Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ANAT 262 > Cytoskeleton: Overview > Flashcards

Cytoskeleton: Overview Flashcards

1
Q

Why should we care about the cytoskeleton

A

Fundamental cellular processes = cell division - mitotic spindle, motility, polarity, stability, diseases
Internal cytoskeleton makes cell move in space -by pushing it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is cytoskeleton assembled by

A

Microtubules
Actin
Intermediate filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe actin thickness

A

7-9nm
Thin
Microfilaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are actin filaments

A

Microfilaments
F-actin = filamental actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe microtubules thickness

A

Hollow tubes
Alpha beta tubulin dimers
Largest diameter = 25 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe intermediate filaments thickness

A

Intermediate filaments - various bundles
10nm - middle size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe structure actin filaments

A

Actin monomers assembled into filaments
ATP binding cleft - hydrolzye
37nm length, 8nm width
2 protofilamnets make up molecule = monomer actin assembles head to tail, helical nature, actin filament so also have side to interaction at form stable filament (also have vertical interactions)
Plus end = business end, form dynamics
Minus end = polarity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is actin found

A

Brush border cells - microvilli, increase surface area absorption
Under pm, forms adhesion - stability of cells
Muscle cells - important for contraction - actin myosin (motor molecule) filament - important for dynamics of actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe microtubule structure

A

Hollow filaments composed of heterodimers
B and alpha tubulin= dimer, each has gtp binding spot, but only one gtp molecule hydrolyzed
50nm length, 25nm width
13 subunits
Lattice shaped structure
+ - ends

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe ex where find microtubules

A

Centre of cell - bc polarity neg end usually attached to microtubule = anchors them in centrosome
Mitotic spindle - can extend and retract- do both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe intermediate filament structure

A

Heterogenous group of molecules made from alpha helical monomers
Less conserved across species than actin and microtubules
Alpha helical region monomer, not round or globule like, long and thin
Forms dimers = side to side interactions, interacts with other molecules of intermediate filaments, eventually assemble into bundles, thicker,
Not hollow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where find intermediate filaments

A

Diameter = 10nm
Mesh work - neurons, nuclear lamina, epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Do the 3 filaments have same mechanical properties

A

NAWWWWWWWWW
Some are more for structural support- not Motor, diff dynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is persistence length

A

How long does it take elongated molecule to bundle or bend
Minimum length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is persistence length of microtubule

A

> 1mm
Very big for cells, so very stiff = wont bend
Stiff rods, like plexiglass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is persistence length Of actin

A

~10um = much shorter, not as long or rigid
Like twizzler

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is persistence length Of intermediate filament

A

<1um = very flexible, like rope, bends super easy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What makes up cytoskeleton mainly

A

Actin. And tubulin =main

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe actin - functions/gen features

A

Atpase
Motility, contractility
Ubiquitous- found in all eukaryotes, also bacteria
Highly conserved sequence
Motor proteins - myosin’s,
Abundant —> 20% of all proteins in your muscles = actins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe microtubules - functions/gen features

A

Most found near/under cell membrane
Support, transport, organization - for cell shape, train tracks
Ubiquitous - found in all eukaryotes
Highly conserved sequence
Motor proteins - kinesins and dyenins - provide directionality = move in diff directions
Gtp ase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe intermediate filaments - functions/gen features

A

Structural support
Found in animal cells - many diff varieties
Divergent sequence s
No motor proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does cytoskeleton provide

A

Shape
To neurons, neutrophils, goldfish keratocyte

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does cytokskeleton confer

A

Cells with internal organization and polarity
Ex = micorvilli =formed bc actin filaments underneath
Apical = -
Basal = +
Important for transport
Intermediate filaments link cells together

23
Q

What does cytoskeleton enable

A

Intracellaulr transport
Middle of cell = mtoc - neg end
Dynenin = transport from + to - end
Kinesin = motor molecules transport reverse of dyenin
Purpose = go to edge of cell
Like roads for travel, motor molecules walk on train tracks (microtubule)

24
Describe movement of pigment granules
Melanosomes in melanophores - animals that change colour quickly Dispersed melanosomes - spread out when high camp Low camp = aggregated melanosomes, concentrated near neg end microtubule
25
Describe axonal transport
Specialized form of intracellular transport Anterograde = transprt to axons Retrograde = to get back to cell body Some meow cells transported to synapse then recycled back into cell - need bidirectional transport Fast axonal Transport moves vesicles and organelles along microtubuels at ~100mm/day
26
What does cytoskeleton help cells do
Helps cells move Actin based motility = protrusions, actin molecules inside cell, moves cell across space Microbtule based motility = cilia, sperm move
27
What does cytoskeleton form - microtubules
Dynamic and stable structures = Mitotic spindle - dynamic, have to extend and retract - microtubule half life = short 45s (eb1 end binding protein, binds ends), Axonemes - stable, stay here and do not go away (but stay for lifetime here, many proteins associate with it)
28
What does cytoskeleton form - actin
Dynamics and stable structures Migrating cell - seconds to mins = move Microvili - forms in hours, renew themselves Hair cell stereocilia for life - actin turnover is weeks to years, can slowly regrow
29
T OR F= cytoskeletal filaments are static
nawwwww Dynamic
30
Which end grows faster
+ end At minus end = things happen slower
30
How are cytoskeleton filaments built
Asymmetric subunits that have diff numbers of protofilaments and display polarity Actin and tubulin share common building principles 2 protfilamets for actin 13 for microtubuels tho
31
Describe self assembly and filament dynamics of tubulin and actin
Intrinsic properties Actin = nucleation is slowest part, actin dimer not stable - likes to form filaments, if dimer = finds monomer = trimer, now have nucleus Microtubule has nucleation process but less known
32
Describe actin - treadmilling
Hydrolysis on other end of where ad more monomers Eventually rate atp hydrolysis catches up and monomer dissociates
33
Describe polymerization characteristics of actin and tubulin
S shaped population growth curves Lag phase = slow, bc monomers need to form trimers, nucleation phase Growth phase = fast, almost linear Equilibrium phase= still many dynamics but length stays the same- continually lose and add molecules
33
Are actin and tubulin enzymes
Yurrrrrrr Actin = atpase Beta subunit tubulin = gtpase (only b tubtulin hydrolzyes gtp, to conduct instability of microtubuels)
34
Describe dynamic instability - microtubules
Shoot out and come back
35
What happens when hydrolysis of ntp in filaments
Resuslts in nucleotide caps
36
Describe ntp vs ndp bound
Hydrolysis of ntp in free monomers in solution is slow - hydrolysis in filament is fast Ntp subunits like to assemble but ndp subunits like to disassemble Subunits add in ntp state and dissociate in ndp state (ndp form less stable bc structural differences) Kon(ntp)>>Kon(dnp)=add Kon(ntp)<
37
When does ntp cap form
Rate of addition of subunits> hydrolysis rate Ntp cap helps regulate dynamics not hydrolyzing fast enough
38
When will loss cap and disassemble
Rate of Addition fo subunits < hydrolysis rate Microtubule catastrophe = disassemble
38
Why are actin and tubulin ntpase based filaments
NEED for dynamics Ndp form v unstable, ntp form - come together quickly Ntp hdyrolysis renders filament inherently unstable - what we want for dynamics - treadmilling and dynamic instability ATP vs gtp - bc need to regulate actin vs microtubules diff
39
What controls filament dynamics
Cells Allows cells to sculpt cytoskeleton = where, when, how many filaments, how it grows, complex signalling, nothing random
40
How to control cytoskletal growth and organization
Manipulating the fundamental polymerization properties of subunits Parameters cells can control = controlled by manu other proteins, can modify s shaped growth curve
41
Describe nucleation
If speed up = no lag phase
42
Describe elongation
Elongation - grows faster and makes longer - extends growth phase
43
How are cytoskeletal filaments regulated
Cells use accessory proteins to control every aspect of cytoskeletal dynamics - have to be conserved bc so many proteins associated with it Bundlers and cross linkers, monomer binders (stabilize filaments), severing proteins (cut it up), nucleation factors
44
Is the cytoskeleton highly conserved
Yesssss 88% identical 97% simailr = many conserved differences If differences - swapped for aa with simailr characteristics mostly
45
Describe viruses and cytoskeleton
Microtubule - cell edge to nucleus Virus can hijack dyenin
46
Describe double cortex syndrome
Neurodevelopemtal disorder Smooth brain Point mutations in neuronal microtubule associated protein double cortin - dcx which results in failure in neuronal migration One single aa change = causes disease
47
Describe diseases when reduced microtubule stability
Alzheimer's disease (AD) * tauopathies * Parkinson's disease (PD) * Amyotrophic Lateral
48
Describe diseases when Hyperstable microtubules
Hereditary Spastic Paraplegia (HSP) - stiff lower limb
49
Describe tau and Alzheimer’s
Hallmark of neurodegenrative diseases = loss of neurons Tau = microtubule associated protein Tau tangles = dementia
50
Describe microtubules and cancer
Microtubule misrgeylation can cause anueploidy and cancer Chrom lag behind = end up in wrong place Microtubule drugs being used in chemotherapy - taxol paclitaxel, very hydrophobic = cannot be dissolved easily
51
Describe cytoskeleton as drug target
Epothilion d staibilzies microtubuels Can give ppl small dosages

ANAT 262 (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions