Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecular cell > molecular motors > Flashcards

molecular motors Flashcards

1
Q

larger objects almost do not

A

diffuse in the cell–> due to the cytoplasm being crowded

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

molecular motors ar

A

mechano-enzymes

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

mechano enzymes

A

protein complies that utilise ATP to walk along the cytoskeleton e.g. mechanical motors

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

what do molecular motors do

A

walk along the cytoskeleton (F-actin and microtubules), carrying cargo such as organelles

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

which parts of the cytoskeleton do molecular motors work on

A

F-actin and microtubules

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

examples of molecular motors

A

kinesin, dynen, myosin

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

without ATP

A

motors cannot attach tightly

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

once the motor is attached–> tight binding

A

hydrolysis and a ‘power stroke’ occur and this causes the movement of the motor and also the release of ADP and pi

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

initially motors attach

A

weakly, then ATP binds and tight binding occurs

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

myosin and kinesis go towards..

A

the PLUS end of microtubules or F-actin

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

dynein walks to

A

the MINUS end

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

kinesin

A

dances on the microtubules using several protofilaments

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

dynein

A

stays on the same protofilament and walks in a straight line

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

motor recycling

A

kinesin and dyneon ind tot he same cargo- they can be active in transport or a passive passenger e.g. kinesis can be carried along with a cargo by myosin V molecular moto

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

myosin II

A

muscle myosin

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

Myosin V

A

membrane trafficing

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

how can one prove that motors are mechano enzymes

A

using microscopes and GFP–> fluorescent microtubules ‘slide’ over a layer of glass attached kinesis motors –> motors move latex beads n ceil-free assays

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

myosin motors are used in

A

muscle function

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

40% of your body is

A

muscle

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

20% of the muscle is

A

protein

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

12-15%

A

actin

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

skeletal muscle mainly consists of

A

myosin and F-actin- striated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

the sarcomere is the reason it looks

A

striated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

muscle organisation

A

sarcomere–> muscle fibril –> muscle cell–> muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

why bright and dark parts

A

think and thick filaments only cross over at some points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

thick filaments consists of

A

myosin 2–> with motor protein heads and tail –> motor head will stick out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

z line

A

the two parts that come closer tofether

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

dark band

A

decreases in size during contraction as the filaments cross each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

thin filaments consists of

A

f-actin and associated proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

in a relaxed muscle there will be no interaction between

A

myosin heads and actin filament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

tropomyosin

A

wraps around thin filaments and holds troponin complexes in place

32
Q

how is contraction controlled

A

1) stimulus for neutron spreads over the plasma membrane
2) depolarisation of men. Calcium released from sarcoplasmic reticulum into cytoplasm
3) bind of calcium to troponin releases the block of the myosin binding site on actin
4) myosin now binds actin and walks towards the Z-disk–> contraction
5) calcium is removed by calcium pumps and myosin releases the actin filament and slides back –> relaxation

33
Q

cardiac myocytes

A

form another type of straight muscle

34
Q

cardiac muscle

A

is less order but the structural and mechanistic principles are the same –> spontaneous contraction

35
Q

flagella and most cilia are

A

motile structures

36
Q

cilia

A

-numerus per cell
- function in fluid and particle movement
-back and forth motion
12-230 beats per second

37
Q

flagellum

A
  • few or one per cell
  • cell locomotion
  • propella like motion
  • 10-40 beats per second
38
Q

can be distinguished due to

A

different movement

  • cilia–> back and forth
  • Flagellum–> propel like motion
39
Q

what si the core of cilium/flagellum called

A

axoneme

40
Q

axoneme

A

core of flagellum and cilia made from microtubiles

41
Q

ultrastructure of the standard cilium

A

9 microtubules, with outer and inner arm dynein

  • structure is hollow
  • outer: 3 motor heads
  • inner- 2 motor heads
42
Q

cytoplasmic dynein is different to

A

dynein found in cilium

43
Q

outer of cilium

A

3 motor heads

44
Q

inner of cilium

A

2 motor heads

45
Q

centrioles and flagella

A

form the basal bodies of the flagella

46
Q

basal bodies

A

is a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum).

47
Q

centrioles structure

A

made up of a mother centriole and daughter centriole joined by a flexible linker

48
Q

axonemal dynein is ..

A

variable in its molecular structure: having 3 heads (alpha, beta, gamma) on outer and 2 heads on inner (alpha and beta)

49
Q

flagella dynein

A

connects adjacent microtubules–> sliding movement similar to in the sarcomere

50
Q

flagella dynein and movement

A

B-tubulus slides against A-tubulies and this leads to bending activity against the protein bridges between the tubules

51
Q

most cells form a

A

non-motile primary cilium

52
Q

non-motile primary cilium function

A

Detects signals that govern cell proliferation. senses flow and bending –> triggering various pathways
–> essential for developmental processes

53
Q

motile cilia vs non-motel cilia

A

motile cilia: generating flow and cleaning surfaces- has dynein, nexins, spokes and central microtubule pair

non-motile: sensing environmental cues: chemo, mechano, thermosensation e.g. a stimulus results in mem. depolarisation

54
Q

examples of non-motile cila

A

rods and cones in the eye retina

  • rhodopsin discs are found in the cilium.
  • photoreceptors in the human eye are specialised cilium
55
Q

IFT

A

intraflagellar transport

56
Q

intraflagellar transport

A

supports the formation and function of cilium

  • rafts travel along the axoneme
  • kinesin and dynein drive the bidirectional transport
57
Q

kinesin II in cilia

A

anterograde

58
Q

dynein in cilia

A

retrograde

59
Q

what supports cell migration

A

actin treadmilling

60
Q

examples of cell migration

A

amoeba and human phagocytes

61
Q

f-actin in a fibroblast

A
  • f-actin concentrates at the leading edge of the cell–> f actin grows via tread milling–> appears as waves
  • overtime cell will grow
  • leading edge is at the from of the cell directing the end part of the cell which is called the tail
62
Q

role of cell motility (3)

A

1) protects against pathogens–> neutrophil chases bacterium
2) cell motility helps with healing wounds–> when skin tears cells actively move in to close the wound
3) organ development–> neurones that extend neurites

63
Q

treadmilling

A

as one unit leaves another joins

64
Q

actin organisation in a fibroblast

A

stress fibre nearer the centre of the cell has contractile function. Cell cortex- gel like network. Filopodium- extension from the cell which contain tight parallel bundles

65
Q

these stress fibres in fibroblasts are

A

contractile like muscle–> form fibres of f actin and myosin II (muscle myosin)

66
Q

steps during cell migration

A

1) extension
2) adhesion
3) translocation
4) de-adhesion

67
Q

name a cytoskeleton dependent process

A

intracellular membrane trafficking

68
Q

motors are responsible for

A

intracellular motility–> not just vesicles, but entire organelle e.g. they transport organelles along microtubules

69
Q

cool motor example

A

motors change the colour of the fish skin. the dispersal and conc depends on kinesis, dynein that move along the microtubules
- change in black part of fish is due to a change in mem. trafficking e.g. organelles containing melanin are moved to the centre and then the vesicles get dispersed outwards and make the whole cell look darker

70
Q

what shape the ER and make them mobile

A

motors

  • the ER will also form without pro
  • ER grows paallel on the microtubules- another way to be distributed
71
Q

the ER will also form without proteins so..

A

not just due to molecular motors

72
Q

axonal transport keeps

A

the cell alive and connects the synapses in the cell body–> in neurons

73
Q

why is axonal transport important in neurones

A

have to cope with long distance

  • the synapse must communicate with the cell body in order to keep the neurone alive
  • the distance to overcome may be meters! (Giraffes)
74
Q

axonal transport

A

is a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other cell parts (i.e. organelles) to and from a neuron’s cell body, through the cytoplasm of its axon (the axoplasm).

75
Q

dynein and kinesin in a neurone

A

In axons there is a MINUS end (cell body) and a PLUS end (synapse)

  • ->synapse to cell body is done by dynein proteins (retrograde signaling)
  • ->cell body to synapse is done by kinesin (antergrade)
76
Q

in neutrons growing and shrinking in the axon is suppressed

A

1) microtubule-binding proteins stabilise dendrite

77
Q

If microtubules depolarise (shrinking) the transport stops- leading to

A

the cells death

Molecular cell (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions