Transcript Ch 18 - protists

Ch 18: Protists
Protists
unicellular
eukaryotic
Prokaryotes vs
Eukaryotes
Classification
115,000
species
Major debate
regarding how
they should be
classified
“animal-like” =
zooplankton or
protozoans
“plant-like” =
phytoplankton

Endosymbiotic Theory
It is believed that protists evolved from a symbiotic
relationship between different types prokaryotic cells
Chloroplasts resemble cyanobacteria
Mitochondria resemble aerobic bacteria
endosym.theory tutorial animation
endosymbiosis generated mitochondria
and chloroplasts
Anaerobic-lacking oxygen; referring to an organism, environment
or cellular process that lacks oxygen and may be poisoned by it
Aerobic heterotrophic prokaryote -Proteobacteria
Photosynthetic prokaryoteCyanobacteria
(Some cells)
Chloroplast
Aerobic cells
use oxygen to release energy
from organic molecules by
cellular respiration
Mitochondrion
Photosynthetic eukaryotic cell
endomembrane
system evolved
from inward
folds of the
plasma
membrane of a
prokaryotic cell
DNA
Plasma membrane
Cytoplasm
Ancestral
prokaryote
Endoplasmic
reticulum
Nuclear
envelope
Nucleus
Cell with nucleus and
endomembrane
system
Animal-like
Protists
4 phyla:
Ciliophora (ciliates)
- Paramecium
Zoomastigina
(zooflagellates)
Sporozoa – Parasitic Plasmodium
Sarcodina - ameoba
Phyla #1. Ciliophora –
Ciliates
Covered in cilia
used for locomotion
and for directing
food into the oral
cavity
Most are free-living
(not parasites)
Ex: Paramecium
Structure
1. Pellicle – cell
membrane and
underlay (looks
quilt-like) controls
entry and exit from
the cell
Embedded in the
pellicle are the:
2. Trichocysts – spiny
projectiles used for
protection
3. Macronucleus –
controls cell’s
activities
4. Micronucleus –
used in conjugation
to mix the genetic
information
5. Gullet (mouth). Cilia move food particles to
the end of the gullet where they enter the cell
by endocytosis. This traps the food particles
into FOOD VACUOLES.
The food vacuoles will fuse with LYSOSOMES
(sacks of digestive enzymes) and be digested.
ENDOCYTOSIS
6. Anal
pore: Waste
particles
leave the
cell by
exocytosis
at the ANAL
PORE
Exocytosis
7. Contractile Vacuoles
Paramecium live in
FRESH water
Osmosis causes
water to move into
the paramecium
The contractile
vacuole collects the
extra water so that
the paramecium
doesn’t lyse
Osmosis Review
Reproduction
Like bacteria, paramecium reproduce
mainly by BINARY FISSION
Paramecium Sex
Again, like bacteria, paramecium will occasionally
engage in conjugation – usually when they are
stressed.
Conjugation is not actually “reproduction” – it is a
trading and mixing of genetic material but no new
paramecium are formed. However, new combinations
of genes are created in both partners
Phyla #2: Zoomastigina
Called the
zooflagellates since
they all move
around using
FLAGELLA
Many are parasitic
Trichomonas causes
intestinal and
veneral diseases in
humans
Giardia –
causes
“beaver fever”
Phyla #3: Sporozoa
All produce spores
All are parasites
All non-motile
Ex: Plasmodium
(causes malaria)

Sporozoa
Plasmodium Life Cycle
1. Spores
transferred to
humans through
mosquito saliva
2. Spores grow in
liver and blood cells,
causing them to
lyse, releasing
toxins (creates
fever, chills)
3. Mosquitoes pick
up Plasmodium in
the blood when it
bites the human
4. Mosquitoes
become infected
with Plasmodium –
eventually, spores
form in the salivary
glands and the
parasite is passed
on to a new human
How to Avoid
Malaria
1. Don’t go where there
are malaria outbreaks
2. In areas where there
is malaria, don’t get bit
by mosquitoes
3. Chloroquinine will
destroy some
Plasmodium spores
4. Most often, countries
with malaria try to control
the mosquito host rather
than the Plasmodium
(insecticides and
breeding ground
removal)
Phyla #4: Sarcodina
Use PSEUDOPODS to feed and move around
Ameoba