The Cytoskeleton

Question 1

what is defined as the cellular scaffolding or skeleton contained with the cytoplasm in all cells?

Answer 1

the cytoskeleton

Question 2

What are the 5 functions of the cytoskeleton

Answer 2

1. it maintains cell shape
2. protects the cell
3. enables cellular motion (using structures such as flagella and cilia)
4. intracellular transport (ie movement of vesicles and organelles)
5. cell division

Question 3

name the three different types of cytoskeleton filaments

Answer 3

1. microfilaments (actin)
2. intermediate filaments
3. microtubules

Question 4

Where are microfilaments most concentrated in the cell?

Answer 4

just beneath the cell membrane

Question 5

what are microfilaments comprised of?

Answer 5

two intertwined filamentous actin ( F-Actin) chains

Question 6

which parts of the cytoskeleton are responsible for resisting tension?

Answer 6

microfilaments

Question 7

Which aspect of the cytoskeleton is important for cytokinesis

Answer 7

microfilaments

Question 8

which parts of the cytoskeleton are responsible for maintaining cellular shape

Answer 8

microfilaments

Question 9

which parts of the cytoskeleton are responsible for participating in some cell to cell or cell to matrix junctions?

Answer 9

microfilaments (F-actin)

Question 10

Which aspect of the cytoskeleton is important for muscular contraction (with myosin)?

Answer 10

microfilaments

Question 11

Which aspect of the cytoskeleton is important for cytoplasmic streaming (with myosin)

Answer 11

microfilaments

Question 12

what diameter are intermediate filaments

Answer 12

8-10 nanometers

Question 13

Where are intermediate filaments found in the cell?

Answer 13

throughout the cell

Question 14

Why are intermediate filaments more stable than microfilaments?

Answer 14

they are more strongly bound than actin filaments

Question 15

what is vimetin

Answer 15

Vimentin is a structural protein that in humans is encoded by the VIM gene. Its name comes from the Latin vimentum which refers to an array of flexible rods.

Question 16

what is keratin

Answer 16

one of a family of fibrous structural proteins known as scleroproteins. α-Keratin is a type of keratin found in vertebrates. It is the key structural material making up hair, nails, feathers, horns, claws, hooves, calluses, and the outer layer of skin among vertebrates.

Question 17

which aspect of the cytoskeleton can be composed of vimetins

Answer 17

intermediate filaments

Question 18

which aspect of the cytoskeleton can be made of keratin

Answer 18

intermediate filaments

Question 19

which aspect of the cytoskeleton is found in neural cells

Answer 19

neurofilaments

Question 20

which aspect of the cytoskeleton is very dynamic in behaviour (constantly elongates and shortens)

Answer 20

microtubules

Question 21

which aspect of the cytoskeleton is made of alpha and beta tubulin

Answer 21

microtubules

Question 22

which aspect of the cytoskeleton is able to resist compression compared with other cytoskeletal filaments

Answer 22

microtubules

Question 23

how wide is the lumen of a mictotubule

Answer 23

15 nanometers

Question 24

which cytoskeletal filament is arranged in an imperfect helix

Answer 24

microtubule

Question 25

which cytoskeletal filament is composed of two heterodimers ( a and b tubulin)?

Answer 25

microtubule

Question 26

which cytoskeletal filament has polarity

Answer 26

microtubule (due to alpha-tubulin at one end and beta-tubulin at the other)

Question 27

how many tubulin dimers does each turn of the microtubules helix have?

Answer 27

13 tubulin dimers each from a different protofilament

Question 28

what is a protofilament

Answer 28

A protofilament is a linear row of tubulin dimers

Question 29

which cytoskeletal filament plays a key role in Intracellular transport (they transport organelles like mitochondria or vesicles)

Answer 29

microtubules

Question 30

which cytoskeletal filament plays a key role in the cytoskeleton (axoneme) of cilia and flagella

Answer 30

microtubules

Question 31

which cytoskeletal filament plays a key role in synthesis of the cell wall in plants?

Answer 31

microtubules

Question 32

which cytoskeletal filament plays a key role in The mitotic spindle?

Answer 32

microtubules

Question 33

what organelle can microtubules form?

Answer 33

centrioles

Question 34

how are the microtubules in centrioles arranged?

Answer 34

9 triplet sets

Question 35

what organelle is involved in the organisation of the mitotic spindle and in the completion of cytokinesis

Answer 35

centrioles

Question 36

what form cilia and flagella

Answer 36

microtubules

Question 37

how are the microtubules oriented in cilia or flagella?

Answer 37

9+2 arrangement; Microtubules are in nine doublets oriented about two additional microtubules (wheel-shaped)

Question 38

Which part of the cytoskeleton thickens the cortex around the inner edge of a cell and resist tension like rubber bands?

Answer 38

microfilaments

Question 39

Which part of the cytoskeleton are found in the interior of the cell where they maintain cell shape by resisting compressive forces?

Answer 39

microtubules

Question 40

Which part of the cytoskeleton is found throughout the cell and hold organelles in place.

Answer 40

intermediate filaments