Cytoskeleton
Burnside, Glenn, Vanscoy, White, Conrad
Actin Filaments
Actin Filaments
Main Function: to help the contraction of cells
Found in: eukaryotic cells only
If Actin filaments were not present: myosin molecules would be scattered
throughout the cell, and the cell would very disorganized and mishaped.
Analogy:the actin filament is like an old mp3 player. It has a specific
function and is limited. The intermediate filament is like an iPod. It has its
specific function and is more dynamic .
This analogy works because:
Actin filaments
•
Thin, flexible fibers that occur in bundles or mesh like networks
•
Each actin filament contains 2 chains of globular actin
monomers twisted around each other
Intermediate filaments
•
A rope like assembly of fibrous polypeptides
•
Give great mechanical strength to skin cells
•
Several types of these filaments
How Actin filaments work together with other organelles
Networks of Actin filaments are found beneath the cell cortex which is the
meshwork of membrane-associated proteins that support and strengthen the
plasma membrane
INTERMEDIATE FILAMENTS
The intermediate filaments are
generally strong and rope like and
they play an important role as the
structural and functional elements of
cytoskeleton. They function as
tension bearing elements to maintain
cell shape and to anchor other
organelles.
Intermediate filaments
are found in eukaryotes
(plant and animal cells)
and fungi
Diseases
Desminopathy: A disease that begins with muscle
weakness in the lower body and moves upwards.
Malfunctions in keratin also cause many skin diseases
Is similar to
1. The intermediate filaments help create
the structure of a cell. The base of the
boat creates its structure so that it can
function properly.
2. The intermediate filaments anchor
down other organelles, like how the
anchor of a boat anchors down the boat in
the water.
3. These things work together as the
intermediate filaments functions. Just like
how a boat and an anchor work together.
CENTRIOLES
CENTRIOLES
Centrioles organize mitotic apparatus which
consists of asters and spindle fibers which
help in division of chromosomes.
Found in only animal cells.
Centrioles are like
spindles or nails.
1. like a nail in old times was
used to hold information the
centrioles acts as an organizing
center
2. Has a rod shape like a spindle
3. keeps cells be more efficient
DISEASES
Centrioles are barrel-shaped
structures that are essential for
the formation of centrosomes,
cilia, and flagella.
Deregulation of centrosome
numbers has been connected to
genome instability and tumor
formation, also mutations in
centrosomal proteins have
recently been genetically linked
to microcephaly and dwarfism.
Centrioles is an area in the cell where
microtubles are produced. The two
centrosomes move to opposite ends of
the nucleus, and from each centrosome,
microtubules grow into a "spindle"
which is responsible for separating
replicated chromosomes into the two
daughter cells.
Microtubules
organelles function
- responsible for various kinds of movement in
cells
- main structural component of cytoskeleton
- provide structure and rigidity, determine shape
- directionally transport vesicles and proteins
within cytoplasm through transport proteins
Microtubules
type of cell found in
ALL eukaryotic cells
Microtubules
diseases caused if the organelle malfunctions
1. Parkinson's
2. Alzheimer's
Microtubules
how the organelle works with other cells
the flagella and cilia are composed of
microtubules
Microtubules
analogy
a microtubule
is similar to
railroad tracks
Microtubules
analogy explained
1. microtubules provide structure to the cell, just
like the railroad tracks provide structure to the
train
2. microtubules directionally transport vesicles and
proteins, just like how the tracks provide the
train with direction and allows the train to travel
and transport materials
3. microtubules transport proteins called kinesins
and dyneins, which act just like the railroad cars
FLAGELLA AND CILIA
Cilia and Flagella
• Formed from specialized groupings of
microtubules called basal bodies.
• Have a core composed of microtubules
connected to the plasma membrane
Function:
• If there are several along the surface of the
cell, they are called cilia, in only one or very few,
then they are called flagella.
• Cilia and flagella move liquid past the surface
of the cell
• In single celled organisms, such as sperm, then
it is used to swim
Type of Cell it is Found in:
• Found in most prokaryotic and eukaryotic cells
– Eukaryotes tend to have cilia while prokaryotes
such as bacteria have flagella
Diseases in Organelle malfunctions
• ulcer-causing Helicobacter pylori, which uses multiple flagella to
propel itself through the mucus lining to reach the stomach
epithelium.
• General effects of malfunctioning flagella and cilia:
– Developmental defects that cause internal organs to be misplaced or
malformed
– A disease that results in numerous cysts developing in the kidneys
which damage the kidneys
– Degeneration of the retina and loss of sight in diseases like retinitis
pigmentosa
– Bardet-Biedl syndrome, a relatively rare disorder associated with a
variety of health problems including retinal degeneration, obesity,
kidney malformations, polydactyly, and learning disabilities
– Defects in brain development (hydrocephalus)
– Male infertility due to immotile or poorly motile sperm, Reduced
female fertility due to immotile oviductal cilia
Analogy:
Flagella are like the wings of a hummingbird.
1) They aid in the mobility of the cell
2) They propagate bends down their length like the muscles in
a bird’s wings
3) They move so fast that they cannot be seen by the human
eye.
Cilia are like the legs of a water spider.
1) There are multiple.
2) While in water, they are used to propel and move around.
3) They control the water flow around the main body.
How organelle works with other
organelles:
• This organelle works with the cell membrane
by transporting the cell. By transporting, the
flagella or cilia can help the cell get away from
harmful toxins or to get closer to a food
source. Cilia also help the cell propel water
around the cell membrane to help aid in
diffusion.