Cell biology VI

Question 1

What is the role of microtubule-associated proteins?

Answer 1

Stabilize microtubules

Question 2

What is the diameter of a microfilament?

Answer 2

6-8 nm

Question 3

What are the subunits of microfilaments?

Answer 3

Actin

Question 4

Actin subunits make up what cytoskeletal component?

Answer 4

Microfilaments

Question 5

What drug inhibits polymerization of actin?

Answer 5

Cytocalasin B

Question 6

What is the function of Cytocalasin B?

Answer 6

Prevents polymerization of actin subunits

Question 7

What are the functions of microfilaments?

Answer 7

1) Structural support2) Form core of microvilli and stereocilia3) Cell movement4) Cytokinesis5) Formation of filopodia and lamellipodia

Question 8

What is the diameter of thick filaments?

Answer 8

12-16 nm

Question 9

What are the subunits of thick filaments?

Answer 9

Myosin

Question 10

Myosin makes up which cytoskeletal component?

Answer 10

Thick filaments

Question 11

What is the diameter of intermediate filaments?

Answer 11

About 10 nm

Question 12

Cytokeratins are what kind of cytoskeletal component?

Answer 12

Intermediate filament

Question 13

Desmin is what kind of cytoskeletal component?

Answer 13

Intermediate filament

Question 14

Where are cytokeratins localized?

Answer 14

Epithelial cells

Question 15

Where is desmin localized?

Answer 15

Muscle (smooth and striated)

Question 16

Glial fibrillary acidic proteins (GFAPs) are what kind of cytoskeletal component?

Answer 16

Intermediate filament

Question 17

Where are glial fibrillary acidic proteins (GFAPs) localized?

Answer 17

Astrocytic glial cells

Question 18

Neurofilament proteins are what kind of cytoskeletal component?

Answer 18

Intermediate filament

Question 19

Where are neurofilaments localized?

Answer 19

Neurons

Question 20

Nuclear lamins are what kind of cytoskeletal component?

Answer 20

Intermediate filament

Question 21

Where are nuclear lamins localized?

Answer 21

Nucleus of all cells

Question 22

Vimentin is what kind of cytoskeletal component?

Answer 22

Intermediate filament

Question 23

Where is vimentin localized?

Answer 23

Many mesodermal tissues

Question 24

Mallory bodies are characteristic of what disease?

Answer 24

Alcoholic liver disease

Question 25

Mallory bodies are made up of what type of intermediate filament?

Answer 25

Cytokeratins

Question 26

Epidermolysis bullosa simplex is a disease characterized by lack of assembly of what intermediate filament?

Answer 26

Keratin

Question 27

What do cytokeratins form?

Answer 27

Tonofilaments

Question 28

Vimentin is found in what cell types?

Answer 28

1) Fibroblasts2) Chondroblasts

Question 29

GFAP aggregates are observed in what diseases?

Answer 29

1) Alexander disease2) Chronic gliosis3) Astrocytomas

Question 30

What are Rosenthal's fibers?

Answer 30

Aggregations of GFAPs

Question 31

Pathologists can determine tumor type based on what cytoskeletal component?

Answer 31

Intermediate filaments

Question 32

The centrosome (MTOC) conducts what microtubular processes / properties?

Answer 32

1) Number2) Polarity3) Direction4) Orientation5) Organization

Question 33

What makes up the centrosome (MTOC)?

Answer 33

Two centrioles and an amorphous pericentriolar material

Question 34

What is the arrangement of centrioles?

Answer 34

9x3 arrangement of microtubules

Question 35

How are basal bodies formed?

Answer 35

Centrioles replicate to form procentrioles, which then become basal bodies

Question 36

What are basal bodies required for?

Answer 36

Formation of microtubules associated with cilia and flagella

Question 37

How is the centrosome involved in mitosis?

Answer 37

Formation of mitotic spindle

Question 38

Are neoplastic cells with well-differentiated nuclei usually benign or malignant?

Answer 38

Benign

Question 39

Are nuclei basophilic or acidophilic?

Answer 39

Basophilic

Question 40

What are the components of the nucleus?

Answer 40

1) Nuclear envelope (double unit membrane)2) Nuclear matrix (nucleoplasm)3) Chromatin4) Nuclear bodies (domains)

Question 41

What is the function of Cajal bodies?

Answer 41

Modification and assembly of molecular machinery to splice newly transcribed pre-mRNA into mRNA

Question 42

What are GEMs?

Answer 42

Gemini of Cajal bodies

Question 43

What is the cause of spinal muscular atrophy?

Answer 43

Mutation of survival of motor neurons (SMN) gene. SMN protein localizes to GEMs and causes death of motor neurons in anterior gray horns of spinal cord

Question 44

What are PML bodies and what do they do?

Answer 44

1) Promyelocytic leukemia bodies2) Modify and assembly proteins involved in DNA repair and triggering of apoptosis

Question 45

What is the diameter of a nuclear pore?

Answer 45

70 nm

Question 46

How many subunits make up a nuclear pore?

Answer 46

8

Question 47

What is the diameter limit for freely permeable molecules and ions passing through the nuclear pore?

Question 48

The nuclear pore selectively transports what molecules?

Answer 48

1) RNA2) Ribosomal subunits3) Proteins4) Other molecules and ions

Question 49

What are the functions of the nuclear lamina?

Answer 49

1) Supports inner nuclear membrane2) Disassembly of nuclear envelope during prometaphase - lamins are phosphorylated3) Reassembly of nuclear envelope during telophase - lamins are dephosphorylated

Question 50

During disassembly of the nuclear envelope in prometaphase, are lamins phosphorylated or desphosphorylated?

Answer 50

Phosphorylated

Question 51

During reassembly of the nuclear envelope in telophase, are lamins phosphorylated or desphosphorylated?

Answer 51

Dephosphrylated

Question 52

Mutations in the nuclear lamina are associated with what diseases?

Answer 52

1) One form of muscular dystrophy2) Two forms of progeria

Question 53

What is the basic structural unit of chromatin?

Answer 53

Nucleosome

Question 54

Is heterochromatin transcriptionally active or inactive?

Answer 54

Inactive

Question 55

Is euchromatin transcriptionally active or inactive?

Answer 55

Active