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Online Counseling Resource
YCMOU ELearning Drive…
School of Architecture, Science and Technology
Yashwantrao Chavan Maharashtra
Open University, Nashik – 422222, India
OC-SBT082-U01-01
Introduction
Programmes and Courses
 SBT082 – CP01- Unit 01
School of Science and Technology, Online Counseling Resource…
Credits

Academic Inputs by

Arun Punaji More.
M.Sc. (Microbiology)

Experience: 11 Years

[email protected]
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
How to Use This Resource

Counselor at each study center should use this presentation to deliver
lecture of 40-60 minutes during Face-To-Face counseling.

Discussion about students difficulties or tutorial with assignments should
follow the lecture for about 40-60 minutes.

Handouts (with 6 slides on each A4 size page) of this presentation should
be provided to each student.

Each student should discuss on the discussion forum all the terms which
could not be understood. This will improve his writing skills and enhance
knowledge level about topics, which shall be immensely useful for end
exam.

Appear several times, for all the Self-Tests, available for this course.

Student can use handouts for last minutes preparation just before end
exam.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Learning Objectives

After studying this module, you should be able to:

Describe what are cytoskeletons

Describe the various types of cytoskeletons present in cells

Describe the various functions of various types of
cytoskeletons
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School of Science and Technology, Online Counseling Resource…
Introduction
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

Our body limbs move because of
contraction and relaxation of skeleton
muscles.
But do you know that cell also possess
some kind of muscles to its various
activities such as transport of cellular
organelles in the cytoplasm, for cell
division, for its own movement?
Yes cells possess the kind of muscles for
its above mentioned activities and they
are called as cytoskeleton.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-1
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Cytoskeleton is network of micro proteins
filaments having dimensions of 7nm to 25
present in the cytoplasm.
it is dynamic structure that continuously
organized.
The functions of cytoskeleton include
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
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i) providing structural support to maintain the
structural integrity of the cell.
ii) carrying out transport of cell organelles in the
cytoplasm
iii) facilitate cell movement
iv) involvement in cell division
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-2
The
cytoskeleton is made of three types of
protein filaments which are

Actin filaments

Intermediate filaments

Microtubules
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-3
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Actin filaments:
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
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The actin filaments are made of with a protein
called as actin.
The actin proteins account for 5 to 10% of the
total proteins in the eukaryotic cells.
The actin proteins can polymerize to form
actin filaments.
The actin protein with association of actin
binding proteins can assembled, disassembled
and form bundles of actin filaments.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-4

Actin filaments:
The actin-binding proteins involved in the
formation of actin filaments or
polymerization of actin monomers are
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

Apr2/3 complex proteins
ADF/cofilin proteins
Profilin proteins
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-5

Polymerization of actin proteins:-
School of Science and Technology, Online Counseling Resource…
Cytoskeleton-5

Branching of actin filaments:-
Arp2/3 and ATP molecules actively cause the branching of the actin
Filament.
School of Science and Technology, Online Counseling Resource…
Cytoskeleton-6

Formation of actin filament bundles and
networks:-
School of Science and Technology, Online Counseling Resource…
Cytoskeleton-5

Actin filaments:
The actin bundling proteins involved in
formation of actin filaments bundles by cross
linking the actin filaments are
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Fimbrin
Alpha actinin
Filamin
Spectrin
Dystrophin
Integrin
Talin
vanculin
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-7

Molecular motors:
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
Molecular motors are the proteins that convert
chemical energy in the form of ATPs into the
mechanical energy.
The molecular motors proteins get associated
with cytoskeleton filaments and bring about
their movement.
The molecular motors proteins are
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

Myosins
Kenesins
Dyneins
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-6
The
actin filaments are abundant beneath
the plasma membrane forming a network of
actin filaments, a cytoskeleton that
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gives mechanical support to the plasma
membrane,
determine cell shape,
allow cell surface movement required for food
uptake, engulfment of particles and
cell migration.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-7

Actin filaments:


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The actin filaments cause muscle contractions.
The actin-myosin contraction in non-muscle
tissues involved in cytokinesis —cell division.
Actin filaments cause cell movements, cell
migration, movements in phagocytosis.
Actin filaments are involved in extensions of
nerve cells during nerve development.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-8

Cytokinesis:The actin filaments are Actively involved in the
Separation of newly formed Daughter cells, a
Process known as Cytokinesis.
School of Science and Technology, Online Counseling Resource…
Cytoskeleton-8
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Intermediate filaments:
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Intermediate filaments are made of with
variety of proteins polymers.
The intermediate filaments have got diameter
of 10 nm.
The intermediate proteins are grouped into six
types.
The specific type of intermediate proteins are
expressed in a type of cells.
For example, the acidic keratin proteins are
expressed in epithelial cell.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-9

Intermediate filaments:
Types of intermediate proteins:
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Acidic keratins
Basic keratins
Vimentins
Desmins
Neurofilament proteins – NF-L, NF-M, NF-H, alpha
internexin
Nuclear lamins
Nestins.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-10

Structure of intermediate filaments:-
Steps in formation of intermediate filament.
School of Science and Technology, Online Counseling Resource…
Cytoskeletons-10

Intermediate filaments:- Functions-
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
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The intermediate filaments are more stable
than actin and microtubules filaments.
The intermediate filaments strengthen the
cytoskeletons of cells in the tissues enabling
the cells to withstand any mechanical stress in
the tissues.
Keratin filaments provide mechanical strength
to epithelial cells in the tissues.
The intermediate filaments are responsible for
the structures of number of tissues such as
skin, intestine, skeleton muscle and heart
which are subjected to mechanical stress.
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School of Science and Technology, Online Counseling Resource…
Cytoskeletons-11

Microtubules filaments:


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These are hollow rigid rods of 25 nm in
diameter made of with single type of globular
protein polymer called as tubulin.
Tubulin is dimer of alpha tubulin and β
tubulin polypeptides.
Like actin filaments the microtubule filaments
are dynamic structures and assemble,
dissemble constantly.
The movements of microtubules is caused by
the associations of motors molecules such as

Kinesin and dyneins
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School of Science and Technology, Online Counseling Resource…
Cytoskeletons-12

Microtubules filaments:

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The main functions of the microtubule
filaments are to maintain the cell shapes and
cause variety of cell movements.
They are involved in intracellular transport of
organelles and separation of chromosomes
during mitosis.
They are responsible for the movements of
cilia and flagella.
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School of Science and Technology, Online Counseling Resource…
Cytoskeleton-13

Separation of chromosomes during ana
phase:-
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What We Learn…




The Definition of cytoskeletons
Chemical characteristics of cytoskeletons
Various types of cytoskeletons
Functions of cytoskeletons
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Critical Thinking Questions

What will be effects of defective actin
filaments in the body?
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School of Science and Technology, Online Counseling Resource…
Hints For Critical Thinking Questions

The actin filaments are involved in
structural stability as well as locomotion of
cellular organelles.
© 2008, YCMOU. All Rights Reserved.
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School of Science and Technology, Online Counseling Resource…
Study Tips

Book
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
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
Title: The Cell, A Molecular Approach
Author: Geoffrey M. Cooper, Robert E. Hausman
Publication: ASM press, Washington,D.C.
Book



Title: Cell and Molecular Biology
Author: E.D.P. De Robertis and E.M.F. De Robertis, Jr.
Publication: Lippincott and Williams & Wilkins
© 2008, YCMOU. All Rights Reserved.
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End of the Presentation
Thank You!