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Nucleus Flashcards

Understand structure of nucleus and its role in cell cycle/death (62 cards)

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1
Q

What is the arrangement of centrioles?

A

9 sets of MTs arranged in triplets

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2
Q

How many centrioles in a centrosome?

A

2 centrioles

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3
Q

Function and clinical significance of primary cilia

A

act as receptors

ciliopathies stem from defects

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4
Q

What proteins cross-links actin filaments in the cytoplasm?

A

Filamen & also spectrin acid

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5
Q

What proteins cross-link actin filaments w/i microvilli?

A

Fimbrin & fascin

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6
Q

What sites are IM filaments anchored to on PM?

A

Desmosomes & hemidesmosomes

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7
Q

What tissue types are IM filaments abundant in & what are their functions there?

A

epithelial cells of skin (form tough outer layer thru packing together) & neurons (anchor membrane ion channel proteins via the link protein ankyrin)

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8
Q

Describe aggresomal response

A

in damaged cells, IM filament network collapses around abnromal/damaged cell proteins to facilitate proteolysis/autophagy; will then re-expand

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9
Q

Give clinical examples of aggresomal response

A
  1. Liver cells: xs alc –> accumulation of collapsed cytokeratin IM bundles (Mallory’s hyaline)
  2. Parkinson’s: accumulation of Lewy bodies in neurons of brain
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10
Q

Match specific IM to its localization:

  1. cytokeratins
  2. vimentin
  3. desmin
  4. glial fibrillary acidic proteins
  5. neurofilaments
  6. nuclear lamin
A
  1. epithelial cells
  2. mesenchymal, lymphocyte, & phagocyte cells
  3. muscle (both types)
  4. asctrocytic glial cells
  5. neurons
  6. nucleus of all cells
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11
Q
  1. defects in org of MT & dynein
  2. immobilization of cilia in resp epithelium
  3. resp dysfunction
  4. defects in sperm motility & male sterility
  5. female sterility due to impaired ovum transport from overy to uterine cavity
  6. autosomal recessive
  7. caused by mutations in DYNEIN gene
A

Kartagener’s syndrome (aka immotile cilia syndrome)

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12
Q

Name this drug:

  1. binds tubulin & prevents polymerization
  2. treats gout attacks
  3. prevents neutrophil migration so they can’t respond to urate crystal deposits in tissues
  4. inhibits mitosis
A

Colchicine

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13
Q

Which cytoskeletal filament plays a crucial role in endo/exocytosis?

A

Microtubules

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14
Q

Name these 2 drugs:

  1. bind MTs and inhibit formation of mitotic spindle
  2. antiproliferative agents in cancer therapy
A

Vinblastine & vincristine

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15
Q

Name that drug:

  1. chemotherapy for breast cancer
  2. prevents depolymerization of MTs by stabilizing them
  3. arrests cancer cells during cell division
A

Paclitaxel

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16
Q

Function of cytochalasin B & D?

A

prevent actin polymerization by binding to + end of actin filament –> inhibition of lymphocyte migration, phagocytosis, & cell division –> apoptosis

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17
Q

Function of phalloidin toxin?

A

stabilize & prevent depolymerization of actin filaments –> disruption of dynamic equilibrium

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18
Q

Which filament is assoc w/ Alzheimer’s?

A

IM filaments; production of neurofibrillary tangles of neurofilaments

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19
Q
  1. Mutations of GFAP gene
  2. presence of Rosenthal fibers in astrocytes
  3. inhibit astrocyte mitosis & division
  4. leukoencephalopathy (brain infection)
  5. macrocephaly (large head)
  6. seizures
  7. psychomotor impairment
  8. death in 1st decade of life
A

Alexander disease

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20
Q

T/F, the nuclear envelope is permeable to most proteins & ions

A

False, impermeable to ions/proteins of all sizes; pathways provided by nuclear pores

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21
Q

Which is more electron-dense: euchromatin or heterochromatin?

A

Heterochromatin

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22
Q

Describe appearance of heterochromatin & euchromatin in EM & LM

A

Heterochromatin: electron-dense, coarse clumps in EM; basophilic clumps in LM
Euchromatin: seen as finely dispersed granular material b/c it is a site of active transcription

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23
Q

Where in the nucleus are rRNA & protein in abundance?

A

Nucleolus

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24
Q

3 components of nucleolus seen by EM?

A
  1. Nucleolar organizer DNA
  2. Pars fibrosa
  3. Pars granulosa
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25
What is Nucleolar organizer DNA?
(base seq's coding for rRNA)
26
What is Pars fibrosa?
(densely packed ribonucleoprotein fibers, primary transcripts of rRNA genes)
27
What is Pars granulosa?
(15-20nm granules rep'ing maturing ribosomes)
28
What stain is used for visualizing heterochromatin under LM & where is it predominantly found?
Feulgen stains; periphery of nucleus
29
T/F, euchromatin is visible w/ LM?
False
30
What happens in G1?
Cells accumulate enzymes & nucleotides req'd for DNA replication
31
What happens in S?
DNA replication
32
What happens in G2?
Short prep pd for mitosis
33
What are the 3 major checkpoints of the cell cycle?
1. start/restriction checkpoint just before start of S 2. G2/M checkpoint to ensure completion of DNA replication 3. metaphase spindle checkpoint ensures all chromo's are segregated
34
What category of cells are CNS, skeletal, & cardiac cells?
static cells
35
What category of cells are periosteal/perichondrial, smooth mm, blood vessel endothelial, & connective tissue fibroblast cells?
Stable cells, divide rarely & slowly
36
What category of cells are smooth mm of hollow organ, fibroblast of uterine wall, & lens epithelial cells?
Slowly renewing cells
37
Category of blood, epithelial, dermal fibroblast, & epithelial/subepithelial cells of alimentary tract musocal lining?
Rapidly renewing cells
38
Type of cell death w/o rupture of PM or immune activation?
Apoptosis
39
Type of cell death that is accidental & caused by pathologic mechanism?
Necrosis
40
Similarities/differences in histo presentation of apoptosis vs. necrosis
Apoptosis: caspase-induced; compact (pyknotic nuclei) --> nuclear fragmentation (karyorrhexis); blebs @ cell periphery; cytoplasm --> condensed & stains darker; cell fragmentation Necrosis: swollen cells; bleb formation; cell contents free in extracell space; pyknotic nuceli --> lysis (karyolysis); phagocytosis of remnants Similarities: pyknotic nuclei; bleb formation
41
Regulated cell process that uses autophagosome to induce self-degradation & lysis?
Autophagy
42
Cell death mediated by mitogen-activated protein kinases (MAPKs), recognized by formation of multiple large vacuoles & swollen mitochond
Paraptosis
43
Cell death dep on caspase-1 & inflammatory cytokines (IL-1/18)
Pyroptosis
44
Characteristics of nucleoli in malignant cells?
1. nucleoli more prominent 2. larger than normal 3. mutliple 4. perinuclear cap -- distinct area around nuceolus
45
Diseases characterized by presence of nuclear inclusions (abnormal proteins in nucleus)
Huntington's disease | Frontotemporal dementia
46
Method used to detect changes in chromo # & chromo abnormalities?
Cytogenetic testing
47
Key gene mutations in cell cycle regulation & roles (4)
BRCA-1 & BRCA-2 (tumor suppressors); RAD-51 (homologous recombo/DNA repair); p53 (triggers apoptosis)
48
Where are + and - ends of MTs located?
+ end = periphery | - end = MTOC (nucleus)
49
Whet tissue contains the IM filament desmin?
Cardiac mm
50
What tubule are dynein arms always attached to?
Tubule A
51
Is the Nissl substance (neuronal RER) located w/i or outside nucleus?
Outside, in cytoplasm
52
What end of microfilament does F-actin bind to along w/ ATP?
+ end
53
What is a major symptom of phalloidin poisoning?
Acute hunger due to destruction of liver cells (necrosis)
54
Name this disease: 1) a genetically determined hemolytic anemia chracterized by spherical shaped RBCs 2) deficiency of spectrin, ankyrin, or band 3 protein
Hereditary spherocytosis
55
What Cyclin-CDK pair allows G1 --> S?
Cyclin E-Cdk2
56
What Cyclin-CDK pair allows G2 --> M?
Cyclin A-Cdk1
57
Role & location of progenitor cells?
- similar to stem cells except pushed to differentiate into their designated target cells - located in tissue lining of small intestine
58
What organelle is well-dvp'd in large neurons active in protein synth?
Nucleolus
59
What is a Nissl body?
- granules of RER w/ rosettes of free ribosomes | - site of protein synht
60
What is a Barr body?
Inactive X chromosome
61
Major feature of Aprt syndrome?
Webbing/fusion of digits
62
Cause of Apert syndrome?
Failure of DNA degradation by endonucleases

Histology (7 decks)

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