 43

Tubulin hydrolyzes ____ shortly after addition to the _____ end

Answer 43

GTP | (+) end

Question 44

When polymerization of GTP-tubulin is occuring rapidly, addition is

Answer 44

Faster than GTP hydrolysis | The end of the microtubule is comprised mostly of GTP-tubulin

Question 45

The end of the microtubule is comprised mostly of GTP-tubulin

Answer 45

GTP-cap

Question 46

When the rate of polymerization slows down and the tubulin dimers can hydrolyze GDP, this promotes

Answer 46

Disassembly of the microtubule

Question 47

If the rate of polymerization is faster than the rate of GTP hydrolysis

Answer 47

The microtubule will grow (it contains a GTP-cap)

Question 48

If the rate of GTP hydrolysis is faster than the rate of polymerization

Answer 48

The microtubule will disassemble (GTP-cap is lost)

Question 49

Microtubules can be stabilized by

Answer 49

Attachment to proteins or cell structures that stabilize the ends

Question 50

Microtubules can be both

Answer 50

Highly dynamic and highly stable

Question 51

Binds and stabilizes microtubules

Answer 51

Taxol

Question 52

Binds subunits and prevents polymerization

Answer 52

Colchicine, colcemid

Question 53

Commonly used chemotherapeutic drugs

Answer 53

Taxol and Cochicine

Question 54

Microtubules serve as

Answer 54

Tracks

Question 55

Carry vesicles and organelles along the microtubule tracks

Answer 55

Motor proteins

Question 56

Use ATP hydrolysis to power their movement

Answer 56

Motor proteins

Question 57

Two main types of motor proteins

Answer 57

1. Kinesins | 2. Dyneins

Question 58

Move towards the (+) end of the microtubule

Answer 58

Kinesins

Question 59

Move towards the (-) end of the microtubule

Answer 59

Dyneins

Question 60

Motor Protein structure

Answer 60

Dimers | Two Globular heads: ATPase and Microtubule binding

Question 61

Motor proteins exist as

Answer 61

Dimers

Question 62

Two globular heads of motor proteins

Answer 62

ATPase | Microtubule binding

Question 63

Make up cilia and flagella

Answer 63

Microtubules

Question 64

Hair-like structures that extend from the surface of eucaryotic cells

Answer 64

Cilia

Question 65

Provide a regular "beating" movement

Answer 65

Cilia

Question 66

Epithelia cells in the respiratory tract use these to sweep dust particles out of the lungs

Answer 66

Cilia

Question 67

Larger structures similar to cilia that provide the force to propel bacteria and sperm

Answer 67

Flagella

Question 68

Made up of a column of stable microtubule array

Answer 68

Cilia and Flagella

Question 69

Microtubules are arranged in a

Answer 69

9+2 array

Question 70

9+2 array

Answer 70

9 microtubule doublets | 2 central singlet microtubules

Question 71

Microtubule doublet

Answer 71

Two microtubules bound to each other

Question 72

Microtubule doublets are all linked to each other through

Answer 72

Protein nexin

Question 73

Attaches to one doublet and interacts with the adjacent doublet

Answer 73

Dynein

Question 74

Causes the microtubules to bend

Answer 74

Because of the nexin links, as dynein walks towards the (-) end of the adjacent doublet, the microtubules bend

Question 75

Provides the movement of the cilia and flagella

Answer 75

Microtubule bending