Cilia and flagella

1. Cilia and FlagellaCilia and Flagella
Structure and Function in Structure and Function in
EukaryotesEukaryotes
By Justin Robbins and Katrina By Justin Robbins and Katrina
TruebenbachTruebenbach

2. OverviewOverview

Cilia and Flagella are Cilia and Flagella are
organelles that are organelles that are
primarily used for the primarily used for the
transportation of the cell. transportation of the cell.
They propel the cell by They propel the cell by
flicking back and forth.flicking back and forth.

Cilia are short and Cilia are short and
reminiscent of hairs. reminiscent of hairs.
There are many per cell.There are many per cell.

Flagella are longer and Flagella are longer and
there are far fewer per there are far fewer per
cell. They are reminiscent cell. They are reminiscent
of a tail.of a tail.

3. Real-life Examples:Real-life Examples:
EukaryotesEukaryotes

Most common in single-celled organisms Most common in single-celled organisms
(protists). (protists).

However, some multi-cellular organisms have However, some multi-cellular organisms have
cilia and flagella. cilia and flagella.

Human windpipe cells and some lung cells have cilia Human windpipe cells and some lung cells have cilia
to clean the respiratory system of breathing hazards. to clean the respiratory system of breathing hazards.

Fish have cilia to help bring water through the gills. Fish have cilia to help bring water through the gills.

Many types of sperm have flagella to help them move. Many types of sperm have flagella to help them move.

4. Structure: 9+2 PatternStructure: 9+2 Pattern

Cilia or flagella is composed of Cilia or flagella is composed of
microtubules that are encased in a microtubules that are encased in a
plasma membrane. This bundle of plasma membrane. This bundle of
microtubules is called the axoneme.microtubules is called the axoneme.

A plasma membrane is made of lipids A plasma membrane is made of lipids
and proteins and is essentially the same and proteins and is essentially the same
as a normal cell membrane.as a normal cell membrane.

There are 9 pairs of connected There are 9 pairs of connected
microtubules in a circle towards the microtubules in a circle towards the
outside edge of the cilia/flagella. These outside edge of the cilia/flagella. These
are called the outer microtubule are called the outer microtubule
doublets.doublets.

The outer microtubules are connected The outer microtubules are connected
to each other in a ring with cross-links to each other in a ring with cross-links
(not pictured).(not pictured).

The outer microtubules also connect to The outer microtubules also connect to
the center structure with radial spokes.the center structure with radial spokes.

These outer microtubules surround These outer microtubules surround
another pair of central microtubules, another pair of central microtubules,
which are not connected.which are not connected.

5. Structure: Basal BodyStructure: Basal Body

The 9+2 pattern The 9+2 pattern
continues throughout the continues throughout the
entire organelle until the entire organelle until the
base.base.

The base is called the The base is called the
Basal Body. It is the Basal Body. It is the
foundation of the cilia or foundation of the cilia or
flagella and is embedded flagella and is embedded
in the cell membrane.in the cell membrane.

It does not have a pair of It does not have a pair of
central microtubules. central microtubules.
Instead, it has nine Instead, it has nine
triplets of microtubules. triplets of microtubules.

6. How They Work: Dynein ArmsHow They Work: Dynein Arms

Each of the outer microtubule pairs Each of the outer microtubule pairs
have a set of dynein, a functional have a set of dynein, a functional
protein, arms.protein, arms.

These arms change shape and These arms change shape and
subsequently create a sliding force, subsequently create a sliding force,
therefore moving the tubule pairs.therefore moving the tubule pairs.

Since the pairs are held together Since the pairs are held together
with cross-links and are anchored in with cross-links and are anchored in
the cell membrane, the the cell membrane, the
microtubules bend as a result of this microtubules bend as a result of this
force. force.

If they were not held together, the If they were not held together, the
force exerted would cause the two force exerted would cause the two
doublets to slip past each other.doublets to slip past each other.

This bending motion makes the cilia This bending motion makes the cilia
or flagella to flick back and forth, or flagella to flick back and forth,
therefore propelling the cell therefore propelling the cell
forwards.forwards.

7. How They Work: ATPHow They Work: ATP

The change of shape The change of shape
of the dynein arms is of the dynein arms is
powered by ATP.powered by ATP.

ATP, or Adenine-Tri-ATP, or Adenine-Tri-
Phosphate, is Phosphate, is
molecule that most molecule that most
cells use as their cells use as their
main energy source.main energy source.

8. Differences in Motion:Differences in Motion:
single-celled organisms single-celled organisms

Cilia movement is well timed with each Cilia movement is well timed with each
other and propel the organism in a wave-other and propel the organism in a wave-
like motion. like motion.

Flagella in eukaryotes give the organism Flagella in eukaryotes give the organism
smoother movement.smoother movement.

Flagella in prokaryotes rotate, like a motor.Flagella in prokaryotes rotate, like a motor.

9. Primary CiliaPrimary Cilia

Primary Cilium are an alternate type of cilia. Primary Cilium are an alternate type of cilia.
They do not aid in motion and are therefore They do not aid in motion and are therefore
referred to as immotile cilia.referred to as immotile cilia.

Primary cilia do not have central microtubules. Primary cilia do not have central microtubules.
They have a 9+0 structure.They have a 9+0 structure.

They have sensory functions.They have sensory functions.

Examples: monitoring flow in the kidneys and Examples: monitoring flow in the kidneys and
detecting smells.detecting smells.

Defects in kidney primary cilia can lead to Defects in kidney primary cilia can lead to
kidney disease.kidney disease.

10. SourcesSources

Campbell, Mitchell, and Reece. "Cilia and Flagella Move When Microtubules Bend." Campbell, Mitchell, and Reece. "Cilia and Flagella Move When Microtubules Bend."
Biology: Concepts and ConnectionsBiology: Concepts and Connections. 3rd ed. Reading, Massachusetts: . 3rd ed. Reading, Massachusetts:
Benjamin/Cummings, 2000. 65. Print. Benjamin/Cummings, 2000. 65. Print.

Campbell, Mitchell, and Reece. "Glossary." Campbell, Mitchell, and Reece. "Glossary." Biology: Concepts and ConnectionsBiology: Concepts and Connections. 3rd . 3rd
ed. Reading, Massachusetts: Benjamin/Cummings, 2000. G-18. Print. ed. Reading, Massachusetts: Benjamin/Cummings, 2000. G-18. Print.

Cilia and FlagellaCilia and Flagella. Photograph. University of Illinois. Web. 21 Nov. 2010. . Photograph. University of Illinois. Web. 21 Nov. 2010.
<http://www.uic.edu/classes/bios/bios100/lectf03am/cilia_flagella.jpg>. <http://www.uic.edu/classes/bios/bios100/lectf03am/cilia_flagella.jpg>.

Davidson, Michael W. "Cilia and Flagella." Davidson, Michael W. "Cilia and Flagella." Molecular ExpressionsMolecular Expressions. Florida State . Florida State
University, 13 Dec. 2004. Web. 21 Nov. 2010. University, 13 Dec. 2004. Web. 21 Nov. 2010.
<http://micro.magnet.fsu.edu/cells/ciliaandflagella/ciliaandflagella.html>. <http://micro.magnet.fsu.edu/cells/ciliaandflagella/ciliaandflagella.html>.

Diagrams of Cilia and Flagella. Digital image. Diagrams of Cilia and Flagella. Digital image. Both Brains and BeautyBoth Brains and Beauty. Web. . Web.
<http://www.bothbrainsandbeauty.com/academic-discussions/cilia-vs-flagella-<http://www.bothbrainsandbeauty.com/academic-discussions/cilia-vs-flagella-461>. 461>.

Diagrams of Dynein Arms. Digital image. University of Illinois. Web. 21 Nov. 2010. Diagrams of Dynein Arms. Digital image. University of Illinois. Web. 21 Nov. 2010.
<http://www.uic.edu/classes/bios/bios100/lectures/07_35_flagellas_bend-<http://www.uic.edu/classes/bios/bios100/lectures/07_35_flagellas_bend-
L.jpg>. L.jpg>.

Kimball, John W. "Cilia and Flagella." Kimball, John W. "Cilia and Flagella." Kimball's Biology PagesKimball's Biology Pages. 28 July 2007. Web. 21 . 28 July 2007. Web. 21
Jan. 2010. Jan. 2010.
<http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Cilia.html>. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Cilia.html>.