Single-celled eukaryotes, or protists, are a diverse group of unicellular organisms. They include protozoa, algae, slime molds, and yeasts. Protists can be photosynthetic, heterotrophic, or mixotrophic. They live in water and soil and play an important role in ecosystems by decomposing nutrients. Protists move using flagella, cilia, pseudopods, or they may be non-motile. They reproduce asexually through mitosis or sexually through conjugation. Some protists are pathogens that can cause diseases in humans and other organisms.

1. SINGLE
CELLED EUKARYOTES
Presented by-
Hasnahana Chetia
M.Sc BT IInd sem,
G.U.

2. A eukaryote is an organism whose cells
contain complex structures enclosed
within membranes. The defining membrane-
bound structure that sets eukaryotic cells apart
from prokaryotic cells is the nucleus,
or nuclear envelope, within which the genetic
material is carried.

3. The single celled eukaryotes are classified under
the kingdom “PROTISTA”.
It is a being a paraphyletic group.
They are first eukaryotes, having a well organized
nucleus and complex membranous organelles.
Protozoa; some unicellular algae,
phycomycetes; myxomycetes and yeasts come
under this kingdom.
The term protista was first used by Ernst
Haeckel in 1866.
The simplest protist is “Amoeba”.

4.  They are microscopical, unicellular eukaryotes.
 They are unicellular or colonial forms without
distinct division of labor.
 They generally live in water.
 They maybe heterotrophic or autotrophic.
 They may use pseudopodia, flagella or cilia for
locomotion.
 They showed mitosis and meiosis.

6. There are four phyla of Animal-like Protists
classified by how they move-
1.Zooflagellates – flagella.
2.Sarcodines - extensions of cytoplasm
(pseudopodia).
3.Ciliates – cilia.
4.Sporozoans - do not move.

7. They move using one or two flagella
absorb food across membrane, eg-Leishmania
Fig. Leishmania

8. They moves using pseudopodia (false
feet),which are like extensions of the cytoplasm
--ameboid movement.
They ingest food by surrounding and engulfing
food (endocytosis),creating a food vacuole.
They reproduce by binary fission.
contractile vacuole - removes excess water
can cause amebic dysentery in humans -
diarrhea and stomach upset from drinking
contaminated water

9. Fig. Amoeba
Fig.
Foraminiferan
Fig. Heliozoa

10.  Paramecium-
They move using cilia;has
two nuclei: macronucleus,
micronucleus;food is
gathered through food
vacuole;anal pore is used
for removing
waste;contractile
vacuole removes excess
water;reproduces asexually
(binary fission) or sexually
(conjugation);paramecia
are always the same
shape,like a shoe.
Fig. Paramecium

11. They do not move on
their own.
They are parasitic.
Plasmodium
falciparum and
Plasmodium vivax
are sporozoans,
infects the liver and
blood and causes
malaria.
Fig. Plasmodium vivax

12.  They contain chlorophyll and carry out
photosynthesis.
 There are four phyla:
euglenophytes, chrysophytes, diatoms, dinofla
gellates.
 Their accessory pigments help absorb
light, and give them a variety of colors.

13.  Euglena-
They live in water,have 2
flagella for
movement,use
chlorplasts for
photosynthesis, but turn
into heterotrophs if kept
in the dark,
has an eyespot used for
sensing light and dark
pellicle - like a cell
wall, helps maintain
their shapes.
Fig. Euglena

14.  Chrysophytes-
Yellow-green algae,
"golden plants“.
 Diatoms-
produce thin cell
walls of silicon.
 Dinoflagellates-
Often have two
flagella
luminescent.
Fig. Chrysophytes
Fig.Diatoms
Fig. Dinoflagellates

15. Yeasts are eukaryotic, mostly unicellular micro-
organisms.Most
reproduce asexually by budding, although a
few do so by mitosis. They are phylogenetically
diverse and are placed under phyla
Ascomycota and Basidiomycota. Yeasts
are chemorganotrophs. They usually reproduce
by budding or by meiosis and spore formation
(under stress conditions).

16. Fig. Yeast

17. Nutrition in some different types of protists is
variable. In flagellates, for example, filter
feeding may sometimes occur where the
flagella find the prey. Other protists can engulf
bacteria and digest them internally, by
extending their cell membrane around the food
material to form a food vacuole. This is then
taken into the cell via endocytosis usually
phagocytosis; sometimes pinocytosis.

18. Nutritional
type s
Source of
energy
Source of
carbon
Examples
Phototrophs Sunlight Organic
compounds or
carbon fixation
Algae, Dinoflage
llates or Euglena
Organotrophs Organic
compounds
Organic
compounds
Apicomplexa, Tr
ypanosomes or
Amoebae

19. Some protists
reproduce sexually (conjugation), while others
reproduce asexually (binary fission).
Some species, for example Plasmodium
falciparum, have extremely complex life
cycles that involve multiple forms of the
organism, some of which reproduce sexually
and others asexually.

20.  Protists form a broad base across the bottom of the
food chain, and they supply approximately one-half of
the world’s oxygen.
 Protists, along with bacteria and fungi, are responsible
for decomposing and recycling nutrients.
 Euglena are used to help treat sewage because of their
unique ability to switch from an autotrophic to a
heterotrophic nutritional mode, helping to maintain
oxygen levels in the balance.
 Trichonympha which lives in the digestive system of
termites and produces cellulase, an enzyme that enables
termites to digest wood.
 Products derived from protists are used in treatment of
ulcers, high blood pressure and arthritis.

21. Some protists are significant pathogens of
both animals and plants; for
example Plasmodium falciparum and P. vivax,
which causes malaria in humans,
and Phytophthora infestans, which causes potato
blight. Balantidium Coli and Entamoeba
Histolytica causes severe dysentry in animals,
eg-pigs and humans. Mastigophorites that
belong to the genus trypanosoma,causes
African Sleeping Sickness, a disease which
often leads to death.

22.  http://biology.clc.uc.edu/courses/bio106/pro
tista.htm
 http://answers.yahoo.com/question/index?qi
d=20061030191849AA5001g
 http://www.blurtit.com/q658222.html
 http://single%20celled%20euk/Introduction%
20to%20the%20Protists.htm
 http://www.zephyrus.co.uk/index.html
 http://users.rcn.com/jkimball.ma.ultranet/Bio
logyPages/P/Protists.html