Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biochemistry and Cell biology > Week 3 > Flashcards

Week 3 Flashcards

1
Q

what determines cell shape/form

A

physical stress on walls, will change rigid/flexible

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

functional purpose of a cytoskeleton

A

provides framework for cell form and function

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

how to increase intermediate filament stability?

A
  • increasing number of filaments associated and sorting into stable conformations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

properties of intermediate filaments?
- length
- polarity
- remodeler of IMFs?
- mechanism of IMF growth?

A
  • 10 nm
  • apolar
  • remodeled by phosphorylation
  • growth via lateral exchange
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

briefly describe the role of cytoskeleton of muscle cells

A

supports large shape changes

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

role of cytoskeleton in epithelia?

A
  • aid in polarization, barrier formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

role of cytoskeleton in neurons

A
  • drives polarity, shape changes
  • Microtubule system uses cytoskeleton to transport nts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what proteins mediate dynamic polarity of cells?

A

actin, tubulin

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

what is the difference (in terms of function) between basal and apical membrane of epithelial cells?

A

Apical– allow Na driven symport of glucose into the cell
Basal– allow diffusion of glucose out of cell into extracell fluid

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

purpose of polarity in cells (ex. in the event of to different concentrations on either side of cell)?

A

to ensure that cell function is directionally defined

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

what protein constitutes the brush border of epithelial cells?

A

actin filaments

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

purpose of capping actin filament ends?

A
  • confer stability– preventing dynamic remodeling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

in cochlear hair cells, what proteins constitute stereocilia
- describe stereocilia response mechanism to sound

A
  • actin bundles, which tilt in response to sound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what motor protein is responsible for the mediating thin, thick actin filament movement in a sarcomere

A

myosin motor protein

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

describe the polarized actin distribution in filopodia (leading edge of a crawling cell)

A
  • tight parallel bundle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the role of actin in the fate of opsonized bacteria

A
  • actin is crucial in assembling/isolating and degrading opsonized bacteria during phagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what 3 location make up junctional complex

A
  • tight junction
  • adhesion belt
  • desmosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what junction/complex mediates adhesion of the cell to cell matrix proteins and is associated with intracellular actin?

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

describe adheren (cell-cell) junction in terms of:
- transm linker protein
- ligand
- intracell cytoskeletal attachment

A
  • cadherin
  • cadherin in neighboring cell
  • actin filaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe Desmosome junctions in terms of:
- transm linker protein
- ligand
- intracell cytoskeletal attachment

A
  • desmoglein/collins, cadherins
  • cadherin in neighbor cell
  • intermediate filaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe (cell-matrix) junction in terms of:
- transm linker protein
- ligand
- intracell cytoskeletal attachment

A
  • integrin
  • extracell matrix proteins
  • actin filaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe hemidesmosome junctions in terms of:
- transm linker protein
- ligand
- intracell cytoskeletal attachment

A
  • integrin (a6b4)
  • extracell. matrix
  • intermediate filaments
23
Q

what do adhesion molecules (cadherins) and signaling molecules (RAS) have in common (in terms of disease causing)?

A

they are both oncogenic

24
Q

purpose of targeting microtubule therapeutically?
i.e. what are MTs important for
- effect of medication on mt?

A

mts are important in cell division
- medication tries to confer mt stability

25
describe Taxol and its therapeutic target/effect?
- obtained from pacific yew, -- used in breast, lung cancer treatment (paclitaxel) - encourages mt bundle formation
26
genetic mutation in what cytoskeletal genes can lead to deafness, blindness?
- mutations in myosin, kinesin-type motors
27
describe the characteristics of intermediate filament (IMF) assembly - energy requirement for polymerization - types of structures formed - head/tail domain
- robust proteins (require denaturants to dissolve) - IMF polymerization is energy free - assembly into apolar higher oligomers - head essential/tail contributes to filament assembly
28
describe the structure formation of alpha helical rod domain of IMFs
- assembles first into Parallel dimers, then antiparallel tetramers
29
describe the formation of coiled-coil in IMF protein dimers
- coiled coil formation occurs due to heptad repeats in alpha helices
30
where on IMFs does subunit exchange occur
- subunit exchange occurs along the entire filament
31
describe the order in which an IMF protofilament is formed
parallel dimer assembly--antiparallel tetramer assembly--- tetramers assemble to form a protofilament
32
distinguish between type 1/2 keratin IF proteins (most abundant type of IF)
1- acidic, isoelectric-- lower molecular weight 2- neutral/basic-- higher molecular weight
33
which type 1/2 basal cell keratins are, when mutated, implicated in skin blistering (epidermolysis bullosa simplex)?
- K5 (typeII) - K14 (Type I)
34
what property allows for keratin IFs to be dynamic
- soluble keratins that can be incorporated into filaments
35
what facilitates nuclear assembly/disassembly during mitosis?
phosphorylation of key proteins
35
characteristics of Lamin IFs? - location - bonus: difference between A, B type and what they form?
- found in all nuclei - only found intranuclear - A type-- all nuclei, B type-- differentiated cells -- form framework for nuclei lamina
36
briefly describe cross linking system that links lamin IF (nuclear interior) with cytoplasmic components. - what other filaments involved - what proteins involved
- IF network linked to cytoskeleton via plakins plakins connect cytoskeletal filaments (actin, mt, IFs) to each other/junctional complexes - plakins to nuclear interior via KASH--SUN domain proteins--> which bind to nuclear lamina in nucleus
37
describe role of lamin in nuclear pore formation
- lamin, lamin associated proteins (LAPs) anchor nuclear pore complex to nuclear membrane
38
what IF surrounds sarcomere in skeletal muscle (hint: part of vimentin like filament family)?
Desmin
39
role of profilin in actin assembly - control of elongation? - where does it complex associate - effect on critical concentration
binds G-actin/ATP, associating it to barbed end - prevents spontaneous elongation - lowers critical concentration
40
Role of capping protein in actin filament polymerization
- stops elongation at barbed ends
41
what is a unique property of ubiquitous protein profilin
has nucleotide exchange factor capabilities helps to maintain ATP pool
42
role of thymosin beta 4 in actin filament assembly (beta4 most common isoform in mammals)
- sequesters G actin, thereby preventing polymerization - ensures there is an actin pool ready once barbed end becomes uncapped
43
difference in dynamic regulation of actin and tubulin networks?
Actin assembly involves ATP, tubulin requires GTP
44
describe the role of ARP2/3 complex in actin filament assembly - where does it associate
- associates at minus end and conducts elongation of branch filaments
45
result of upregulation of actin isoform beta-actin on cell movement
- increases cell movement
46
location of gamma, alpha actin?
- gamma--- cell periphery - alpha--- stress fibers
47
role of spectrin in actin filaments?
- provides scaffold at plasma membrane/cortex
48
effect of Rho hormone on actin configuration?
- causes stress fiber formation/focal adhesions (internal of cell is streaked)
49
effect of Cdc42 on actin configuration
filopodium formation (thin,spiky projections)
50
effect of RAC on actin configuration
- lamellipodium formation (flat, spread out)
51
consequences of Rho activation (Rho-GTP) - on formin/crosslinking - myosin activity? - cofilin - stress fiber formation - focal adhesions/integrins
- increased crosslinking, myosin activity - stress fiber formation - inhibition of cofilin - increased focal adhesion formation, integrin clustering
52
result of RAC activation (Rac-GTP) - effect on myosin activity, ARP, Filamin, PIP2
- decreased myosin activity - increased filamin crosslinking - increased branching - promotes PIP2 inhibition of capping protein--- allows branching in lamellipodium

Biochemistry and Cell biology (6 decks)

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