Cell VI Flashcards

1
Q

How to Tau tangles appear with E staining?

A

“Flame” inclusions

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2
Q

tau tangles are c/w what disease?

A

Alzheimers

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3
Q

Microtubule assembly occurs at what end? Disassembly?

A

Assembly at the + end

Disassembly at the - end

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4
Q

Where is myosin located in muscle cells?

A

A band

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5
Q

Where is actin filaments located in muscle cells?

A

I band

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6
Q

What are the molecules that stabilize microtubules?

A

Microtubule-associated proteins (MAPs)

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7
Q

What are examples of MAPs?

A

MAP-1-4, MAP-τ (tau), and TOGρ

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8
Q

What is the diameter of microfilaments?

A

6-8 nm

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9
Q

What are the subunits that comprise microfilaments?

A

Actin

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10
Q

What is the drug discussed in class that inhibits the polymerization of actin?

A

Cytochalasin B

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11
Q

What are the five functions of microfilaments?

A
  1. Structural support (cell cortical fibers)
  2. Form core of microvilli and stereocilia
  3. Movement
  4. Cytokinesis
  5. Formation fo filopodia and lamellipodia
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12
Q

What is the diameter of thick filaments?

A

12-16 nm

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13
Q

What is the proteins that makes up thick filaments?

A

myosin

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14
Q

mutation in the gene encoding the protein myosin causes what?

A

Cardiomyopathy

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15
Q

What is the diameter of intermediate filaments?

A

10 nm

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16
Q

What are the six types of intermediate filaments?

A
  1. Cytokeratin
  2. Desmin
  3. Vimentin
  4. Neurofilaments
  5. Glial fibrillary acidic proteins
  6. Nuclear lamins
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17
Q

What is the general function of the intermediate filaments?

A

Structural support

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18
Q

Why would you want to analyze a CA cell for the type of intermediate filaments?

A

To determine where the tumor came from. Changes the therapy

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19
Q

Where is cytokeratin found? What does it form?

A

Found in epithelial cells where it forms tonofilaments

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20
Q

What are mallory bodies found in?

A

Alcoholic liver disease

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21
Q

What is Epidermolysis bullosa simplex?

A

Mutations in keratin 5 or 14 gene prevent keratin from assembling into strong networks b/t dermis and epidermis.

Epidermis of skin becomes fragile, and blisters easily.

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22
Q

Where is the intermediate filament Desmin found?

A

Striated muscle and non-vascular smooth muscle

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23
Q

Where is the IF Vimentin found (2)?

A

Fibroblasts

Chondroblasts

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24
Q

Where are neurofilaments found? Mutations in them are associated with what?

A

Found in nerve cells

Mutations = neuropathies

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25
Q

Where are glial fibrillary acidic proteins (GFAPs) found in?

A

Astrocytic glial cells

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26
Q

Aggregates of GFAP are demonstrated in what disease?

A

Alexander’s disease (white matter disease)

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27
Q

You analyze a tumor cell using immunocytochemistry, and find cytokeratins being expressed. Where did the tumor originate from?

A

Epithelial cells

28
Q

You analyze a tumor cell using immunocytochemistry, and find desmin being expressed. Where did the tumor originate from?

A

Smooth and striated muscle cells

29
Q

You analyze a tumor cell using immunocytochemistry, and find glial fibrillary acidic proteins being expressed. Where did the tumor originate from?

A

Astrocytic glial cells (type of nerve cell(

30
Q

You analyze a tumor cell using immunocytochemistry, and find neurofilament proteins being expressed. Where did the tumor originate from?

A

neurons

31
Q

You analyze a tumor cell using immunocytochemistry, and find vimentin being expressed. Where did the tumor originate from?

A

mesodermal tissue

32
Q

How do neurofilaments impart tensile strength to nerve cell axons?

A

Have extensive cross links between each other

33
Q

How do you tell the different between neurofilaments and glial intermediate filaments?

A

Crosslinks greater in neurofilaments

34
Q

What type of intermediate filament constitutes the mallory body? How do these appear with H&E staining?

A

Cytokeratin

Glossy “twisted rope” areas that are eosinophilic

35
Q

What are Rosenthal’s fibers? How do they appear with H&E staining? What disease are the found in?

A
  1. Aggregates of GFAPs.
  2. Eosinophilic “worm-like” structures
  3. Pilocytic astrocytoma (glial cell tumors)
36
Q

What is the centrosome?

A

Specialized cytoplasmic region near the nucleus containing two centrioles and an amorphous pericentriolar material

37
Q

The centrosome is a conductor for what type of microtubule characteristics (5)?

A
  1. Number
  2. Polarity
  3. Direction
  4. Orientation
  5. Organization
38
Q

How are centrioles oriented relative to one another?

A

Perpendicular

39
Q

Centrioles are composed of microtubules. How are these arranged?

A

9 sets of triplets in a circular fashion

40
Q

What is the role of centrioles in mitosis?

A

Form mitotic spindle

41
Q

What are procentrioles? What do they turn into?

A

Replicating centrioles that eventually form basal bodies. (Basal bodies are needed for microtubule in cilia and flagella)

42
Q

How can nucleus shape aid you in determining the type of neoplasm?

A

Well differentiated neoplasms are benign.

Vice versa

43
Q

Why are nuclei basophilic?

A

Negatively charged phosphates on nucleic acids

44
Q

What is the typical size of a nucleus?

A

3-25 um (most 5-10 um)

45
Q

Where are cajal bodies? What is their significance?

A

aid in splicing of pre-mRNA to mRNA

46
Q

What process would a cell likely be heavily involved in, if its nucleus has more than one nuceloli?

A

Protein synthesis (need rRNA)

47
Q

What arePromyelocytic leukemia (PML) bodies are involved in?

A

modifying and assembling proteins tasked with DNA repair and triggering apoptosis

48
Q

What is the space between the inner and outer nuclear membranes called?

A

Perinuclear space

49
Q

What is the average diameter of nuclear pores? How many subunits comprise it?

A

70 nm comprised of 8 subunits

50
Q

What happens to the inner and outer membrane at nuclear pores?

A

fuse

51
Q

On the inner aspect of the nuclear membrane, there is a lattice material. What is this?

A

Nuclear lamina (intermediate filament)

52
Q

How can you identify nuclear pores with EM?

A

fusion of the iner and outer nuclear membranes

53
Q

What should you review from biochem for this section?

A

Ran- import/export

54
Q

What types of protein are imported/exported from the nucleus through nuclear pores?

A

Ribosomal subunits

55
Q

True or false: the nuclear membranes remain chemically distinct from each other, despite being united at the pores

A

True

56
Q

The nuclear pores allow free passage of molecules of up to what diameter?

A

9 nm

57
Q

What are the four molecules that pass through nuclear pores?

A

RNAs
Ribosomal subunits
proteins
other molecules and ions

58
Q

What is the nuclear lamina composed of?

A

three classes of polypeptides, all called lamins

59
Q

What are the three functions of the nuclear lamina?

A
  1. Structural support of inner membrane
  2. Dis-assembly of nuclear envelope during mitosis
  3. Reassembly of the nuclear envelope during mitosis
60
Q

What is the chemical change that signals lamins to disassemble?

A

Phosphorylation

61
Q

Mutations with the nuclear lamina are associated with what diseases (3)?

A
  1. cardiomyopathy
  2. a form of muscular dystrophy
  3. two forms of progeria
62
Q

What is progeria?

A

Premature aging

63
Q

Why does heterochromatin stain more intensely than euchromatin?

A

tight charge density (basophilic)

64
Q

How many pairs of histone proteins make a nucleosome?

A

4 pairs

65
Q

Orphan Annie eye nuclei are indicative of what disease?

A

Papillary thyroid cancer