Chapter 6: Protist

Naegleria

A change in the sense of smell or taste. Fever. Sudden, severe headache. Stiff neck. Sensitivity to light. Nausea and vomiting. Confusion. Loss of balance.

Describe the length and width of a trypanosome compared to a red bloodcell.

A trypanosome is thinner, about one-half the thickness of a red blood cell, but four to five times longer.

What is phagocytosis? What function does it serve?

A type of endocytosis in which large particles are engulfed by cells. In amoebas, phagocytosis is the method used to obtain food.

Why would excess water tend to accumulate in amoebas?

Amoebas live in a hypotonic environment (fresh water lakes and streams) and have constant diffusion of water into their cell down the osmotic gradient that exists between them and their environment.

Gymnodinium

Causes red tides.

What evolutionary benefit does conjugation provide that fission does not?

Conjugation creates new genetic diversity among populations of Paramecium that diversifies the population and could provide some members of that population with increased survivability in environments that are rapidly changing.

Why is conjugation considered a form of sexual reproduction?

Conjugation is considered a form of sexual reproduction because genetic material is transferred between two independent organisms resulting in genetically distinct daughter organisms.

Excavata

Contain excavated feeding groove. Includes Giardia, Trichomonas, and Euglena.

Chromalveolata

Contain plastids (double membrane organelles); auto, hetero, or mixotrophic. Includes Plasmodium, Paramecium, and dinoflagellates.

Micronucleus

Contains genetic material and functions in both binary fission and conjugation.

Macronucleus

Contains many copies of a few genes and primarily controls metabolic functions of the cell.

Do the cilia surrounding the peristome of Vorticella beat in random fashion or in coordinated waves?

Coordinated waves.

Giardia

Diarrhea, nausea, vomiting

Do dinoflagellates push or pull themselves through the water with their flagella? How does this compare to euglenoid movement?

Dinoflagellates push themselves along with their flagella where as euglenoids pull themselves along with theirs.

In what ways might Euglena be considered plant-like? In what ways is it animal-like?

Euglena is considered plant-like because it possesses chloroplasts and has the ability to produce its own energy photosynthetically. Euglena is considered animal-like because it stores its food as lipids, rather than as starch, and can resort to heterotrophic means of energy acquisition if sunlight is unavailable.

Acanthamoeba

Eye pain Eye redness Blurred vision Sensitivity to light Sensation of something in the eye Excessive tearing

Describe the process of feeding in Paramecium

Food particles are first swept into the oral groove by current secreted by ciliary action. Food particles are moved toward the end of the cytopharynx where pieces of the inner cell membrane surround the food particles and break off to create food vacuoles. These food vacuoles contain powerful digestive enzymes that break down the food particles into usable nutrients for the cell.

Trichomonas

Foul-smelling vaginal discharge, genital itching, and painful urination in women. Men typically have no symptoms.

Cilia

Hairlike projections used for locomotion and feeding.

Definitive Host

Harbors the sexual stages of the parasite. (e.g. Anopheles mosquitoin Malaria)

How might such an eyespot be advantageous for an autotrophic organism?

It equips the organism with a mechanism to monitor brightness as it moves through its environment, which enhances its ability to photosynthesize.

How are kinetoplastids similar to euglenoids?

Kinetoplastids and euglenoids are both unicellular, motile organisms that possess a single flagellum, flexible cell membranes, and may reproduce asexually through binary fission.

What ecological problems do they occasionally cause?

Large population blooms of dinoflagellates often poison fish and make shellfish in these areas inedible for humans.

Plasmodium

Malaria

Intermediate Host

May be involved where parasites reproduce asexually. (e.g. humansin Malaria)

Amoebozoa

Move and feed via moving cytoplasm and false feet. Pseudopodia: Temporary cell extensions for feeding and moving. Some have a test.

Do apicomplexans (such as Plasmodium) possess organelles for locomotion?

No

Does every red bloodcell contain a parasite? Estimate the percentage of red bloodcells that are infected.

No, percentages vary from slide to slide.

Do amoebas have a rigid cell wall? How can you tell?

No, they have a flexible plasma membrane that permits them to constantly alter their shape.

Do amoebas have a "permanent" anterior end like many other motile protists? Explain.

No, they may move forward with any portion of their "body" serving as the leading edge because the formation of pseudopodia can occur at any place on the cell and take the amoeba in any direction.

Rhizaria

Pseudopodia different than Amoebas. Foraminifera are common marine Rhizarians that posses thin pseudopodia.

Contractile Vacuole

Pumps water out of the cell to maintain an internal osmotic balance.

What color is thephotoreceptive eyespot of Euglena?

Reddish

Trypanosoma

Sleeping Sickness

Food Vacuole

Small organelle containing enzymes to digest ingested food.

Oral Groove

Sweeps food into the organism by ciliary action.

Observe the amoeba and you may be lucky enough to catch it in the act of feeding! If so, describe the feeding process as it unfolds.

The amoeba uses it pseudopodia to engulf its food and pinch off a portion of its plasma membrane to enclose the food within a food vacuole inside the organism. Over time, digestive enzymes will gradually break down the food into usable organic compounds.

Do the cilia of Paramecium beat in unison or in small groups?

The cilia beat in coordinated waves (small groups).

In which direction does the primary flagellum move the organism?

The flagellum pulls the animal forward, toward the flagellum.

Is the plane of division during fission along the longitudinal or the transverse axis?

The plane of division during fission is along the transverse axis.

Relative to other unicellular protists, how would you characterize the size of amoebas?

They are larger than most unicellular protists.

What ecological importance do dinoflagellates have?

They are one of the most important primary photosynthetic producers of organic matter in the oceans.

Which type of flagellum, whiplash or tinsel, does Euglena possess?

Tinsel

Are trypanosomes larger or smaller than Euglena?

Trypanosomes are much smaller than Euglena.

Do trypanosomes possess chloroplasts? How do they obtain nutrients?

Trypanosomes do not possess chloroplasts. Instead, they absorb raw nutrients from their host organism's bloodstream.

Toxoplasma

Tsetse Fly It can cause serious complications for pregnant women and people with weakened immune systems. Symptoms include muscle pain, fever, and headache, all of which can last for weeks.

Can you detect different stages of infection on the same slide? If so, how many?

Usually, yes. The number of stages varies from slide to slide.

While viewing a specimen that is fully extended through the microscope, have your lab partner tap once or twice gently on the cover slip with a dissecting needle and describe the organism's response.

Vorticella will contract rapidly by coiling its contractile stalk.

Which type of flagellum, whiplash or tinsel, do dinoflagellates possess?

Whiplash flagellum