BSC 2011 Ch 28

Which of the following is the best description of protists' contribution to photosynthesis?

About 30% of the world's photosynthesis is performed by protists.

Which of the following is not a group included in the protists? All of the listed groups are protists. Ciliates Brown algae Forams Diatoms

All of the listed groups are protists.

Which of the following is not a structure used for locomotion in protists? Flagella Pseudopodia All of the listed structures are used for locomotion in protists. Undulating membrane Cilia

All of the listed structures are used for locomotion in protists.

The members of _____ are characterized by cells with small membrane-bounded cavities under their cell membranes.

Alveolata

Which of these groups includes parasitic unicellular organisms with a complex of organelles specialized for penetrating host cells and tissues?

Apicomplexans

Which example below is a characteristic shared by diplomonads and parabasalids?

Both lack plastids.

Which of the following is not a protist genera that parasitizes humans?

Chlamydomonas

Which of these groups is characterized by cells that have more than one nucleus?

Ciliates

Which of these groups includes unicellular organisms that, due to the structure of their cell walls, can withstand pressures equal to the pressure under each leg of a table supporting an elephant?

Diatoms

Which of these groups includes photosynthetic unicellular organisms with flagella and contractile vacuoles?

Euglenids

Protists are best described as which of the following?

Eukaryotes that are not plants, animals, or fungi

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

False

Parasites of the genus Trypanosoma evade immune responses through what defense?

Frequently changing their surface proteins

Which term describes the multicellular haploid form of a protist that shows alternation of generations?

Gametophyte

How does the haploid form of Ulva "switch" to its diploid form?

Gametophytes produce cells that undergo mitosis to produce gametes that fuse to form a zygote.

Which of the following statements about Ulva's haploid stage is true?

Haploid cells are produced by meiosis of diploid cells.

Which structure mediates the attachment of spores to a surface on which to grow?

Holdfast

Plasmodium is a parasitic apicomplexan that causes malaria in humans. The figure below illustrates the Plasmodium life cycle. Select the four statements about Plasmodium that are true. The life cycle of Plasmodium involves only haploid forms. Inside an infected mosquito, haploid gametes fuse, forming a diploid zygote that develops into an oocyst. The complete life cycle of Plasmodium requires two hosts. Plasmodium cells infect two specific types of cells in humans. Inside an infected mosquito, haploid gametes fuse, forming a haploid zygote that develops into an oocyst. Plasmodium cells are transferred to humans through mosquito saliva. When a mosquito bites a human with malaria, diploid Plasmodium cells enter the mosquito.

Inside an infected mosquito, haploid gametes fuse, forming a diploid zygote that develops into an oocyst. The complete life cycle of Plasmodium requires two hosts. Plasmodium cells infect two specific types of cells in humans. Plasmodium cells are transferred to humans through mosquito saliva.

Which of the following is one of the main weaknesses of the proposed classification scheme in which all eukaryotes are divided into five supergroups?

It shows all five supergroups diverging simultaneously from a common ancestor.

Why have protists been "mixed in" with plants, animals, and fungi under the hypothesis that groups eukaryotes into five supergroups?

Many protists are more closely related to plants, animals, or fungi than they are to each other and recent evidence makes it clear that the former kingdom Protista was paraphyletic.

Which protists were once categorized as fungi due to their multinucleate filaments that resemble hyphae?

Oomycetes

Which group is characterized by cells with fine hairlike projections on their flagella?

Stramenopila

Which term describes the fusion of two gametes to form a diploid zygote?

Syngamy

What advantage do organisms that reproduce sexually have over organisms that reproduce asexually?

Their offspring may be more adaptable to changes in the environment.

Which of the following is not a cellular organelle possessed by a protist?

They all have alveoli beneath a plasma membrane

The diagram below illustrates the life cycle of Dictyostelium, a cellular slime mold. Label the diagram to indicate the processes that are occurring as well as whether each cell type is haploid or diploid. Drag the labels to their appropriate locations on the diagram. Use the pink labels for pink targets. Labels can be used once, more than once, or not at all.

a. amoeba emerge from large capsules b. haploid c. cells aggregrate when food is scare d. two amoeba fuse to form zygote e. haploid f. diploid g . aggregates migrate h. haploid i.fruiting body releases spores j. haploid k. one amoeba emerges from each spore l. haploid

Plasmodium, the parasitic organism that causes malaria, is a _____.

apicomplexan

The largest seaweeds are _____.

brown algae

Which three groups contain large algae known as seaweeds?

brown algae, red algae, and green algae

Stramenopiles include all of the following groups EXCEPT ______.

cellular slime molds

Which algal group has chloroplasts much like those of green plants in structure and pigment makeup?

chlorophytes

A paramecium is a(n) _____.

ciliate

All of the organisms classified as _____ move and feed using cilia.

ciliates

Molecular data suggest that plastids originated as __________ engulfed by a heterotrophic eukaryote.

cyanobacteria

Which of these groups is characterized by glasslike walls containing silica?

diatoms

The cells of _____ and _____ have modified mitochondria.

diplomonads ...parabasalids

Although controversial, chromalveolates are proposed as a clade whose common ancestor __________.

engulfed a photosynthetic red alga in a secondary endosymbiosis event

Which of these groups consist of parasitic flagellated cells, such as Trypanosoma, the organism that causes sleeping sickness?

kinetoplastids

Organisms are classified as Excavata based on __________.

morphological studies of the cytoskeleton

Which of these groups includes both aquatic decomposers and the parasites responsible for late potato blight?

oomycetes

Golden algae, brown algae, red algae, chlorophytes, and charophyceans are some examples of protists that are _____.

photosynthetic

Which of these algal groups possess a photosynthetic pigment that allows them to live in deep water?

red algae

The term algae refers to __________.

several diverse groups of photosynthetic protists

Apicomplexans are currently assigned to the chromalveolates because __________.

the apicoplast, a modified plastid, appears to be of red algal origin