Protozoans Flashcards
Protozoans are a large, highly diverse, group of _________ organisms
Unicellular
Basic characteristics of protozoans
- body
- reproduction
- habitat
- organelles
- unicellular organisms that occur as solitary, or colonial
- specialization of organelles has led to complexity in locomotion, nutritional modes, osmoregulation and behaviour
- asexual reproduction by fission and sexual reproduction
- found in moist environments, like soil, freshwater and marine habitats. Many commensal, mutualistic or parasitic
4 groups of protozoans
Ciliated (ciliophora)
Apicomplexans (Sporozoans)
Amoeboid (Sarcodina)
Flagellated (Mastigophora)
Ciliated protozoan characteristics
- locomotion
- nuclei
- reproduction
- lifestyle/ habitat
- cilia for locomotion and/or feeding
- two nuclei: macro and micro
- asexual reproduction by transverse fission and or budding
- sexual reproduction by conjugation
- free-living species in freshwater, marine and moist soil or parasites
In what direction do Paramecium move?
- move against current
- cilia move in opposite direction backing it up a bit before moving forward
Do paramecium have distinct anterior and posterior ends?
- yes, anterior is smaller and rounded
- posterior is cone shaped and larger
Oral groove in paramecium
-depression on one side of the body. Extends from anterior end to middle. Serves to guide food particles into the gut (pharynx)
Types of vacuoles in paramecium
- contractile: osmoregulation
- food vacuole: storage of food/ waste elimination
Does paramecium have 2 nuclei?
Shape of nuclei?
Yes
Macro is kidney shaped and larger than micro nuclei
Paramecium pellicle
-Rigid**, thin and and flexible firm membrane. Are elastic in nature and support cell membrane to help keep shape.
Ciliature pattern of paramecium
Arranged in tufts called ciri. Move against current with a power stroke propelling then and a recovery stroke moving with current that doesn’t move then backward too much.
Function of paramecium Trichocyst
Defence
Why is binary fission considered to be asexual reproduction?
- only one cell involved
- no exchange of genetic material
What is the plane of division during binary fission in paramecium?
Transverse
What happens to the macro nucleus and the micro nucleus during binary fission
Macronucleus divides transversely amitotically (unevenly) by elongated and constricted in the middle
Micronucleus divides by mitosis into 2 daughter micronuclei which move to opposite ends of the cell
Why is conjugation sexual reproduction?
-two different organisms and exchange of genetic material
Which nucleus is involved in conjugation?
Micronucleus
Shape of Vorticella sp. Macronucleus and general body
Horse-shoe shape
Funnel shaped with a stalk or in defence can construct and become more rounded
Where are cilia in Vorticella?
Located at the mouth. Used for filter feeding and use cilia to grab food.
Which specific structures in the stalk of Vorticella sp. allows for “popping” movement in Vorticella
Contractile myonemes/ fibers
Shape of stentor and Macronucleus
Size of stentor
Snake like body and funnel shaped head (trumpet)
Macronucleus is many small, round pieces all in a line (macronuclear nodes)
0.5 mm
Does stentor have anterior and posterior ends?
-anterior is funnel and posterior is the stalk
Is the ciliate capable of changing its general shape through contention and extension in Stentor sp.?
Yes, can contract it’s head to hide mouth or extend body (stalk) to reach food
Apicomplexans characteristics
- organelle arrangement
- life cycle
- have specialized arrangement of organelles called the apical complex at some point during life cycle
- life cycle include sexual stage plus one or more stages of asexual reproduction.
- all are parasitic
How does a humans host become infected with plasmodium
Mosquito transfer sporozoites
Where does asexual reproduction occur in the human host in Plasmodium sp.?
Liver/ blood cells
Which lifecycle stage is infective to the mosquito host in Plasmodium?
Haploid sporozoite
Where does Plasmodium fertilization occur?
In mosquitos gut
Amoeboid protozoan locomotion
-use Pseudopodia for locomotion and/ or food capture
Amoeba Proteus
- general shape and size
- type of Pseudopodia
- does it have a test or is it naked?
- reproduction?
- rounded, shapeless
- lobopodia
- naked amoeba (Gymnamoeba)
- asexual binary fission or multiple fission in harsh environments
How to differentiate food vacuoles and contractile vacuoles in amoebas…
- Contractile vacuoles are larger and transparent
- food vacuoles smaller and in greater number and have particles in them
Why do amoebas have contractile vacuoles?
- maintains water balance (osmoregulation)
- protects cells from absorbing too much water, otherwise amoeba would burst
Chaos (Pelomyxa) carolinesis differences and similarities to Amobea proteus
-larger
More branched out Pseudopodia
-may have 2 nuclei or thousands (multi-nucleated)
- lobopodia
- cytoplasmic streaming
- no specific shape
Entamoeba histolytica, a parasitic amoeba that causes _______ in humans. This amoeba is capable of forming a life cycle stage known as a _____
Amoebic dysentery
Cyst: inactive, nonmotile, infected stage
-cysts are infested and stomach/ duodenum cyst walls are digested away allowing trophozoites to be released.
-protects from acidic environment
Arcella sp.
- shape and size
- test and Pseudopodia
- nuclei
- round, umbrella shaped, microscopic
- test surrounds cell, Pseudopodia at test opening on underside. Test made of calcium carbonate
- 2 nuclei, one on each side
Globigerina so. Is a ____
Planktonic foraminiferan
Globigerina sp.
- test material
- Pseudopodia type
- how do these Pseudopodia differ from lobopodia
- Calcium carbonate
- Reticulopodia
- Thinner, protrude through pores in test, branched extensively to form sense networks
Radiolarians
- composition of test
- type of Pseudopodia
- how do these Pseudopodia differ from lobopodia
- silica
- axopodia
- microtubules supports, thin/spiky and many!!!
Actinosphaerium sp. (a heliozoan)
- can you differentiate endoplasm and ectoplasm
- type of Pseudopodia do heliozoans possess
- yes, ectoplasm surrounds endoplasm
- axopodia
Flagellated protozoa characteristics (mastigophorans)
- locomotion
- feeding style
- one or more flagella for locomotion
- includes autotrophic phytoflagellates, and heterotrophic species
Euglena sp.
- shape
- flagella
- stigma (eyespot)
- pellicle?
- long, blunt/ round head with flagella
- two flagella (one hidden in reservoir)
- red dot at anterior end to detect light
- yes, beneath outer membrane
Movement of Euglena sp.
- quick, fish like movement
- flagella not visible
- very little shape change when moving
Does Euglena belong to phytoflagellates or Zooflagellates?
Phytoflagellates
Has chloroplast
Volvox sp.
- shape
- how do colonies form
- why are these colonies included in protozoa
- round sphere
- reproduce asexually through formation of auto colonies. Special cells divide to form daughter colonies that are smaller versions of the parents but with flagella onwards. Sexual colonies have reproductive cells called gonidia, which produce small daughter colonies that are released when mature. Sexual colonies develop ova+spermatozoa
- they are individual cells that live together
Volvox sp.
- describe movement of colony
- are flagella visible
- are daughter colonies able to move
- why green
- revolves in circles
- flagella not visible in some views
- doesn’t appear so
- choloplasts
Trypanosoma sp. are _____ parasites
Blood
In vertebrates
Trypanosoma sp.
- what and where is kinetoplast
- describe flagella
- phyto or Zooflagellata
- specialized region of mitochondria that harbours most complex and inhaled mitochondrial DNA. Found near basal body (kinetosome)
- one flagellum (part free, part attached)
- Zooflagellates
Trichonympha sp. lives where
Digestive tract of termites
Trichonympha sp.
- shape
- flagella
- why are termites dependent on them?
- bud shaped
- many flagella (over 10000)
- symbiotic relationship with termites, where they digest cellulose or termites die
Ceratium sp. (dinoflagellate)
- flagella
- what type of covering
- red tides
- two flagella (one longer sulcus and one shorter and horizontal girdle)
- encased in sturdy cellulose plates
- red tides are toxic to fish and crustaceans and accumulate in tissues of molluscs resulting in diarrhetic shellfish poisoning (human)
