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Diatoms
Colm Lippig
Diatoms
Diatoms are a
major type of
algae/plankton.
Most are unicellular
although they have
been known to grow
in colonies of
different shapes
and sizes like
spirals. Most
diatoms are motile.
A diatom colony living alongside
other algae
Diatoms
Diatoms grow hydrated
silica “shells” to protect
themselves from harm.
These cell walls often
form in two pieces that
fit together like a box
and a lid. There is a
wide diversity in how
they look. Tiny pores in
the silica allow for gas
exchange
Different types of diatoms
Diatoms
Most of the time,
diatoms reproduce
asexually by mitotic
cell divisions. Each
daughter cell
receives half the
cell wall of the
original diatom and
then regenerates
the other half.
They also
reproduce sexually.
The regeneration of the second piece of the
cell wall causes a unique shrinking effect
Diatoms
Diatoms are capable
of photosynthesis.
They have unique
green-brown
chloroplasts. By
releasing oxygen as a
waste product of
photosynthesis,
diatoms are hugely
important to aqueous
life.
Most diatoms exhibit unique
green-brown chloroplasts
General video on
Diatoms:
A murder
conviction is
based on
diatoms:
http://www.youtube.com
/watch?v=aNM3AfGPHfw
&NR=1
http://www.pbs.org/wn
et/nature/episodes/cri
me-scenecreatures/video-diatomdetective/5208/
Review Questions
1. What type of protists are diatoms?
2. What unique color do the chloroplasts of most
diatoms share?
3. True or false, diatoms can be found in both fresh and
salt water.
4. The asexual division of diatoms leaves each daughter
with how much of the cell wall?
5. The cell walls of diatoms are made of what material?
6. Although diatoms are unicellular, they have been
known to form what?