BSC-116-001 Chapter 28

Radiolarians

Have delicate, intricately symmetrical internal skeletons that are generally made of silica.

Tubulinids

Have lobe- or tube- shaped pseudopodia; unicellular protists; ubiquitous in soil, freshwater, and marine environments; most are heterotrophs.

Alveolates (SAR Clade)

Have membrane-enclosed sacs (alveoli) just under the plasma membrane.

Diplomonads

Have reduced mitochondria called mitosomes; many diplomonads are parasites. (E.g., Giardia intestinalis)

Green Algae

Have structure and pigment composition much like the chloroplasts of land plants. Includes two main groups: charophytes and chlorophytes.

Amoebozoans

Includes many species of amoebas that have lobe- or tube- shaped pseudopodia. Include slime molds, tubulinids, and entamoebas.

Stramenopiles (SAR Clade)

Includes some of the most photosynthetic organisms on the planet. Most have two flagella, a long hairy one, paired with a shorter smooth one.

Archaeplastida

Is a monophyletic group that descended from ancient the ancient protist that engulfed a cyanobacterium.

Rhizarians (SAR Clade)

Many species in this group are amoebas, protists that move and feed by means of pseudopodia, extensions that may bulge from almost anywhere on the cell surface.

Ciliates

Named after their use of cilia to move and feed. Most are predators, typically of bacteria or small protists. (E.g., Paramecium)

Forams

Named for their porous shells, called tests. Form tests consist of of a single piece of organic material hardened with calcium carbonate.

Apicomplexans

Nearly all are parasites of animals. (e.g., Plasmodium, the parasite that causes malaria).

Entamoebas

Parasites that infect all classes of vertebrate and some invertebrates.

Secondary endosymbiosis

Red algae and green algae were ingested in the food vacuoles of heterotrophic eukaryotes and became endosymbionts themselves.

Alternation of Generations

The alternation of multicellular haploid and diploid forms.

Brown Algae

The largest and most complex algae. All are multicellular, and most are marine. Structure (think of palm tree): -Blade (palm fronds) -Stipe (tree trunk) -Holdfast (roots)

Euglenozoans

The main morphological feature that distinguishes them is the presence of a rod with either a spiral or crystalline structure inside each of their flagella.

Diatoms

Unicellular algae that have a unique glass-like wall made of silicon dioxide embedded in an organic matrix.

Excavata

A clade that was originally proposed based on morphological studies of the cytoskeleton.

Endosymbiosis

A relationship between two species in which one organism lives inside the cell or cells of another organism (the host).

The members of _____ are characterized by cells with small membrane-bounded cavities under their cell membranes. A. Alveolata B. Mycetozoa C. Stramenopila D. Rhodophyta E. Chlorophyta

A. Alveolata Dinoflagellates, apicomplexans and ciliates are classified in Alveolata, a group characterized by cells with small membrane-bounded cavities under their cell membranes.

Which of the following statements supports the hypothesis of an endosymbiotic origin of mitochondria? A. Each mitochondrion has its own DNA molecule. B. Diplomonads have modified mitochondria called mitosomes. C. Some algae contain plastids surrounded by four membranes.

A. Each mitochondrion has its own DNA molecule. The fact that mitochondria have their own DNA provides strong support for the hypothesis of an endosymbiotic origin of mitochondria.

Which of the following statements about Ulva's haploid stage is true? A. Haploid cells are produced by meiosis of diploid cells. B. Gametes of the same mating type fuse to produce a diploid zygote. C. The haploid Ulva cells are genetically identical to their diploid parents. D. Haploid cells produce gametes by meiosis.

A. Haploid cells are produced by meiosis of diploid cells. This statement is true; the diploid sporophyte produces haploid spores through meiosis.

Many types of foraminiferans form a symbiotic relationship with _____. A. algae B. bacteria C. seaweed D. fungi E. amoebas

A. algae Forams derive nourishment from photosynthetic algae living within their shells.

Plasmodium, the parasitic organism that causes malaria, is a _____. A. apicomplexan B. entamoeba C. ciliate D. diatom E. plasmodial slime molds

A. apicomplexan Plasmodium, is an apicomplexan.

Stramenopiles include all of the following groups EXCEPT ______. A. cellular slime molds B. golden algae C. brown algae D. water molds E. diatoms

A. cellular slime molds Cellular slime molds are amoebozoans

Golden algae, brown algae, red algae, chlorophytes, and charophyceans are some examples of protists that are _____. A. photosynthetic B. decomposers C. chemoautotrophic D. photoheterotrophic E. chemoheterotrophic

A. photosynthetic All of the listed groups are photosynthetic.

Parabasalids

Also have reduced mitochondria called hydrogenosomes. (E.g., Trichomonas vaginalis)

Cercozoans

Are a large group of amoeboid and flagellated protists that feed using threadlike pseudopodia. Common inhabitants of marine, freshwater, and soil ecosystems. Most are heterotrophs. Many are parasites of plants, animals, or other protists.

Red Algae

Are reddish because of the photosynthetic pigment phycoerythrin. Most abundant in warm coastal waters. Their pigment allows them to absorb blue and green light which in turn allows them to survive at great depths.

Dinoflagellates

Are reinforced by cellulose plates. Two flagella located in grooves in this armor "armor" make dinoflagellates spin as they move through water. Cause the "red tide" phenomenon.

To infer evolutionary relationships based on homologies, we rely on shared ancestral characters, NOT shared derived characters A. True B. False

B. False

True or false? Organisms that exhibit alternation of generations reproduce sexually in the diploid stage. A. True B. False

B. False Organisms that exhibit alternation of generations reproduce asexually in the diploid stage by producing haploid cells that form spores, which then germinate into haploid adults. The haploid adults produce haploid gametes that can then participate in sexual reproduction.

Which term describes the multicellular haploid form of a protist that shows alternation of generations? A. Spore B. Gametophyte C. Zygote D. Sporophyte

B. Gametophyte A gametophyte is the multicellular haploid form of a protist that shows alternation of generations.

What advantage do organisms that reproduce sexually have over organisms that reproduce asexually? A. Their offspring are bigger and better able to reproduce. B. Their offspring may be more adaptable to changes in the environment. C. Their offspring may have more mutations. D. Their offspring can exist in both haploid and diploid stages.

B. Their offspring may be more adaptable to changes in the environment. Offspring produced by sexual reproduction are genetically different from their parents and may be better able to thrive if the environment changes.

Biologists think that endosymbionts gave rise to mitochondria before plastids partly because A. the products of photosynthesis could not be metabolized without mitochondrial enzymes. B. all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids. C. mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA. D. without mitochondrial CO2 production, photosynthesis could not occur.

B. all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.

The largest seaweeds are _____. A. dinoflagellates B. brown algae C. red algae D. diatoms E. green algae

B. brown algae Brown algae are the largest of the seaweeds.

Molecular clocks are useful for measuring the time of evolutionary change because the genes examined: A. have a large number of base pairs. B. evolved at a relatively constant rate. C. recently underwent mutation. D. are acted upon by natural selection.

B. evolved at a relatively constant rate.

Which of these groups includes both aquatic decomposers and the parasites responsible for late potato blight? A.plants B. oomycetes C. red algae D. plasmodial slime molds E. diatoms

B. oomycetes Correct. Oomycetes (water molds and their relatives) include both decomposers and the parasites responsible for late potato blight.

Which group is incorrectly paired with its descriptions A. diatoms -> important producers in aquatic communities. B. red algae -> eukaryotes that acquired plastids by secondary endosymbiosis. C. apicomplexans -> unicellular parasites with intricate life cycles. D. diplomonads -> unicellular eukaryotes with modified mitochondria.

B. red algae -> eukaryotes that acquired plastids by secondary endosymbiosis.

Coral bleaching, which causes high coral mortality, has been occurring widely in coral reefs. Coral bleaching actually refers to the death of symbiotic dinoflagellates living within the corals. Why does coral bleaching cause the corals to die? A.Dinoflagellates protect the corals from UV radiation. B. Dinoflagellates protect the corals from pathogenic bacteria. C. Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live. D. Dinoflagellates attract zooplankton and other prey that the corals eat. E. Dinoflagellates secrete the calcium carbonate that forms the "exoskeleton" of coral animals.

C. Dinoflagellates provide nutrients from the products of photosynthesis to the corals in exchange for a safe place to live. Without the extra nutrients provided by symbiotic protists, the corals cannot compete with other organisms for resources.

Bacteria and Archaea share all of the following traits except: A. Lacking membrane-bound organelles. B. Having circular chromosomes. C. Having peptidoglycan in their cell walls. D. Lacking nuclear envelopes.

C. Having peptidoglycan in their cell walls.

_____ are eukaryotic autotrophs that float near the surface of water and are the basis of the food chain. A. Zooplankton B. Slime molds C. Phytoplankton D. Cyanobacteria E. Symbionts

C. Phytoplankton These photosynthetic organisms serve as the basis of the food chain.

Which group is characterized by cells with fine hairlike projections on their flagella? A. Rhodophyta B. Alveolata C. Stramenopila D. Metazoa E. Euglenozoa

C. Stramenopila Stramenopiles are characterized by cells that bear fine hairlike projections on their flagella.

A paramecium is a(n) _____. A. apicomplexan B. diatom C. ciliate D. metazoan E. dinoflagellat

C. ciliate A paramecium makes use of its cilia to move and feed.

Archaeplastids, which include red and green algae and land plants, are thought to have descended from a heterotrophic protist that engulfed a(n) _____. A. slime mold B. alpha proteobacterium C. cyanobacterium D. apicomplexan E. archaean extremophile

C. cyanobacterium Structural and molecular biological evidence supports the idea that endosymbiotic cyanobacteria gave rise to the chloroplasts found in red and green algae and land plants.

Which of these algal groups possess a photosynthetic pigment that allows them to live in deep water? A. metazoans B. brown algae C. red algae D. green algae E. diatoms

C. red algae The phycobilins and other accessory pigments of red algae allow them to absorb the wavelengths of light that penetrate deep water and to use them in photosynthesis.

Golden Algae

Color results from their yellow and brown carotenoids. The cells of golden algae are typically biflagellate, with both attached near one end of the cell.

Mixotrophs

Combine photosynthesis and heterotrophic nutrition.

Which of the following is a correct statement about slime molds? A. Cellular slime molds have haploid zygotes. B. Cellular slime molds have fruiting bodies that function in sexual reproduction. C. In plasmodial slime molds, the haploid condition is the dominant part of the life cycle. D. Cellular slime molds form masses when food is scarce, but their cells remain separated. E. Cytoplasmic streaming helps distribute nutrients and oxygen in cellular slime molds.

D. Cellular slime molds form masses when food is scarce, but their cells remain separated. Cellular slime molds function almost like multicellular organisms when food is depleted. They form a multicellular mass that forms fruiting bodies.

How does the haploid form of Ulva "switch" to its diploid form? A. Sporophytes produce cells that undergo mitosis to produce gametes that fuse to form a zygote. B. Sporophytes undergo meiosis to produce spores that germinate into diploid adults. C. Gametophytes produce cells that undergo meiosis and produce spores that germinate into diploid adults. D. Gametophytes produce cells that undergo mitosis to produce gametes that fuse to form a zygote.

D. Gametophytes produce cells that undergo mitosis to produce gametes that fuse to form a zygote. Gametophytes are haploid adults that produce cells that undergo mitosis and form gametes that fuse to form a diploid zygote.

Which structure mediates the attachment of spores to a surface on which to grow? A. Chloroplast B. Sporophyte C. Flagella D. Holdfast

D. Holdfast A holdfast attaches spores to surfaces on which they can grow.

Which term describes the fusion of two gametes to form a diploid zygote? A. Mitosis B. Meiosis C. Alternation of generations D. Syngamy

D. Syngamy Syngamy is the fusion of two gametes to form a diploid zygote.

Genetic variation in prokaryotes arises because: A. They have long generation times and small populations. B. Mutation rates in prokaryotes are slower than in eukaryotes. C. They have a relatively small genome. D. They can exchange DNA with other prokaryotes via horizontal gene transfer.

D. They can exchange DNA with other prokaryotes via horizontal gene transfer.

According to the phylogeny presented in this chapter, which protists are in the same eukaryotic supergroup as land plants? A. green algae B. dinoflagellates C. red algae D. both a and c

D. both a and c (green algae and red algae)

Which three groups contain large algae known as seaweeds? A. chlorophytes, charophyceans, and red algae B. diatoms, golden algae, and brown algae C. plants, fungi, and choanoflagellates D. brown algae, red algae, and green algae E. dinoflagellates, apicomplexans, and green algae

D. brown algae, red algae, and green algae All three of these are seaweeds.

All of the organisms classified as _____ move and feed using cilia. A. diatoms B. diplomonads C. dinoflagellates D. ciliates E. apicomplexans

D. ciliates Ciliates move and feed using cilia.

A sign on the beach states, "Beach Closed. Red Tide." The organisms interfering with your use of this beach are probably _____. A. amoebas B. ciliates C. diatoms D. dinoflagellates E. species of red algae

D. dinoflagellates Dinoflagellate blooms, episodes of explosive population growth, cause red tides in coastal waters.

The cells of _____ and _____ have modified mitochondria. A.dinoflagellates ... metazoans B. chlorophytes ... ciliates C. fungi ... stramenopiles D. diplomonads ...parabasalids E. euglenozoans... alveolates

D. diplomonads ...parabasalids The cells of diplomonads and parabasalids have modified or reduced mitochondria.

In a life cycle with alternation of generations, multicellular haploid forms alternate with A. unicellular haploid forms B. unicellular diploid forms C. multicellular haploid forms D. multicellular diploid forms

D. multicellular diploid forms

Plastids that are surrounded by more than two membranes are evidence of A. evolution from mitochondria. B. fusion of plastids. C. origin of the plastids from archaea. D. secondary endosymbiosis.

D. secondary endosymbiosis.

Why has the kingdom Protista been abandoned? A.Some protists are multicellular. B. The kingdom Protista is not monophyletic. C. Some protists are more closely related to plants, animals, or fungi than they are to other protists. D. Some protists are as small as prokaryotes. E. The second and third answers are correct.

E. The second and third answers are correct. (B. The kingdom Protista is not monophyletic; C. Some protists are more closely related to plants, animals, or fungi than they are to other protists.) Recognizing that the kingdom Protista as originally defined was not monophyletic and that some protists are more closely related to other eukaryotes than to each other, scientists have abandoned the kingdom Protista and reorganized the entire domain Eukarya.

Which algal group has chloroplasts much like those of green plants in structure and pigment makeup? A. red algae B. brown algae C. golden algae D. diatoms E. chlorophytes

E. chlorophytes Chlorophytes (green algae), like green plants, contain both chlorophylls a and b.

Which of these groups is characterized by glasslike walls containing silica? A.plants B. brown algae C. diplomonads D. plasmodial slime molds E. diatoms

E. diatoms Diatoms are characterized by glasslike walls containing silica.

Which of the following are two groups that are adapted to anaerobic conditions and contain modified mitochondria that lack DNA? A. dinoflagellates and diatoms B. chlorophytes and radiolarians C. apicomplexans and forams D. gymnamoebas and slime molds E. diplomonads and parabasalids

E. diplomonads and parabasalids These groups are known for their modified mitochondria.

Which of these groups consist of parasitic flagellated cells, such as Trypanosoma, the organism that causes sleeping sickness? A. diatoms B. ciliates C. brown algae D. metazoans E. kinetoplastids

E. kinetoplastids Parasitic flagellated cells, such as Trypanosoma, are classified as kinetoplastids.

Opisthokonts

Extremely diverse group of eukaryotes that includes animals, fungi, and several groups of protists.

Unikonta

Extremely diverse super group of eukaryotes that includes animals, fungi, and some protists.

Euglenids

Has a pocket at one end of the cell from which one or two flagella emerge. Some euglenids are mixotrophs.

Kinetoplastids

Have a single, large mitochondria that contains an organized mass of DNA called a kinetoplast. These protists include species that feed on prokaryotes in freshwater, marine, and moist terrestrial ecosystems, as well as species that parasitize animals, plants and other protists. (E.g., Trypanosoma)