Brainscape's Knowledge GenomeTM

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


See full index

Cell Biology > Cytoskeleton Filaments > Flashcards

Cytoskeleton Filaments Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Name the 3 major filaments in cytoskeleton

A

Intermediate filaments
Microtubules
Actin filaments

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

What are the major functions of the cytoskeletal filaments

A

Facilitate cell movement and also maintain shape

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

Where are intermediate filaments located

A

Cytoplasm and nucleus

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

What are cells/intermediate filaments linked by

A

Desmosomes (proteins)

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

What are intermediate filaments called when in nucleus and what is their job in nucleus

A

Nuclear lamins

Form mesh along inner membrane to act as anchors for chromosomes and pores

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

Explain the structure of IF from monomer to tetramer

A

A- helical monomer which forms a coiled dimer when 2 helixes

Then the tetramer means 4 A helical strand (2 coiled dimers)

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

What is assembly and disassembly of IF regulated by

A

Phosphorylation (ATP)

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

What are the subunits called which make up the nuclear lamins

A

Lmna Lmnb LmnC

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

What happens to IF in cell division

A

Phosphorylated to segregate the nucleus

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

The protein domains of IF differ between each area /cell of body

Eg keratin, neueofilaments, nucleus

What does this allow

A

Determination of source of tumours

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

Where are microtubules found and what’s their role

A

Cytoplasm (grow from centromere)

Function is division of chromosomes
Shuttling of vesicles in cytosol
Facilitate cilia movement

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

What are the monomers of microtubules called and how are they built up

A

Tubulin monomers

Built and dissembled by GTP

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

Why are microtubules found in ciliated cells extending from basal body?

A

They facilitate cilia movement

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

Explain the full structure of microtubules

A

Made of tubulin heterodimers which include both Beta and Alpha

Tubulins form protofilaments

There are 13 protofilaments giving the tube like structure

They have a plus end (beta) and a negative (alpha)

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

What does it mean that microtubules have polarity

A

The plus end is Beta groups

The minus end is alpha - this is where they break down

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

What are the 2 motor proteins found attached to microtubules to carry cargo?

A

Dynein

Kinesin

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

What do kinesin and Dynein motor proteins use to move across microtubules

A

Atp hydrolysis (when atp is bound to their globular heads)

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

Which end does dynein and kinesin move cargo to

A

Dynein = minus

Kinesin = plus end

19
Q

What does the cargo carried depend on for dynein and kinesin

A

Their tail shape

20
Q

How are cilia arranged (in terms of microtubules and dynein)

A 
9 doublets (a,b microtubules) 
2 singlets joined by nexins

Moved by dynein arms

21
Q

What if nexins didn’t join singlets

A

Dynein would cause sliding in the tubules and wouldn’t be able to bend

22
Q

What is actins job

A

Cell contraction and preventing too much stretch
Cell movement
Keep microvilli upright

23
Q

Explain actin filaments structure

A

2 stranded helix which is coiled

37nm

24
Q

What do actin filaments use to build/disassemble

A

ATP hydrolysis (phosphorylation)

25
Q

Why is actin found in microvilli

A

Keeps the microvilli upright

26
Q

When actin is in high concentrations in cytoplasm what do they form

A

Cross linked bundles

27
Q

Actin is polar because it has a - end and a + end. Why does the + end grow rapidly

A

Due to Globular actin monomers

28
Q

There are 6 actin binding proteins. Name them

A 
Myosin motor proteins 
Bundling proteins 
Severing proteins 
Cross linking proteins 
Side binding proteins
29
Q

What do severing proteins do to actin filaments

A

They fragment them to form a fluid state

30
Q

What do bundling proteins do

A

Hold actin filaments in a gel mesh network in the cortex for example for microvilli support

31
Q

What do myosin motor proteins do

A

Form contractile bundles with actin

32
Q

Actin filaments cause cells to move across surfaces. First step is protrusion explain it

A

Actin polymerisation at the + end pushes the membrane of the cell forward

Forms protrusion (new actin cortex)

33
Q

Explain the next step after protrusion of cellular movement

A

New Anchorage points form at the new actin cortex (protrusion) which allows movement across the cell

Contraction of myosin motor proteins at the end of the cell pushes it forward

34
Q

What are myosins and what is their job

A

Motor proteins which move vesicles or membrane via their tails

Globular heads which use ATP hydrolysis to move are attached to actin filaments

35
Q

Which type of myosin moves membranes and vesicles?

A

Myosin I

36
Q

What does myosin II do

A

It slides actin filaments past one another using the globular heads in muscle contraction

37
Q

Spectrin is another cytoskeleton protein in inner membrane of cells. Explain the structure and function

A

Tetramer of spectrin is bound to actin molecules in a pentagon structure

This allows stability and cell shape to be maintained

38
Q

What 2 reasons are there actin associated proteins

A

For regulation / polymerisation

For movement - eg
Motor myosins

39
Q

Name the 4 types of intermediate filaments and where found

A

Nuclear lamins

Keratins filaments (eg in skin,nails)

Vimentin- muscle

Neurofilaments- in neurones

39
Q

What is keratins IF job

A

Found in cytoplasm of cells stuck to desmosomes and prevent excess stretching and rupturing of cells

39
Q

What is IF job in neurofilaments (neurones)

A

Determine axon diameter and provide neurone strength

40
Q

What is IF job in vimentin (muscle)

A

Lines the sarcomere and prevents muscle fibre misalignment

41
Q

What is an example of where bundling proteins bundle actin together

A

Microvilli support

42
Q

Where is cross linking protein action found in actin

A

In spectrin network in RBCS

Cell Biology (21 decks)

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