Cytoskeleton

Question 1

What are the components of the cytoskeleton?

Answer 1

Microtubules
Microfilaments
Intermediate filaments

Question 2

What are microtubules?

Answer 2

The largest and thickest elements of the cytoskeleton (25nm in diameter)
Long hollow tubes

Question 3

What is tubulin?

Answer 3

A globular protein that has two versions, alpha and beta.
Alpha and beta tubulin bond to form AB dimer

Question 4

What is a protofilament?

Answer 4

A chain of AB dimers

Question 5

How many protofilaments form a hollow tube?

Answer 5

13 protofilaments

Question 6

Where are microtubules assembled?

Answer 6

In the microtubule organizing center (MTOC)

Question 7

What is the MTOC in animal cells?

Answer 7

The centrosome

Question 8

What is the MTOC in plant cells?

Answer 8

It is unknown, but evidence shows that it is probably the nuclear envelope

Question 9

What does the MTOC organize?

Answer 9

Centrioles, cilia, and flagella

Question 10

What are centrioles?

Answer 10

Spindle-shaped bundles of microtubules located in the centrosome

Question 11

How many microtubules do centrioles contain?

Answer 11

There are 9 sets of microtubule triplets in centrioles

Question 12

What is dynein?

Answer 12

Filaments that form cross hatches/bridges between the microtubules

Question 13

What do centrioles assemble?

Answer 13

Basal bodies located at the base of every cilium and flagellum

Question 14

What do basal bodies assemble?

Answer 14

Cilia and flagella

Question 15

What are cilia and flagella?

Answer 15

Basically the same thing. Used for movement. Blah blah blah

Question 16

What is the difference between cilia and flagella?

Answer 16

Cilia are short and there are multiple of them on a cell
Flagella are long and there is typically one or two per cell

Question 17

How many microtubules do cilia and flagella contain?

Answer 17

There are nine sets of microtubule doublets in cilia/flagella

Question 18

What is an axoneme?

Answer 18

A structural and functional unit of ciliar/flagellar movement

Question 19

What is the mechanism of ciliar and flagellar movement?

Answer 19

It is not well understood, but it is similar to the Sliding Filament Model in muscle cell contraction

Question 20

What are microfilaments?

Answer 20

Smallest and thinnest element of the cytoskeleton
Structural support of the cell; cell movements

Question 21

What is actin?

Answer 21

The most abundant protein in eukaryotic cells

Question 22

What is alpha-actin?

Question 23

What is G-actin?

Answer 23

Globular protein (idk what else to put uh)

Question 24

What is F-actin?

Answer 24

Filament formed from two chains of G-actin coiled around each other

Question 25

What is alpha-actin?

Answer 25

Actin found in skeletal muscle cells

Question 26

What is tropomyosin?

Answer 26

Filamentous protein that runs along the outer edge of the F-actin filaments

Question 27

What is the troponin complex?

Answer 27

A protein with three subunits that 1. attaches to troponin 2. attaches to tropomyosin 3. binds to Ca2+

Question 28

What are intermediate filaments?

Answer 28

The medium-sized elements of the cytoskeleton (10nm in diameter)

Question 29

What do intermediate filaments consist of?

Answer 29

Various rope-like fibrous proteins with tensile strength

Question 30

What is tensile strength?

Answer 30

The resistance to being pulled apart High tensile strength = hard to pull apart

Question 31

What is the main function of intermediate filaments?

Answer 31

To enable cells to withstand mechanical stresses when stretched

Question 32

What are the four types of intermediate filaments?

Answer 32

Keratin Vimentin and desmin Neurofilaments Nuclear lamins

Question 33

Where is keratin found?

Answer 33

In epithelial cells of vertebrates, especially in the skin (cytoplasm)

Question 34

Where are vimentin and desmin found?

Answer 34

Found in connective tissue cells, muscle cells, and glial cells of nerve tissue

Question 35

Where are neurofilaments found?

Answer 35

Found in neurons (cytoplasm)

Question 36

Where are nuclear lamins found?

Answer 36

Found in nuclear envelope and strengthens it