Tissue Architecture Flashcards

1
Q

what is the function of the cytoskeleton at the sub cellular level?

A

organization, tensile strength, chromosome segregation, cell polarity, vesicular movement

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2
Q

what is the function of the cytoskeleton at the cellular level?

A

cell morphology/shape, motility, cell adhesion, division

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3
Q

what is the function of the cytoskeleton at the tissue level?

A

muscle contraction

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4
Q

what is the main component of microfilament?

A

actin 7nm

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5
Q

what is the main component of microtubules?

A

tubulin 25 nm

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6
Q

what is the main component of intermediate filaments?

A

lamin/cell specific proteins (8-12 nm)

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7
Q

what type of monomers make up microfilaments? what do they form?

A

g actin monomers

come together to form f actin (filamentous actin)

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8
Q

why is f actin unstable?

A

it is constantly undergoing addition (plus end) and removal (minus end) of g actin monomers

it has structural polarity

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9
Q

what is the main functions of microfilaments?

A

cell movement, locomotion, phagocytosis, cell division, contraction

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10
Q

how does f actin become more stable? (give specific examples)

A

becomes more stable by joining other proteins

accessory proteins, nucleating proteins, monomoer sequestering proteins, bundling proteins, side binding proteins

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11
Q

how do these proteins work with f actin?

accessory proteins
nucleating proteins
monomoer sequestering proteins
bundling proteins
side binding proteins
A

accessory proteins- stabilize, strengthen, cross link
nucleating proteins- stop monomer removal
monomoer sequestering proteins- semester monomers lol
bundling proteins
side binding proteins- stabilize and bind blocking sites for other proteins

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12
Q

what does phalloidin do?

A

bind and stabiles microfilaments
(death cap mushroom)
used in microscopy

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13
Q

what does cytochalasin do?

A

caps microfilaments plus end (no polymerization)

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14
Q

what does latrunculin do?

A

binds actin monomers and prevents polymerization

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15
Q

what are microtubule subunits and how do they work?

A

tubulin proteins - made of alpha and beta subunits

form heterodimers

heterodimers come together and form protofilaments
(polarity- heterodimers get added to the plus end of protofilaments )

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16
Q

how many protofilaments make up a microtubule

A

13

come together around a microtubule core

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17
Q

what is the main function of microtubules?

A

support shape of cell/organization

  • cell organization: make tracks/roads for vesicles to move through
  • cell division: interaction with mitotic spindle (extend from centrosome to chromosome)
  • part of cilia and flagella in ciliated cells
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18
Q

how do drugs target microtubules in cancer cells?

A

microtubules targeted –> can’t pull apart chromatin in cell division –> cancer cells cant undergo cell division

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19
Q

how does taxol work?

A

binds to and stabilizes microtubules

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20
Q

how do colchicine and colcemid work?

A

binds tubulin dimers/ prevents polymerization

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21
Q

how do vinblastine and vincristine work?

A

binds tubulin dimers and prevents polymerization

22
Q

What is the most important quality of Intermediate filaments?

A

rope like property that gives it high tensile strength (allows it to resist mechanical forces)

23
Q

how do intermediate filaments form?

A

form coil coil proteins and accessory proteins that form bundles of filaments

(bring dimers and tetramers together)

24
Q

what are the cytoplasmic elements that make intermediate filaments?

A

keratin filaments (epithelial cells)
vimentin (CT cells, muscle cells, glial cells)
neurofilaments (nerve cells)

*form based on the needs of the cell

25
Q

what are the nuclear elements that make up intermediate filaments?

A

nuclear lamina (in all cells)

26
Q

what is the function of nuclear lamina and where does it develop?

A

aids and stabilizes the nuclear membrane

a mesh like structure (of intermediate filaments) that forms adjacent to the nuclear envelope)

27
Q

what is hutchinson Gilford progeria syndrome?

A

disease in the encoding of lamina A (nuclear lamina) (Intermediate Filament)

lose nuclear stability - leads to cellular instability - leads to accelerated aging

28
Q

what are the main functions of the ECM/basal lamina?

A

anchor/engulf cells
maintain solid tissue (biochemical properties)
help define tissue boundaries
play role in cell polarity, survival, proliferation
inhibit or help cell migration

29
Q

how do cells in the ECM interact with the basal lamina?

A

cell adhesion molecules

30
Q

what makes up the ECM

A

tissue components secreted by nearby cells that aggregate into interlocking fibrous proteins/proteoglycans/adhesive matrix proteins

31
Q

how is collagen made?

A

3 peptides made in the RER –> synthesized into pre-pro collagen–> turned into procollagen (trimer)–> alteration/processing in Golgi–> secreted into the ECM where it undergoes more processing

32
Q

what processing can collagen undergo in the ECM?

A

cleavage of amino and carboxy terminals

collagen trimers form into fibers/sheets

33
Q

what processing does collagen undergo in the ER?

A

hydroxylation of proline/lysine int he ER (before the trimer is formed)–> allows the proteins to form and stay stable

34
Q

what is scurvy?

A

lack of ascorbate or iron (vit c deficiency)

vit c is an important cofactor for the hydroxylation of collagen

with hydroxylation - there is no folding/stability of trimeric collagen–> leads to unstable collagen which leads to the symptoms of scurvy

35
Q

what are anchoring junctions?

A

attach cells to one another or to the ECM
keep cells together/ structural cohesion tissue

examples: adhering junction, desmosome, hemidesmosome

36
Q

what are occluding junctions?

A

they create an impermeable/semi-permable barrier between adjoining epithelial cells

inhibit material transportation and control the movement of membrane transport proteins

37
Q

what are gap junctions

A

link cytoplasm of adjacent cells to allow transport of molecules between adjacent cells

stretch across cell membrane

38
Q

what are connexions?

A

make up gap junctions

interact and form complete gap channels

39
Q

what are signal relaying junctions?

A

allow signals to be relayed across membranes (synapses)

40
Q

what kind of interactions do cadherins have?

A

homophilic interaction on the extracellular side/ bind to actin on the intracellular side

41
Q

what do all cell adhesion molecules have in common?

A

all ca2+ dependent glycoproteins

42
Q

what kind kind of cell adhesion molecules make tight junctions?

A

cadherins

43
Q

what are the types of cell adhesion molecules?

A

cadherins, interns, selections, Ig superfamily

44
Q

what do integrins connect?

A

cell/ECM and cell/cell

connect cytoskeleton to ECM

45
Q

what are integrins?

A

transmembrane cell adhesion molecules

46
Q

what kind of interactions to integrins form?

A

interact with actin (intracellular) and fibronectin/collagen/laminin (extracellular)

47
Q

what are the subunits of integrins?

A

alpha and beta subunits

B subunit determines integrin family

48
Q

what type of cell adhesion molecules interact with RTK?

A

integrins

interact with RTK receptor on cell

initiate cell signaling cascade based on mechanical signal from outside the cell/ECM

49
Q

what integrin subunit interacts with selectins? What is the pathway?

A

B2 integrins on monocytes – interact with selectins (e/p)

bind with ligand on selectins - localize white blood cells to the site during infection

50
Q

how do selectins work during an infection?

A

inflammation/injury causes cytokines to be released –> this increases the amt of selectins on endothelial cells (on blood vessels)

these recruit WBC (with B2 integrins)

there is a low affinity interaction between WBC and selectins–> which causes the WBC to slow down/stop –> the WBC moves from blood into the tissue

51
Q

what happens if there is a mutation in B2?

A

becomes difficult to fight infection (WBC can’t bind to selectin to slow down/stop)

52
Q

what are the functions of the Ig superfamily as cell adhesion molecules?

A

expressed on endothelial cells

can bind to various leukocyte integration molecules (aid in immune response)

help with self recognition by immune cells

can take part in giving cell polarity