PROTIST
Protist Characteristics :
- Eukaryotic organisms
- Either unicellular or multicellular
Protists Are Grouped Into :
- Animal – like Protist
- Plant – like Protist
- Fungus – like Protist
ANIMAL LIKE – PROTIST
- They are more usually called Protozoa
- Their characteristics are :
1. Unicellular and heterotrophic : they prey on bacteria, other protists and organic waste
2. Microscopic in size, around 10 to 200 microns
3. Their cell shape is variable : some are fixed while others are changeable
(berubah-ubah)
4. Protozoan have motion appendage, such as pseudopodia (fake foot), cilia (soft
hair), or flagella (whip – hair)
5. Protozoa are composed of a cell membrane, cytoplasm, food vacuole, contractile, vacuole, and nucleus
-Membrane acts as a protective barrier and regulates food and gas exchange
-The function of food vacuole is digesting food
-The contractive vacuole is a pump that excretes liquid food remains out of the
cell by controlling water content
-The nucleus function is to control the cell metabolic activity
- Protozoans are solitary or form colonies
- Habitat :
– Live freely in oceans or fresh water, ponds or rivers
– Live inside the soil, live symbiotically inside the bodies of animals or humans
- Reproduction :
– Asexually by binary fission
– Sexually by the union of vegetative nuclear is called conjugation
- Classification :
Animal – like protists are classified into 4 groups, based on their method of motility :
1. Rhizopoda (Sarcodina), which move with pseudopodia (fake foot)
2. Ciliata , which move with cilia
3. Flagellata , which move with flagella
4. Sporozoa , which have no motility tool
RHIZOPODA ( SARCODINA)
- This pseudopod allows the rhizopod to move and be able to prey
upon other organisms
- Cytoplasm : Ectoplasm and Endoplasm
Ectoplasm is the outer-most part of the cytoplasm that is bordered by the cell membrane, while endoplasm is the inner part.
Ectoplasm has low viscosity compared to endoplasm.
- During feeding, a pseudopod surround they prey and forms a food vacuole. They prey is then digested inside this vacuole. Digestion products enter the cytoplasm by diffusion and by-products will be excreted through the cell membrane
- Reproduce asexually by binary fission
- In unfavorable condition, rhizopod can adapt by forming cysts and grow again when the environment is back to optimum condition
- Mostly free-living in damp soil, seawater or freshwater
- Heterotrophic rhizopods prey on unicellular algae, bacteria or other protozoa.
- Example of Rhizopods :
a. Amoeba proteus lives freely in soil
b. Difflugia lives in freshwater regions
c. Foraminifera and Gobligerina lives in seawater
(kerangka tubuh tersusun dari zat kapur)
d. Entamoeba hystolytica that cause dysentery diseases
e. Entamoeba gingivalis that cause gumtooth problems
f. Radiolaria and Spaerostylus
CILIATA
- Cilia found on the surface of the cell or just on particular parts
- Besides movement, cilia also help to collect food
- They have 2 nucleuses, a macronucleus and a micronucleus
The macronucleus has a vegetative function : growth and cell division
The micronucleus has a reproductive function in conjugation
- Ciliates have trichocysts to defense against enemies or predators
- Ciliates live freely in marine and freshwater, live symbiotically or parasitically inside other organisms.
- Ciliates reproduce :
– Asexually by transversal binary fission
– Sexually by conjugation
- Examples of ciliates :
a. Paramecium caudatum
b. Didinium : as predator of paramecium
c. Stentor form of the body is like trumpet
d. Vorticella form of the body is like bell
e. Stylonichia form of the body is oval
f. Balantidium coli, lives in cattle or human colons and causes
diarrhea (Balantidiosis)
FLAGELLATA
- Move by means of a flagellum or whip-tail
- Most flagellates have two flagella
The location of the flagellum can be posterior (behind) or anterior (front)
- Flagellates reproduce asexually by transversal binary fission as in Tryponosoma
- They live freely in marine and freshwater and symbiotically or parasitically inside the bodies of animals
- Cell membrane is called a pellicle
- Examples of Flagellata (Mastigophora) :
a. Trichonympha companula : live inside the intestines of termites
(rayap) and wood cockroaches (kecoa kayu). It helps to digest wooden.
b. Trypanosoma brucei, the causes of human sleeping sickness in Africa
Trypanosoma brucei-gambiense is carried by the tsetse fly Glossina morsitans
Trypanosoma brucei-rhodesiense is carried by the tsetse fly Glossina palpalis
Trypanosoma brucei destroys the central nervous system and bood veins
c. Trypanosoma evansi, the causes of animal surra disease
d. Trichomonas vaginalis, the cause of human genital tract disease
e. Leishmania donovani, the cause of kala-Azar disease that destroys human blood cells
f. Trypanosoma cruzi, the cause of chagas disease, the hospes is child
SPOROZOA
- Sporozoa doesn’t have a motility structure
- All species of sporozoa are parasitic in humans or animals
- Sporozoa reproduces :
– Asexually by binary fission
– Sexually by fertilization of male and female gametes
- They live parasitically inside the bodies of animals and humans
- Examples of Protozoa :
a. Toxoplasma gondii that causes toxoplasmosis
T. gondii enters human body through contaminated food such as meat infected with toxoplasma cysts that comes from cat feces
b. Plasmodium that causes malaria disease
Plasmodium enters human bodies by the bite of the female Anopheles mosquito. Inside the body, plasmodium attacks liver cells and red blood cells (erythrocytes)
- There are 4 species of Plasmodium :
1. Plasmodium falciparum causes malaria tropika / tropikana
Phase sporulation : 1 X 24 hours
2. Plasmodium vivax and Plasmodium ovale causes malaria tertiana
Phase sporulation : 2 X 24 hours
3. Plasmodium malariae causes malaria kuartana
Phase sporulation : 3 X 24 hours
- Efforts to eradicate malaria have focused on :
1. The elimination of the mosquito vectors
with the way of preventing water pools for forming or closing
water containers
2. The development of drugs to poison the parasites once they
have entered the human body
For example : Quinine tablets
3. The development of vaccines
- Roles of Protozoa in human life :
Protozoa can be both beneficial and detrimental to human
- Benefit of Protozoa :
– Protozoa important roles in controlling the population
of bacteria in the wild
– In aquatic regions, protozoa as zooplankton and benthos
are food sources for aquatic animals which are
economically important to humans
– Foraminifera, their shells and skeletons can be guides
to find oil, natural gas, and mineral resources
– Radiolaria, exoskeleton made of silica (zat kersik) and
can be used as polisher material (bahan penggosok)
– Entamoeba coli, help to decompose food waste
- Detriment of Protozoa :
– Entamoeba histolytica, the cause of dysentery
– Trypanosoma brucei, the cause of African sleeping
sickness
– Trypanosoma evansi, the cause of cattle surra disease
It is carried by Tabanus fly
– Leishmania donovani, the cause of kala-Azar disease
It is carried by Pholobotomus mosquito
– Trichomonas vaginalis, a human genital tract parasite
– Balantidium coli, the cause of diarrhea
– Toxoplasma gondii, the cause of toxoplasmosis
– Plasmodium, the cause of malaria
PLANT LIKE – PROTIST
- Plant – like protists are all algae
- Body characteristics :
ü Algae are range in size, from the invisible (microscopic) to the visible (macroscopic).
ü There are unicellular and multicellular.
ü Unicellular algae can live alone or in colonies.
Some species of unicellular algae have flagellum for motion.
Usually there are 2 to 4 flagella at the tip of the cell.
Solitary unicellular algae there are round, oval, or pear-shaped.
The colony is shaped like a disc in Gonium, a ball in volvox or
net in Hydrodictyon.
- Multicellular algae have the form of thread and sheet-like.
Oedogonium and Spirogyra have filament-shaped bodies, while Laminaria, Ulva and Macrocystis have a sheet form.
- The sheet-like algae have simple forms and thereby do not develop true leaves, stems, or roots.
Structure like that are called thallus.
Hence algae are classified as Thallophyta.
- All algae are eukaryotic.
- Algae has chloroplasts. A chloroplast is an organelle that contains pigment responsible for photosynthesis.
There are different forms of chloroplasts in algae :
- Spherical in Chroococcum
- Bowl-shaped in Chlorella and Chlamydomonas
- Belt-shaped in Ulothrix
- Disk-shaped in Vaucheria and Chara
- Net-like shaped in Oedogonium
- Spiral shaped in Spirogyra
- The pigments in chloroplast capture energy from sunlight to be used in photosynthesis.
- The main pigment of photosynthesis is chlorophyll (green pigment)
- Some kinds of pigment that are had algae include :
v Chlorophyll : a, b, c, d.
Chlorophyll a (hijau kebiruan)
Chlorophyll b (hijau kekuningan)
Chlorophyll c (hijau kecoklatan)
Chlorophyll d (hijau kemerahan)
v Carotene : Xanthophylls (golden pigment)
Fucoxanthin (brownish pigment)
v Phycobilin : Phycocyanin (bluish pigment)
Phycoerythrin (reddish pigment)
- Algae have a structure within their chloroplast which is called a pyrenoid. It function is as the algal food storage container.
- The types of stored food, include :
v Amylum and oil (green algae)
v Leucosin and oil (golden algae)
v Laminarin (brown algae)
v Florid starch (red algae)
- Life cycle and Habitat :
- Phototrophic organisms
Algae are capable of photosynthesis which means making their own food from inorganic materials using energy from the sun.
- Algae live freely in aquatic or damp habitat.
- In their habitats, algae act as producers that provide food and oxygen for heterotrophic organisms.
- Reproduction :
- Algae reproduce asexually and sexually.
- Asexual reproduction :
a. Binary fission
Occurs only in unicellular algae. A mother cell devides into two to form two identical daughter cells.
Example : Euglena and Chlorella
b. Fragmentation
Occurs in multicellular filamentous and thallus algae. Broken filament or
thallus can grow into new individual organism.
Example : Spirogyra, Laminaria, and Sargassum
c. Spore formation
Occurs in unicellular or multicellular algae.
Spores are formed by division of mother cell’s wall. Spores will be released after
cell wall breaks and grow into haploid new algae.
Example : Chlamydomonas and Ulothrix
- The thallus type undergo metagenesis
- Metagenesis occurs between a spore-forming generation (vegetative /sporophyte) and a gamet-forming generation (generative /gametophyte). Example : Ulva and Chlamydomonas
- Sexual reproduction :
ü In unicellular and filamentous algae
Sexual reproduction occurs by the union of two different types of gametes and results of a zygote.
The zygote forms thick-walled zygospore. The zygospore devides into 4 flagellated haploid daughter cells called zoospores, which are released when the zygospore’s wall ruptures and grow into haploid algae called vegetative cells.
ü In thallus algae
Sexual reproduction occurs by the union of two different types of gametes and results of a zygote.
Gametes are produced by gametangium. Gametangium is produced by the gametophyte (generative algae).
Gametangium that produces egg cells (ovum) are called Oogonium.
Gametangium that produces spermatozoids are called Antheridium .
The zygote grows into new diploid organism called a sporophyte.
- Algae sexually reproduction is divided into :
- Isogamy, which is the union of 2 different gamete types with the same shape and size.
- Anisogamy, which is the union of 2 different gemete types with the same shape but different size.
- Oogamy, which is the union of 2 gametes with different shape and size.
- Algae Classification
Some biologists classify algae based on their dominant pigment, components of cell wall, number and position of flagella and the type of stored food.
These criteria separate algae into 6 groups, include :
-
-
- Euglenoid (Euglenophyta)
- Chrysophyta
- Pyrrophyta
- Chlorophyta
- Phaeophyta
- Rhodophyta
-
l EUGLENOID ( EUGLENOPHYTA )
ü Euglenoids have disc-shaped eye spot that contains photoreceptors covered by a layer of red pigment.
The presence of this red pigment layer results in the ability of euglenoid to detect and move toward light.
ü Euglenoid is a unicellular organism that lacks a cell wall.
ü The cell is covered by an elastic protein called pellicle.
ü Euglenoid have been identified as photosynthetic organisms.
However, there are heterotrophic Euglenoid as well.
ü Photosynthetic euglenoids have chloroplasts that contain chlorophyll a, band carotene.
ü The photosynthetic product is stored as a backup in the form of paramylon ( a type of starch)
ü Generally, it has 2 flagella, one is long and the other one is short.
The long flagellum is used for movement.
ü Live in freshwater such as ponds or lakes.
ü Reproduction is done asexually by binary fission.
Example : Euglena
- CHRYSOPHYTA ( GOLDEN ALGAE )
- Golden algae have some pigments :
Xantophyll (a dominant pigment), chlorophyll a and c, fucoxanthin
- Body shape :
– Solitary unicellular algae = Ochromonas
– Colony and lacking flagella
– Multicellular = Vaucheria
- The cell wall contains hemicellulose, silica and pectin.
- Food in golden algae is stored as fats and carbohydrates.
- Diatoms, such as Navicula, have shell-like cell wall composed of the base-valve (hypotheca) and the lid-valve (epitheca).
- Live in freshwater and in the sea.
- Reproduction :
– Asexually by binary fission or spore formation.
– Sexually by uniting 2 types of gametes.
- Examples of chrysophyta are Navicula, Synura, and Mischococcus
- FIRE ALGAE ( PYRROPHYTA / DINOFLAGELLATA)
ü Some species living in the sea appear fluorescent at night.
ü Some other species are blooming at certain times of the year (seasonal) and cause the appearance of red tides along the seashore.
ü Some species of fire algae can cause a toxic red tide that kills fish and sea animals.
ü People who consumed the toxic seafood may experience brain damage.
ü Fire algae have different kinds of colors : yellowish-green, green, blue, brown or red.
ü Generally have pigments are chlorophyll a and c, xantophyll, dinoxanthin, and phycobilin.
ü Mostly unicellular, photosynthetic organisms.
ü Cell wall consist of cellulos.
ü They usually have 2 flagella positioned laterally at the side or apical (at the tip) of the cell.
ü Live in the sea as the major sea phytoplankton
ü They reproduce asexually by binary fission.
– Gymnodinium breve that produces brevetoxin (nerve toxin)
– Gambierdiscus toxicus that produces ciguatoxin
– Gonyaulax that produces saxitoxin
– Noctiluca scintillans that produces fluorescent substance
- GREEN ALGAE ( CHLOROPHYTA )
- Green algae have pigment : chlorophyll a and b, carotene.
Dominant pigment : chlorophyll a and b.
- Unicellular and multicellular
- Some unicellular green algae have flagella
- Cell wall composed of cellulose
- Store food as amylum
- Live in freshwater such as ponds, puddles, or other damp places.
Live in seawater, example : ulva
- Reproduction :
Asexually by binary fission, spore formation, and fregmentation.
Sexually by isogamy, anisogamy, and oogamy.
- Examples : Chlorella, Chroococcum, Chlamidomonas, Volvox, Gonium, Hydrodictyom, Ulothrix, Spirogyra, Oedogonium, Ulva, Halimeda, and Acetabularia.
- BROWN ALGAE ( PHAEOPHYTA )
ü Brown algae have pigment carotene, i.e. fucoxanthin.
The other pigments are chlorophyll a and c, and xantophyll.
ü Most of the members are filamentous or thallus multicellular algae.
ü Cell wall contain pectin or algin.
ü Food is stored as laminarin (a form of glucose or fat).
ü Live in seawater, shore and tidal region.
ü Reproduction :
Asexually by fragmentation and zoospores.
Sexually by isogamy, anisogamy, and oogamy.
ü Brown algae experience alteration of gametophyte and sporophyte generation or metagenesis.
ü Examples : Sargassum, Laminaria, Turbinaria, Facus Vesiculosus Macrocystis, Nereocystis, Harmosira.
ü Macrocystis and Nereosystis are giant algae that can reach length of 50 meters.
- RED ALGAE ( RHODOPHYTA )
ü Red algae have pigments : phycoerithrin, chlorophyll a and d, carotene, and phycocyanin.
Dominant pigment : phycobilin i.e. phycoerithrin.
ü Most of them are filamentous or sheet-shape multicellular.
ü The cell wall contains cellulose and pectin.
ü Food is stored as floridean starch.
ü Live in deep sea.
ü Reproduction :
Asexually by forming spores.
Sexually by oogamy.
ü Red algae undergo alteration of gametophyte and sporophyte generations (metagenesis)
ü Examples :
Eucheuma spinosum, Gelidium robustum, Chondrus crsipus, Gigartina mammilosa, Gracillaria verrucosa, Polysiphonia Sp.
- Importance of Algae for human :
- Chlorella as source of highly nutritious food supplement.
- Ulva, Caulerpa, and Enteromorpha as vegetables.
- Eucheuma and Gelidium to produce gelatin for the food industry (making pudding)
- Golden algae, i.e. remains of Diatom shell that can be used to explosive mixtures, construction cement, scrubber, isalator material, and colander / sieve production.
- Laminaria laveniea as high potassium agricultural fertilizer.
- Laminaria digitalis as a source of iodine (good for treating goiter).
- Macrocystis and Laminaria as alginate acid producer used as a thickening agent in food industries such as ice cream, adhesive in plastic industry, cosmetics and textile production.
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