Transcript The Three Major Parts of the Cell - Belle Vernon Area School District

Opening Questions
• Do you think the organelles that
are found in the cell move around
the cell or stay in one place in the
cell?
• If you think they move…how do
they?
Learning Outcomes
• Tell what molecules make up the
cytoplasm.
• List the important parts of the cell
that are found in the cytoplasm.
• Distinguish between cytoskeleton
proteins and motor proteins.
• Discuss why the cytoplasm is a
major part of every cell.
The Three Major
Parts of the Cell
A.
The
cytoplasm is found
between the plasma
(cell) membrane and the
nucleus
It is MADE UP of
organic substances and
water.
FOUND
IN the
cytoplasm :
all the
ORGANELLES
AND
CYTOSKELETON
1. CYTOSKELETON
The
cytoskeleton
MADE UP OF protein
filaments, motor
proteins, and
microtubules
These
fibers extend from
the nucleus to the
cell(plasma) membrane
Gives shape and allows
the cell and organelles to
move.
Cytoskeleton
1.
Microtubules
2. Protein Filaments
 A. Intermediate
B. Actin
3. MotorProteins
A.
B.
C.
2. Tubules of the
Cytoskeleton
a.
microtubules
b. intermediate filaments
c. actin filaments
B and C are PROTEIN
FILAMENTS
A.
MICROTUBULES
Microtubules
are small
hollow cylinders
composed of 13 chains of
proteins.
Their assembly is
controlled by a structure
called a centrosome.
The
centrosome is a
structure that is found
very near the nucleus.
Microtubules are said to
radiate out from the
centrosome.
This
pattern of
microtubules helps to
maintain a cell’s shape.
It also serves as a track
system (like train tracks)
in which organelles and
materials move throughout
the cell.
A
centriole is a structure
that comes in pairs and is
said to work closely with
the centrosome.
The centrioles in the cell
play a very important role
in cell division (discuss
later in the year)
B. INTERMEDIATE
FILAMENTS
They
are called
intermediate because
they are medium in size.
(between microtubules
and actin filaments)
They are rope like
chains of proteins.
The
intermediate
filaments are found mainly
between the nuclear
envelope (membrane) and
the plasma (cell)
membrane.
The
proteins that make up
these filaments are unique
to the cell they are found
in.
Example
Intermediate fibers made
up of keratin give strength
to skin cells.
C.
ACTIN FILAMENTS
Actin
filaments are long
filaments.
They are the largest of
the three filaments
They are said to be
made up of a globular
protein.
These
proteins tend to
twist around each other in
a helical manner.
The actin filaments form a
complex web just under the
plasma(cell) membrane.
The
web supports the
cell and projections that
may come of the
membrane.
3. Major Motor Proteins of
the Cytoskeleton
•a. myosin
•b. kinesin
•c. dynein
•Help move organelles
around the cell.
•Help move materials
in and out of cell.
•Myosin works hand and hand
with the actin filaments to help
with movement in the cell.
•They are helpful when the cell
engulfs a large molecule.
•(pinocytosis or phagocytosis)
•Myosin hand the actin filaments
also are used by the cell to pinch
the original cell into two new cells
during cell division.
A process known as
cytokinesis.
•Myosin is also used by
muscles cells
•When muscles contract,
myosin pulls actin filaments to
the middle of the cell
• Finally kinesin and dynein are
motor proteins that help move
organelles around the cell…
• They attach to the
organelle..unattach and then
reattach to the organelle further
down a microtubule.
• They also perform the same way
when moving material to and
from the Golgi Apparatus
Wrap It Up
•The cytoplasm is ONE
of the THREE major
parts of the EVERY
cell.
Major Functions of
Cytoplasm/Cytoskeleton
• 1. Helps give cell its shape.
• 2. Moves things for the cell.
• 3. Holds organelles.
• The cytoplasm is ONE of the
THREE major parts of the cell.
• It is made up of organic
molecules (motor
proteins/microtubules) and
water
• Found floating and moving
around it are organelles
• Protein filaments and Motor
Proteins together in the
cytoplasm to give the cell
shape and move organelles
and materials around the cell.
• These are the main reasons
that the cytoplasm is
considered ONE of the
THREE major parts of every
cell.