LECTURE 19 - MIDTERM 3
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141 Terms
In this lecture, what is a protist?
A eukaryote that is not an animal, plant, or fungus.
Are protists a single, well-resolved clade?
No; the overall eukaryote tree is still a work in progress.
Which named group on the eukaryote tree includes animals and fungi?
Unikonta.
Which eukaryote clade includes land plants, green algae, and red algae?
Archaeplastida.
What three major protist groups are shown within Excavata?
Diplomonads, parabasalids, and euglenozoans.
Which protist group contains dinoflagellates, apicomplexans, and ciliates?
Alveolates.
Which clade includes forams, cercozoans, and radiolarians?
Rhizarians.
Which clade contains diatoms, golden algae, and brown algae?
Stramenopiles.
What TWO processes make the base of the tree of life especially complex?
Endosymbiosis and horizontal gene transfer.
Why can different regions of the genome produce different evolutionary trees?
They have different histories due to gene transfer and endosymbiosis.
Are all protists unicellular?
No; many are, but some are multicellular.
Why can a single-celled protist be highly complex?
One cell must carry out all essential biological functions.
Where do unicellular organisms carry out specialized processes?
Within subcellular organelles.
How is biological work often divided in multicellular organisms?
Among specialized tissues.
What are algae, according to the lecture?
A polyphyletic group of photosynthetic protists.
Why are algae described as polyphyletic?
Photosynthetic protists occur in several distinct lineages.
Name the FIVE algal examples listed on the slide.
Diatoms, brown algae, dinoflagellates, red algae, green algae.
What is phytoplankton?
Planktonic algae (photosynthetic plankton).
What is SECONDARY endosymbiosis?
A heterotrophic eukaryote engulfs an autotrophic eukaryote.
What distinguishes primary from secondary endosymbiosis?
Primary engulfs a prokaryote; secondary engulfs a eukaryotic alga.
Which algae were engulfed in the dinoflagellate example?
Red algae.
Which algae were engulfed in the Euglena example?
Green algae.
Name TWO protist groups used to illustrate secondary endosymbiosis.
Dinoflagellates and Euglena.
In the secondary-endosymbiosis diagram, which group inherits a red-algal plastid?
Dinoflagellates (also stramenopiles in the diagram).
In the secondary-endosymbiosis diagram, which group inherits a green-algal plastid?
Euglenids (also chlorarachniophytes in the diagram).
What material makes up dinoflagellate cell walls?
Cellulose.
Are dinoflagellates unicellular or multicellular?
Unicellular.
Where is a dinoflagellate flagellum positioned?
In a groove.
What distinctive movement do dinoflagellates make?
They spin as they move.
Are many dinoflagellates photosynthetic?
Yes; many are photosynthetic phytoplankton.
What evolutionary process explains the plastids of many dinoflagellates?
Secondary endosymbiosis.
Identify a protist: cellulose wall, grooved flagellum, spinning motion.
Dinoflagellate.
Which protists commonly cause red tides?
Dinoflagellates.
What is a red tide in the lecture?
A dinoflagellate algal bloom.
What hazard can accompany a red tide?
Toxins (a toxic algal bloom).
Which TWO algae groups were named as stramenopiles?
Diatoms and brown algae.
What flagellar feature characterizes stramenopiles in some life stages?
Two different kinds of flagella.
What are the two types of stramenopile flagella shown in the diagram?
One hairy and one hairless.
What material forms the glass-like diatom cell wall?
Silica.
Are diatoms usually unicellular or multicellular?
Unicellular.
What nutritional mode do diatoms have?
Photosynthetic.
What plankton category includes diatoms?
Phytoplankton.
Why are diatoms ecologically important in oceans?
They are abundant and absorb CO₂.
What algal group is closely related to brown algae?
Diatoms.
What trait supports the diatom–brown algae relationship?
Similar flagella.
Are brown algae often large and multicellular?
Yes.
What is the lecture’s example of large brown algae?
Kelp.
What habitat structure can kelp form?
Kelp forests.
Where are many brown algae attached?
To the seafloor/bottom.
In kelp anatomy, what anchors it to the bottom?
The holdfast.
In kelp anatomy, what is the stalk-like part called?
The stipe.
In kelp anatomy, what is the broad leaf-like part called?
The blade.
What gives red algae their red or reddish-brown color?
Additional pigments.
Can red algae be unicellular as well as multicellular?
Yes.
Compared with green/brown algae, where may red algae grow?
Much deeper in the sea.
Which algal group is more closely related to red algae: green or brown?
Green algae.
What food-related example of red algae is on the slide?
Seaweed wrappers used for sushi.
What gives green algae their bright green appearance?
Bright green chloroplasts.
Are green algae exclusively multicellular?
No; they can be unicellular or multicellular.
Which major organism group is closely related to green algae?
Land plants.
What TWO main green-algae groups does the slide name?
Chlorophytes and charophytes.
What is the scientific name of the pictured sea lettuce?
Ulva.
What algal group includes sea lettuce (Ulva) and Volvox?
Chlorophytes.
Which group is labeled as a land-plant relative on the green-algae slide?
Charophytes.
What is a mixotroph?
An organism capable of both autotrophy and heterotrophy.
Which protist is the example of a mixotroph in Lecture 19?
Euglena.
What can Euglena turn on or off?
Its photosynthetic processes.
In what type of habitat is Euglena common, according to the slide?
Freshwater.
Which main eukaryote group contains Euglena?
Euglenozoans.
Which TWO genera were given as examples of parasitic protists?
Trypanosoma and Plasmodium.
Which protist genus causes African sleeping sickness?
Trypanosoma.
Which other protist is Trypanosoma related to?
Euglena.
What eukaryotic clade includes Trypanosoma and Euglena?
Euglenozoans.
Which TWO human systems does Trypanosoma infect?
Bloodstream and nervous system.
What physiological cycle does Trypanosoma disrupt?
The sleep cycle.
What insect transmits Trypanosoma?
Tsetse fly.
Where is the Trypanosoma tsetse-fly example located?
Africa.
What is the vector of malaria?
Mosquitoes.
What human cells does Plasmodium invade?
Red blood cells (RBCs).
What happens to infected RBCs in malaria?
They undergo lysis (burst).
Name THREE malaria symptoms listed on the slide.
Fever, sweating, and chills.
What was the lecture’s historical impact statement about malaria?
It has killed millions of people.
Which organism is the site of fertilization in the Plasmodium life cycle?
The mosquito.
Where does Plasmodium undergo meiosis?
In the mosquito.
Where are Plasmodium gametes produced?
In the mosquito.
Are most Plasmodium life-cycle stages haploid or diploid?
Haploid (n).
What Plasmodium stage is injected into humans by a mosquito?
Sporozoites (n).
Which human organ does Plasmodium infect FIRST?
The liver.
Which human cells does Plasmodium infect AFTER the liver?
Red blood cells.
What is the name of the stage that invades RBCs?
Merozoites (n).
What Plasmodium cells does a mosquito ingest from human blood?
Gametocytes (n).
What do gametocytes develop into in the mosquito?
Gametes.
What ploidy is the Plasmodium zygote?
Diploid (2n).
What developmental process restores haploid stages after fertilization?
Meiosis.
Order Plasmodium infection in humans after a mosquito bite.
Sporozoites → liver → merozoites → red blood cells.
Which stage is labeled as n in the mosquito immediately after meiosis?
Sporozoites.
What monophyletic eukaryotic group includes animals, fungi, and amoebozoans?
Unikonta.
What TWO types of organisms are included among amoebozoans?
Slime molds and amoebae.
What eukaryotic subgroup is linked with slime molds?
Amoebozoans.
Which Unikonta subgroup includes fungi and animals in the tree?
Opisthokonts.