The Cytoskeleton Flashcards

1
Q

What are the three filament types of the cytoskeleton?

A
  1. Microtubules
  2. Microfilaments
  3. Intermediate filaments.
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2
Q

What are the functions, components, and diameter of microtubules?

A
  • Movement and support.
  • Made up of the protein tubulin.
  • The diameter is about 25nm.
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3
Q

What are the functions, components, and diameter of microfilaments?

A
  • Movement and support.
  • Made up of the protein Actin
  • The diameter is about 6nm.
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4
Q

What are the functions, components, and diameter of intermediate filaments?

A
  • Support.
  • Made up of various proteins.
  • The diameter is about 10nm.
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5
Q

What are the two ends of the microtubules called?

A

The plus end and the minus end.

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6
Q

Which end of the microtubules grows the fastest?

A

The plus end.

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7
Q

What end of the microtubules are anchored close to the centrioles?

A

The minus end.

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8
Q

In what cellular structures can you find microtubules?

A

In cilia and in centrioles.

Microtubules fuse side by side to form doublets or triplets

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9
Q

What microtubule structures do cilia contain?

A

9 peripheral doublets (18 microtubules fused together in pairs)
2 central microtubules.

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10
Q

What microtubule structures do a centriole contain?

A

9 peripheral triplets.

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11
Q

What is a centrosome?

A

A centrosome is a pair of centrioles.

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12
Q

In which cases are microfilaments stable?

A

In cell-cell junction, microvilli, terminal web in epithelial cells, thin myofilaments in muscle cells.

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13
Q

What is the function of the motor enzymes (motor proteins)?

A

Motor enzymes walk along the cytoskeletal filaments transporting vesicles of compounds. They are together with the microtubules responsible for the intracellular movement of vesicles, organelles, and chromosomes.

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14
Q

What motor enzyme walks toward the + end of the microtubules?

A

Kinesin

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15
Q

What motor enzyme walks toward the - end of the microtubules?

A

Dynein

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16
Q

What motor enzyme does the actin filaments (microfilaments) cooperate with?

A

Myosin.

17
Q

Which end of the actin does the myosin walk towards?

A

The + end

18
Q

What motor enzymes does the intermediate filaments cooperate with?

A

None. The intermediate filaments do not participate in movement in the cell and their only function is to reinforce the cell structure and participate in cell-cell junctions. Hence, do not cooperate with any motor enzymes.

19
Q

What proteins do you find in the intermediate filaments of epithelial cells?

A

Keratins (>40 subtypes)

20
Q

What proteins do you find in the intermediate filaments of muscle cells?

A

Desmin

21
Q

What proteins do you find in the intermediate filaments of connective tissue cells?

A

Vimentin

22
Q

What proteins do you find in the intermediate filaments of neurological cells?

A

Glial fibrillar acidic protein

23
Q

What proteins do you find in the intermediate filaments of nerve cells?

A

Neurofilament proteins.

24
Q

What proteins do you find in the intermediate filaments of the inner lining of nuclear envelopes in all cells?

A

Nuclear lamins A, B

25
Q

What induces and controls the growth of cytoplasmic microtubules in the MTOC - microtubule-organizing center?

A

The centrioles and the surrounding material containing tubulin G.

26
Q

What are microfilaments built up of?

A

Microfilaments are built up by F-actin (formed by G-actin)

27
Q

What are some pigment granules found in the cytoplasm of the cell?

A
  1. Melanin

2. Lipofuscin